Vehicle Dynamics and Control

Transcription

1 Rajesh Rajamani Vehicle Dynamics and Control Springer

2 Contents Dedication Preface Acknowledgments v ix xxv 1. INTRODUCTION Driver Assistance Systems Active Stabiüty Control Systems RideQuality Technologies for Addressing Traffic Congestion Automated highway Systems Traffic fnendly adaptive cruise control Narrow tilt-controlled comuuter vehicles Emissions and Fuel Economy Hybrid electric vehicles Fuel cell vehicles 11

3 xi i VEHICLE D YNAMICS AND CONTROL References LATERAL VEHICLE DYNAMICS Lateral Systems Under Commercial Development Lane departure warning Lane keeping Systems Yaw stability control Systems Kinematic Model of Lateral Vehicle Motion Bicycle Model of Lateral Vehicle Dynamics Motion of Particle Relative to a rotating Frame Dynamic Model in Terms of Error with Respect to Road Dynamic Model in Terms of Yaw Rate and Slip Angle From Body-Fixed to Global Coordinates Road Model Chapter Summary 46 Nomenclature 47 References STEERING CONTROL FOR AUTOMATED LANE KEEPING State Feedback Steady State Error from Dynamic Equations Understanding Steady State Cornering Steering angle for steady State cornering Can che yaw angle error be zero? 64

4 Contents xiii Is non-zero yaw error a concern? Consideration ofvarying Longitudinal Velocity Output Feedback Unity feedback Loop System Loop Analysis with a Proportional Controller Loop Analysis with a Lead Compensator Simulation of Performance with Lead Compensator Analysis if Closed-Loop Performance Performance Variation with vehicle speed Performance Variation with sensor location Compensator Design with Look-Ahead Sensor Measurement Chapter Summary 90 Nomen clature 90 References LONGITUDINAL VEHICLE DYNAMICS Longitudinal Vehicle Dynamics Aerodynamic drag force Longitudinal tire force Why does longitudinal tire force depend on slip? Rolling resistance Calculation of normal tire forces Calculation of effective tire radius 108

5 xiv VEHICLE DYNAMICS AND CONTROL 4.2 Driveline Dynamics Torque Converter Transmission dynamics Engine dynamics Wheel dynamics Chapter Summary 120 Nomenclature 120 References INTRODUCTION TO LONGITUDINAL CONTROL Introduction Adaptive cruise control Collision avoidance Automated highway Systems Benefits of Longitudinal Automation Cruise Control Upper Level Controller for Cruise Control Lower Level for Cruise Control Engine torque calculation for desired acceleration Engine control Anti-Lock Brake Systems Motivation ABSfunctions 141

6 Contents xv Deceleration threshold based algorithms Other logic based ABS control Systems Recent research publications on ABS Chapter Summary 148 Nomenclature 149 References ADAPTIVE CRUISE CONTROL Introduction Vehicle Following Specifications Control Architecture String Stability Autonomous Control with Constant Spacing Autonomous Control with the Constant Time-Gap Policy String stability of the CTG spacing policy Typical delay values Transitional Trajectories The need for a transitional Controller Transitional Controller design through R R diagramsl Lower Level Controller Chapter Summary 180 Nomenclature 180 References 181

7 xvi VEHICLE DYNAMICS AND CONTROL Appendix 6,A LONGITUDINAL CONTROL FOR VEHICLE PLATOONS Automated Highway Systems Vehicle Control on Automated Highway Systems Longitudinal Control Architecture Vehicle Following Specifications Background on Norms of Signals and Systems Norms of Signals System norms Use of System norms to study signal amplification Design Approach for Ensuring String Stability Constant Spacing with Autonomous Control Constant Spacing with Wireless Communication Experimental Results Lower Level Controller Adaptive Controller for Unknown Vehicle Parameters Redefined notation Adaptive Controller Chapter Summary 214 Nomenclature 215 References 216 Appendix 7.A 218

8 Contents xvii 8. ELECTRONIC STABIL1TY CONTROL Introduction The functioning of a stability control System Systems developed by automotive manufacturers Types of stability control Systems Differential Braking Systems Vehiclemodel Control architecture Desired yaw rate Desired stde-slip angle Upper bounded values of target yaw rate and slip angle Upper Controller design Lower Controller design Steer-By-Wire Systems Introduction Choiceof output fordecoupling Controller design Independent All Wheel Drive Torque Distribution Traditional four wheel drive Systems Torque transfer between left and right wheels Active control of torque transfer to all wheels Chapter Summary 251

9 xviii VEHICLE DYNAMICS AND CONTROL Nomeclature 252 References MEAN VALUE MODELING OF SI AND DIESEL ENGINES SI Engine Model Using Parametric Equations Engine rotational dynamics Indicated combustion torque Friction and pumping losses Manifold pressure equation Outflow rate from intake manifold Inflow rate into intake manifold SI Engine Model Using Look-Up Maps Introduction to engine maps Second order engine model using engine maps First order engine model using engine maps Introduction to Turbocharged Dieset Engine Maps Mean Value Modeling of Turbocharged Diesel Engines Intake manifold dynamics Exhaust manifold dynamics Turbocharger dynamics Engine crankshaft dynamics Control System objectives Lower Level Controller with SI Engines 279

10 Contents xix 9.6 Chapter Summary 281 Nomenclature 282 References DESIGN AND ANALYSIS OF PASSIVE AUTOMOTIVE SUSPENSIONS Introduction to Automotive Suspensions Füll, half and quarter car Suspension modeis Suspension functions Dependent and independent suspensions Modal Decoupi ing Performance Variables for a Quarter Car Suspension Natural Frequencies and Mode Shapes for the Quarter Car Approximate Transfer Functions Using Decoupling Analysis ofvibrations in the Sprung Mass Mode Analysis of Vibrations in the Unsprung Mass Mode Verification Using the Complete Quarter Model Verification of the influence of Suspension stiffness Verification of the influence of Suspension damping Verification of the influence of tire stiffness Half-Car and Full-Car Suspension Models Chapter Summary 321 Nomenclature 322 References 323

11 xx VEHICLE DYNAMICS AND CONTROL 11. ACTIVE AUTOMOTIVE SUSPENSIONS Introduction Active Control: Trade-Offs and Limitations Transfer functions of interest Use of the LQR Formulation and its relation to H 2 Optimal Control LQR formulation for active Suspension design Performance studies of the LQR Controller Active System Asymptotes 339! 1.4 Invariant Points and Their Influence on the Suspension Problem Analysis of Trade-Offs Using Invariant Points Ride quaüty/ road holding trade-offs Ride quaüty/rattle Space trade-offs Conclusions on Achievable Active System Performance Performanceof a Simple Velocity Feedback Controller Hydraulic Actuators for Active Suspensions Chapter Summary 352 Nomenclature 353 References SEMI-ACTIVE SUSPENSIONS Introduction Semi-Active Suspension Model 359

12 Contents xx 12.3 Theoretical Results: Optimal Semi-Active Suspensions Problem formulation Problem definition Optimal Solution with no constraints on damping Optimal Solution in the presence of constraints Interpretation of the Optimal Semi-Active Control Law Simulation Results Calculation of Transfer Function Plots with Semi-Active Suspensions Performance of Semi-Active Suspension Systems Moderatel yweightedridequality Sky hook damping Chapter Summary 383 Nomenclature 383 References LATERAL AND LONGITUDINAL TIRE FORCES Tire Forces Tire Structure Longitudina! Tire Force at Small Slip Ratios Lateral Tire Force at Small Slip Angles Introduction to the Magic Formula Tire Model Development of Lateral Tire Model for Uniform Normal Force Distribution 400

13 xxii VEHICLE DYNAMICS AND CONTROL Lateral forces at small slip angles Lateral forces at large slip angles Development of Lateral Tire Model for Parabolic Normal Pressure Distribution Combined Lateral and Longitudinal Tire Force Generation The Magic Formula Tire Model Dugoff' s Tire Model Introduction Model equations Friction Circle Interpretation of Dugoff s Model Dynamic Tire Model Chapter Summary 430 Nomenclature 430 References TIRE-ROAD FRICTION MEASUREMENT ON HIGHWAY VEHICLES Introduction Definition of tire-road friction coefficient Benefits of tire-road friction estimation Review of results on tire-road friction coefficient estimation Review of results on slip-slope based approach to friction estimation Longitudinal Vehicle Dynamics and Tire Model for Friction Estimation 438

14 Contents xxiii Vehicle longitudinal dynamics Determination of the normal force Tire model Friction coefficient estimation for both traction and braking Summary of Longitudinal Friction identification Approach Identification Algorithm Design Recursive least-squares (RLS) identification RLS with gain switching Conditions for parameter Updates Estimation of Accelerometer Bias Experimental Results System hardware and Software Tests on dry concrete surface Tests on concrete surface with loose snow covering Tests on surface consisting of two different friction levels Hard braking test Chapter Summary 461 Nomenclature 462 References