Abstract
Path-following is a typical operating condition for underactuated unmanned surface vehicles (USVs), and the effectiveness of its control directly affects whether the USV can complete the designated tasks. This paper proposes an event-triggered fuzzy path-following control approach for underactuated USVs. First, an improved prescribed performance control (PPC) is applied to constrain the tracking errors within a predefined envelope. Not only are the constraints on the initial tracking error can be eliminated, but also the convenient adjustment of the envelope’s convergence time and decay rate can be achieved. Subsequently, to approximate the unknown model nonlinearities of the USV, error compensator-based fuzzy logic systems (FLSs) are proposed. Compared with the traditional FLS, the proposed method can adaptively estimate and compensate for the approximation errors of FLSs, achieving higher approximation accuracy. Finally, a switching threshold event-triggered mechanism is constructed to reduce the execution frequency of command control signals. The stability of the closed-loop system is proven by employing the Lyapunov stability theory. The effectiveness and the remarkable performance of the proposed method is verified through simulation and experimental results.
•An improved PPC approach is proposed. Compared to the traditional methods, it can not only remove the initial value constraint, but also facilitate the convergence time and decay rate of the envelope.•A modified FLS with error compensator is presented to approximate the unknown model nonlinearities and disturbances. The approximation accuracy of the FLSs can be greatly enhanced due to the designed error compensator.•Unlike the fixed threshold ET method and relative threshold ET method, a switching threshold ET method is proposed, which can provide a more nuanced control strategy by switching between different thresholds.