模型不确定时滞欠驱动AUV的模糊变结构控制

A fuzzy sliding mode controller for underactuated autonomous underwater vehicles with uncertain time delay

摘要:

为了实现具有时变水动力系数、未建模动态和时滞等不确定性的欠驱动自主水下航行器的鲁棒控制,以变结构控制的切换函数及其变化率为模糊控制器的输入,以变结构控制律的变化率为模糊控制器的输出设计了一个模糊变结构控制器;为了得到更好的性能,引入了压缩扩张隶属度函数,设计一定的模糊规则自适应地调整模糊控制器中的比例因子和量化因子;将该控制器和模糊变结构控制器,准滑模控制器进行了仿真对比,证明本文设计的控制器有更好的性能;最后基于该控制器对具有水动力系数不确定性,未建模动态和控制输入时滞的AUV运动模型进行了数值仿真,结果表明该控制器有很强的鲁棒性,而且控制成本很小,只在某些情况有极弱的抖振.

Abstract:

To realized the robust control of underactuated autonomous underwater vehicle with uncertainties of time-delay,un-modeled dynamics and time-varying hydrodynamic parameters,a fuzzy sliding mode controller is proposed,with switching function of variable structure control and its derivative as fuzzy control inputs,and derivative of the variable structure control law as fuzzy control output.The design method of the controller offers a systematical means of constructing a set of shrinking-span and dilating-span membership functions for the controller.A technique to adaptively tune scaling factors of fuzzy controller is presented for better performance of eliminating chattering.The contrast simulation results indicate that the proposed adaptive fuzzy sliding mode controller has better performance.And then the controller is applied to the dive plane control of AUV with parameter uncertainties,un-modeled dynamics and control input time delay.The results demonstrate the effectiveness and robustness of the controller with low control effort.