Vehicle dynamics and stability have been of considerable interest for a number of years. The obvious dilemma is that people naturally desire to drive faster and faster yet expect their vehicles to be “infinitely” stable and safe during all normal and emergency maneuvers. For the most part, people pay little attention to the limited handling potential of their vehicles until some unusual behavior is observed that often results in accidents and even fatalities.
This book presents several model-based estimation methods which involve information from current potential-integrable sensors. Improving vehicle control and stabilization is possible when vehicle dynamic variables are known. The fundamental problem is that some essential variables related to tire/road friction are difficult to measure because of technical and economical reasons. Therefore, these data must be estimated.
It is against this background, that this book’s objective is to develop estimators in order to estimate the vehicle’s load transfer, the sideslip angle, and the vertical and lateral tire/road forces using a roll model. The proposed estimation processes are based on the state observer (Kalman filtering) theory and the dynamic response of a vehicle instrumented with standard sensors. These estimators are able to work in real time in normal and critical driving situations. Performances are tested using an experimental car in real driving situations. This is exactly the focus of this book, providing students, technicians and engineers from the automobile field with a theoretical basis and some practical algorithms useful for estimating vehicle dynamics in real-time during vehicle motion.
Vehicle Dynamics Estimation using Kalman Filtering......Page 2
Copyright......Page 3
Table of Contents......Page 5
Preface......Page 10
I.1. Needs of ADAS systems......Page 14
I.3. This book versus existing studies......Page 16
I.4. Laboratory vehicle......Page 17
I.5. Outline......Page 18
1.1. Introduction......Page 20
1.2.1.1. Vertical/normal forces......Page 21
1.2.1.2. Longitudinal forces and longitudinal slip ratio......Page 22
1.2.1.3. Lateral forces and sideslip angle......Page 23
1.2.1.4. Aligning moment......Page 24
1.2.1.5. Coupling effects between longitudinal and lateral tire forces......Page 25
1.2.2. Tire?road friction coefficient......Page 26
1.2.2.2. Normalized lateral traction force......Page 28
1.2.3. Quasi-static tire model......Page 29
1.2.3.1. Pacejka’s magic tire model......Page 30
1.2.3.2. Dugoff’s tire model......Page 36
1.2.4. Transient tire model......Page 37
1.3. Wheel rotational dynamics......Page 38
1.3.2. Effective tire radius......Page 39
1.4. Vehicle body dynamics......Page 40
1.4.1. Vehicle’s vertical dynamics......Page 41
1.4.1.2. Quarter-car vehicle model......Page 42
1.4.2.1. Four-wheel vehicle model......Page 44
1.4.2.2. Wheel-ground vertical forces calculation......Page 46
1.4.2.3. Bicycle model......Page 49
1.4.3. Roll dynamics and lateral load transfer evaluation......Page 50
1.5. Summary......Page 53
2.1. Introduction......Page 55
2.2. State-space representation and system observability......Page 56
2.2.2. Nonlinear system......Page 57
2.3. Estimation method: why stochastic models?......Page 58
2.3.1. Closed-loop observer......Page 59
2.3.2. Choice of the observer type......Page 60
2.4. The linear Kalman filter......Page 61
2.5. Extension to the nonlinear case......Page 62
2.6.1. Unscented transformation......Page 64
2.6.2. UKF algorithm......Page 66
2.7.1. Motivation......Page 68
2.7.2. Observer design......Page 69
2.7.3.1. Comparison with LPA signal......Page 71
2.7.3.2. Comparison with GMP signal......Page 74
2.8. Summary......Page 77
3.1. Introduction......Page 79
3.2. Algorithm description......Page 80
3.3. Techniques for lateral load transfer calculation in an open-loop scheme......Page 82
3.3.2. Roll angle calculation......Page 83
3.3.3. Limitation of the open-loop mode......Page 84
3.4. Observer design for vertical forces estimation......Page 85
3.5. Vertical forces estimation......Page 87
3.5.1. Observer OFzE design......Page 88
3.5.2. Observer OFzL formulation......Page 90
3.6. Analysis concerning the two-part estimation strategy......Page 91
3.8. Determining the vehicle’s mass......Page 92
3.8.1. Experimental validation of the vehicle’s weight identification method......Page 93
3.9. Detection of rollover avoidance: LTR evaluation......Page 94
3.10. Experimental validation......Page 96
3.10.1. Regulation of Observers......Page 98
3.10.2. Evaluation of observers......Page 99
3.10.3.1. Starting-slalom-braking test......Page 100
3.10.3.2. Circle-braking test......Page 104
3.10.3.3. Turn test......Page 105
3.10.4. Comparison between linear and nonlinear observers: OFzL versus OFzE......Page 111
3.10.6. LTR evaluation......Page 112
3.10.7. Road geometry effects......Page 115
3.11. Summary......Page 117
4.1. Introduction......Page 118
4.2. Background on lateral force parameters calculation......Page 119
4.2.1. Lateral force parameters evaluation......Page 120
4.2.1.1. Sideslip angle estimation......Page 121
4.2.1.2. Tire?road friction estimation......Page 122
4.2.1.4. Effect of camber angle......Page 123
4.3. Lateral force reconstruction in an open-loop scheme......Page 124
4.3.1. Test at low lateral acceleration level......Page 125
4.4. Techniques for lateral tire force evaluation......Page 129
4.5. Estimation process for sideslip angle and individual lateral tire force estimation......Page 132
4.5.1. Estimation algorithm......Page 133
4.5.2. Vehicle model......Page 134
4.5.3. Dynamic tire model representation......Page 135
4.5.4. Reference lateral tire force model......Page 136
4.5.5. Further consideration for the cornering stiffness Cα......Page 137
4.5.6. Lateral force observers: state-space representation......Page 138
4.5.8. Estimation methodologies......Page 141
4.6. Experimental validation......Page 142
4.7.1. Left?right bend combination test......Page 145
4.7.2. Single left bend test......Page 149
4.7.3. Slalom test......Page 154
4.7.4. Circle test......Page 158
4.7.5. Longitudinal forces estimation......Page 160
4.7.6. Concluding remarks on experimental results......Page 169
4.7.8. Tuning of observers......Page 170
4.8. Analysis and observations......Page 171
4.8.1. Robustness with respect to road friction variation......Page 173
4.9. Summary......Page 175
5.2. Laboratory vehicle......Page 176
5.2.1. Embedded sensors......Page 177
5.2.3. DLL configuration......Page 181
5.3. Estimation process: VSO system......Page 182
5.4. Test tracks......Page 184
5.5. Test results......Page 185
5.5.1. Bourbriac test......Page 186
5.5.2. Callac test......Page 196
5.5.3. Rostrenen test......Page 202
5.5.4. Concluding remarks......Page 216
5.6. Summary......Page 217
APPENDICES......Page 218
Appendix 1......Page 219
Appendix 2......Page 223
Appendix 3......Page 225
Appendix 4......Page 232
Appendix 5......Page 235
Appendix 6......Page 238
Bibliography......Page 239
Index......Page 248
