Study on Control Strategy of Handling Stability for an Eight In-Wheel Motor Drive AWS Electric Vehicle

Abstract

This paper took an eight in-wheel motor independent driven and all-wheel independent active steering vehicle as research object, and proposed a hierarchical optimized tire force distribution control strategy (8WD8WS+) based on sliding mode control and control allocation to coordinate the output torques and steering angle of eight wheels. The hierarchical control strategy included an upper vehicle motion controller, a lower tire force distribution controller, and a tire force tracking controller. The upper controller adopted the sliding mode control algorithm focusing on the vehicle motion state control. The lower controller used the optimal control allocation method to realize the tire force distribution control under the constraint condition, and proposed the error approximation objective function and performance objective function. And the tire force distribution was solved by the active set method. The desired tire force tracking controller used the sliding mode control algorithm to realize the tracking of the desired slip ratio and sideslip angle calculated by the inverse tire model, and calculates the actuator output. Finally, the control strategy was verified by simulation based on the MATLAB/Simulink model, and the closedloop slalom test at high speed verified the effectiveness of the control strategy.