LOS Guidance for Fuzzy Adaptive Fault-Tolerant Path Following Control of USV With Side-Slip Compensation and Actuator Fault

This article addresses the fuzzy adaptive fault-tolerant path following control (PFC) problem of unmanned surface vessels (USV) with side-slip compensation, unmeasurable states, and actuator fault. The indirect control strategy is adopted to decompose the PFC into a guidance system and a heading control system. For the guidance system, an adaptive line-of-sight (ALOS) guidance with a time-varying lookahead distance, which yields the desired heading by side-slip estimation and compensation, is designed, thus transforming the PFC problem into the heading tracking control problem. Meanwhile, for the heading control system, a fuzzy state observer is first developed to estimate the unmeasurable states. Next, an adaptive scheme is designed to estimate the time-varying actuator fault and an adaptive fault-tolerant controller is designed by combining the state and fault estimation to enhance the fault-tolerance of PFC system and ensure the performance of path tracking control. Then, the observer and controller are designed integrally, and the stability is analyzed using the integrated design principle. Finally, the simulation case study and comparison experiments of PFC for USV are conducted to demonstrate the performance of this method.