Adaptive sliding mode control for a vehicle steer-by-wire system

This paper presents an adaptive sliding mode (ASM) controller designed for a vehicle Steer-by-Wire (SbW) system. First, the SbW system is modeled as a second-order system from the steering motor input voltage to the front wheel steering angle. For simplicity, the tire-to-ground frictions and the self-aligning torque are treated as external disturbances acting on the SbW system. Next, an ASM controller is designed for the SbW system, which utilizes sliding mode control to handle the parametric uncertainties and an adaptive estimation scheme to estimate the coefficient of the self-aligning torque, respectively. Finally, experiments are carried out to validate the performance of the ASM control. The experimental results indicate that the proposed ASM controller possesses strong robustness and high tracking accuracy.