Abstract：To improve the system stability and tracking accuracy of the four-wheel independent steering(4WIS) unmanned vehicle during path tracking and improve the tire wear, the path tracking control algorithm was proposed based on double-layer control strategy. The upper layer was a model reference adaptive path tracking controller based on Popov hyperstability theory. Based on the two-degree-of-freedom model, the path tracking error state equation was derived. The linear quadratic optimal method was used to solve the problem that the positive linear link of the system was not strictly positive reality. The Popov integral inequality was solved to ensure the hyperstability of system. In the lower layer controller, based on Ackermann steering theorem, the angle allocation control algorithm was designed with considering tire sideslip. The simulation experiment was carried out on the CarSim/Simulink co-simulation platform. The results show that the designed path tracking controller based on double-layer control strategy can realize the path tracking task with high precision and ensure the driving stability of 4WIS unmanned vehicle to improve the tire wear.
XIONG L, YANG X, ZHUO G R, et al. Review on motion control of autonomous vehicles[J]. Journal of Mechanical Engineering, 2020, 56(10): 127-143. （in Chinese）
［2］
GUO H Y, CAO D P, CHEN H, et al. Model predictive path following control for autonomous cars considering a measurable disturbance: implementation, testing, and verification[J]. Mechanical Systems and Signal Processing, 2019, 118: 41-60.
［3］
ABDUL HAMID U Z, ZAMZURI H, YAMADA T, et al. Modular design of artificial potential field and nonlinear model predictive control for a vehicle collision avoidance system with move blocking strategy[J]. Journal of Automobile Engineering, 2018, 232(10): 1353-1373.
［4］
AMIR M, VAHID F, GIVARGIS T. Switching predictive control using reconfigurable statebased model[J]. ACM Transactions on Design Automation of Electronic Systems, 2019, 24(1): 1-21.
［5］
ALIPOUR K, ROBAT A B, TARVIRDIZADEH B. Dynamics modeling and sliding mode control of tractor trailer wheeled mobile robots subject to wheels slip[J]. Mechanism and Machine Theory, 2019, 138: 16-37.
［6］
JI X W，HE X K，LYU C，et al. Adaptiveneuralnetworkbased robust lateral motion control for autonomous vehicle at driving limits[J]. Control Engineering Practice, 2018, 76:41-53.
［7］
KIM E, KIM J, SUNWOO M. Model predictive control strategy for smooth path tracking of autonomous vehicles with steering actuator dynamics[J]. International Journal of Automotive Technology, 2014, 15(7): 1155-1164.
［8］
POPOV V M. Hyperstability of control systems[J].Journal of Dynamic Systems Measurement & Control, 1974, 96(3): 372.
ZONG C F, SUN H, CHEN G Y. Steering angle allocation method for distributed independent steering vehicles[J].Journal of South China University of Technology (Natural Science Edition), 2017, 45 (2): 16-22. （in Chinese）
[10]
余志生.汽车理论\[M\].北京: 机械工业出版社,2018.
[11]
柴天佑,岳恒.自适应控制\[M\].北京: 清华大学出版社,2016.
[12]
陈家瑞.汽车构造\[M\].北京: 机械工业出版社,2013.
[13]
WANG R R, WANG J M. Tireroad friction coefficient and tire cornering stiffness estimation based on longitudinal tire force difference generation[J]. Control Engineering Practice, 2013, 21: 65-75.
