Optimal allocation of tire force based on vehicle stability

 

 

LIU Zhentao, WEI Qiang, ZHU Shaopeng, JIANG Dongdong

 

(Institute of Power Machinery and Vehicular Engineering, Zhejiang University, Hangzhou 310027, China)

 

 

Abstract: Aiming at the problem of driving stability under high speed condition for electric vehicle, the electric vehicle which can be steered and drived/braked independently for each tire were researched. A tire force optimal allocation control strategy was proposed to improve vehicle stability under ultimate driving condition. Firstly, the desire value of yaw rate and slip angle of the vehicle were calculated according to driver′s steering, driving/braking based on two degrees freedom vehicle model. Then the errors between actual value and desire value of yaw rate and slip angle were figured out by compare them. The total longitude force, total lateral force and yaw moment of the vehicle were calculated via sliding mode control based on the errors. At the last, the longitude force and lateral force were figured out by optimal allocation method based on an eightdegree freedom vehicle model. The control strategy was validated by cosimulation of vehicle dynamic software CarSim and Simulink. The results indicate that under the condition of high speed and large steering angle, the stability control strategy could keep yaw rate and slip angle of vehicle close to the desire value, which improves vehicle stability under extreme condition obviously.

 

Key words: electric vehicle; vehicle stability; tire force; optimal allocation