Dynamic surface event-triggered control for unmanned sailboat path following based on adaptive tanh line-of-sight

Abstract

In this article, a dynamic surface control algorithm based on the adaptive tanh line-of-sight with speed adjustment is proposed to solve the problem of path-following control of unmanned sailboat with event-triggered input, considering the dynamic model uncertainty and unknown external disturbance. First, the adaptive tanh line-of-sight method is used to improve the following accuracy and robustness, then an extended state observer is used to estimate the external disturbance and the uncertainty of the internal model, the heading error and the yaw angular velocity error are considered to design the recursive sliding mode dynamic surface controller, at the same time, the speed of the unmanned sailboat is constrained to improve its stability. In addition, to reduce the action frequency of the steering gear, the relative threshold event-triggered control is applied to the controller. According to the Lyapunov stability analysis, it is proved that the proposed control scheme can ensure that all errors in the closed-loop system are semi-globally consistent and ultimately bounded, while the Zeno behavior can be avoided. Finally, the effectiveness of the proposed scheme is verified by simulation and comparative experiments.