Event-Triggered Adaptive Fuzzy Switching Fault-Tolerant Control of Dual-Motor Steer-by-Wire System Considering Load Fluctuation and Limited Communication Bandwidth

In order to promote the safety redundancy of steer-by-wire system, a dual-motor steer-by-wire (DMSBW) system is designed in this article. However, when one of the steering motors fails seriously, the vehicle's angle tracking performance is affected, which is exacerbated by load fluctuation and limited CAN communication bandwidth in the control system. Therefore, we innovatively establish DMSBW switching control model and propose an event-triggered adaptive fuzzy switching fault-tolerant control strategy. First, the interval type-2 fuzzy state observer is used to estimate the state of the nonlinear DMSBW system and the time-varying fluctuation of the load torque before and after switching. Then, the prescribed performance adaptive backstepping controller is designed to solve the control output by fusing the error and fault event-triggered controller to realize the unification of switching fault tolerance and accurate tracking while reducing communication resources. And the switching fault-tolerant performance under both transient and steady state is guaranteed by proving Lyapunov stability and boundedness. Finally, hardware-in-the-loop experiments show that the proposed method is effective.

I. Introduction

With the flexible operation and high degree of intelligence and electrification [1], [2], the steer-by-wire (SBW) system plays a crucial role in the advancement of intelligent vehicle. Although its freedom from mechanical connections of the traditional steering column provides greater design freedom and space utilization for the vehicle, it also makes it susceptible to component failures and unforeseen changes in the external environment, which can bring serious consequences to the driver [3]. Thus, how to improve the reliability and fault-tolerance of the SBW system is an urgent challenge in the research field of SBW systems.