Robust Trajectory Tracking Control of Underactuated Surface Vehicles with Prescribed Performance

Shasha Wang,Yulong Tuo

doi:10.2478/pomr-2020-0075

Abstract

Abstract In this paper, a robust sliding mode tracking controller with prescribed performance is developed for an underactuated surface vehicle (USV) with time-varying external disturbances. Firstly, to guarantee the transient and steady-state performance of the closed-loop system, the error transformation technique is presented. Further, the design of the prescribed performance function implements predefined tracking performance constraints, which eliminate the requirement for prior knowledge about the initial errors. Then, a Lyapunov stability synthesis shows that all closed-loop signals remain bounded and the tracking errors remain strictly within the predefined bounds. Finally, simulations and a comparative study are performed to illustrate the robustness and effectiveness of the proposed robust sliding mode control scheme.

Highlights

Tracking control of underactuated surface vehicles (USVs) has been widely used in military and civil fields such as coastal patrols, mine countermeasures, oceanographic sampling, military reconnaissance, and so on [1], [2]
In the case of tracking problems, trajectory tracking is more difficult than path following, since the control laws require the USV to be driven to reach and track a time-varying trajectory on time
In the presence of time-varying external disturbances, the problem of trajectory tracking control for a USV with prescribed performance has been solved in this paper

Summary

Introduction

Tracking control of underactuated surface vehicles (USVs) has been widely used in military and civil fields such as coastal patrols, mine countermeasures, oceanographic sampling, military reconnaissance, and so on [1], [2]. In the case of tracking problems, trajectory tracking is more difficult than path following, since the control laws require the USV to be driven to reach and track a time-varying trajectory on time. The challenge comes mainly from the nonlinearity and underactuation of USV dynamical systems. USVs inevitably suffer from uncertainties, complex hydrodynamics, and time-varying external disturbances such as wind, waves, and ocean currents [3]. An actual mathematical model of a USV is hard to obtain precisely using current modeling methods. The other challenge, is that the number of USV control inputs is less than the degrees of freedom, which means that its system causes non-integral constraints [4]

Methods

Results

Conclusion