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An electromechanical synchronization of driving simulator and adaptive driving aide for training persons with disabilities

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Title:
An electromechanical synchronization of driving simulator and adaptive driving aide for training persons with disabilities
Physical Description:
Book
Language:
English
Creator:
Berhane, Rufael
Publisher:
University of South Florida
Place of Publication:
Tampa, Fla
Publication Date:

Subjects

Subjects / Keywords:
Simulator system international
Electron mobility control
Driving controls
Coupler
Joystick
Dissertations, Academic -- Mechanical Engineering -- Masters -- USF   ( lcsh )
Genre:
non-fiction   ( marcgt )

Notes

Abstract:
ABSTRACT: Cars have become necessities of our daily life and are especially important to people with disability because they extend their range of activity and allow participation in a social life. Sometimes driving a normal car is impossible for individuals with severe disability and they require additional driving aide. However, it is dangerous to send these individuals on the road without giving them special training on driving vehicles using an adaptive aide. Nowadays there are a number of driving simulators that train disabled persons but none of them have joystick-enabled training that controls both steering, gas and break pedal. This necessitates the design of a method and a system which helps a person with disabilities learn how to operate a joystick-enabled vehicle, by using a combination of an advanced vehicle interface system, which is a driving aide known as Advanced Electronic Vehicle Interface Technology (AVEIT) and virtual reality driving simulator known as Simulator Systems International (SSI). This thesis focuses on the mechanism that synchronizes both AVEIT and SSI systems. This was achieved by designing a mechanical and electrical system that serves as a means of transferring the action between the AVEIT and SSI system. The mechanical system used for this purpose consists of two coupler units attached to AVEIT and SSI each combined together by the electrical system. As the user operates the joystick, the action of AVEIT is transferred to the SSI system by the help of the electromechanical system. The design provides compatibility between the AVEIT and SSI system which makes them convenient for training persons with disability.
Thesis:
Thesis (M.S.M.E.)--University of South Florida, 2008.
Bibliography:
Includes bibliographical references.
System Details:
Mode of access: World Wide Web.
System Details:
System requirements: World Wide Web browser and PDF reader.
Statement of Responsibility:
by Rufael Berhane.
General Note:
Title from PDF of title page.
General Note:
Document formatted into pages; contains 119 pages.

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University of South Florida Library
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University of South Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 002007395
oclc - 403809692
usfldc doi - E14-SFE0002350
usfldc handle - e14.2350
System ID:
SFS0026668:00001


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ABSTRACT: Cars have become necessities of our daily life and are especially important to people with disability because they extend their range of activity and allow participation in a social life. Sometimes driving a normal car is impossible for individuals with severe disability and they require additional driving aide. However, it is dangerous to send these individuals on the road without giving them special training on driving vehicles using an adaptive aide. Nowadays there are a number of driving simulators that train disabled persons but none of them have joystick-enabled training that controls both steering, gas and break pedal. This necessitates the design of a method and a system which helps a person with disabilities learn how to operate a joystick-enabled vehicle, by using a combination of an advanced vehicle interface system, which is a driving aide known as Advanced Electronic Vehicle Interface Technology (AVEIT) and virtual reality driving simulator known as Simulator Systems International (SSI). This thesis focuses on the mechanism that synchronizes both AVEIT and SSI systems. This was achieved by designing a mechanical and electrical system that serves as a means of transferring the action between the AVEIT and SSI system. The mechanical system used for this purpose consists of two coupler units attached to AVEIT and SSI each combined together by the electrical system. As the user operates the joystick, the action of AVEIT is transferred to the SSI system by the help of the electromechanical system. The design provides compatibility between the AVEIT and SSI system which makes them convenient for training persons with disability.
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An Electromechanical Synchronization of Driving Simulator and Adaptive Driving Aide for Training Persons with Disabilities by Rufael Berhane A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Mechanical Engin eering Department of Mechanical Engineering College of Engineering University of South Florida Co-Major Professor: Rajiv Dubey, Ph.D. Co-Major Professor: Shuh-Jing Ying, Ph.D. Craig Lusk, Ph.D. Kathryn J. De Laurentis, Ph.D. Date of Approval: March 24, 2008 Keywords: simulator system international, electron mobility control, driving controls, coupler, joystick Copyright 2008, Rufael Berhane

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Acknowledgements First and foremost I would like to tha nk God for his help and guide throughout my daily life and giving me strength whenever I need it. I would like to thank Dr. Rajiv Dubey fo r providing me an opportunity to conduct my masters research under him and for his gui dance and support over th e course of it. I also want to thank Dr. ShuhJing Ying for his valuable s uggestions and his advice and help on this research and especially helping me on the design of the electrical system. This work would not have been completed without his help. To Dr. Kathryn J. De Laurentis, for taking her time to read a nd comment on my paper that has greatly improved and clarified this work. Mr. Be rnard Batson for his endless effort in accomplishment of my study and for keeping me focused only in my research and study without any financial worries. Lastly, my family without whose support none of this would have been possible.

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i Table of Contents List of Tables......................................................................................................................v List of Figures....................................................................................................................vi ABSTRACT..................................................................................................................... viii Chapter 1: Introduction .......................................................................................................1 1.1. Motivation ........................................................................................................1 1.2. Thesis Objectives .............................................................................................3 1.3. Thesis Outline ..................................................................................................3 Chapter 2: Background .......................................................................................................5 2.1. Introduction ......................................................................................................5 2.2. Background ......................................................................................................6 2.3. Disabilities .....................................................................................................10 2.4. Rehabilitation Engineeri ng and Assistive Technology ..................................11 2.5. Disabilities and Driving Facts ........................................................................13 Chapter 3: Adaptive Driving Modifications for Persons with Physical Limitation ........................................................................................................16 3.1. Introduction ....................................................................................................16 3.2. Automotive Adaptive Driving .......................................................................17 3.3. Vehicle Modifications ....................................................................................19 3.3.1. Primary Control Modification .........................................................22

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ii 3.3.1.1. Steering Wheel Aid Modification ....................................23 3.3.1.2. Gas and Brake Modification ............................................24 3.3.2. Joystick Driving Control .................................................................25 Chapter 4: Simulator Systems International and AEVIT Driving Control System .............................................................................................................26 4.1. Introduction ....................................................................................................26 4.2. The AVEIT Driving System..........................................................................27 4.2.1. Information Center ..........................................................................28 4.2.2. Input Devices ..................................................................................29 4.2.2.1. Joystick ............................................................................30 4.3. Simulator Systems Intern ational Driving Simulator ......................................32 Chapter 5: Electromechanical Design and Synchroni zation of the Driving Systems ...........................................................................................................34 5.1. Introduction ....................................................................................................34 5.2. Van Assembly ................................................................................................35 5.3. Friction Clutch ...............................................................................................39 5.4. Mechanical Design ........................................................................................40 5.4.1. SSI Coupler .....................................................................................41 5.4.2. AVEIT Coupler ...............................................................................45 5.5. Electrical Design ............................................................................................47 5.6. Final Synchronization ....................................................................................51 5.7. Testing of System ..........................................................................................53 5.8. Block Diagram of the Mechanism .................................................................55 5.9. Quantitative Result ........................................................................................56

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iii 5.9.1. Zero Rotation of Steering ................................................................58 5.9.2. Clockwise Rotation of Steering......................................................60 5.9.3. Counter-Clockwise Rotation of Steering ........................................62 5.10. Analysis of Testing ......................................................................................64 Chapter 6: Conclusions and Recommendations ...............................................................68 6.1. Conclusions ....................................................................................................68 6.2. Final Recommendation ..................................................................................70 List of References .............................................................................................................71 Appendices........................................................................................................................74 Appendix A: Step-Wise Procedures .....................................................................75 A.1. Procedure for Booting the AEVIT Driving System ..........................75 A.2. Procedure for Booting the SSI Computer .........................................75 A.3. Procedure for Calibrating the AVEIT and SSI Systems ...................76 A.4. Procedure for the Use of the Synchronized Circuit ..........................77 Appendix B: Oscillosco pe Captured Signals ........................................................79 B.1. Mid Steering Position........................................................................79 B.2. Right Steering Rotation .....................................................................85 B.3. Left Steering Rotation.......................................................................90 Appendix C: Recorded Data of Potentiometer Voltage ........................................95 C.1. Data Collected for Mid Steering Position .........................................95 C.2. Data Collected for Right Steering Rotation ......................................98 C.3. Data Collected for Left Steering Rotation .......................................101 Appendix D: Disabilities and Driving Facts .......................................................105

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iv D.1. Aging and Driving ..........................................................................105 D.2. Driving and Alzheimer's or Dementia ............................................107 D.3. Driving After a Traumatic Brain Injury ..........................................108 D.4. Driving After a Spinal Cord Injury .................................................109 D.5. Driving with Rheumatoid Arthritis .................................................110 D.6. Driving with Multiple Sclerosis ......................................................112 D.7. Driving After a Limb Amputation ..................................................113 D.8. Driving After a Stroke .....................................................................114 D.9. Driving and Spina Bifida ................................................................116 D.10. Driving and Cerebral Palsy ...........................................................117 D.11. Driving and Attention De ficit Hyperactivity Disorder .................118

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v List of Tables Table 2.1. Categories of Assistive Devices [13] ...............................................................12 Table 3.1. Classifications of Automotive Adaptive Equipment [17] ................................18 Table 3.2. Modified Vehicle Types and Vehicle Safety Ratings [19] ..............................20 Table 3.3. Types of Modifications and Vehicle Safety Ratings [19] ................................21 Table C.1. Mid Steering Position ......................................................................................95 Table C.2. Right Steering Rotation ...................................................................................98 Table C.3. Left Steering Rotation ...................................................................................101

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vi List of Figures Figure 2.1. KMRRECs Virtual Rea lity Driving Simulator [6] ..........................................7 Figure 2.2. Simulator Hardware with St eering Column and Hand Controls [7] ................8 Figure 2.3. Steering Wheel and Pedal Contro l for Persons with Disability [8] ..................9 Figure 4.1. AEVIT System Layout [23] ...........................................................................28 Figure 4.2. Information Center [23] ..................................................................................29 Figure 4.3. Digital Joystick [23] .......................................................................................30 Figure 4.4. Joystick Control Steering Bands [23] .............................................................31 Figure 4.5. Drift Band [23] ...............................................................................................32 Figure 4.6. SSI Driving Simulator [25] ............................................................................33 Figure 5.1. Wood Bar ........................................................................................................36 Figure 5.2. Stress Analysis of the Base Holder ................................................................37 Figure 5.3. Assembled Van ...............................................................................................38 Figure 5.4. Adjustable Friction Clutch [26]......................................................................40 Figure 5.5. Assembled Coupler for SSI Driving System ..................................................42 Figure 5.6. Stress Analysis of the Shaft ............................................................................44 Figure 5.7. Assembled Coupler for AVEIT Driving System ............................................47 Figure 5.8. Circuit Diagram for Synchronized Rotation ...................................................48 Figure 5.9. Electrical System of the Design .....................................................................50

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vii Figure 5.10. Synchronized System of SSI Unit ................................................................52 Figure 5.11. Testing of System .........................................................................................53 Figure 5.12. Block Diagram of Mechanism ......................................................................55 Figure 5.13. DSO-8500 Series Di gital Oscilloscope [28] .................................................57 Figure 5.14. Signal of Center Position of Steering ...........................................................59 Figure 5.15. Signal for Right Direction Steering ..............................................................61 Figure 5.16. Signal for Left Direction Steering ................................................................63 Figure B.1. Mid Steering Position Signals .......................................................................81 Figure B.2. Right Steering Rotation Signals .....................................................................86 Figure B.3. Left Steering Rotation Signals .......................................................................91

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viii An Electromechanical Synchronization of Driving Simulator and Adaptive Driving Aide for Training Persons with Disabilities Rufael Berhane ABSTRACT Cars have become necessities of our da ily life and are especially important to people with disability because they extend their range of act ivity and allow participation in a social life. Sometimes driving a normal car is im possible for individuals with severe disability and they require a dditional driving aide. However, it is dangerous to send these individuals on the road without giving them special training on driving vehicles using an adaptive aide. Nowadays there are a number of driving si mulators that train disabled persons but none of them have joystick-e nabled training that controls both steering, gas and break pedal. This necessitates the design of a me thod and a system which helps a person with disabilities learn how to operate a joystick-enabled vehicle, by using a combination of an advanced vehicle interface system, which is a driving aide known as Advanced Electronic Vehicle Interface Technology (AVEIT ) and virtual reality driving simulator known as Simulator Systems International (SSI).

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ix This thesis focuses on the mechanism that synchronizes both AVEIT and SSI systems. This was achieved by designing a m echanical and electrical system that serves as a means of transferring the action between the AVEIT and SSI system. The mechanical system used for this purpose cons ists of two coupler uni ts attached to AVEIT and SSI each combined together by the electr ical system. As the user operates the joystick, the action of AVEIT is transferre d to the SSI system by the help of the electromechanical system. The design provides compatibility between the AVEIT and SSI system which makes them convenient for training persons with disability.

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1 Chapter 1 Introduction 1.1. Motivation Assistive technology and rehabilitation engineering have been contributing in various fields over the past in relation to devising and improving various assistive techniques in domestic, commercial and work environments. The introduction of electrical and mechanical devices for driving has mainly focused on enhancing the functions of existing vehicles with primary a lternate controls (gas/brakes/steering) and to provide easy access and exit for a disabled pe rson. In addition to the assistive device there are driving simulators that are used to train people with disa bilities on their driving skills. This simulator enables a person with impairment to experience realistic outcomes of their performance, providi ng an opportunity for individua ls to confront errors and more accurately self-assess their driving abilities. Certain people with disabilities, such as paraplegia or tetraple gia, can not drive a vehicle using a steering wheel. However they are capable of using other interfaces such as a sip-and-puff mechanism, keyboard, or joystick. Presently a common vehicle modification uses a joystick as a driving aid. But this population needs training in driving vehicles with a joystick before they enter onto the road. So the development of a driving system with a joystick is of great importance for trai ning persons with disability.

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2 Nowadays there are a number of driving simulators that trai n individuals with impairment. However, all those driving si mulators which use to train the handicap people use the same method, with the capabil ity of maneuvering a steering wheel and gas/break pedal functionality. It is important to take into consideration persons with disabilities who do not have enough mobility to turn or maneuver the steering wheel and press the gas/brake pedal of the vehicle. As the severity of their di sability is high, they use a joystick to operate or maneuver the st eering wheel and gas/brake pedal, meanwhile it is hard for them to get acquainted to the func tionality of the joystick in the real world. As mentioned previously ther e are a number of driving simulators that helps to train the aged, young people and persons with disa bilities, but all thos e individuals have a capability of using their hand to turn th e steering wheel and functional leg to use gas/brake pedal. It is hypothesized that if a person with disa bility requires a joystick for operating a vehicle with adaptiv e driving aide, a driving simu lator that can be operated via a joystick is the best tool to train them before they are introduced to the real world. This is the motivation for the research to bui ld a system that helps to train a person who has severe disability, such as quadriplegic or paraplegic, and who can only move specific parts of their body, e.g. their fingers in whic h case they use a joys tick to maneuver the vehicle. By synchronizing the driving aide and the driving simulato r, this method will help in training and developing an assessment tool to evaluate the capability of persons with disability to operate or maneuver the prim ary control of the vehicle before they are sent onto the road.

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3 1.2. Thesis Objectives This thesis focuses on the development of training tools for adaptive driving control systems. The following thesis objectives aim to: Identifying disabilities which affect normal driving and the technologies for adaptive driving control for the disabled. Develop an electromechanical interface be tween the SSI driving simulator and the AEVIT driving control system. Conduct system test and use it as an asse ssment tool for obtaining the results of the test. Analyze the results and demonstrate the efficacy of the design. 1.3. Thesis Outline This thesis starts with the motivation a nd thesis objectives in Chapter 1, which discusses the need for the development in synchronization of driving simulator with driving aid for individuals with disab ilities. Chapter 2 includes the background information of areas related to this work such as assistive technology, rehabilitation engineering and provides stat istical data on age and disabilities; it also describes disability and driving facts, which affect normal driving. Chapter 3 discusses adaptive driving modification for persons with physic al limitation and various primary adaptive controls used. Chapter 4 describes the soft ware and hardware of the Simulator Systems International (SSI) and AEVIT driving control system. Chapter 5 includes the mechanical and electrical de signs to synchronize the two steering systems and test the

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4 system. Chapter 6 provides the conclusions based on the system test along with recommendations for future work.

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5 Chapter 2 Background 2.1. Introduction The freedom to travel where and when we want, permits freedom to seek employment, attend social activities and in general become involved in the main stream of life. The ability to drive a vehicle can make unlimited freedom of travel possible [1]. This is particularly true for the person with a disability because it is hard for them to bike, walk, and ride the bus. There have been ma ny advances made in the area of adaptive driving equipment for persons w ith disabilities over the past few years. For persons who have severe disability, like tetraplegic and paraplegic, adapting their cars with joystick operated driving aides will help them operate a vehicle. In addition to this technology, virtual reality was also evolved as a means of training for person with severe disability and trains them how to drive an adapted vehicle before they had been introduced to real world. This chapter discusses some background on driving simulator integrated with driving aide. Next it descri bes some few facts about disa bilities, and then it gives a highlight on assistive technology and rehabilitation engineerin g. It also mentions the kinds of disabilities that aff ect the normal driving skills.

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6 2.2. Background Driving an automobile is a deeply ch erished part of American culture and acquiring a drivers license is a rite of passage into adulthoo d that signifies the onset of privileges and independence [2]. People driving with the help of assistive technology range from those in their 20s with head or spinal cord injuries to thos e in their 70s who have had a stroke. About 215,000 people use adaptive equipment to drive, according to a 1992 survey by the National Centers for Disease Control [3]. Todays driving aids feature devices that require less effort to turn a steering wheel a nd gas/break pedal, and also include products that fit into more than one type of vehicle. Some of the driving ai de includes a joystick that requires less effort to operate and c ontrol than the standard steering wheel and gas/brake pedal of the vehicle. Driving simulation, like virt ual reality, is a relative ly recent application of computer technology. Although the aerospace i ndustry has used simulators for almost fifty years, the automotive industry has been much slower to develop simulators of ground vehicles, relying instead on the use of actual vehicles for testing and development [4]. Driving simulators have been developed as a way to assess driving skill while maintaining the safety of the patient, te sters, and community. Moreover, driving simulators also provide the opportunity to present challenging/hazardous conditions or events that may not be prudent to presen t during on-road testing. Once a driving simulator is obtained, it can also be a more co st-effective way to assess driving abilities than an on-road evaluation [5].

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Driving simulators have been used in a number of studies to determine their value as predictors of on-the-road performance and as training ai ds in helping people overcome challenges resulting from any disabilities. The knowledge of this background is important in this research in order to check the uniqueness of our research. Since the main idea is to build a system that can help to train persons with disabilities on how to drive the modified vehicle, the background focu ses mainly on different ways of modified adaptive methods that is used to train or retrain persons with disability. Figure 2.1. KMRRECs Virtual Rea lity Driving Simulator [6] 7 Figure 2.1 shows a virtual reality system th at was designed to re-train individuals after spinal cord injury. This study is conducted at Ke ssler Medical Rehabilitation Research and Education Center (KMRREC ) The simulator consists of a modified driving console fitted with ad aptive driving equipment specialized toward an individuals needs. The modified console includes severa l types of hand controls so that individuals can experience these devices before they are behind the wheel of a car, allowing repetitive and hierarchal presentation of driving challeng es which can be used to enhance

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driving ability and confidence. The hardware for the simulator was designed to provide a realistic driving interface, and includes a real steering wheel a nd adaptive equipment including hand controls (gas and brake), st eering wheel knobs, tri-pin. The system is fully adjustable, i.e. height, tilt, and tele scope, for control to provide a comfortable interface for most wheelchair configurations. The system can deliver a variety of virtual driving environments and conditions [6]. Research has also been done at New Je rsey Institute of Technology (NJIT) on developing a driving simulator for people with sp inal cord injury to retrain driving skills using the virtual reality simulator. In th eir research they developed custom driving hardware by integrating the real steering column with the clinically recommended adaptive driving equipment such as hand contro lled equipment and then interfaced with a custom driver retraining virtual environment. Figure 2.2. Simulator Hardware with St eering Column and Hand Controls [7] 8

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As seen in Figure 2.2 NJIT use a hand c ontroller for acceleration and braking system which is located to the left of the wheel, a nd a spinner or tri-pin knob located in one of four quadrants on the wheel (upper right, upper left, lower right, or lower left) for turning the steering wheel [7]. The use of a driving aide incorporated w ith driving a simulator also conducted in a number of countries. One study conducted in Korea in which a virtual reality driving simulator was used to check and enhance the driv ing ability of persons with disability [8]. Figure 2.3. Steering Wheel and Pedal Contro l for Persons with Disability [8] As seen in Figure 2.3 above a real car wa s remodeled for persons with disability with knob to control th e steering wheel and hand operated hardware to control gas/brake pedal. From previous studies it has been show n that there are a number of researches were done on building a mechanism for traini ng persons with disabi lities using driving aide incorporated to driving simulator. However for peoples who can only use joystick 9

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10 as a means of controlling the steering wheel and gas/brake pedal of the vehicle, such instrument was not developed as a means of tr aining. As a result it is considered that building a system that incorporates both driving simulator and driving aide to operate the primary control via joystick would be important for research. As the primary control of the vehicle controls the steeri ng and gas/brake pedal of the ve hicle, the joystick operated primary control differs from the other mean s, as mentioned above, of controlling the primary control. That is when a person with disability uses joystic k only one input, i.e. the joystick, is used to control both parts of the primary cont rol and this could be harder to control as compared to a primary c ontrol that operated by hand for controlling gas/brake pedal and knob or tri-pin for steering. 2.3. Disabilities Different kinds of disabilities affect pe ople in different ways Disability can become a fact of life for anyone at any time. Today, 54 million people in the United States are living in the community with a disa bility. Thats one in every five people. According to the most recent census data, around 52 million of them live in their community (U.S. Census Bureau 2002). Additionally, about 2 million live in nursing homes and other long-term care f acilities. Some people are born with a disability; some people get sick or have an accident that resu lts in a disability; a nd some people develop a disability as they age. Th e reality is that just about everyone; women, men and children of all ages, races and ethnicities; will experi ence a disability some time during his or her lifetime. As we age, the likelihood of havi ng a disability of some kind increases. For example, 22.6 percent of 45 to 54 year olds ha ve some form of disa bility; 44.9 percent of

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11 65 to 69 year olds have some form of disa bility; and 73.6 percent of those 80 years and older have some form of disability [9]. Disabilities were cl assified in one of three domai ns: communication, physical, or mental. Responses to several questions were used to arrive at th e overall measures of each domain. About 26.0 million people had disa bilities in one domain (communication: 2.7 million; physical: 18.9 million; ment al: 4.4 million); 14.2 million people had disabilities in two domain s (communication and physica l: 7.8 million; communication and mental: 651,000; physical and mental: 5.8 million); and 4.4 million people had disabilities in all three domains [10]. 2.4. Rehabilitation Engineering and Assistive Technology Rehabilitation engineering is a people-ori ented field, more than most fields of engineering [11]. It is th e application of science and technology to ameliorate the handicaps of individuals with di sability. Various terms have b een used to describe this sphere of activity, including prosthetics/orthotics, assis tive technology, assistive device design, rehabilitation technology, and even biomed ical engineering applied to disability. [12]. In contrast, an assistive de vice is a tool or implement that makes a particular function easier or possible to perform. An assistive device may be as simple as an electric toothbrush, or as ela borate as an environmental control system that persons who have lost the use of their limbs can operate with a mouth switch [11] One widely used definition for assistive technol ogy is found in Public Law 10 0-407. It defines assistive technology as any item, piece of equipmen t or product system whether acquired

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12 commercially off the shelf, modified or custom ized that is used to increase or improve functional capabilities of indivi duals with disabilities [13]. Under the definition of rehabilitation and assistive technology there are a number of assistive devices that are used for peoples with disabilities. Th e definition divides the assistive device into 5 categories based on th e specific kinds of di sability. Table 2.1 shows the different categories of assistive devices and adaptive driving aide is one of the subcategories of the manipulation and mobility aids. Table 2.1. Categories of A ssistive Devices [13] Prosthetics and orthotics Artificial hand, wrist and arms Artificial foot and legs Hand splints and upper limb braces Assistive device for persons with severe auditory impairments Digital hearing aids Telephone aids (e.g. TDD and TTY) Lip-reading aids Assistive devices for tactile impairments Cushions Customized seating Sensory substitution Alternative and augmentati ve communication devices Interface and keyboard emulation Specialized switches, sensors and transducers Computer-based communication devices Manipulation and mobility aids Grabbers, feeders, mounting systems, and page turners Robotic aids Manual and special-pur pose wheelchairs, scooters, recliners Adaptive driving aids Modified personal licensed vehicles

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13 2.5. Disabilities and Driving Facts As mentioned many times driving is a ch erished part of everybodys daily life. However persons with disability have limitation in their driving ability and t hey require some special assistance in their driving activ ities. As there are different types of disability, a specific need is re quired for a particular type of disabilit y. Before a vehicle has been modified, a thorough study should be done by the rehabilita tion or occupational therapist to determine what type of disabili ty the person has and what driving aide is important for modifying their needs. Under the association for rehabilitation specialist driving fact sheet there are a number of disabilities that a ffect normal driving skills and the following disability was categorized as th e main factors that affect normal driving skills [14]. Aging Alzheimer's or Dementia Traumatic brain injury Spinal cord injury Rheumatoid arthritis Multiple sclerosis Limb amputation Stroke Spina bifidia Cerebral palsy Attention deficit hype ractivity disorder

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14 Out of theses main categories spinal cord injury, rheumatoid arthritis, and limb amputation were the main disability that re quires the use of joystick modification. For this research these are the targ eted populations. However, it is important to have a better understanding of all the ma in factors of disabilities and its effect on driving facts in order to develop the proper driving aide for a sp ecific population. For this reason a detailed discussion is referenced in Appendix D. After a spinal cord injury has occurred, a person is no longer able to drive an automobile in the normal manner. However, there are several types of adaptive equipment and vehicle modifications that can allow an individual with a spinal cord injury to drive. Similarly due to rheumatoid arthritis there occur a loss of joint mobility that result in lack of ability to reach, ma nipulate, and release objects. More extensive adaptive equipment or vehicle modifications may be needed for persons whose ability to use their arms and legs is severely affected by a disability. So for th ese types of disability a choice of adaptive modification for their vehicle is important based on their specific needs. However if the person seems to be high ly disabled the use of joystick is important as a means of modification their vehicles. It is also hard to drive an automobile in the normal manner for persons with limb amputation. There are, however, several t ypes of adaptive devices that can allow an individual with an amputation to safely cont inue driving. The site of amputation(s) will determine the degree of difficulty an amputee w ill have with driving a standard equipped vehicle. In most cases, the adapted equipm ent will involve compensation for the inability to reach and operate primary and secondary driv ing controls [14]. Pe rson with specific type of amputation their vehicle is adapted on their specific needs. Even though there are

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15 different kinds of amputee, such as right leg, left leg and upper extremity amputee, joystick is mostly important for person with triple or quadruple am putation as it is hard for them to operate the primary control of the vehicle safely as needed as compared to the other amputee. Discussing the background about different t ypes of training methods for disability helps the research to focus on other kinds of disabili ties, such as tetrap legic or paraplegic, and try to find out other means of training method for driving a modified vehicle. This background shapes the research to build a joystick enabled system by integrating the driving aid and driving simulato r that are not available as a means of training for persons with disability. The knowledge of different kinds of disability and its number is important for the research. As there are different kinds of disability it is good to know the type of disability that needs specific m odification on their vehicle and especially with joystick operated driving aide vehicle. K nowing different kinds of disability and its driving facts shapes the research to focus on specific kinds of disability types, such as spinal cord injury, arthritis and amputation, as these disabilities influence the normal use of primary control of the vehi cle as mentioned previously.

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16 Chapter 3 Adaptive Driving Modifications for Persons with Physical Limitation 3.1. Introduction For most people, driving a motor vehicle has become essential to the tasks of everyday living-commuting to work, running errands, or taking children to school for example, and synonymous with freedom, indepe ndence, and self-sufficiency [15]. There are same needs to persons with disability when it comes to driving motor vehicles. However the physical limitation of their disability makes their life harder as compared to normal drivers. Many persons with physical disabilities can safely drive using some variety of the adaptive devices available today. Some of th ese devices are often found in almost all vehicles and are used by people with and without physical disabilities. Some of the commonly found adaptive aids are: Automatic transmission replaces the clutch and manual shift Power steering reduces physical effort to steer Power brakes reduce physical effort to brake Left foot accelerator elimin ates left leg cross-over Right hand turn signals eliminate right hand cross-over Foot pedal extensions raise hei ght of brake and accelerator pedals

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17 Hand controls operate horn, wipers, turn signals, dimmer switch; can also operate brake and accelerator Steering devices allow steering by sp inner knobs, amputee ring, quad fork, or tri-pin Custom seating creates balance, positioning, and stability Lifts and ramps permit access into and out of the vehicle Joystick permit the replacement of th e primary control of the vehicle Since the research deals with adaptive driving it is important to understand what type of modification a person needs for his/ her vehicle. As it was mentioned earlier persons with specific limitation can use a joystick to operate their vehicle. This joystick is one of the main adaptive equipment that has been modified in any vehicle to control the steering and gas/break pedal of the automobile. This chapter discusses the different automotive adaptive equipment needed for m odification. Next it discusses types of vehicle modified and its modi fication type. It further describes on the primary control modification since joystick controls the primar y control of the vehicle which is the main concern of the research. 3.2. Automotive Adaptive Driving Automobile adaptive equipment is used to permit physically challenged persons to enter, exit, and or operate a motor vehicle or other conveyance. It includes, but is not limited to, power steering, power brakes, power windows, power seats, and other special equipment necessary to assist the eligible pe rson [16]. Automotive adaptive equipment is classified into many types which include pr imary control, seconda ry control, access

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18 devices, mobility aide handling devices, occupant protection, vehicle structural modification, vehicle electrical modification, which each type include different modifications as shown on Table 3.1 below [17]. Table 3.1. Classifications of Automotive Adaptive Equipment [17] Primary Control Hand Control Steering Assist Device Steering Modification Foot Steering Brake Modification Left Foot Accelerator Pedal Extension Powered Primary Controls Secondary Control Secondary Control Panels and Systems Transmissions Turn Signals Hazard Warning Signals Windshield Wiper Ignition and Engine Start Lights Seat Adjustments Power Windows HVAC Controls Door Locks Parking Breaks Horn Cruise Control Mirrors Rear Accessories Access Devices Automatic Wheel Chair Lifts Semi-automatic Wheelchair Lifts Exterior Access Device Controls Automatic Door Openers Ramps Personal Lifting Devices Assist Handles Mobility Aid Handling Devices Racks Hoists Vehicle Electrical Modification Battery Charging Systems Other Electrical Modifications

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19 Table 3.1. (Continued) Vehicle Structural Modification Flooring Full-size Van Lowered Floor Minivan Structural Conversions Fuel Tanks Lowering Pan Raised Roofs Modified Doors Out of this adaptive equipment, adaptive driving controls ar e basically divided into two categories, primary and secondary cont rols. Primary controls directly affect the speed and position of the car which controls the above mentioned parts on the table, while secondary controls consist of all other controls, which allow the car to be safely operated in normal traffic situa tions. A joystick adapted vehi cle controls the steering and gas/brake pedal of the auto mobile and it replaces the primary control components mentioned on the table above. 3.3. Vehicle Modifications Vehicle modifications are any mechanical or structural changes to a passenger car, van, or other motor vehicle that permits an individual with a disability to safely drive or ride as a passenger. It also includes wheelchair or sc ooter loaders which mount on the roof, in the passenger area, or in the trunk or other storage areas of a car, van, or other motor vehicle. Automotive Adaptive C ontrol Devices (AACDs) are mechanical or electrical devices added to a standard motor vehicle to enable an individual with mobility restrictions to control the accelerator, foot brake, turn signals, dimmer switch, steering wheel, and/or parking brake [18].

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20 Many people with disabilities need specific types of modifications or adaptive equipment added to their motor vehicles to meet their transportation needs. As the technology has improved in quality and availa bility, the number of persons using adapted vehicles has also increased. The 1990 Nati onal Health Interview Survey (NHIS-D) estimated 299,000 adaptive equipment user s, while the 1and 1995 NHIS-D estimated 510,000, an increase of 211,000 users over a five-year period [19]. In December of 1997, the National Highway Traffic Safety Administration (NHTSA) estimated the number of vehicles m odified for those with disabilities to be 383,000. The number of vehicles with adaptive equipment is expected to continue to increase as the U.S. population ages and as access to employment, travel, and recreation continues to improve for persons with di sabilities, as a result of the ADA [19]. From the data collected out of 398 questi onnaires the majority (293 or 74 percent) of respondents over the six year period from 1997 to 2003 were drivers of adapted vehicles [19]. Table 3.2 shows the modifi ed vehicle types and their safety rating. Table 3.2. Modified Vehicle Types and Vehicle Safety Ratings [19] Vehicle Type Percent of Total Count Safety Rating of 4/5 Cars 33% 130 85% Van 28% 110 60% Minivan 24% 97 71% Other Types 15% 60 75% Pickup 6% 26 SUV 6% 23 Truck 2% 7 Other 1% 4

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21 Respondents were asked to identify what types of modifications or adaptations they had made to their vehicles. They were given a list of 25 specific vehicle modification categories and could select as many as were applicable to their vehicle. The choices, listed in Table 3.3, ranged from modifications for the purposes of accommodating wheelchair users to vehicle control adaptations [19]. Table 3.3. Types of Modifications an d Vehicle Safety Ratings [19] Type of Modification Percent of Total Count Safety Rating of 4/5 Hand control 50% 200 80% Wheelchair securement 32% 127 63% Steering control device 30% 119 79% Automatic door opener 29% 114 66% Dropped floor 23% 90 64% Modified safety belts 18% 73 70% Power seat base 16% 63 73% Ramp 15% 59 61% Wheelchair or scooter hoist 14% 57 63% Modified switches, touch pads 13% 52 69% Drive from wheelchair 12% 46 63% Low-Effort steering 10% 40 75% Raised roof 10% 39 72% Low-Effort braking 9% 34 62% Remote ignition 8% 30 80% Zero-Effort steering 7% 28 71% Left foot accelerator 7% 27 85% Electronic gas, break 6% 22 64% Reduced diameter steering 5% 20 75% Joystick/other steering system 4% 16 75% Zero-Effort braking 4% 14 71% Horizontal steering 2% 9 56%

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22 Table 3.3. (Continued) Type of Modification Percent of Total Count Safety Rating of 4/5 Power assist hand control 2% 9 78% Foot steering 1% 2 100% Other equipment 16% 63 75% Zero-Effort steering 7% 28 71% From the above statement it could unde rstood that joystick was one kind of adaptive modification that has been done on vehicles and it was mounted as a driving aide on any vehicle. This thesis focuses mainly on developing a synchronized AVEIT system with an SSI driving simulator that will help disabled person on training how to use the modified vehicle before they have been sent to the real world. As a result this thesis mainly focuses on training the person how to use the primary control, steering system and gas/brake pedal system, using th e AVEIT joystick component. The following subchapters will discuss the different types of primary control modification system and its advantage with its differen t way of modification system. 3.3.1. Primary Control Modification Primary controls are controls for impl ementing the throttle, brake and steering inputs to the motor vehicle [20]. Primary c ontrols are the main controls in a vehicle which consist of gas/brake systems along w ith steering systems. As previously mentioned primary control consists of other devices too. But for the sake of simplicity and since this research only focuses on gas/brake and on steering devices then the thesis focuses mainly on those devices.

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23 3.3.1.1. Steering Wheel Aid Modification Steering wheel aid modification is one of the main modifications applied on vehicles. It helps to contro l the factory manufactured wheel by installing some important parts on either four quadrant of the wheel base d on the users need. This modification can either be removable or fixed. The steering wheel aid can take the form of a knob or an adaptor to connect the hand, wris t or arm of a disabled pers on to the steering wheel or sometimes use a joystick for person who has a paraplegic or tetrap legic disability. It is generally intended to allow single -handed operation of the steering wheel. However, those with restricted use of their hand or those with some parts of their arm missing will require some degree of manipulatin g of the steering wheel aid. An assessor of an adaptation should check that the adaptation confor ms to the objectives and specifications stated by the aid manufacturer [21]. To enhance the usefulness of the adaptation it is advisable that it can be adjusted or fitted with different configurations of grips to meet the needs of people with differe nt types of disability e.g. shape, size and axis angle, etc. For those unable to grip a knob, an adaptor can be provided to attach the hand, wrist or arm of the disa bled person to the steering wh eel aid or sometimes if the person has severe disability the vehicle can be modified with joystick capable driving aide which includes: Back-Up Steering System: provides emergency power steering in the event the factory-installed power steering system fails due to engine failure, power steering pump failure, broken power steering belt, or ruptured lines. The back-up system activates instantaneously when the steering fails and allows the driver to steer the

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24 vehicle out of traffic. The back-up sy stem can be operated with or without reduced-effort steering modifications a nd is available for most vehicles. Foot Steering: is a car st eering device designed for indi viduals with limited or no use of the hands and arms. This specia l floor-mounted device is intended to afford complete steering capability with the foot. Horizontal Steering: is a horizontal steering column manufacturer recommended for drivers with limited reach and strengt h capabilities. The system utilizes a level-planed steering wheel as opposed to the conventiona l vertical-planed steering wheel that is extended over the driver's lap. Zero-Effort Steering Modifications: are sensitized steering components designed to enable drivers with hand and/or ar m weakness to steer a vehicle by reducing the effort needed. Approximately 450 to 500 in. oz. of torque are needed to control standard factory installed power steering. These modifications are intended to reduce that effort to le ss than 50 in. oz. of torque [22]. 3.3.1.2. Gas and Brake Modification Most of the procedures and restrictions that apply to gas/brake modifications are similar to the steering modifications. Reduced and zero-effort gas/brake systems are available in the pneumatic and electronic m odels. The term reduced-effort braking is defined as a modification to reduce the effort re quired to brake the ve hicles to a specified level below that needed for a factory pow er breaking which is up to 112 lbs [21]. Reduced-effort brake is one of the two types: Low-effort and zero-effort braking which its modifications include:

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25 Zero-Effort Braking Modification: is se nsitized brake modifications designed to enable drivers with little streng th in their hands and/or arms. Back-Up Brake System: is an emergency braking system designed for drivers with hand and/or arm weakness to break the vehicle in the event the factoryinstalled power brakes fail due to en gine failure or low vacuum [22]. 3.3.2. Joystick Driving Control The joystick driving control is a one-h and drive control sy stem for steering, acceleration, and braking control operated with a joystick. The joystick mounts in any position on the left or right side. Acce leration is achieved by pulling back on the joystick; braking by pushing forward, and st eering with a side-t o-side motion [22].

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26 Chapter 4 Simulator Systems International and AEVIT Driving Control System 4.1. Introduction In the last chapter the need for au tomotive adaptive driving controls was discussed. I also described some existing adap tive driving controls for the disabled and how they are incorporated into the drivi ng environment through vehicle modifications. This chapter describes one such adaptive driving system, which is currently in use for modified driving by persons with disabiliti es. It is known as the AEVIT (Advanced Electronic Vehicle Interface Technology) driv ing control system manufactured by EMC (Electronic Mobility Controls ), LLC. Also, this chapter provides a description of a driving simulator which is introduced by Simulator Systems International. It is fullyinteractive driver rehabilitation training and assessment simulator. The AEVIT driving system and the driving simulator device are connected through an interface of mechanical parts be tween the gas/brake servo of the AVEIT device and the gas/brake pedal of the driving simulator. The steering wheel of the AVEIT system and the driving simulator also connected mechanica lly through the use of motor and a mechanically designed coupler th at couples the steering wheels of AVEIT and SSI system interfaced with electrical device.

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27 The intention of this thesis is to obtain a qualitative result of electromechanical synchronization between the steer ing wheels of the AVEIT system and that of the driving simulator and also a mechanical synchroni zation between the gas/ brake servo of the AVEIT system and gas/brake pedal of the drivin g simulator. In this chapter the hardware and software of the AVEIT system and the driv ing simulator that is important to use in this research will be discussed. 4.2. The AVEIT Driving System The AEVIT System (Advanced Electroni c Vehicle Interface Technology) is a product of Electronic Mobility Controls, LLC (EMC). EMC manufactures a variety of primary driving control options designed to operate the gas, brake and steering controls of a motor vehicle. It basically combines the primary driving cont rol devices, the DS2000 (steering wheel), the EGB (gas/brake), and the DIGIDRIVE (joystick) into one single control system, AEVIT. The AEVIT system has more than ten input devices available to meet different user-needs a nd capabilities, thus making it an easier alternative for operating the f actory installed steering, brak e and gas controls [23]. The AEVIT primary driving control system provides a low-effort control solution for operation of the factory gas, brake, and st eering control. Each of the different control inputs can be used in conjunction with the same control drives and output servomotor. The two servomotors, one for the device and th e other for the steeri ng device, convert the mechanical input into motion [20].

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A diagram has been provided to show a ll of the components of the AEVIT system and how they connect. Each line below repres ents a connection and is marked with the type of information that it carries. Figure 4.1. AEVIT System Layout [23] 4.2.1. Information Center The information center provides constant f eedback regarding the system's current status. The information center has a four line display with easy to r ead characters [23]. 28

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When the AVEIT driving aide is rebooted, the information center is the one that tells the exact information weather the primary cont rol is rebooted or not to default position. Figure 4.2. Information Center [23] The SCROLL keys are used to move around within a menu. At the end of a Menu, they will also bring you back to the first screen. These keys are safe to use at all times. The SELECT key performs two functions. First, it is used to select a processor to view diagnostic information. Second, it is us ed to clear any diagnostic information that may be displayed during normal operation. The OFF (ESC) key is used to boot down AEVIT after the ignition has b een turned OFF. There are two connections on the bottom of the information center. The Controller Area Network (CAN) bus port is the only port that will be connected to the AEVIT touchpad [20]. 4.2.2. Input Devices AEVIT utilizes a variety of input devi ces to control the vehicles primary functions. These include a single-axis leve r, a 6" wheel, two single-axes and one dual29

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axis joysticks, and a wheel/joystick combinati on. All input devices ha ve three electronic position sensing components called potentiometers that monitor each controllers position at all times. With three components mon itoring the same circu it and their respective input, the systems safety and reliability is e nhanced far beyond that of a system that uses only one type of sensing device [23]. For this thesis the joystick is the focus. Figure 4.3. Digital Joystick [23] 4.2.2.1. Joystick The Y-axis joystick (gas/brake) is an extrem ely low effort device. It requires only 4 6 ounces of force to move the joystick through its full range of travel. This force is fixed and cannot be adjusted. As a safety f eature, when the joystick is at full brake and the vehicle's ignition is ON, the electric park brake will automatically be applied and will remain on until the full brake input is released. If the ignition is OFF, and AEVIT has not yet booted down, the lever can be used to SET the park brake. It is not recommended to hold the joystick to full brake when stopped at a red-light or stop sign. Extended use may cause the circuit to thermal limit and lock the park brake in the SET position. A way to 30

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avoid this is once it comes to a complete stop; ease off the j oystick just enough to no longer activate the park brake, but not e nough to allow the vehi cle to roll [23]. For steering, the X-axis joystick can trav el approximately 30 degrees from center in each direction, and is divided into three input control "bands": the Centering Band, the Holding Band, and the Motion Band, and one output band: the Drift Band [22]. Centering Band: returns the steering ser vomotor to the straight ahead" steering position. The rate at which the servomotor is returned is proportional to the distance that the joystick is moved away from center. The closer the joystick is to center, the faster the servomotor will travel toward center. Holding Band: is an area between the centering band and the motion band. When entered, this band will cause the steering se rvomotor to hold its present position. Motion Band: will cause the steering servomotor to move in the appropriate direction at a rate that is proportional to the position of the joystick within the band. For example, the steering servo will travel slower when motion band first entered, and will increase proportionately as the stick is moved outward toward an end stop, away from center [22]. Figure 4.4. Joystick Control Steering Bands [23] 31

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Drift Band: This band is called an output band because it relates to what the steering wheel or vehicle is doing, not to the position of the joystick. The drift band is the first five degrees of steering wheel or vehicle movement, both left and right. If the joystick is moved so that the wheel moves less than 5 degrees, and release the joystick back to center, the wheel will remain fixed. This allows a driver to make small alignment corrections without the wheel returning to center when the joystick is released. This feature helps to compensate for wind, road crown and other factors that can cause a vehicle to wander during straight ahead driving [23]. Figure 4.5. Drift Band [23] 4.3. Simulator Systems Intern ational Driving Simulator The driving simulator consists of a series of computers and television screens, a steering wheel, pedals, and a seat with a s eat belt. The TV screens offer a simulated dash-board panoramic view that features computer animated roads, buildings and traffic signs as well as other vehicl es and driving hazards [24]. Simulator Systems International introduces the fully-interactive driver rehabilitation training and assessment simulator. It offers a full 120-degree view of the 32

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virtual driving environment and realistic driv ing conditions with full controls found in a typical car [25]. Figure 4.6. SSI Driving Simulator [25] 33

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34 Chapter 5 Electromechanical Design and Sync hronization of the Driving Systems 5.1. Introduction Prior to starting this project a van whic h is used for the research was bought and modified to accommodate the research. As a result half of its length was cut and almost all parts of its motor and the dashboard was removed. In order to move the van easily wheels were attached to it which makes the van to easily movable around the lab. At the same time the AVEIT driving aide and SSI driving simulator were also bought for the purpose of the study. This chapter begins with modification of the inside of a working van so that it will be suitable to install or assemble the dr iving aide and driving simulator for training persons with disabilities. It explains what methods are used to come up with the particular kind of design and why the material wa s selected to hold the driving aide parts. This chapter also explains how the two driving systems are synchronized together. That is, it explains the different approaches of mechanical and electrical designs. The mechanical parts of the design are classified into two parts which include a design for the AVEIT driving aide and SSI dr iving simulator couplers. Some other parts such as bearing, gears and collars were bought from outside vendors to make the mechanical design to a complete working sh ape. It also explains the particulars of the design and

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35 part of the factors that suit an engineering design. For the electrical part it shows the circuit diagram and also explains how the systems of the electrical circuit work. When this design was successfully finished the system was synchronized to show that it is in a working condition and it is feasible. Finally a test was made to check on whether the driving aide is working with driving simula tor or not and made conclusion based on the result. 5.2. Van Assembly As the main idea of the project is to sync hronize the driving aide with the driving simulator and then study the use of this met hod to train persons with disability how to drive a motor vehicle, it is necessary to make the virtual reality driv ing system inside the van. As a result it was found to be necessary to assemble the entire driving aide, some driving simulator parts and other necessary pa rts inside the van. Du e to the bulkiness of the SSI unit the monitor and ga s/brake control was the only pa rts that were assembled but the SSI console was not assembled inside it However, the entire AVEIT driving aide was assembled inside the van. Before the AVEIT driving aide was installed to the van, a mechanical part to hold the system was built. As a result, detailed dimensions of the inside of the van were measured and at the same time, the di mensions of all parts of the driving aide were also measur ed. Because all the AVEIT driv ing system has to be built inside the van, it is necessary to take into consideration the strength of the design that holds all the parts. As a result before the design was given to machine shop for machining a stress analysis was performed on th e parts. The cost of the parts was also taken into consideration. A two angle bars of 2x3x10 steel metal were used as a side

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support. These angle bars were mounted on each side of the van. A longitudinal bar of wood 4x2x64 crossed the van and placed on top of the two steel bar. Figure 5.1. Wood Bar As shown in Figure 5.1 above the wood bar is crossing the van longitudinally and placed on top of the steel metal. The wood ba r is used to hold the entire driving aide parts and the monitor. The total weight of the AVEIT driving aide and the monitor of the driving simulator is approximately 75 lb. The CAD software Solidworks was used to design the two steel bars. A stress calcula tion was done on the longitudinal wood bar to check the strength of the material and ANSYS was also used to check the hand calculation. The value of stress at any point was calculated using the following formula where =stress, P=Load, x=distance, l=length, b=base, h=height, S=section modulus, SF=safety factor, Y=yield stress. 36

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lS xlxP **2 )(** where 6 *2hb S S lPcenter*8 Y Stress Strength SF The maximum stress for constant cross secti on area is located at the center. From the calculation max 225 lbf/in 2 and the material property Y = 7977 lbf/in 2 giving a safety factor of 35. From this result it can be determined that the design is safe to hold the material. A stress analysis was done using ANSYS and the maximum stress was located at the center of the ma terial and it shows the same result as obtained using hand calculation. Figure 5.2 below shows the ma ximum bending stress on the bar with a unit in Megapascal (MPa). Figure 5.2. Stress Analysis of the Base Holder 37

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Figure 5.3 is a picture showing the comp lete assembled AVEIT driving system and SSI monitor inside the van. The picture was taken from the back of the van and the front mirror of the van was replaced by the SSI monitor. The idea behind this installation as shown in the figure below is the driver us es the joystick located to the right of the steering to rotate the steering. The information center is located to the left of the steering. So the two main parts of the AVEIT system were mounted on an elongated arm so that it will be easy as it was extended to the driver The other parts were placed below the monitor. Some of the electrical parts of the van were not dismantled as it does not affect the installations. Figure 5.3. Assembled Van 38

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39 5.3. Friction Clutch The friction clutch is a part that is put in between the motor and the SSI steering. When the motor starts to rotate, the rotation of the motor is transferred to SSI steering. The two steering, AVEIT and SSI, have a fixed number of turns which ends their rotations in one direction at approximately 1-1/4 1-1/2 tu rns in either clockwise or counterclockwise. This fixed number of turns of the two steering bri ngs to the idea of putting a friction clutch in between the motor and the SSI steering for safety reason. The idea behind this design is, if there is a minor error occurred du ring calibration of the systems the motor starts to rotate continuously but the steering of the SSI ends its rotation in one side, as a result the clutch will dise ngage and then the motor only rotates in which the rotation of the motor does not affect the SSI unit. Since the SSI steering system does require moderate torque to turn either side the friction clutch is chosen to have an adjustable torque so that the torque betw een the motor and the SSI steering can be adjusted. There are some friction clutches av ailable in market and miniature friction slip clutch was chosen for this research that ha s a torque capacity of 11.7 in-lbf. Since the other friction clutch available has a maxi mum torque capacity of 4.5 in-lbf, it will disengage prematurely after some torque applie d to the system. As a result it is not a good choice to have a friction cl utch that is less than the maximum torque required to turn the steering.

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Figure 5.4. Adjustable Friction Clutch [26] Figure 5.4 shows the friction clutch used for this research. This clutch is connected between the motor and the shaf t that runs toward the SSI steering. 5.4. Mechanical Design This mechanical part is the main design of the project. Since the project includes both mechanical and electrical synchroniza tion, an accurate and precise design of mechanical parts was important for this pr oject. As it was mentioned earlier the two systems, AVEIT and SSI, are separate units Since there is a simultaneous rotation between the two steering system, i.e. AVEIT and SSI steering system, a mechanical coupler that is used to tran sfer and synchronize the rotati on between these systems has to be built. As there are two st eering systems, two couplers ar e to be designed. There was additional part such as collars, bearings and gears also bought from the vendors in order the mechanism to work as desired. As it was known there are two systems of steering, 40

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41 hence this mechanical design includes two kinds of coupler design and explains in detail how it works with the help of figures. 5.4.1. SSI Coupler The SSI system is located in a separate unit and has a shaft elongated from its steering. A coupler is build to help all the rotation and that holds all the necessary parts inside. Since the mechanical part of the c oupler attaches the moto r and the SSI steering wheel, the coupler consist of different parts including long shaft, two gears, potentiometer, and different size of bearings, collars and frict ion clutch. The coupler is attached to the motor via friction clutch on one side of the shaft and it has an extension on the other side attached to the steering of SSI The shaft is designed in order to fit the desired dimensions of the bore size of the gears and collars. Since it is the main part that translates the rotation between the motor and the steering system, the material has to have an appropriate criterion of engin eering design in its strength. As a result the material that is used for the shaft was chosen to be steel. The shape and size of the shaft was designed based on the parts that it couples.

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Figure 5.5. Assembled Coupler for SSI Driving System As shown in Figure 5.5 the middle secti on of the shaft is designed to have a narrow size due to the fact that the gear that is appropriate for this design has a narrow bore diameter and this gear is mounted to this shaft. The two ends of the shaft have a wider diameter based on the other extension to be inserted on. The main concern for the shaft design was the strength due to torsion stress applied. As the motor rotates and transfer its rotation to steering system there is a torsion applied on the narrow part of the shaft and this could lead to the failure of the design. As a result it is important to figure out how much torque is needed to rotate the steering of the SSI system. The torque needed to turn the SSI steering to a full tu rn in one direction was measured using the torque wrench and it was found around 10 in-lbf A friction clutch that is mounted between the motor and the shaft has an adjust able torque size of maximum 11.7 in-lbf. Based on this amount it is important to find weather the shaft desi gn can withstand this amount of rotation force. A 12 in-lbf torque is applied to the narrow part of the shaft that 42

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has a diameter of 0.3125 in. Based on the Von Misses criterion, the torsion stress, is obtained 2003.65 lbf/in xy 2 and a the Von Misses stress, is found 3470 lbf/in 2 and from the material property the steel ha s a yield strength of 76870 lbf/in 2 From theses values the safety factor (SF) is calcula ted and obtained a value of 18. 3* 16 d Tm xy xy3 Stress Strength SF Solidworks was used to design this shaft and the material was assigned as steel AISI 1045. Taking all its mechanical pr operties a maximum amount of torque was applied to the material. Based on the test obtained from Solidworks it was found out that the design was safe with a reasonable safe ty factor of 18 which is similar the hand calculation. As shown in the Figure 5.5 a bove there is a small connector between the motor and friction clutch. This has a narrow part that was designed to connect the motor and friction clutch and it has the same diamet er as the long shaft di scussed previously. A torsion stress analysis was also made for th e part that connects between the motor and the friction clutch and it shows the same result as the previous torsion stress analysis. As shown in Figure 5.6 the stress analysis made on the narrow part of the shaft indicates the design is safe where the value of safety factor is shown on top left side of the plot detail. 43

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Figure 5.6. Stress Analysis of the Shaft There is another short shaft also used in this design which is attached on one end to the potentiometer and the other end to the be aring of the coupler. This is mainly used to transfer the rotation between the steering and the potentiometer. A gear is attached to this shaft in conjunction to the other gear that was mounted on the long shaft. So as the long shaft rotates the gears transf er the rotation to the gears that are attached to the short shaft. As a result the potentiometer is rotate d simultaneously to the motor and steering. The gear ratio is the most important to be cons idered in this design. As the potentiometer is rotated it switches the voltage supply to th e circuit which at same time the rotation of the motor is changed due to the voltage supply. As a result th e gear ratio has to be taken into consideration. One full turn of th e steering from the center to one end have approximately 1-1/2 turn. The potentiometer that used in this research has a 10 turn modes with 5 turn to right and 5 turns to left from the zero position. So from this 44

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45 criterion a 1:1 ratio between the two gears was chosen. This ratio gives to the design so that no damage will be done on the potentiometer as a result of the ro tation of the shafts. In order to smooth out the rota tion, bearings were used on th e connection according to its bore size and at same time to make the shafts in constant position co llars are also used. These gear, bearings and collars were ordere d from vendors based on the desired design. To discuss the operation of this design in short, as the AVEIT steering system rotates, it initiates the potentiometer and this also initia tes the motor to turn due to voltage change. When the motor turns it rotate s the long shaft and the rotation transferred to the steering of SSI and at same time a gear attached to long shaft also rotates and it transfers the rotation to the other gear attached to the shor t shaft. Then the potentiometer rotates until it is turned off due to voltage change. The electrical process will be explained later on the electrical system. Figure 5.5 shows the asse mbled design of the coupler in detail that is going to be mounted to the SSI steering system. 5.4.2. AVEIT Coupler This is another mechanical part of the c oupler that attached to the steering of the AVEIT system. Similar to the previous coupl er this one also cons ists of two shafts, gears, potentiometer, bearings and collars. Th is coupler is used to transfer the rotation between the steering and the potentiometer by the help of the gears. The ratio between the two gears is the most important to take into consideration in this design because it helps a synchronized transfer of rotati on between the steerin g and that of the potentiometer. To determine what gear ratio to use in this design, first it is important to know the one sided full turn of the AVEIT steering from the center or zero degree

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46 position. From manufacturer the default AVEIT steering turns almost 1-1/2 to make a full one side turn. Similarly to the previous one the potentiometer us ed for this coupler also has 10 turn model with 5 turn in either si de. So from these two factors it is important to determine what ratio to use for the two gear s and from this relationship a factor of 1:1 ratio was chosen. The long shaft of this mech anism attached or connected on one end only to the steering servo of the AVEIT system and the s hort shaft extended inside the coupler and its one end is attached to potentiometer. Th e gears are mounted on each shaft. These two gears are interconnected so th at they translate an angular rotation between the steering servo and the potentiometer. The idea behi nd this design was when the handicap person maneuver the joystick by turning either side horizontally, i.e. X-ax is, the steering of the AVEIT rotates with it. So as the long shaft rotates it translates the rotation of the steering servo to the potentiometer by the help of gears. Then potentiomete r will be powered on the circuit and it changes the vol tage supply of the circuit. Since there are no constraints on this coupler and the unit rotates with insignificant amount of torque, stress calculation is not of importance for the shaft. Figure 5.7 shows the detailed design of the assembled coupler.

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Figure 5.7. Assembled Coupler for AVEIT Driving System 5.5. Electrical Design This design was one of the main parts of the research and it makes the two mechanical systems synchronized in rotation. There are two different steering systems, AVEIT and SSI, in the design and is hard to synchronize the two systems mechanically together. As a result it is important to build an electrical system that synchronizes and runs the two systems simultaneously. 47

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48 Figure 5.8. Circuit Diagra m for Synchronized Rotation

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49 Figure 5.8 shows the schematic drawing of the electrical design. The main component of the electrical design consists of resistors, capacitors, potentiometer, operational amplifier (OP-Amp), NAND gate s, DPDT (Double Pole Double Throw) relays, diodes and latch. The idea of this elect rical design is to create a working electrical component that synchronizes the rotation of mechanical systems of steering of the AVEIT and the SSI system. As shown in the diagram the circuit has potentiometers that are attached to each of the steering system. Th ese two potentiometers were mentioned in previous mechanical design part that was connected to the coupler. When the AVEIT steering rotates it translates the rotation to the potentiometer through the gears. When the AVEIT steering rotates clockwis e from zero position, the rotation is transferred to the potentiometer. Once the po tentiometer rotates there occur changes in voltage and there is a difference in voltage between the two OP-Amps (AD706). When the voltage output from the OP-Amp is posi tive, the current moves to the positive NAND (TC4011) gate then the current passes to the DPDT relay. Once the relay is initiated by the voltage supply its power was turned on and si nce the circuit is att ached to the motor it triggers the motor and finally the motor runs. As a result it transfers the rotation to the SSI steering. At the same time the gears of th e SSI coupler starts to rotate and it transfer its rotation to the pot entiometer of the SSI coupler. This system makes the two potentiometers rotates together with a small amount of voltage change and keeps the motor to run at a controlled speed. As the AVEIT steering rotates counter cl ockwise the voltage output from the OPAmp becomes negative, then the current move s to the negative latch. The reason for

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adding a negative latch for this design was in order to receive this negative current that was out from the two OP-Amp differences. So once the current passes through this negative latch, the negative latch converts the sign from negative to positive then the positive current flows to NAND gate. From N AND gate the current flows to the second DPDT relay. Once the relay is initiated by the voltage supply its power was turned on then the circuit attached to the motor is tri ggered finally the motor runs as a result it transfers the rotation of the SSI steering as opposed to the direction of the previous rotation. At the same time the gears of the SSI coupler starts to rota te and it transfer its rotation to the SSI coupler. Then it starts to change the voltage difference between the two OP-Amps. As the joystick of the AVEIT driving aide keeps moving horizontally either to the right or left this cycle of st eering rotation runs simultaneously with the change in voltages of the potentiometer and this cycle repeats ag ain as the joystick rotation changes. Figure 5.9 shows the physical body of the electrical part. 50 Figure 5.9. Electrical System of the Design

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51 5.6. Final Synchronization In order for the two systems of the steering have to have constant and simultaneous rotation together, the system needs to be synchronized and calibrated together. The assembled part of the AVEIT coupler was mounted behind the steering shaft and their axis was aligned concentrically to each other. However, the two shafts were not fastened as it needs rotational calibra tion. Every time the AVEIT driving aide is powered on, all the primary cont rol system, i.e. steering, and gas/brake servo, needs to be rebooted to the default position using the joystick as discussed in Appendix A1. So when the AVEIT is rebooted every time the power is on, it affects the previous calibration of the AVEIT steering and the potentiometer of th e coupler connected to it. As discussed above on the mechanical design of the AVEIT coupler, the two shafts are interconnected by the help of the gears. Anytime the shaft rotates the potentiometer attached through the gear also rotates which results to a change of the potentiometer orientation from its zero position. So before engaging the two gears of th e AVEIT coupler, there is a need to calibrate the steering first as mentioned in Appendix A1. Prior to calibrating the AVEIT system, the screw that attaches the two shaf ts needs to be loosen. After the AVEIT system was rebooted and calibra ted, the potentiometer of the AVEIT coupler needs to be calibrated manually to zero or center positi on. Once theses synchronization of the AVEIT system and its coupler finished the screw that attaches the two shafts was fastened. The SSI unit and the motor with its c oupler were assembled as one unit and placed in fixed place. Similarly, prior to test for its synchronization there is a need for

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calibration between different part s of this system too. Afte r the handle of the SSI steering was removed, the coupler shaft was inserted to the shaft of the SSI steering. Since the SSI system is at zero position every time the system was rebooted, there is no need to calibrate the SSI steering system. Howeve r the potentiometer placed on the coupler should be calibrated to center pos ition. At the same time th e friction clutch attached to the motor also needs to be calibrated to desired torque and the calibration is done. When the systems were calibrated the electr ical circuit was attached to the power then the system testing was started. Fi gure 5.10 shows the complete picture of the synchronized SSI system, the motor and electric part. All the AVEIT system was built inside the van and a wire is elongated from the potentiomet er of the AVEIT coupler to the electrical system. At same time the SSI system is shown in the picture with all the motor, coupler, and SSI system. A wire also connected from the electrical system to the potentiometer of SSI coupler and the motor. 52 Figure 5.10. Synchronized System of SSI Unit

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5.7. Testing of System After the two systems are synchronized mechanically, testing the system was important in order to see the simultaneous el ectrical and mechanical operation of the two systems as needed. As it was mentioned ear lier the difference in voltage between the two potentiometers are the one that makes the system in simultaneous rotation. Prior to running the two system, AVEIT and SSI system the voltage difference between the two potentiometer was measured to check weather it is less than one volt, as high voltage difference could damage the electric circuit. If the difference is greater than the expected volt, it was adjusted by turning the potentiome ters assuming the gear is not fixed to the shaft connecting the SSI steer ing and the motor. Once the voltage difference was checked, the gear was fixed to the shaft of the coupler. Figure 5.11. Testing of System 53

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54 The rotational direction of steering of both systems is the main concern in this testing. As the direction of rotation change s either clockwise or counter-clockwise, the difference in voltage also changes. For this reason once the potentiometer is calibrated to the AVEIT steering, the steering was rotated to the right and the diffe rence in voltage was increases as expected. Figure 5.11 shows testing of voltage change between two potentiometers using a voltmeter. After this result was obtained the wires of the motor were connected to the electrical system in orde r to see the direction of motor rotation and make sure that the direction of motor rotati on was the same as the AVEIT steering. Once the direction of the motor rotation was the same as the AVEIT steering, the shaft that connects the motor and SSI steeri ng was fastened to both ends. Finally after all the steps were completed, the AVEIT and SSI system started to run together and a simultaneous rotation of the steering was obt ained. Once this simultaneous rotation was obtained, test drive was done using the virt ual reality of the SSI system. The simulation was conducted for 10 minutes with a road that has three lanes with a shoulder on side of the road. As the joystick started to operate the AVEIT, a ll the primary control of the vehicle was controlled by the joystick and the virtual vehicl e starts to move forward as the accelerator was pressed. When the joystick starts to ro tate the wheel, the virtual vehicle starts to change its lane same direction as the AVEIT steering wheel. In general the action of the AVEIT was transferred to the virtual vehicle of SSI system to a desired and expected action. A full step by step process on how to synchronize the test is illustrated on Appendix A.4.

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5.8. Block Diagram of the Mechanism In order to provide a quick and good level view of the work and also to rapidly lead to a point of interest, a block di agram will be of great help in giving a comprehensive idea on how the mechanism work. For the mechanism the input will be an AVEIT steering and the output is SSI load or SSI steering rotation. Figure 5.12. Block Diagram of Mechanism Figure 5.12 shows the block diagram of th e mechanism. The potentiometer 2 and the gear are located on the SSI coupler and the potentiometer 1 is located on the AVEIT coupler. After the AVEIT system starts to run, there is an input signal from the potentiometer 1 and at same time an output from potentiometer 2. The difference between the input and output cr eates a potential difference or error signal and this error signal, which is voltage difference, amplifie d at the electric circuit where its output voltage applied to the motor. As the motor r uns its torque applied to the SSI system. If 55

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56 the AVEIT input was reversed by turning the opposite direction the system output also reverse simultaneously and SSI system rotates same as AVEIT system. 5.9. Quantitative Result After testing of the mechanism shows that the system is working properly, it is necessary to support th e practical outcome by a qualitativ e result. A test was done to check the change in voltage between the two potentiometers using a digital oscilloscope. The objective of this test is to confirm the be havior of the previous practical test based on the specific key points. As it was mentione d before in the practical test, rotating the AVEIT steering clockwise or counter-clock wise changes the sign of the voltage difference, i.e. clockwise rotation of steer ing gives a positive voltage difference and counter-clockwise rotation gives a negativ e voltage difference, between the two potentiometers. As a result testing using qua ntitative method confirms the behaviors of the system. In addition this method helps in finding the average value of voltage required to rotate the motor by finding the voltage di fference between the input and output voltage applied to the potentiometers. Similarly fi nding the time delay between the two input and output of the systems is of main objective of this test. Before a qualitative test was started, a di gital oscilloscope was used to gather the data between the two potentiome ter differences. The oscilloscope that been used for this test was a PC based digital oscillosc ope, DSO-8500, which is a product of Link Instrument, Inc.

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Figure 5.13. DSO-8500 Series Digital Oscilloscope [28] As seen in Figure 5.13 the oscilloscope is a two channel oscilloscope with USB cable for computer data transfer. The two ch annels (A1 and A2) are attached to the two potentiometer and USB cable was plugged to computer. The digital oscilloscope has its own program which comes with its CD instal lation. Once the program is started the voltage per division, time per division, tim e per acquisition, cursor and window position was setup to a desired setting. For the best result the voltage for the two channels was setup to 5V per division and the time was setup to 5milliseconds per division. For clear view, channel A2 was set to an offset of 2V from the center. Once the wave of the signal started to upload to the screen, the voltage setup makes the view of the signal in clear view and inside the limit of the desired wi ndow. Similarly setup of time per division helps the response of the signal to be faster with optimum signals on screen, i.e. if the time per division is too small it leads to a window with less signals and similarly if the time per division is large th e signal waves are difficult to view on the window. 57

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58 When the joystick is moved in x-axis to ei ther right or left direction the steering starts to rotate in respons e to the joystick input. As it was mentioned earlier about joystick description the reacti on of the steering depends on the rate the joystick is turned either direction from the center. However fr om visual observation of the joystick and the steering reaction, the angle of steering rotation in response to an input joystick is quite different. That is as the joystick is moved to either right or left slowly the response of the steering is slow but as it reaches to some degr ee it starts to rotate fast. However this will not affect the voltage difference of the input and output of the system as both work or react simultaneously. When everything was setup, measurement started to be taken. Data was collected from the oscilloscope for each positioning of the steering. The output that was obtained from the digital oscilloscope was stored to computer and the signal that was obtained from the voltage difference between the tw o potentiometers was plotted. Since the number of data captured during th e test is too long, the data was placed on spread sheet in Appendix C and also the signal pl ot also put in Appendix B. 5.9.1. Zero Rotation of Steering From practical test that has been ma de previously using voltmeter, rotating AVEIT steering to right or le ft direction changes the volta ge difference between the two potentiometers. From previous voltmeter test, as the AVEIT steering was not rotated or in center position there was no change in volta ge between the two potentiometers and this was confirmed by the signal obtai ned from the oscilloscope.

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Figure 5.14. Signal of Cent er Position of Steering Figure 5.14 shows a signal obtained when the steering was in center position. The yellow line, F1, represents the change between the two channels. For the sake of clarity a cursor was aligned to the peak of the three signals and kept at same place all the time throughout the testing. As mentioned earlier channel A1 represents AVEIT potentiometer and channel A2 represents SSI potentiometer. From this diagram it can be understood that as the AVEIT steering is not rotated there is no ch ange in voltage. The figure is taken from the signal obtained during te sting. It measures the response of voltage change be tween two potentiometers. When there is no input rotation from the steering or the steering is set at center position. As mentioned earlier time per division of the program was set to 5 milliseconds and this result the collected data of the 59

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60 reading to have a quite big files when the pr ogram runs for quite few minutes. For this reason the first page of the figure is plotted on this section to repr esent the responses of the two voltage difference. However, the de tailed signal is shown in Appendix B.1. 5.9.2. Clockwise Rotation of Steering When the steering of AVEIT is rotated towa rd right or clockwise direction, there occur changes in voltage between the two potentiometers. This change in voltage between the potentiometer makes the motor to rotate toward right. While the motor runs its rotation also transferred to the other potentiometer which helps to control the change in voltage between the potentiometers. The right rotation of the AVEIT steering makes a positive change in voltage difference and this helps the motor to run in right direction. Data collected on to the oscilloscope shows th e two channels change its position from the previous position by shifting upward. However th e rate of change is not similar to both channels which lead to a difference in voltage change between them. This difference in voltage, F1, is represented by the yellow line which equals to the change in voltage between the two potentiometers.

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Figure 5.15. Signal for Ri ght Direction Steering From Figure 5.15 it can be observed that the change in voltage which is represented by the yellow line, F1, is in creasing upward as compared to the signal obtained from center position of steering. This indicates that there is a positive change in voltage between the two potentiometers and it also indicates that a positive change in voltage makes the steering to rotate toward right direction. Unlik e the center positioned steering, the peak of the signa l increases and passes the constant cursor that was marked as benchmark. The figure is taken from the signal obtained during te sting. It measures the response of voltage change between two poten tiometers when the i nput rotation of the steering is to the right. As mentioned earlier time per division of the program was set to 61

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62 5 milliseconds and this result the collected data of the reading to have a large file when the program runs for few minutes. For this reas on the first page of the figure is plotted on this section to represent the responses of the two voltage difference. However, the detailed signal is shown in Appendix B.2. 5.9.3. Counter-Clockwise Rotation of Steering Again when the steering of AVEIT is rota ted toward left or counter-clockwise direction, there occur changes in voltage betw een the two potentiometers. This change in direction creates an opposite or negati ve voltage difference between the two potentiometers which makes the motor to rotate to left. The left rotation of the AVEIT steering makes a negative change in voltage difference and which make the motor to run counter-clockwise direction. Same to previous method data collected on to the oscilloscope shows a change in voltage signa l, F1, as compared to the previous two positions. It is already known that count er-clockwise rotation of steering makes a negative change in voltage which was confir med from the downward sign of the signal oscilloscope.

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Figure 5.16. Signal for Left Direction Steering Opposite to right steering, the signal for left steering was downward. From Figure 5.16 it can be observed th at the change in voltage which is represented by the yellow line, F1, is decreasing downward as co mpared to the signal obtained from the previous two positioning of steering. The signa ls indicate that there is a negative change in voltage between the two potentiometers and it also indicates that a negative change in voltage makes the steering to rotate toward left direction. Similarly when the peak of the two channels was observed, its peak point is below the cursor line which was assigned as fixed bench mark to all three positions. This indicates that both steering are turning left or counter-clockwise. 63

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64 The figure is taken from the signal obtained during te sting. It measures the response of voltage change between two poten tiometers when the i nput rotation of the steering is to the left. As mentioned earlier time per division of the program was set to 5 milliseconds and this result the collected data of the reading to have a large file when the program runs for few minutes. For this reason the first page of the figure is plotted on this section to represent the responses of the two voltage difference. The detailed signal is shown in Appendix B.3. 5.10. Analysis of Testing Once the mechanical and electrical designs were synchronized, a practical test was conducted to check how the two systems act with each other. From the practical test, using a voltmeter, it was found that with no input from the AVEIT potentiometer, through AVEIT steering, there is zero voltage difference between the input and output potentiometer of the systems. To confirm th e practical test a quali tative test has been made using the digital oscilloscope. As mentioned before, the potentiometers were connected to the analog inputs (A1 and A2) of the digital oscilloscope and the data was captured into the computer. After setting up the program to a desired setting, the program was started to capture data and create a viewable signal on the oscilloscope window of the computer. From the data st ored and the signal captured there shows a constant voltage reading and signal oscillati on between the two potentiometers. The data shows the two channels have an average vol tage of 5.5V for each potentiometer and a constant oscillation of the signal observed on the window. Th e difference in voltage, F1, between the two channels show s a value of zero voltage difference. As it was mentioned

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65 earlier, a constant cursor that needs to be used as a bench mark was assigned at the top peak of the signal waves. As shown in Figur e 5.14 the yellow signal which represents the math character function on the oscillosc ope reads the difference between the two channels. Since there in no input from the AVEIT steering the voltage difference between the two potentiometers is equal to ze ro and as a result there is no upward or downward curve of the signal difference. This result confirmed the prac tical test that was done during the testing of the systems using the voltmeter. During the practical test that has been made to check the voltage difference between the two potentiometers using the voltmet er, a rotational input was applied to the potentiometer thorough an AVEIT steering. These tests were conducted by rotating the steering clockwise and counter-clockwise once at a time and check the voltage difference response between the two potentiometers. First the AVEIT steering was rotated clockwise from the mid position and the response between the two voltage differences shows that the needle of the voltmeter increases its voltage. To check this test a qualitative test is conducted usin g the digital oscilloscope. After setting the oscillos cope an input was applied to the AVEIT potentiometer. The oscilloscope starts to cha nge its signal in relation to the two channels or potentiometers and data wa s recorded on the computer. It is already known from the practical test using voltmeter, a clockwise rotation of the steering creates a positive voltage difference between the two potentiometers. Figure 5.15 shows the relationship betw een the two potentiometers. As the AVEIT steering gives a positive input of voltage to the potentiometer the figure shows that the two signals increase its position by moving upward from the previous cursor line

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66 that is set as a bench mark. From Figure 5. 15 it can be seen that the peak of the two signals increases upward and pa ssed the cursor line that was marked as a benchmark. The yellow signal wave defines the voltage difference between the two potentiometers and the upward signal represents for the positive voltage difference between the potentiometer. This voltage difference im plies that the value of voltage required initiating a rotation onto motor. From the da ta collected an average value of voltage difference required to rotate the motor was clos e to 1.2V. The oscilloscope program also shows a time delay between the tw o channel changes and it shows that there is an average time delay of about 10 milliseconds. From th is qualitative method it could be confirmed that the practical test that has b een conducted was accurate as expected. Conversely when the steering was rotated counter-clockwise th e needle of the voltmeter moved toward left which represent a negative change in voltage. Similarly to pervious method data was stored onto oscillos cope and the signal of the oscillation was plotted. From the visual part, Figure 5.16, of the signal waves it could be observed that the peak point of the two channels lie below th e cursor line. This indicates that as the AVEIT steering input was counter-clockwise the voltage of the two channels decrease toward negative value. The yellow line, F1 shows a downward curve which represents the voltage difference between the two potentio meters was negative as compared to the other previous signals. From data collected a voltage difference of -1.25V was required to initiate the motor to star t running. Similarly from the measurement value of the program it could be understood th at there is a time delay be tween the two potentiometers which is approximately close to 10 millisecond s. This time was close enough to make a change in voltage which cr eates a rotation in motor.

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67 From the analysis it was understood th at the two systems, AVEIT and SSI, function simultaneously as expected. As th ere is an input rotation from the AVEIT steering, the change in voltage that was created between the two potentiometers makes the motor to run and simultaneously the output will transfer to SSI steering. This practical test is supported by doing the qualitati ve test. From analyzing the test it is confirmed that the change in input of AVEIT steering rotation to either clockwise or counter-clockwise direction gi ves a simultaneous output of SSI steering rotation. This test supports the thesis hypothesis by pr oviding a qualitative result and showing how effective the training method will be for persons with disability, i.e. as the there is an input to steering from joystic k the output obtained was cons istent for both clockwise and counter-clockwise direction. This test also helps the objectives of the thesis to meet its goal by showing the accurate in terface between the mechanical and electrical system and also confirms the outcome of the practical te st as expected which makes the system ready for training.

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68 Chapter 6 Conclusions and Recommendations 6.1. Conclusions All AVEIT parts and SSI monitor were mounted inside the van as desired. The longitudinal bar was strong enough to carry a ll the loads and the space was suitable for operation during training. The AVEIT coupler was installed at the back of the AVEIT steering system. When the joystick change s its direction, it shows a simultaneous translation of rotation between the steering and the potentiometer. The electrical system was put inside a commercialized box with wiring outlet so that it would be easy to attache with the wiri ng of the battery and the potentiometers. In addition to this, the motor, SSI coupler and SSI system was assembled together. When all the design and assembly was fi nished the AVEIT driving aide and the SSI unit are synchronized together electro mechanically and have shown a smooth transition of rotations between the two sy stems. This synchronization enables the mechanical system of the AVEIT system to in itiate the electrical system and change the voltage outputs and from the electrical system it also converts to mech anical action of the SSI system. Since the torque capacity of the SSI steering is about 10 in-lbf and the motor has a torque capacity of 50 in-lbf, the friction clutch was adjusted closely to 10 in-lbf and from the rotation test it could be observed th e system will not face overload. The testing

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69 of the system shows that a voltage difference of less than one volt is necessary to have between the two potentiometers. Therefore prior to starting the mechanism again it is necessary to check the voltage difference betw een the two potentiometers. After all this procedure was taken into consideration the system was tested and both the AVEIT and SSI system run successfully with a constant and smooth rotation. The result for the practical part of th e research was obtained as expected. However it is important this practical test to be supported by quantitative result. For this reason a digital oscilloscope was used to measure the action between the two systems by checking its potentiometer difference. The voltage difference captured using the oscilloscope confirmed that with a change in rotation there is a change in voltage between the two potentiometer. The results show when the steering rotates in a clockwise direction an upward voltage di fference occurs and when the steering rotates oppositely, a downward voltage difference occurs on the signal Overall the objectiv es of the research were met successfully. This research helps in learning joystick operated driving aide by giving the real feeling or feedback of the actual steering that is built on real vehicles as opposed to the virtual joystick mounted on driving simulator. In addition to simultaneous rotation, the use of electromechanical synchronization helps in its flexibility to a space constraint, i.e. if there is no enough space be tween the two systems, AVEIT and SSI, integrating the two systems electromechanically is of best advantage.

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70 6.2. Final Recommendation The primary control of the AVEIT driving system, i.e. steering and the gas/brake servo, have been successfully interfaced a nd synchronized with the SSI system. When the joystick started to activ ate on steering servo, the j oystick does not have high sensitivity. This necessitate s an application of some extr a force on the joystick for the steering to rotate, however on ce the joystick turns approxima tely 10 degree, the rotation of the steering wheel speeds up faster. This becomes a minor problem which needs an extra care and practice when operating the joys tick. To improve the electro-mechanical synchronization of the two systems it is r ecommended to use a joystick with high sensitivity. When the system starts to run, the electric circuit get overheat after the motor runs for over 30 minutes. It is recommended to modify the resistors so that it could withstand extra current. During operation the motor have loud noise which is not comfortable to operate close to the system. For the benefit of the operator it is recommended to improve the sound of the moto r by either changing the motor or build a sound proof cover. The power supply that was used during this re search was AC power supply. It is recommended to conduct a DC power supply and compare the result of the two powers. In order to check the robustness of the system it is recommended to conduct a multiple trials. As future work it is recommended to conduct testing on persons with disability and make conclusion based on the outcome of the result. As an additional recommendation, an evolution of AVEIT syst em with its driving simulator in one unit will be of great benefit for training persons with disability.

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71 List of References 1. Moss Rehab Resources Net, Driving with a Disability Fact Sheet, http://www.mossresourcenet.org/drive.htm 2. Handler B. S., Patterson J. B., 1995, Driving after brain injury, J. Rehabil ., 61, pp. 43-49. 3. Tressel, P., 1995, Driving Opportunities : New Technology is Opening the Road for People with Disabilities Who Want to Drive to Remain Independent, J. Rehabil ., pp. 51-53. 4. Virtual Environments Laboratory Driving Simulation http://users.rcn.com/olevine/thesis/intro.htm 5. Brown L. B., Ott B. R., 2004, Driving a nd Dementia, J. Geriatric Psychiatry and Neurol. 17, pp. 232-240. 6. A Virtual Reality System to Retrain Drivers after Spinal Cord Injury http://www.kmrrec.org/rehabengi neering/research.php?resid=6 7. Development of Driving Simulator for Spinal Cord Injury http://web.njit.edu/~simone/Pape rs/%5BSimone%202005%5D%20Development %20of%20a%20Portable%20Virtual%20Reality%20Driving% 20Interface%20to %20Retrain%20Drivers %20with%20Spinal%20Cord%20Injury.pdf 8. Ahn, H. B., Ku, J.H., et al., 2001 The Development of Virtual Reality Driving Simulator for Rehabilitation IEEE Paper Turkey. 9. U.S. Department of Health and Human Se rvices The Surgeon Generals Call to Action to Improve the Health and Welln ess of Persons with Disabilities, http://www.surgeongeneral.gov /library/disabilit ies/calltoactio n/WhatIsDisability. pdf 10. Ku J. H., Jang D. P., Lee B. S., Lee J. H., Kim I. Y., Kim S. I. ,2002, Development and Validation of Virtual Dr iving Simulator for the Spinal Injury Patient, CyberPsychology Behavior, 5, pp.151-156.

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72 11. Cooper R. A., 1995 Rehabilitation Engi neering Applied to Mobility and Manipulation, CRC Press. 12. Andrew Y.J., 2004, Rehabilitation Engi neers in Government Service, IEEE Engineering in Medicine and Biology Magazine, 23(4), pp 8-9. 13. Enderle J., Blanchard S. M., Bronzino J., 2000, Introduction to Biomedical Engineering, Academic Press. 14. The Association for Driver Rehabilitation Specialists, Disabilities and Driving Fact Sheets, http://www.driver-ed.org/i4a/ pages/index.cfm?pageid=258 15. Driving while Disabled, http://www.fairfaxcounty.gov/dsb/drivingdisabled.htm 16. Department of Veterans Affairs, Automobile Adaptive Equipment Program, http://www1.va.gov/vhapublications /ViewPublication.asp?pub_ID=340 17. Texas Department of Rehabilitative a nd Assistive Technolog y, Standards for Vehicle Modifications http://www.dars.state.tx.us /drs/providermanual/ch4.htm 18. State of Rhode Island Department of Hu man Services, Vehicle Modifications, http://www.ors.state.ri.us/Pdffiles/VEHICLEMOD7.07.pdf 19. U.S. Department of Transportation, Update on Safety Issues for Vehicles Adapted for Use by People with Disabilities, http://www.nhtsa.dot.gov/cars/rules/ adaptive/BTSRN/AdaptedDisability.pdf 20. Upadhyay A. 2004, Development of Asse ssment Tasks to Measure the Driving Capabilities of Persons with Disabilities 21. Vehicle Adaptation for Disabled People Code of Practice. http://www.equalityhumanrights.com/Doc uments/Disability/T ransport/Vehicleren tal.doc 22. ABLEDATA, Assistive Information Technology, http://www.abledata.com/abled ata.cfm?pageid=113582&orgid=110795 23. Electronic Mobility Co ntrol Owners Manual, http://www.emc-digi.com/ 24. ALLINA Hospitals and Clinics, Driving Simulator, http://www.abbottnorthwestern.co m/ahs/ski.nsf/page/ar_driving 25. Excel Driving School, Driving Simulator, http://www.excel-driving-school.com/id29.htm 26. MSC Industrial Supply, 2007/2008, The Big Book

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73 27. Operation manual S-3100/S-3300 Series http://www.simulatorsystems.com/Auto/handcontrolp1.htm 28. Link Instruments, Inc. 2006, DSO Software Manual

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74 Appendices

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75 Appendix A: Step-Wise Procedures A.1. Procedure for Booting the AEVIT Driving System Make sure the battery is fully charged, if not charge the battery using the charger accompanied with the system. Check all the connections for the system ; the steering device and the gas/brake device should be connected to their respective drive modules. Now connect the two probes of the vehicl e simulator to the battery, be careful regarding the polarity to pr event any short circuit. After connecting the vehicle simulator put the three switches ON (simulator power, ignition and engaged buttons). This makes the system ready for booting. At this point the information center displa y is on. Now rotate the steering input device in clockwise and counter-clockwise direction until the message on the display shows steering device OK. Next push the gas and brake lever forward and backward until the message shows gas/brake device OK. After both the devices show ok on the messa ge the system is booted and ready for further operation. To put the system off, switch off the same three switches and also the remote switch. This will shut the system completely. A.2. Procedure for Booting the SSI Computer After all the components have been prope rly placed and connected the system is ready to turn the power on and start the simulator.

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76 Appendix A (Continued) On the back panel of the control consol flip the switch from O to the I position. At this time nothing happens to the system. Push and hold for one second the reset/power on switch located at the back of the consol to turn on the control consol. Turn the power on to the video monitor. At this point the main computer is bo oting up and various video images being displayed on the monitor. If this video image does not come up, it is necessary to check the monitor connections and make sure power is on. Once the simulator software has finished loading a touch pad screen image will be displayed on the monitor. Either using the built in Touch Pad or USB mouse click on the screen and this leads to the Log in Screen. As user name and password were entered the system will allow the user to take to the simulation by clicking on GO TO THE SIMULATION button. The main menu will then appear and chos e one level from the 5 available main areas. Then the system will show different areas of driving and also helps the user to get acquainted with the system [27]. A.3. Procedure for Calibrating the AVEIT and SSI Systems Make sure all the power connection to the electrical circuit is dismantled. Loosen the connection between the potentiometer and the AVEIT steering.

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77 Appendix A (Continued) Boot the AVEIT steering according to the appendix A.1. Once the AVEIT is calibrated to zero positio n start to calibrate the potentiometer to center position by turning five turns from the end position. After the potentiometer positioned at center, fasten the screw that attaches the steering shaft and the shaft of the coupler. Boot the SSI system according to the appendix A.2. The steering of the SSI system is at ce nter position and does not need calibration. Loosen the screws that tight th e two gears in the SSI coupler. Calibrate the SSI potentiometer by turning five turns from the end to make it at the center position. Then tighten the screws of the gears attached to the shaft. Once all are calibrated connect the electric wiring to the power. A.4. Procedure for the Use of the Synchronized Circuit Check the voltage between the two potentiometers. The center wire connected to #3 of AD706 is to be connected with th e potentiometer for AVEIT system. The voltage should be less than one volt. Assume that the shafts of the potentiometers are not fixed to the steering shaft. The sh aft of the potentiometer can be moved by fingers. Fix the shafts of potentiometers to the steering shafts. Rotate the shaft of the potentiometer connected to AVEIT system and check the voltage difference. The right direction is for increasing of the vo ltage difference. Keep the cover on the

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78 Appendix A (Continued) synchronized circuit and watch the solenoids, see they are on and off as expected, as the potentiometer turned to two different directions. If the above operation is normal, connect the wires to the motor. Plug in the power to the synchronized circuit very brie fly to see the motor is rotating in the same direction as AVEIT steering system. If every thing is normal, plug in the power 115 VAC, rotate AVEIT steering with a small angle and stop. Watch carefully what the response of the SSI steering. The SSI steering is expected to rotate back and forth in the small angle of rotation. If everything is normal then watch it to operate by itself for a while and then practice to drive the AVEIT system. Before stop the two systems make cert ain the two steering wheels are in the middle positions. Unplug the power and tu rn off the powers for the two systems. Do not move the steering wheels on both systems. Before start the systems again, turn on the AVEIT system, boot the system, and keep the steering wheel in the middle. Turn on the SSI system and keep the steering wheel in the middle position. Plug in the power 115 VAC for the synchronized circuit. Start the operati on of the AVEIT system. And watch the response of the SSI system.

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79 Appendix B: Oscilloscope Captured Signals B.1. Mid Steering Position This is a plot captured from the digital PC oscilloscope for mid steering position. The plot represents a voltage signal of two channels (A1 and A2) representing the input and output potentiometer. A1 represents input potentiometer for AVEIT steering and A2 represents output potentiometer for SSI stee ring. The difference between the A1 and A2 is representing by F1. As you see on the plot A1 has blue line color, A2 has orange line color and F1 has yellow line color. Base d on system test preference the voltage per division was set to 5V and time per division was set to 5 milliseconds per division. For the sake of clear view, the two channels are o ffset differently. Offset for channel A1 is zero while A2 is offset by 2V; hence this offs et helps the view of the two channels as clear as possible. From the pl ot it is easy to see A2 above A1; however this difference in offset does not influence the voltage value of the channels. The plot has a cursor line crossing horizontally with a different color line of green, red and cyan. These cursor lines were set as a bench mark for all thr ee steering rotation and become fixed at same position for the entire test. This will help to examine how the peak point of the voltage signal changes with changing the rotation. From the test it can be observed that when the steering is not rotating or the position of the steering is at mid position, there is no change in voltage between the two channels A1 and A2. The cursor line touches the peak point of each channel A1 and A2 and the difference in voltage of F1. Since there is no difference in voltage between the two channe ls, the yellow line, F1, has a straight line which means zero difference in voltage between the two potentiometers. The zero value

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80 Appendix B (Continued) of the voltage difference between the two systems shows that the two systems are synchronized successfully, i.e. when the di fference between the two voltages in the steering system are the same it tells that the system are synchronized successfully.

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Appendix B (Continued) Figure B.1. Mid Steering Position Signals 81

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Appendix B (Continued) Figure B.1. (Continued) 82

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Appendix B (Continued) Figure B.1. (Continued) 83

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Appendix B (Continued) Figure B.1. (Continued) 84

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85 Appendix B (Continued) B.2. Right Steering Rotation Similar to the Appendix B.1 this is a plot captured from the digital PC oscilloscope for right steering position. All th e setup for the three steering rotation is set the same. The channel representation, time pe r division, voltage per division and cursor line and its color was set the same. For re ference it can be looked on Appendix B.1 above. As mentioned previously on the practical test of system, the rotation of the steering to right or clock-wise direction re sult in positive change in voltage difference between the two potentiometer. From the qualitative test using the digital oscilloscope test it can be observed that wh en the steering is rotated to right or clockwise direction, there is a change in voltage between the two channels A1 and A2. Observing the signal lines, the two channels move upward and pass th e cursor line that was set the benchmark. Similarly the yellow line, F1, which represen t the difference in voltage between the two channels or potentiometers, was curved upw ard as compared to the previous steering position. This indicates that as the steering rotates to right, there is a positive difference in voltage and as a result the output of the rotation is positive.

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Appendix B (Continued) Figure B.2. Right Steering Rotation Signals 86

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Appendix B (Continued) Figure B.2. (Continued) 87

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Appendix B (Continued) Figure B.2. (Continued) 88

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Appendix B (Continued) Figure B.2. (Continued) 89

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90 Appendix B (Continued) B.3. Left Steering Rotation This is a plot captured from the digital PC oscilloscope for left steering position. All the setup for the three steering rotation is set the same. The channel representation, time per division, voltage per division and curs or line and its color was set the same. For reference it can be looked on Appendix B.1 above. As mentioned previously on the practical test of the system, the rotation of the steering to left or counter cl ock-wise direction result in negative change in voltage difference between the two potentiometers. Fr om the qualitative test using the digital oscilloscope test it can be obs erved that when the steering is rotated to left or counterclockwise direction, there is a change in vol tage between the two channels A1 and A2. Observing the signal lines, the two channels move downward below the cursor line. Similarly the yellow line, F1, which represen t the difference in voltage between the two channels or potentiometers, was curved downw ard as compared to the previous steering positions. This indicates that as the steering rotates to left, there is a negative difference in voltage and as a result the out put of the rotati on is negative.

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Appendix B (Continued) Figure B.3. Left Steering Rotation Signals 91

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Appendix B (Continued) Figure B.3. (Continued) 92

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Appendix B (Continued) Figure B.3. (Continued) 93

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Appendix B (Continued) Figure B.3. (Continued) 94

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95 Appendix C: Recorded Data of Potentiometer Voltage Similar to Appendix B, this is a data captured from the reaction of the system when the steering was rotated in different di rection. The data captured include time, offset value of the two channels (A1 and A2), the voltage value of the channels, and the voltage difference between the two channels (F1). In this data A1 and A2 is replaced by V1 and V2 respectively to represent voltage Before running the program the setup for Appendix B and Appendix C is the same a nd the value obtained on Appendix C is a numerical representati on for Appendix B. C.1. Data Collected for Mid Steering Position This data shows when the st eering is not rotated or in mid position. From the data it can be understood that the change in voltage, F1, has an average value of zero. This result is a numerical representation to the signals obtained an Appendix B.1. Table C.1. Mid Steering Position Time Offset V1 Offset V2 V1 V2 F1 Sec V V V V V 0 0 2 8.6 6.2 0.4 0.005 8.6 6.6 0 0.01 8.6 6.8 -0.4 0.015 8.6 6.8 0 0.02 8.6 7 -0.2 0.025 8.6 7 -0.4 0.03 8.4 7.4 -0.4 0.035 8.6 7 0 0.04 8.4 7.6 -0.4 0.045 8.6 7.6 -0.4 0.05 8.6 7.6 -0.2 0.055 8.6 7.8 -0.4 0.06 8.6 8 -0.4 0.065 8.4 8 -0.4

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96 Appendix C (Continued) Table C.1. (Continued) Time Offset V1 Offset V2 V1 V2 F1 Sec V V V V V 0.07 8.4 8.2 -0.4 0.075 8.4 8.2 -0.6 0.08 8.4 8.4 -0.6 0.085 8.2 8.2 -0.2 0.09 8.2 8 0 0.095 8.2 8.2 -0.4 0.1 8.2 8.2 0 0.105 8.2 8.4 -0.2 0.11 8.2 8.2 0 0.115 7.8 8.4 -0.4 0.12 8 8.8 -0.6 0.125 7.8 9 -0.4 0.13 7.8 9.2 -0.6 0.135 7.6 9 -0.4 0.14 7.6 8.8 -0.2 0.145 7.6 9 -0.4 0.15 7.6 9.2 -0.6 0.155 7.4 9 -0.6 0.16 7.4 8.8 -0.2 0.165 7.4 8.8 -0.4 0.17 7.2 8.8 -0.2 0.175 6.8 8.8 -0.2 0.18 6.8 8.8 -0.2 0.185 6.6 8.8 -0.2 0.19 6.4 9 -0.6 0.195 6.2 8.8 -0.4 0.2 6 8.8 -0.4 0.205 6 8.6 -0.2 0.21 5.8 8.6 -0.4 0.215 5.8 9.2 -0.6 0.22 5.6 9.4 -0.8 0.225 5.4 9.2 -0.6 0.23 5.4 9 -0.4 0.235 5.2 9.2 -0.6 0.24 5.2 9.4 -0.8 0.245 5 9.2 -0.8 0.25 4.6 9 -0.4 0.255 4.6 9 -0.6 0.26 4.6 9 -0.4

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97 Appendix C (Continued) Table C.1. (Continued) Time Offset V1 Offset V2 V1 V2 F1 Sec V V V V V 0.265 4.2 9 -0.4 0.27 4 9 -0.4 0.275 3.8 9 -0.4 0.28 3.8 9.2 -0.8 0.285 3.6 9 -0.6 0.29 3.6 9 -0.6 0.295 3.4 8.8 -0.4 0.3 3.2 8.8 -0.6 0.305 2.8 9 -0.8 0.31 2.8 8.8 -0.6 0.315 2.8 8.6 -0.4 0.32 2.6 8.6 -0.4 0.325 2.2 8.8 -0.6 0.33 2.2 8.4 -0.6 0.335 2 8.4 -0.4 0.34 1.8 8.2 -0.4 0.345 1.6 8.2 -0.4 0.35 1.6 8.2 -0.6 0.355 1.4 8 -0.4 0.36 1.2 8.2 -0.6 0.365 1.4 8 -0.4 0.37 1 8 -0.6 0.375 1 7.8 -0.4 0.38 1 7.6 -0.2 0.385 0.6 7.6 -0.4 0.39 0.6 7.6 -0.8 0.395 0.4 7.2 -0.4 0.4 0.2 7 -0.4 0.405 0.2 6.4 0 0.41 0.2 6.8 -0.6 0.415 0.2 6.6 -0.6 0.42 0.4 6.6 -0.6 0.425 0.6 6.2 -0.4 0.43 0.6 6 -0.2 0.435 5.8 6.2 -0.6 0.44 5.6 6 -0.6 0.445 5.4 5.6 -0.2 0.45 5.4 5.6 -0.4 0.455 0.6 5.6 -0.4 0.46 0.8 5.4 -0.4

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98 Appendix C (Continued) Table C.1. (Continued) Time Offset V1 Offset V2 V1 V2 F1 Sec V V V V V 0.465 0.8 5 -0.4 0.47 1 4.8 -0.2 0.475 1.4 5 -0.4 0.48 1.6 4.8 -0.6 0.485 1.6 4.6 -0.6 0.49 1.8 4.2 -0.4 0.495 1.8 4.2 -0.4 0.5 2 4.2 -0.6 C.2. Data Collected for Right Steering Rotation Similarly to previous data, this shows when the steering is rotated to the right or clockwise direction. As it was discussed ear lier the change in voltage, F1, between the two channels has an average value of positive 1.2V. The value indicates that as the steering is rotated to right, the change in voltage is positive. Table C.2. Right Steering Rotation Time Offset V1 Offset V2 V1 V2 F1 sec V V V V V 0 0 2 6.25 5.05 1.2 0.005 6.25 5.25 1 0.01 6.65 5.45 1.2 0.015 6.85 5.65 1.2 0.02 6.85 6.05 0.8 0.025 7.05 6.05 1 0.03 7.45 6.05 1.4 0.035 7.65 6.25 1.4 0.04 7.65 6.45 1.2 0.045 7.65 6.65 1 0.05 7.85 6.85 1

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99 Appendix C (Continued) Table C.2. (Continued) Time Offset V1 Offset V2 V1 V2 F1 sec V V V V V 0.055 8.25 6.85 1.4 0.06 8.45 7.05 1.4 0.065 8.65 7.25 1.4 0.07 8.65 7.25 1.4 0.075 8.85 7.65 1.2 0.08 8.85 7.65 1.2 0.085 8.85 7.85 1 0.09 9.25 8.05 1.2 0.095 9.25 8.05 1.2 0.1 9.45 8.25 1.2 0.105 9.45 8.45 1 0.11 9.45 8.05 1.4 0.115 9.45 8.45 1 0.12 9.85 8.85 1 0.125 10.05 8.65 1.4 0.13 10.05 8.65 1.4 0.135 10.25 8.85 1.4 0.14 10.25 8.65 1.6 0.145 10.25 9.05 1.2 0.15 10.25 9.05 1.2 0.155 10.25 8.85 1.4 0.16 10.45 8.85 1.6 0.165 10.45 8.85 1.6 0.17 10.85 9.25 1.6 0.175 10.65 9.45 1.2 0.18 10.65 9.25 1.4 0.185 10.85 9.65 1.2 0.19 10.65 9.45 1.2 0.195 10.85 9.25 1.6 0.2 10.85 9.45 1.4 0.205 10.85 9.65 1.2 0.21 10.85 9.25 1.6 0.215 10.85 9.25 1.6 0.22 10.85 9.65 1.2 0.225 11.05 9.65 1.4 0.23 11.05 9.65 1.4 0.235 11.05 9.65 1.4 0.24 11.05 9.65 1.4 0.245 11.05 9.65 1.4

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100 Appendix C (Continued) Table C.2. (Continued) Time Offset V1 Offset V2 V1 V2 F1 sec V V V V V 0.25 11.05 9.65 1.4 0.255 11.05 9.65 1.4 0.26 11.25 10.05 1.2 0.265 10.85 9.65 1.2 0.27 11.25 9.65 1.6 0.275 11.05 9.65 1.4 0.28 11.05 9.65 1.4 0.285 11.25 9.65 1.6 0.29 11.25 9.65 1.6 0.295 11.05 9.65 1.4 0.3 11.05 9.65 1.4 0.305 11.05 9.65 1.4 0.31 10.85 9.65 1.2 0.315 10.85 9.45 1.4 0.32 10.85 9.65 1.2 0.325 11.05 9.65 1.4 0.33 10.85 9.45 1.4 0.335 10.65 9.45 1.2 0.34 10.85 9.45 1.4 0.345 10.85 9.25 1.6 0.35 10.45 9.45 1 0.355 10.45 9.25 1.2 0.36 10.25 8.85 1.4 0.365 10.45 9.25 1.2 0.37 10.25 9.05 1.2 0.375 10.25 8.85 1.4 0.38 10.45 8.85 1.6 0.385 10.45 8.85 1.6 0.39 10.85 9.25 1.6 0.395 10.65 9.45 1.2 0.4 10.75 8.85 1.9 0.405 10.35 8.25 2.1 0.41 10.35 8.25 2.1 0.415 10.15 8.45 1.7 0.42 10.35 8.25 2.1 0.425 10.15 8.05 2.1 0.43 9.95 7.65 2.3 0.435 9.95 7.45 2.5 0.44 9.55 7.65 1.9

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101 Appendix C (Continued) Table C.2. (Continued) Time Offset V1 Offset V2 V1 V2 F1 sec V V V V V 0.445 9.15 7.25 1.9 0.45 8.95 7.25 1.7 0.455 8.75 6.85 1.9 0.46 8.55 6.65 1.9 0.465 8.55 6.85 1.7 0.47 8.35 6.45 1.9 0.475 8.15 6.25 1.9 0.48 7.95 6.25 1.7 0.485 7.95 5.85 2.1 0.49 7.55 5.85 1.7 0.495 7.55 5.65 1.9 0.5 7.35 5.45 1.9 C.3. Data Collected for Left Steering Rotation The data was captured when the steering is rotated to left or counter-clockwise direction. Same as above the data shows th e values of the voltage at each time and the voltage difference between the two channels. From the data it can be understood that when the steering is rotated to the left or counter-clockwise, a nega tive change in voltage, F1, is obtained. The average change in volta ge, F1, when the steering is rotated counterclockwise is about 1.25V. This value is similar but opposite in sign to the change in voltage obtained from Appendix C.2. Table C.3. Left Steering Rotation Time Offset V1 Offset V2 V1 V2 F1 sec V V V V V 0 0 2 4.6 4.8 -0.2 0.005 3.75 4.8 -1.05 0.01 3.55 5.2 -1.65

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102 Appendix C (Continued) Table C.3. (Continued) Time Offset V1 Offset V2 V1 V2 F1 sec V V V V V 0.015 3.95 5 -1.05 0.02 3.95 5 -1.05 0.025 4.35 5.2 -0.85 0.03 4.35 5.2 -0.85 0.035 4.15 5.6 -1.45 0.04 4.15 5.8 -1.65 0.045 4.35 5.8 -1.45 0.05 4.55 5.8 -1.25 0.055 4.55 5.8 -1.25 0.06 4.75 5.8 -1.05 0.065 4.75 6 -1.25 0.07 4.75 6 -1.25 0.075 4.95 6.2 -1.25 0.08 4.95 6.2 -1.25 0.085 4.95 6.4 -1.45 0.09 4.95 6.4 -1.45 0.095 5.15 6.4 -1.25 0.1 5.35 6.4 -1.05 0.105 5.15 6.6 -1.45 0.11 5.15 6.6 -1.45 0.115 5.55 6.8 -1.25 0.12 5.15 6.8 -1.65 0.125 5.55 7 -1.45 0.14 5.55 6.8 -1.25 0.145 5.35 6.8 -1.45 0.15 5.75 7 -1.25 0.155 5.75 7.2 -1.45 0.16 5.75 7 -1.25 0.165 5.75 7 -1.25 0.17 5.75 7 -1.25 0.175 5.75 7 -1.25 0.18 5.75 7 -1.25 0.185 5.75 7.2 -1.45 0.19 5.75 7.2 -1.45 0.195 5.75 7.2 -1.45 0.2 5.75 7.4 -1.65 0.205 5.75 7.4 -1.65 0.21 5.75 7.2 -1.45 0.215 6.15 7.4 -1.25 0.22 5.95 7.4 -1.45

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103 Appendix C (Continued) Table C.3. (Continued) Time Offset V1 Offset V2 V1 V2 F1 sec V V V V V 0.225 5.75 7.4 -1.65 0.23 5.75 7.2 -1.45 0.235 5.95 7.6 -1.65 0.24 5.75 7.2 -1.45 0.245 5.75 7.6 -1.85 0.25 5.75 7.4 -1.65 0.255 6.15 7.2 -1.05 0.26 5.95 7.2 -1.25 0.265 5.75 7.2 -1.45 0.27 6.15 7.2 -1.05 0.275 5.75 7.4 -1.65 0.28 5.75 7.4 -1.65 0.285 5.95 7.6 -1.65 0.29 5.75 7.2 -1.45 0.295 5.95 7.4 -1.45 0.3 5.95 7.2 -1.25 0.305 5.55 7.2 -1.65 0.31 5.75 7.2 -1.45 0.315 5.55 7 -1.45 0.32 5.75 7.4 -1.65 0.325 5.75 7.2 -1.45 0.33 5.35 7 -1.65 0.335 5.55 7 -1.45 0.34 5.75 7 -1.25 0.345 5.55 6.8 -1.25 0.35 5.75 6.6 -0.85 0.355 5.35 6.8 -1.45 0.36 5.35 6.8 -1.45 0.365 5.35 6.8 -1.45 0.37 5.15 6.6 -1.45 0.375 5.15 6.6 -1.45 0.38 5.15 6.6 -1.45 0.385 5.15 6.4 -1.25 0.39 5.15 6.4 -1.25 0.395 4.95 6.4 -1.45 0.4 4.95 6.2 -1.25 0.405 4.95 6.2 -1.25 0.41 4.75 6.2 -1.45 0.415 4.95 6 -1.05 0.42 4.35 5.8 -1.45

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104 Appendix C (Continued) Table C.3. (Continued) Time Offset V1 Offset V2 V1 V2 F1 sec V V V V V 0.425 4.55 5.8 -1.25 0.43 4.35 5.4 -1.05 0.435 4.35 5.2 -0.85 0.44 3.95 5.2 -1.25 0.445 4.15 5.2 -1.05 0.45 3.75 5.2 -1.45 0.455 3.75 5 -1.25 0.46 3.75 4.8 -1.05 0.465 3.55 4.6 -1.05 0.47 3.55 4.6 -1.05 0.475 3.35 4.8 -1.45 0.48 3.15 4.4 -1.25 0.485 3.15 4.2 -1.05 0.49 2.95 4 -1.05 0.495 2.95 3.8 -0.85 0.5 2.75 3.8 -1.05

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105 Appendix D: Disabilities and Driving Facts As mentioned many times driving is a cher ished part of everybodys daily life. However persons with disability have limitation in their driving needs and t hey require some special assistance in their driving activ ities. As there are different types of disability, a specific need is required for a part icular type of disabili ty. Before a vehicle has been modified, a thorough study should have been undergone by the rehabilitation or occupational therapist to determine what t ype of disability the person has and what driving aide is important for modifying thei r needs. The following sub-chapter discusses different types of disability and their drivi ng needs after evaluation has been made by driver rehabilitation specialist. The factors of disabilities and its effect on driving for certain populations are presented in the sections to follow. This information is excerpted from the Association for Driver Rehabilitation Specialists, Disabi lities and Driving Fact Sheets [14] and from Vehicle Adaptation for Disabled People Code of Practice http://www.equalityhumanrights.com/Documen ts/Disability/Transpor t/Vehiclerental.doc [21]. D. 1. Aging and Driving As we all age, changes occur in physical functioning, vision, perception, and processing abilities that could make driving uns afe. While changes are inevitable, they occur at different rates in each individual, a nd age alone is not a good indicator of driving skills [14]. Most often these changes occur slowly over a long period of time, and the

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106 Appendix D (Continued) individual is able to compensa te for minor deficits. If seve ral skill areas are affected, or there is a sudden change in abilities due to illness or disease, driving may become impaired. An evaluation is recommended if the person has a noticeable warning signs of any the following: Doesn't observe signs, signa ls, or other traffic Needs help or instruc tions from passengers Slow or poor decisions Easily frustrated or confused Frequently gets lost, even in familiar areas Inappropriate driving speeds (too fast or too slow) Poor road position, or wide turns Accidents or near misses A driver rehabilitation specialist can provide a comprehensive evaluation and make recommendations regarding drivi ng based on the following assessment: A review of medical history and medications Functional ability Vision Perception Reaction time Behind-the-wheel evaluation [14]

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107 Appendix D (Continued) D.2. Driving and Alzheimer's or Dementia Deciding if and when it is time to stop driving is an extremely difficult and emotional time. When Alzheimer's or demen tia occurs, a decision will need to be made as to when an individual is no longer capable of operating an automobile safely. The individuals' independence needs to be m easured against the potential hazards to themselves, and the community. Studies conducted using driving simulators have detected that demented patients had more driving problems than non-demented elderly controls [14]. An evaluation by the driver rehabilitati on specialist can be of great value in helping to make this difficult decision. A driver evaluation will assess the components of driving that may be compromised by this pr ogressive condition. Areas assessed should include: attention, proce ssing speed, visuospatial f unctioning, decision making, judgment, planning, memory, and behavior [14]. An evaluation is recommended when a di agnosis or problems first arise. Compensatory strategies can be used to help maintain safe driving, and to set limits in preparation for the inevitable. Discussing the issue, and planning for the future, is important to do while the individual has the in sight needed to participate. There are warning that needs to be considered when th e person is to be evaluated who have some disability and those warnings include: Driving too slowly Doesn't observe signs or signals Difficulty interpreting traffic situations and predicting changes

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108 Appendix D (Continued) Failure to yield Easily frustrated or confused Frequently gets lost Needs instructions from passengers [14] D. 3. Driving After a Traumatic Brain Injury Traumatic Brain Injury (TBI) and Closed Head Injury commonly occur due to motor vehicle collisions. Injuries can range fr om a loss of consciousness of less than five minutes to being comatose for many months [14]. Any level of injury can cause an increase in pre-injury bad driving behaviors or create new, unsafe driving issues. These issues can stem from problems with vision, accuracy and speed of eye movements, speed of response, attention, memory, problem solvi ng, judgment and/or loss of physical skills. It can spare one skill and wipe another sk ill completely from memory. It commonly makes learning new information difficult and ma y keep a survivor from quickly learning from their mistakes. All of the above can result in unsafe driving encounters, unpredictable driving actions or repeat collisions for the survivor. Warning signs for someone who has been in an accident or has had a TBI: Inappropriate driving speeds Is slow to identify and avoid pot entially hazardous situations Needs help or instru ction from passengers Doesn't observe signs or signals or speed limits Leaves out important road, tr affic or warning information

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109 Appendix D (Continued) Slow or poor decisions to traffic or road changes Easily frustrated or confused Pattern of getting lost, even in familiar areas Collisions or near misses Blames their driving mistakes on th e behavior of other drivers [14] D. 4. Driving After a Spinal Cord Injury The ability to drive a motor vehicle is a fundamental skill that influences various aspects of daily functioning and independent li ving status. For the i ndividual with spinal cord injury, the inability to drive a car can significantly hi nder return to employment and participation in community activitie s. After a spinal cord injury has occurred, a person is no longer able to drive an automobile in the normal manner. However, there are several types of adaptive equipment and vehicle modifica tions that can allow an individual with a spinal cord injury to drive. Depending on the level of injury and functional ability, either a sedan or van may be an appropriate vehicl e choice and there are some considerations for selecting a vehicle. When considering the use of driving a sedan, the individual must be able to do the following: Lock and unlock the door Open and close the door Transfer to and from the wheelchair Store and retrieve the wheelchair (either independently or with a wheelchair loading device)

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110 Appendix D (Continued) If an individual is unable to drive a se dan, there are several options available for driving a van. Specialized modifications can a llow a person to transfer to the driver seat or to drive from the wheelchair. There are se veral levels of drivi ng control technology to compensate for the loss of strength and/ or range of motion where some include: Reduced-Effort steering systems to compensate for reduced strength Servo brake and accelerator control to co mpensate for reduced range of motion and strength Joystick driving systems, allowing one hand operation of brake, accelerator and steering Adaptive equipment and vehicle modificati ons for wheelchair access are available for some full-size and mini vans; however, al l vans are not suitable for modifications. A driver rehabilitation specialist can assist in making the correct van choice. He/she can provide a comprehensive evaluation to dete rmine a persons ability to drive. The Assessment should include: Vision percepti on, functional ability, reaction time, and a behindthe-wheel evaluation [14]. D. 5. Driving with Rheumatoid Arthritis Rheumatic disease includes nearly 100 different conditions, which cause pain in the joints and connective tissue throughout the body. The key factor in the most serious forms of rheumatic disease is inflammation ev idence by heat, swelling, redness, stiffness, and pain. Depending on the areas affected a nd functional ability, ei ther a sedan or van may be an appropriate vehicle choice. Loss of joint mobility may result in diminished

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111 Appendix D (Continued) ability to reach, grasp, manipulate, and rele ase objects. Strength, endurance, and range of motion difficulties may necessitate adaptive de vices: such as extra mirrors, key holders, extended gear shift levers, power windows a nd door locks. More extensive adaptive equipment or vehicle modifications may be need ed for persons whose ability to use their arms and legs is severely affected by the diseas e. Same as driving after spinal injury there are some considerations to be taken for selecting a vehicle. When considering the use of driving a seda n the individual must be able to do the following task in order to be r ecommended by occupational therapist. Lock and unlock the door Open and close the door Transfer to and from the wheelchair if applicable Store and retrieve the wheelchair (either independently or with a wheelchair loading device) Since characteristics and dimensions of ve hicles vary, it is important that the individual performs these functions in the ve hicle being considered prior to purchase. A driver rehabilitation speciali st can provide recommendations for sedan selection. If an individual is unable to drive a se dan, there are several options available for driving a van. Specialized modifications can a llow a person to transfer to the driver seat or to drive from the wheelchair. There are se veral levels of drivi ng control technology to compensate for the loss of stre ngth and/or range of motion: Reduced-Effort steering systems to compensate for reduced strength

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112 Appendix D (Continued) Servo brake and accelerator control to co mpensate for reduced range of motion and strength. Joystick driving systems, allowing one hand operation of brake, accelerator and steering [14]. D. 6. Driving with Multiple Sclerosis Multiple Sclerosis can affect individuals in varying ways including tingling, numbness, slurred speech, blurred or double vi sion, muscle weakness, poor coordination, unusual fatigue, muscle cramps, bowel and blad der problems and paraly sis. Due to these symptoms, special equipment or accommodations may need to be made to aid a person in safely maintaining their mobility independence for as long as possible. During selecting a vehicle there are physical considerations to look for, i.e. when selecting a van for driving the individual must be able to do the following: Open and close the door Transfer in and out of the vehicle A wheelchair or scooter must be able to be stored and retrieved. Special equipment is available to aid with storage Options may include a mini-van with a lo wered floor and a ramp or a full size van with a lift. Specialized modifications allow a person to transfer to the driver's seat or drive from a wheelchair. Technology may be ab le to compensate fo r the loss of strength or range of motion such as: Reduced-Effort steering and/or brake system s to compensate for reduced strength

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113 Appendix D (Continued) Mechanical hand controls allow for oper ation of the gas and brake using upper extremities Servo brake/ accelerator systems compen sate for reduced strength/range of motion of arms If spasticity is difficult to manage, it ma y lead to an inability to drive [14] D .7. Driving After a Limb Amputation After a limb amputation, a person is someti mes unable to drive an automobile in the normal manner. There are, however, severa l types of adaptive devices that can allow an individual with an amputation to safely resume driving. The site of amputation(s) will determine the degree of difficulty an amputee w ill have with driving a standard equipped vehicle. In most cases, the adapted equipm ent will involve compensation for the inability to reach and operate primary and secondary dr iving controls. Person with specific type of limb amputation their vehicle is adapted on their specific needs. For a right leg amputation the equipment which is necessary to adapt includes: Left foot gas pedal Automatic transmission Power braking For a left leg amputation the equipment which is necessary to adapt includes: Hand controls for brake and accelerator spinner knob Automatic transmission Hand operated dimmer switch

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114 Appendix D (Continued) Emergency Brake Extension Chest strap For an upper extremity amputation the e quipment which is necessary to adapt includes: Automatic transmission Steering device Reduced effort steering Modified gear shifter Modified secondary contro ls (turn signals, dimmers) For a triple or quadruple amputation the equipment which is necessary to adapt includes: Additional modifications can be made to car or van Reduced effort steering system Servo brake and accelerator control Joystick driving systems [14] D.8. Driving After a Stroke Driving is viewed not just as a 'privilege but also as a necessity. When a stroke occurs it can affect the skills necessary for independent driving. A majority of stroke survivors can return to independent driving. The goal is to maintain safe and independent driving for as long as possible [14]. Drivi ng ability has been assessed differently. The most common method has been driving in real tr affic. Another method has been to use a

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115 Appendix D (Continued) driving simulator, in which the driving situa tion can be standardized, but is not quite as realistic as real traffic driving [21]. Adaptive equipment is frequently used for physical problems. A spinner knob can be attached to the steering wheel to a llow controlled steering with the use of one hand. A left gas pedal may be used if you are unable to use your ri ght foot to gas or brake. Training is essential with any equipm ent to be safe with your new adapted driving method [14]. There are a warning signs that can be important to look for after having a stroke and a rehabilitation sp ecialist can determine if the person has some of those sign which includes: Inappropriate driving speed s (too fast or too slow) Needs help or instruc tions from passengers Doesn't observe signs or signals Slow or poor decisions (poor judge of distances, too close to other cars) Easily frustrated or confused Pattern of getting lost, even in familiar areas Accidents or near misses Drifting across lane markings, into other lanes Noticing any of the above warning signs re quire a driver evaluation. A driver rehabilitation specialist can provide a comp rehensive evaluation to determine the ability to drive [14].

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116 Appendix D (Continued) D .9. Driving and Spina Bifida Spina Bifida is a congenital defect in wh ich part of one or more vertebrae (the bone structure that surrounds the spinal column ), fail, to develop completely, leaving part of the spinal cord exposed. It can occur anywhere on the spine but is most common in the lower back. The severity of the c ondition depends on how much nerve tissue is exposed. Frequently special adaptations on a vehicle are necessary for independent driving. The person with spina bifida may al so have impairments in the areas of vision, perception (how the brain interprets what the eyes see) or learning [21]. Adaptive driving equipment is frequently used for physical problems. A spinner knob and hand controls can be used if a person is unable to use either foot for gas or brake. Specialized modifications can also allow a person to transfer to the driver's seat or drive from the wheelchair in a van or minivan where common factors that can affect safe driving are: Limited range of motion and strength Difficulty with coordinated movements Visual impairments (poor acuity) Trouble visually scanning or tracking quickly Learning difficulties Impaired judgment in complex situations Slow processing and reaction time A driver rehabilitation evaluation will ex amine the strengths and weaknesses of each individual as related to the driving task. The goal is independent, safe driving. No

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117 Appendix D (Continued) modifications or vehicle selec tion should be made until the person has completed a driver evaluation and t he assessment should include: Vision Perception Functional ability Behind-the-wheel evaluation [14] D .10. Driving and Cerebral Palsy Cerebral Palsy (CP) applies to a num ber of non-progressive motor disorders present from birth. The involvement varies widely from person to person. The person with CP may or may not be a wheelchair user. Frequently special vehicle adaptations are necessary for independent driving. The pers on with CP may also have impairments in the areas of vision, perception (how the brain interprets what the eyes see) or learning. Adaptive equipment is frequently used for physical problems. A spinner knob can be attached to the steering wheel to a llow controlled steering with the use of one hand. A left gas pedal may be used if a pers on is unable to use the right foot for gas or brake. Hand controls may be indicated for th e person unable to use either foot for gas or brake. Specialized modifications can also allo w a person to transfer to the driver seat or drive from the wheelchair in a van or miniva n with common factors th at can affect safe driving: Limited range of motion and strength Exaggerated startle reflex to loud noise

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118 Appendix D (Continued) Increased muscle tone Difficulty in coordinated movements Visual impairments (poor acuity) Trouble visually scanning or tracking quickly Learning difficulties Impaired judgment in complex situations Slow processing and reaction time A driver rehabilitation evaluation will ex amine the strengths and weaknesses of each individual as related to the driving task. The goal is independent, safe drive. No modifications or vehicle selec tion should be made until the person has completed a driver evaluation where the assessment should include: Vision Perception Functional ability Reaction time Behind-the-wheel evaluation [14] D.11. Driving and Attention Deficit Hyperactivity Disorder Attention Deficit Hyperactivity Disord er (ADHD) commonly becomes evident in early childhood and probably will be chroni c in nature. The disorder consists of developmental deficiencies th at can range from inhibiting behaviors to initiating and

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119 Appendix D (Continued) sustaining behaviors. The individual may im prove with age. Any level of ADD or ADHD may increase the risk of unsafe driving issues. These issues stem from under developed visual perception skil ls, impaired ability to self -regulate behavior, moods and responses. Lack of organization and the in ability to con centrate are also underlining issues. Their ability to learn informati on for the licensing knowledge test works well when one on one instruction is provided. L earning from their driving mistakes takes extra time. All of the above can result in unsafe driving encount ers, unpredictable driving actions or an increas ed number of "minor" accidents and there are warning signs that interfere safe driving: Doesn't observe signs/signals Drifting while driving Failure to yield right of way Difficulty with interpreting traffic envir onments / does not anticipate dangerous situations Impaired eye/ hand/foot coordination Neglects to observe all areas of the vehicle before driving in reverse Multiple minor accidents Slow to respond to traffic lights Speed fluctuation / Inappropriate speeds Unable to coordinate di stractions and driving