基于扩张观测器的船舶动力定位系统反演滑模变结构控制

Back-stepping sliding mode control of ship dynamic positioning system based on extended state observer

针对海洋平台船舶动力定位控制系统,结合反演滑模控制与扩张观测器的优势,提出一种基于扩张观测器的船舶动力定位反演滑模控制方法。考虑到系统存在未知外部干扰以及船舶模型参数不确定性的问题,将系统分为内环观测器和外环控制器分别设计,首先利用扩张观测器估计系统的未知状态及不确定项,然后在外环的反演滑模控制器中进行补偿,最后用Lyapunov方法证明系统的稳定性。通过船舶定点控制仿真实验表明,基于扩张状态观测器的反演滑模控制器使得船舶纵荡和横荡的位置及首摇角度逐渐保持在期望值,具有较强的鲁棒性和控制性,能够有效抑制传统滑模控制的抖振问题,有益于船舶工程应用。

Aiming at the ship dynamic positioning control system in the offshore platform, In view of the advantages of back-stepping sliding mode control and extended observer, a sliding mode control method for dynamic positioning of ship based on extended observer is proposed. Considering the system of unknown external disturbances and parameters of ship model uncertainty, the system is divided as the observer of the inner ring and the outer ring controller. First, using the exten-ded state observer to estimate the unknown state and uncertainty of the system which are compensated in the outer ring of the back-stepping sliding mode control then, finally Lyapunov method is used to demonstrate the system＇s stability. The ship point control simulation experiment shows that back-stepping sliding mode controller based on extended state observer with strong robustness and control performance can make the ship＇s surge position, sway position and swing angle gradually keep in the expected value. It can effectively suppress the chattering problem in the conventional sliding mode control and is bene-ficial to the application of ship engineering.