基于扰动观测器的船舶动力定位反步控制

针对船舶动力定位系统模型受到风浪流等环境未知有界扰动的问题，提出一种基于干扰估计补偿的反步控制算法。首先基于滑模面有限时间收敛特点设计干扰观测器，在有限时间内实现对未知有界干扰的估计，并采用一阶低通滤波器连续化干扰观测器估计值，减少抖振；然后基于干扰观测器设计船舶动力定位反步控制器，并应用Lyapunov函数证明了所设计的控制器使船舶的位置和航向收敛于期望值。最后通过铺缆船仿真结果表明所设计控制器具有较好的控制性能，对系统的有界干扰具有良好的鲁棒性。

Disturbance Observer-based control for Dynamic Positioning Vessel

The positioned vessels are continuously exposed to environmental disturbances of wind, waves and current. So the motions have obviously delay, large inertia and nonlinear characteristics. In order to overcome these problems, a sliding mode disturbance observer (SMDO)-based control strategy is proposed for dynamic positioning of the vessel with unknown time-varying environment disturbances by using backstepping method. This controller is robust to variations in environmental and loading conditions by incorporating SMDO to compensate environmental disturbances. The stability of designed controller is proved by using the Lyapunov theory. The performance of the controller was validated by numerical simulations of pipe-laying vessel in two kinds of sea conditions. The simulation results indicate that the designed controller is very efficient and robust to bounded disturbances.