基于改进切换增益自适应率的欠驱动USV滑模轨迹跟踪控制

针对参数的不确定性和外界干扰的非线性给欠驱动无人艇(USV)的精确轨迹跟踪控制带来的挑战，提出基于改进切换增益自适应率（ISGA）的欠驱动USV滑模轨迹跟踪控制算法. 该算法结合反步法和PI滑模控制，以保证欠驱动USV跟踪并保持期望的轨迹；采用基于理想增益的ISGA算法，以提高系统的鲁棒性和抑制滑模抖振现象. 借助李雅普诺夫直接法证明轨迹跟踪控制系统的全局指数稳定性. 仿真结果显示，所提算法具有鲁棒性强、滑模抖振弱和控制精度高等优点. 相较2种先进的轨迹跟踪控制算法，所提算法的位姿控制精度提高超过25.0%.

Improved switching-gain adaptation based sliding mode control for trajectory tracking of underactuated unmanned surface vessels

An improved switching-gain adaptation (ISGA) based sliding mode control algorithm was proposed for trajectory tracking of underactuated unmanned surface vessels (USVs), aiming to the challenges which the parametric uncertainties and nonlinearity of disturbance bring to the precise trajectory tracking control of underactuated USVs. In the algorithm, the backstepping and PI sliding mode control were combined to ensure an underactuated USV tracking and maintain the desired trajectory. In addition, an ISGA algorithm based on ideal switching gain was adopted to improve the robustness and suppress the chattering phenomenon. The global exponential stability of the trajectory tracking system was verified by the Lyapunov’s direct method. Simulation results show that the algorithm has the advantages of strong robustness, weak chattering and high accuracy. Compared with the two state-of-the-art algorithms, the position-attitude control accuracy of the proposed algorithm is improved by more than 25.0%.