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II

DEVELOPMENT OF A MULTI-WALL VIRTUAL ENVIRONMENT AND
IMPLEMENTATION OF VEHICLE MODEL FOR A DRIVING SIMULATOR




by




SUMANTH RAGHAVENDRA




A THESIS

Presented to the Faculty of the Graduate School of the

UNIVERSITY OF MISSOURI-ROLLA

In Partial Fulfillment of the Requirements for the Degree


MASTER OF SCIENCE IN MECHANICAL ENGINEERING

2006

Approved by







_______________________________
_______________________________
Dr. M. Leu, Advisor
Dr. K. Krishnamurthy





_______________________________
Dr. S. Agarwal





























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ABSTRACT
This thesis describes the construction of a low-cost, four-wall immersive driving
simulator that can perform motions similar to a road vehicle. A driving simulation is a
good example of applications that utilize a dynamic model in a simulated environment.
Such simulations can be decomposed into a graphic model responsible for rendering a
specific space-configuration of entities within a virtual world as well as a dynamic model
responsible for determining the evolution of this configuration over time. This thesis
attempts to address some important aspects of building these two models, with an
emphasis on their cooperation.
To build the simulator car this study concentrates on the integrative methods of
evaluating a dynamic vehicle model. The virtual environment development is
accomplished by using Level of Detail (LOD) application. The experiments prove that
the designed simulator is adequate in performing some realistic vehicle effects as
discussed in the thesis.

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ACKNOWLEDGMENTS
First and foremost, I would like to say thank you to Dr. Ming Leu for his help,
support and guidance throughout the past two years. With his encouragement, I am able
to successfully accomplish my goal of completing my Masters degree. He has taught me
how to become successful in many aspects of life and I am very grateful to have him as
an advisor.
I would also like to thank Dr. Sanjeev Agarwal and Dr. K. Krishnamurthy for
their time in serving on my committee. Thanks are also due to Mr. Ken Gorman for
helping out with various development issues related to building the cockpit.
A special thanks goes to Krishna Nandanoor Reddy and Hua Zeng for being very good
co-researchers on this project. I also want to thank Dr. Wei Zhang, whose stay at UMR
benefited me to a very large extent in this project.
I would also like to take this opportunity to thank the Intelligent Systems Center
for providing financial funding for my graduate studies and as well as the staff and
employees of ISC for their support. It was a pleasure to be a part of the VRPL and would
like to thank Gowthami, Vishal, Amit, Sid, Kasi, Akul, Weihan, and all other co-
researchers at VRPL who have encouraged and helped me from time to time.
I would also like to thank my family and friends for their continuous emotional support.
Last but not least, I would like to thank Avni for her continued patience and support.


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TABLE OF CONTENTS
Page
ABSTRACT....................................................................................................................... iii
ACKNOWLEDGMENTS ................................................................................................. iv
LIST OF ILLUSTRATIONS........................................................................................... viii
LIST OF TABLES.............................................................................................................. x
SECTION
1. INTRODUCTION...................................................................................................... 1
1.1. DRIVING SIMULATOR ................................................................................... 1
1.2. VIRTUAL REALITY FOR DRIVING SIMULATION .................................... 2
1.3. PROJECT OBJECTIVE AND TASKS .............................................................. 3
1.4. THESIS OVERVIEW......................................................................................... 3
2. LITERATURE REVIEW........................................................................................... 4
2.1. EXISTING DRIVING SIMULATORS.............................................................. 5
2.2. COMPONENTS IN DRIVING SIMULATION TECHNOLOGY .................... 9
2.2.1. Visual and Sound.......................................................................................9
2.2.2. Force Feedback........................................................................................10
2.2.3. Vehicle Model .........................................................................................11
2.2.4. Scenario Control......................................................................................11
2.3. APPLICATIONS OF DRIVING SIMULATORS ........................................... 11
2.3.1. Usability Tests.........................................................................................12
2.3.2. Driver Behavior Tests .............................................................................12
3. IMPLEMENTATION OF THE VEHICLE MODEL .............................................. 13
3.1. THE TWO-WHEEL TRACTION MODEL..................................................... 13
3.2. SYSTEM BLOCK DIAGRAM ........................................................................ 15
3.3. EQUATIONS OF MOTION............................................................................. 17
3.3.1. Drag Forces .............................................................................................17
3.3.2. Weight Transfer.......................................................................................18
3.3.3. Tractive Properties of the Tire/Road Interface........................................19
3.4. ENGINE MODEL ............................................................................................ 20

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3.4.1. Engine Torque Curve ..............................................................................21
3.4.2. Gearbox Model........................................................................................23
3.4.3. Brake System Model ...............................................................................24
3.5. TURNING MOTION........................................................................................ 24
3.5.1. Low Speed Turning .................................................................................24
3.5.2. High Speed Turning. ...............................................................................26
3.6. PARAMETER SELECTION............................................................................ 28
3.7. THE SIMULATION CYCLE........................................................................... 28
4. BUILDING THE VIRTUAL ENVIRONMENT ..................................................... 31
4.1. TILED DISPLAY ENVIRONMENT............................................................... 31
4.1.1. Loading OpenGL Performer. ..................................................................34
4.1.2. Setting up the Basic Elements ..36
4.2. SCENE GRAPHS ............................................................................................. 37
4.2.1. Node. .......................................................................................................37
4.2.2. Creating a Scene Graph...........................................................................38
4.2.2.1 Buildings generator.....................................................................39
4.2.2.2 Roads and ground generator .......................................................41
4.2.2.3 Trees and lamp post generator ....................................................42
4.3. CAMERA STRUCTURE, VIEWING FRUSTUM.......................................... 42
4.4. SYSTEM ARC.................................................................................................. 43
4.4.1. Level-of-detail_Tiles. ..............................................................................45
4.4.2. Level-of-detail_Builder ...........................................................................47
4.4.3. LOD_Viewer ...........................................................................................48
4.4.4. Structure and Relationship. .....................................................................50
4.4.5. User Interaction Issues. ...........................................................................50
4.4.6. Design Decisions and Tradeoffs..............................................................50
4.5. CONTROL HARDWARE................................................................................ 50
4.5.1. Immersion Arcade PCB Board................................................................51
4.5.1.1 Happ control steering wheel assembly. ......................................52
4.5.1.2 Integration of pedals instrumentation with the arcade PCB .......54
4.5.2. Control Hardware Interface.....................................................................56

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4.5.3. Visualization Hardware...........................................................................56
4.5.3.1 Frame synchronization hardware................................................57
4.5.3.2 Genlock synchronization hardware......