Generalized Vehicle Dynamics

Description

Author Daniel E. Williams, an industry professional with more 30 years of experience in chassis control systems from concept to launch, brings this experience and his unique approach to readers of Generalized Vehicle Dynamics. This book makes use of nomenclature and conventions not used in other texts. This combination allows the derivation of complex vehicles that roll with multiple axles, any of which can be steered, to be directly predicted by manipulation of a generalized model. Similarly the ride characteristics of such a generalized vehicle are derived. This means the vehicle dynamic behavior of these vehicles can be directly written from the results derived in this work, and there is no need to start from Newton's Second Law to create such insight. Using new and non-standard conventions allows wider applicability to complex vehicles, including autonomous vehicles. Generalized Vehicle Dynamics is divided into two main sections-ride and handling-with roll considered in both. Each section concludes with a case study that applies the concepts presented in the preceding chapters to actual vehicles. Chapters include Simple Suspension as a Linear Dynamic System, The Quarter-Car Model, The Pitch Plane Model, The Roll Plane Mode, Active Suspension to Optimize Ride, Handling Basics, Reference Frames, New Conventions, Two-Axle Yaw Plane Model, Rear Axle Steering and Lanekeeping, Two-Axle Vehicles that Roll, Three-Axle Vehicle Dynamics, Generalized Multi-Axle Vehicle Dynamics and Automated Vehicle Architecture from Vehicle Dynamics. Cover Contents Foreword Acknowledgments 1 Introduction 1.1 Overview 1.2 Historical Perspective 1.3 Structure of the Text References 2 Simple Suspension as a Linear Dynamic System 2.1 Introduction 2.2  The Simply Suspended Mass and Linear Systems Theory 2.3 A Suspended Mass with Damping 2.4 Basic Frequency Responses 2.5  State Space and Block Diagram Algebra 2.6 State Space Realization 2.7  First-Order Matrix Differential Equations 2.8 Summary 3 The Quarter-Car Model 3.1 Introduction 3.2  Representing Reality with the Quarter-Car Model 3.3  Two Fundamental Frequencies of Interest 3.4 The Conventional Quarter-Car Model 3.5  Stochastic Road Input and Human Sensitivity to Vibration 3.6 Nonlinear Damping 3.7 Summary References 4 The Pitch-Plane Model 4.1 Introduction 4.2 Basic Pitch-Plane Model 4.3 Pitch-Plane-Free Response 4.4 Road Inputs to the Pitch-Plane Model 4.5  Pitch-Plane Ride Quality and the Olley Ride Criteria 4.6 Pitch-Plane Model with Damping 4.7  Generalized Pitch-Plane Model and Olley Solution 4.8 Three-Axle Vehicle Example 4.9 Summary References 5 The Roll-Plane Model 5.1 Introduction 5.2 Simple Two-Axle Roll-Plane Model 5.3 The Roll Mode for a Single Axle 5.4  The Roll-Plane Model with Stabilizer Bar 5.5 Single-Wheel Inputs 5.6 Passenger Car Roll 5.7 Generalized Roll-Plane Model 5.8 Roll and Handling 5.9 Summary 6 Active Suspension to Optimize Ride 6.1 Introduction 6.2 Inertial Damping 6.3 Lotus Modal Control 6.4 Modal Inertial Damping 6.5  Sprung Mass Acceleration Feedforward 6.6 Quarter-Car Optimal Control 6.7 Full Vehicle Optimal Control 6.8 Modal Inertial Damping and Handling 6.9 Summary References 7 Handling Basics 7.1 Introduction 7.2 Ackermann Steering 7.3 Steering Efforts 7.4 Slip Angles 7.5 Tire Forces 7.6 The Conventional Bicycle Model 7.7 Summary References 8 Reference Frames 8.1 Introduction 8.2 Reference Frames in General 8.3  Velocity of a Point Translating in a Rotating Reference Frame 8.4  Velocity and Acceleration of a Point in a Translating and Rotating Reference Frame 8.5 External Forces and Inertia 8.6 The Vehicle as a Rigid Body 8.7 Summary Reference 9 New Conventions 9.1 Introduction 9.2 State-of-the-Art Conventions 9.3 New Axle Location Convention 9.4 New Attack Angle Convention 9.5 Summary References 10 Two-Axle Yaw-Plane Model 10.1 Introduction 10.2 The Two-Axle Vehicle Model 10.3  Drift Angle and Yaw Rate Transfer Functions 10.4 Ideal Two-Axle Model 10.5 Steady-State Analysis 10.6 Pole Locations 10.7 Summary References 11 Rear Axle Steering and Lanekeeping 11.1 Introduction 11.2  Vehicle Model with Rear Axle Steering 11.3  Determination of Rear Axle Steer Control 11.4  Open-Loop Response of Ideal Vehicle 11.5 Specified Preview 11.6  Determination of Rear Axle Control of Ideal Vehicle 11.7 Numerical Results 11.8  Theoretical Interpretation of Practical Systems 11.9 Summary References 12 Two-Axle Vehicles that Roll 12.1 Introduction 12.2 Roll Axis Definitions 12.3 Acceleration Equations 12.4 External Roll Forces on Sprung Mass 12.5 Camber Effects 12.6 Roll Steer Effects 12.7  Differential Equations of Motion with Roll 12.8 Roll Steer Compensation 12.9  Including Steering Compliance in Understeer 12.10 Inclusion of Nonlinear Tires 12.11 Summary Reference 13 Three-Axle Vehicle Dynamics 13.1 Introduction 13.2  Peculiarities of the Three-Axle Vehicle 13.3 The Three-Axle Model 13.4 Third Axle Steering 13.5 Trajectory Tracking 13.6 Summary References 14 Generalized Multiaxle Vehicle Dynamics 14.1 Introduction 14.2 General Model 14.3 An Arbitrarily Steered Axle 14.4  All Arbitrary Axles Steered Proportionally 14.5 The Multiaxle Vehicle with Roll 14.6 Summary References 15 Automated Vehicle Architecture from Vehicle Dynamics 15.1 Introduction 15.2  Properties of a Typical Three-Axle Commercial Vehicle 15.3 Control of Rear Axle 15.4  Rear Axle Control for Yaw Rate Equivalence 15.5 Vehicle Results 15.6 Proposed Three-Axle Vehicle 15.7 Summary References Afterword Index About the Author