基于非奇异终端滑模的船舶航迹跟踪自抗扰控制

Active disturbance rejection control for ship trajectory tracking based on nonsingular terminal sliding mode

针对欠驱动船舶受到外界因素和内部不确定状态变量的干扰不能沿着期望路径航行的问题,设计了基于非奇异终端滑模(Nonsingular Terminal Sliding Mode,NTSM)的自抗扰控制器(Active Disturbance Rejection Controller,ADRC).引入自抗扰控制技术,通过扩张状态观测器实时估计船舶外界和内部总干扰;对船舶Nomoto模型进行变形简化,将NTSM和指数趋近律引入到非线性状态误差反馈环节,设计基于NTSM的ADRC控制律,在保证ADRC优点的前提下可减少可调参数,提高系统的收敛速度和稳态跟踪精度;构造降维方程,将复杂的航迹跟踪控制问题转化为易于实现的航向镇定问题.Simulink仿真结果表明,利用该控制器船舶能够快速、精确地跟踪期望直线和曲线航迹,控制器具有较强的鲁棒性.

Considering the problem that underactuated ships can not follow expected trajectories under the disturbance of external factors and internal uncertain state variables,Active Disturbance Rejection Controller（ ADRC） based on Nonsingular Terminal Sliding Mode（ NTSM） is designed. The active disturbance rejection control technology is introduced,and the extended state observer is used to estimate the total external and internal disturbances of ships in real time. The ship Nomoto model is transformed and simplified,and meanwhile,NTSM and the exponential reaching law are introduced to the nonlinear state error feedback to design the control law of NTSM-based ADRC,which can reduce the number of adjustable parameters on the premise of guaranteeing ADRC advantages and improve the convergence speed and steady-state tracking accuracy of the system. A dimension reduction equation is designed so that the complicated trajectory tracking problem is transformed into a manageable heading stabilization problem. Simulation results by Simulink verify that the ships using the controller can follow expected straight and curvetrajectories fast and accurately,and the controller is of good robustness.