基于区间2型T-S模糊系统的自适应逆控制

Adaptive Inverse Controlbased on Interval Type-2 T-S Fuzzy System

复杂非线性系统存在强非线性和不确定性等问题,其建模与控制一直是个极具挑战的工作。自适应逆控制是一种有效的非线性系统控制方法,已经得到广泛的研究;2型模糊系统采用2型模糊集,相比于1型模糊系统,其能够提供更大的自由度,不确定性及非线性处理能力更强,能够采用较少的规则数取得较高的建模与控制精度。因此,本文将2型模糊系统理论与自适应逆控制相结合,提出了一种基于区间2型T-S模糊系统的自适应逆控制方法,实现对复杂非线性系统的有效建模与控制。首先通过离线输出输入数据映射得到非线性系统的离线2型模糊逆模型,然后将该离线区间2型模糊逆模型作为初始控制器,与被控对象串联,进行在线控制,并采用最小均方差(Least Mean Square,LMS)滤波算法在线修正2型模糊逆模型的结论参数,通过数字复制,更新逆模型控制器的参数。最后将该方法应用于两个仿真实例,结果表明本文方法控制精度高,不确定性处理能力强。

With the problem of strong nonlinearity and uncertainty, modeling and control has been a challenging work for complex nonlinear system. Adaptive inverse control is an effective control method for nonlinear systems and has been extensively studied^By using type 2 fuzzy sets,type 2 fuzzy system provides more degree of freedom compared to traditional type-1 fuzzy system and is much more powerful to handle uncertainty and nonlinear than type-1 counterpart. It can achieve a higher level of modeling and control accuracy with less rules. Therefore, in this paper, type-2 fuzzy system theory is combined with adaptive inverse control strategy, and an adaptive inverse control method based on interval type-2 T-S fuzzy system is proposed, so as to modeling and control for complex nonlinear systems effectively. First, obtain offline type-2 fuzzy inverse model by mapping the output datas to input datas, and then take the offline type-2 fuzzy inverse model as the initial controller, in series with the controlled plant for online control. LMS filtering algorithm was used to adjust the parameters of the type-2 fuzzy inverse model online, and the parameters of the inverse controller is updated by digital copying. Finally, the proposed control scheme has been implemented on two simulation examples, and simulation results show the high control precision and uncertainty handling ability of the proposed control method.