Robust Discrete Time Integral Terminal Sliding Mode Control for Steering-By-Wire Systems based on Input–Output Model

摘要

In this paper, a robust discrete integral terminal sliding mode (DITSM) control strategy for the steer-by-wire (SBW) systems with uncertain dynamics is presented. Different from most of existing sliding-mode control strategies using continuous design method, this paper establishes the system model and designs the controller from a discrete perspective, and implements it in the data sampling system. Since the proposed control scheme adopts an integral-type nonlinear terminal sliding surface, it can not only enjoy the finite-time convergence of both the sliding variable and the error dynamics, but also significantly mitigate the system steady-state error. The proposed digital control strategy is developed based on the system’s output feedback alone, whereas the knowledge on system states is not needed. The stability of the control system is demonstrated in theory. The simulation results are presented in support of the superior performance and effectiveness of the proposed control.