Adaptive Discrete Time Sliding Mode Control of Brushless DC Motor Servo System for Unmanned Surface Vehicles
Considering the diverse effect on the electric steering gear servo system of unmanned surface vehicles (USV) caused by the external disturbances and parameter perturbations, a novel discrete adaptive global sliding model control scheme (AGSMC) is proposed in this paper. By introducing a nonlinear switch function, the system trajectory stays on the designed sliding manifold at the initial time. On the basis of discrete nonlinear adaptive reaching law, linear extrapolations are adopted to estimate the system uncertainty dynamics to ensure the robustness of the control system. Simulation results show that, in contrast with other discrete sliding mode control methods which are based on the exponential approach law, the proposed AGSMC schemes achieve enhanced tracking precisions with reduced control consumptions where chattering is significantly suppressed.
CSIA