The unmanned surface vehicles have been used most frequently in recent years in different applications, like environmental research. For this vehicles to accomplish their autonomous missions, a path-following algorithm is necessary to reduce the cross-track error in the presence of environmental disturbance. This article presents a control scheme based on the path-following nonlinear guidance law for a small unmanned surface vehicle called Krick Felix which follows a straight path. A dynamic model of 3 degrees of freedom for this vehicle is presented. The control scheme consists of a cascade control loop that is capable of guaranteeing zero cross-track error in the presence of environmental disturbance without adding an integral action. A nonlinear Lyapunov stability analysis is carried out for this control scheme taking in consideration the dynamics of both the inner loop and the external loop. The simulation was realized by implementing the 3-degree-of-freedom nonlinear model of the Krick Felix. The simulation also took account of the environmental factors, that is, marine currents. An experimental test is carried out with the Krick Felix where the control scheme present satisfactory results.

中文翻译：

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非线性制导律算法应用于小型无人水面车辆

近年来，无人地面车辆在不同的应用中使用最为频繁，例如环境研究。为了让这种车辆完成其自主任务，需要一种路径跟踪算法来减少存在环境干扰时的交叉轨迹误差。本文提出了一种基于路径跟随非线性制导定律的控制方案，用于一种名为 Krick Felix 的小型无人水面车辆，它遵循直线路径。给出了该车辆的 3 个自由度的动力学模型。该控制方案由一个级联控制回路组成，该回路能够在存在环境干扰的情况下保证零交叉跟踪误差，而无需添加积分动作。考虑到内环和外环的动态特性，对该控制方案进行了非线性李雅普诺夫稳定性分析。仿真是通过实现 Krick Felix 的 3 自由度非线性模型来实现的。模拟还考虑了环境因素，即海流。使用 Krick Felix 进行了实验测试，其中控制方案呈现出令人满意的结果。