Abstract
This paper investigates the discrete-time adaptive predictive sliding mode trajectory tracking control problem based on a reference sliding mode trajectory for the dynamic positioning ship with model uncertainty, environmental disturbances and input magnitude and rate saturations. Initially, a two-step delay discrete-time disturbance observer is designed to estimate the model uncertainty and environmental disturbances, and the input constraints are processed by quadratic programming. Then, an adaptive expected heading is proposed to ensure faster trajectory tracking and more stable heading changes simultaneously. Furthermore, using a double closed-loop control strategy, a new discrete-time virtual velocity controller is designed in the outer loop based on Euler discretization to convert trajectory tracking into velocity tracking. In the inner loop, a discrete-time adaptive predictive sliding mode velocity controller is designed based on a new adaptive reference sliding mode trajectory and an integral terminal sliding mode surface with disturbance estimation error. The proposed strategy can adaptively adjust the sliding mode bandwidth and convergence speed, which not only ensures the system’s rapid convergence but also reduces the tracking error and weakens the chattering. Finally, the stability analysis proves that the closed-loop system is uniformly bounded stable. Comparative simulation results verify the effectiveness of the proposed control scheme.
Published Version
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