基于Super-twisting的欠驱动船舶滑模自抗扰控制

Sliding mode active disturbance rejection control for underactuated ship based on super-twisting

针对欠驱动船舶在复杂海况下的航迹跟踪控制问题,提出一种基于Super-twisting的滑模自抗扰控制方法。利用视线导航法(LOS)将船舶的航迹跟踪转化为航向跟踪问题,并设计跟踪微分器来获取期望航向的1阶导数与2阶导数;根据非线性Nomoto模型设计扩张状态观测器对Nomoto模型的辨识误差、非线性项以及3级海况下风浪造成的干扰进行观测并补偿,提高控制器的鲁棒性。设计基于Super-twisting的2阶滑模控制方法,使滑模变量能在存在干扰观测误差的情况下有限时间收敛,并有效地减少了控制输出抖振现象,最终实现高精度的航迹跟踪控制。最后,以海巡船作为被控对象进行仿真验证,仿真结果表明,该控制算法能够有效提高船舶在3级海况下的航迹控制精度,增强对干扰的鲁棒性。

To solve the problem of tracking control of underactuated ship under complex sea conditions, a sliding mode active disturbance rejection control method based on Super-twisting was proposed. Firstly, the tracking control was transformed into course control by line of sight(LOS) method, and a tracking differentiator was designed to obtain the first and second derivatives of the expected course. Secondly, based on the nonlinear Nomoto model, an extended state observer was designed to observe and compensate the identification errors, nonlinear terms and disturbance caused by wind and wave under third-order sea conditions to improve the robustness of the controller. A second-order sliding mode control method based on Super-twisting is designed to make the sliding mode variables converge in finite time with the presence of interference observation error, and effectively reduce the chattering phenomenon of control output, and finally achieve high precision tracking control. Finally, the coast guard boat is taken as the controlled object for simulation verification. The simulation results show that the proposed control algorithm can effectively improve the accuracy of the ship’s tracking control in the third-level sea condition and enhance the robustness to disturbance.