基于自适应模糊滑模控制的船舶航向控制器设计

针对船舶运动系统中固有的非线性、模型不确定性和风、浪、流等的干扰.提出了自适应模糊滑模控制(AFSMC)策略解决船舶的航向控制问题.通过采用模糊逻辑系统逼近系统未知函数,将滑模控制技术与自适应模糊控制技术相结合,设计了船舶航向AFSMC控制器.在滑模边界层内应用PI (proportional-integral)控制代替滑模控制中的切换项,削弱了滑模控制带来的抖振现象.借助李亚普诺夫函数证明了船舶运动系统中的信号都一致有界并利用Barbalat引理证明了跟踪误差渐近收敛到零.在参数摄动和外界干扰情况下进行了航向保持与改变仿真试验,采用AFSMC控制器得到了与无摄动和无干扰情况下相似的输出响应.实验结果表明,所提控制器能有效地处理系统不确定性和外界干扰,控制性能良好,具有很强的鲁棒性.

Controller Design Based on Adaptive Fuzzy Sliding Mode Control for Ship Course

Considering the nonlinear characteristics,modeling uncertainties and external disturbances such as wind,wave and flow in ship motion systems,an adaptive fuzzy sliding mode control(AFSMC) technology is presented to solve the ship course control problem.The fuzzy logic system is used to approximate the unknown system function and the adaptive fuzzy sliding mode controller is designed by combining sliding mode control technology with adaptive fuzzy control technology.The chattering problem of sliding mode control is relieved by adopting PI(proportional-integral) control instead of sliding mode control switching items within the boundary layer.Based on the Lyapunov function,it is theoretically proved that the controller makes all signals in the system of ship motion uniformly bounded,and using Barbalat’s lemma,the tracking errors converge to zero.Simulation experiments on the course keeping and change in the presence of parameter perturbation and environment disturbances are conducted,and similar output responses with those under no perturbation and no interference circumstances by the controller based on AFSMC are obtained.The experiment results show that the proposed controller can handle system uncertainties and external disturbances effectively,and has superior controlling performance and strong robustness.