Trajectory Tracking for Uncrewed Surface Vessels with Input Saturation and Dynamic Motion Constraints

TL;DR

This paper presents a nonlinear feedback control method for uncrewed surface vessels that enforces static and dynamic motion constraints using Barrier Lyapunov Functions, ensuring stability and constraint satisfaction under actuator bounds.

Contribution

It introduces a novel control scheme that handles asymmetric and symmetric constraints with a smooth input saturation model, guaranteeing stability and constraint adherence.

Findings

The control scheme maintains all state variables within prescribed bounds.

Simulations confirm effective trajectory tracking without violating constraints.

The method ensures stability even with actuator saturation.

Abstract

This work addresses the problem of constrained motion control of the uncrewed surface vessels. The constraints are imposed on states/inputs of the vehicles due to the physical limitations, mission requirements, and safety considerations. We develop a nonlinear feedback controller utilizing log-type Barrier Lyapunov Functions to enforce static and dynamic motion constraints. The proposed scheme uniquely addresses asymmetric constraints on position and heading alongside symmetric constraints on surge, sway, and yaw rates. Additionally, a smooth input saturation model is incorporated in the design to guarantee stability even under actuator bounds, which, if unaccounted for, can lead to severe performance degradation and poor tracking. Rigorous Lyapunov stability analysis shows that the closed-loop system remains stable and that all state variables remain within their prescribed bounds at all times, provided the initial conditions also lie within those bounds. Numerical simulations demonstrate the effectiveness of the proposed strategies for surface vessels without violating the motion and actuator constraints.