Adaptive High-Order Sliding Mode Control for the Unmanned Vehicle Steering System

Facing the unmanned vehicle steering system with nonlinearity and uncertainties, model-based control methods could not acquire satisfied performance. In this paper, a novel adaptive high-order sliding mode (HOSM) control algorithm is proposed for the steer-by-wire (SBW) system of unmanned vehicle. There are three original contributions. Firstly, without the priori knowledge of the unmodeled dynamics and external disturbances bounds, the proposed adaptive HOSM controller ensures a real sliding mode established in finite time and a continuous control input signal to the steering motor. Secondly, the developed adaption schemes of switching effectively avoids overestimation, which significantly suppresses the formidable chattering caused by high frequency switching of the control signal. Finally, the effectiveness and superiority of the adaptive HOSM controller are indicated by numerical simulations.