Design of a Trajectory Tracking Controller for Marine Vessels with Asymmetric Constraints Using a New Universal Barrier Function

Abstract

This article introduces an innovative trajectory tracking control methodology for a marine vessel with disturbances. The vessel is driven to track a predetermined trajectory while preventing the constraint violation of the position error. A universal barrier Lyapunov function (BLF) is, for the first time, established to resolve the variable constraint. It should be emphasized that the devised barrier function can handle constraint types including time-varying, time-invariant, symmetric, and asymmetric forms, and it can be employed to devise control schemes for unconstrained systems. Consequently, in comparison to the current BLF-based techniques for vessels, it can be flexible for dealing with practical control issues with or without constraints. A simplified disturbance observer performs estimations of ocean disturbances. It is proven that all the error variables can be exponentially stabilized to a small neighborhood close to the equilibrium point, while violations of the constraints on the position error never occur. The feasibility of the theoretical discoveries is shown by the outcomes of the final simulation.

Keywords

• barrier Lyapunov function (BLF)
• disturbance observer
• constraint control
• marine vessel
• trajectory tracking