To achieve a fully autonomous navigation for unmanned surface vessels (USVs), a robust control capability is essential. The control of USVs in complex maritime environments is rather challenging as numerous system uncertainties and environmental influences affect the control performance. This paper therefore investigates the trajectory tracking control problem for USVs with motion constraints and environmental disturbances. Two different controllers are proposed to achieve the task. The first approach is mainly based on the backstepping technique augmented by a virtual system to compensate for the disturbance and an auxiliary system to bound the input in the saturation limit. The second control scheme is mainly based on the normalisation technique, with which the bound of the input can be limited in the constraints by tuning the control parameters. The stability of the two control schemes is demonstrated by the Lyapunov theory. Finally, simulations are conducted to verify the effectiveness of the proposed controllers. The introduced solutions enable USVs to follow complex trajectories in an adverse environment with varying ocean currents.

为了实现无人水面舰艇 (USV) 的完全自主导航，强大的控制能力至关重要。由于众多系统不确定性和环境影响会影响控制性能，因此在复杂的海上环境中控制 USV 相当具有挑战性。因此，本文研究了具有运动约束和环境干扰的 USV 的轨迹跟踪控制问题。提出了两种不同的控制器来实现该任务。第一种方法主要基于通过虚拟系统增强的反推技术来补偿干扰和辅助系统将输入限制在饱和极限内。第二种控制方案主要基于归一化技术，通过调整控制参数可以将输入的界限限制在约束中。李雅普诺夫理论证明了两种控制方案的稳定性。最后，进行仿真以验证所提出的控制器的有效性。引入的解决方案使 USV 能够在具有不同洋流的不利环境中遵循复杂的轨迹。