Trajectory tracking control considering the transmission backlash of the dual-motor autonomous steering system

Abstract

In order to solve the tracking error caused by transmission backlash in the dual-motor autonomous steering system, and thus improve the trajectory tracking accuracy of autonomous vehicles, a novel steering control strategy combining sliding model control (SMC) with variable weights and linear quadratic regulator (LQR) is proposed in this paper. Firstly, the vehicle dynamics model is built and the steering system model with contact and backlash modes is established by combining it with the simplified gear backlash system. Secondly, the front wheel angle control based on SMC is designed and the weights of contact mode and backlash mode are optimized by Particle Swarm Optimization (PSO) algorithm. Finally, the results of simulation under typical conditions show that the proposed strategy has better accuracy of angle tracking and stronger adaptability to the change of system load. Furthermore, it is also proved by simulation and Hardware-in-Loop (HiL) test under different trajectory tracking conditions that the LQR controller with proposed strategy has better accuracy of trajectory tracking for autonomous vehicles.