Active Brake Proportioning and Its Effects on Safety and Performance
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University of Windsor Scholarship at UWindsor Electronic Theses and Dissertations Theses, Dissertations, and Major Papers 1-1-2006 Active brake proportioning and its effects on safety and performance. Nathan C. Nantais University of Windsor Follow this and additional works at: https://scholar.uwindsor.ca/etd Recommended Citation Nantais, Nathan C., "Active brake proportioning and its effects on safety and performance." (2006). Electronic Theses and Dissertations. 7067. https://scholar.uwindsor.ca/etd/7067 This online database contains the full-text of PhD dissertations and Masters’ theses of University of Windsor students from 1954 forward. These documents are made available for personal study and research purposes only, in accordance with the Canadian Copyright Act and the Creative Commons license—CC BY-NC-ND (Attribution, Non-Commercial, No Derivative Works). Under this license, works must always be attributed to the copyright holder (original author), cannot be used for any commercial purposes, and may not be altered. Any other use would require the permission of the copyright holder. Students may inquire about withdrawing their dissertation and/or thesis from this database. For additional inquiries, please contact the repository administrator via email ([email protected]) or by telephone at 519-253-3000ext. 3208. ACTIVE BRAKE PROPORTIONING AND ITS EFFECTS ON SAFETY AND PERFORMANCE By N athan C. Nantais A Thesis Submitted to the Faculty of Graduate Studies and Research through Mechanical Engineering in Partial Fulfillment of the Requirements for the Degree of Master of Applied Science at the University of Windsor Windsor, Ontario, Canada 2006 © Copyright by Nathan C. Nantais, 2006 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 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Abstract A vehicle undergoing longitudinal or lateral accelerations experiences load transfer, dynam ically changing the load carried by each tire. Conventional braking systems are designed only to work adequately over a large range of conditions, but ignore the dynamic state of the tires. Fortunately, new developments in braking system hardware include electro-hydraulic and electromechanical brakes, which give designers full control over the application of braking pressures. The purpose of this research is to investigate possible advantages of active brake pres sure control. By estimating the tractive ability of the tires as a function of measurable vehicle conditions, brake pressure can be applied in proportions appropriate for the current dynamic state of the vehicle. The result is increased braking ability before the onset of tire lockup (or ABS activation). Stopping distances are improved for all braking situations, and vehicle stability is improved during extreme obstacle avoidance maneuvers. iii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. To my parents. iv Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Acknowledgements This work would not be possible without the support of Drs. Bruce Minaker and Greg Rohrauer, with whose assistance I selected this thesis topic. It was a great pleasure to complete my thesis work under the supervision of Dr. Minaker, whose acumen I have found to be second to none. I was only ever stuck on a problem for as long as it took me to find him and pick his brain. I was extremely fortunate to obtain the generous support of the AUT021 Network of Centres of Excellence, Natural Sciences and Engineering Research Council of Canada (NSERC), and Ontario Graduate Scholarships in Science and Technology (OGSST). The funding allowed me to pursue my automotive engineering research interests, which would not have been otherwise possible. I would be remiss if I did not thank my longtime colleagues Sinisa Draca, E.W.K. Oh, Robert Rieveley, and Alex Wood. In two years we shared a lot of knowledge and laughs. I would also like to acknowledge and thank our fellow AUT021 researchers at the University of Waterloo and the University of British Columbia. v Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Table of Contents Abstract iii Dedication iv Acknowledgements v List of Tables ix List of Figures x List of Symbols xv 1 Introduction 1 2 Literature Review 2 2.1 Braking Systems .................................................................................................. 2 2.2 Antilock Braking System ...................................................................................... 5 2.3 Electronic Braking Hardware and Control ....................................................... 7 3 The Pneumatic Tire 9 3.1 Construction ........................................................................................................ 9 3.2 Slip ........................................................................................................................ 11 3.3 Load sensitivity ..................................................................................................... 15 3.4 The Traction Circle ............................................................................................ 17 3.5 Tire Modeling ........................................................................................................ 19 3.5.1 Tire models for ride and durability ........................................................ 19 3.5.2 Tire models for handling ........................................................................... 20 4 Forming and Solving Equations of Motion 26 4.1 Newton’s Equations and Eigen A nalysis.................................................................. 26 4.2 Vehicle Dynamics and Linear M odels ................................................................ 30 4.2.1 The Bicycle Mo d el .................................................................................... 30 4.2.2 Quarter-Car and Bounce/Pitch Models ............................................ 33 4.3 Vehicle Modeling With C arS im .......................................................................... 34 4.3.1 Model - General ...................................................................................... 35 4.3.2 S uspension ................................................................................................ 36 vi Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 4.3.3 Aerodynamics ............................................................................................. 36 4.3.4 S teering ....................................................................................................... 37 4.3.5 B rakes......................................................................................................... 37 4.3.6 Powertrain ................................................................................................ 38 4.3.7 T ires ............................................................................................................. 39 4.3.8 Solver M e th o d ............................................................................. 39 5 Braking Dynamics 41 5.1 Braking Stability .................................................................................................. 41 5.2 Static Vehicle Properties...................................................................................... 43 5.3 Dynamics and Load Transfer ...........................................................................