一类非线性系统的直接自适应模糊滑模控制

Direct Adaptive Fuzzy Sliding Mode Control for a Class of Nonlinear Systems

研究了一类非线性系统的一种直接自适应模糊滑模控制 ( AFSMC)问题 .首先 ,在系统的非线性动态函数满足可估计和有界两个基本假设的条件下 ,给出了此类系统基于非线性动态函数估计的一般滑模控制律设计 .然后基于目标函数梯度校正的方法 ,通过自适应机构调节模糊逻辑系统 ( FLS)的后件参数 ,所设计的自适应模糊逻辑系统 ( AFLS)能够逼近系统基于非线性动态函数估计的一般滑模控制律 .这样 ,系统的自适应模糊控制律具有一般滑模控制律的控制效果 ,同时由于 AFLS的滤波作用 ,具有消除滑模控制高频抖振的特性 .数值仿真结果证明了所设计控制律的有效性 .

In this paper a new adaptive fuzzy sliding mode control (AFSMC) algorithm for a class of nonlinear systems is proposed. Firstly, under the condition that the nonlinear dynamic function of the systems is estimable and bounded, sliding mode control law is presented. Then by self-tuning the consequent part parameters of the fuzzy logic system (FLS) the designed adaptive fuzzy logic system (AFLS) can approximate the sliding mode control law based on the estimation of the system nonlinear dynamic function. The adaptive law is obtained based on the gradient of the objective function. Hence the performance of the adaptive fuzzy logic control (AFLC) has not only the performance of the sliding mode control law but also the characteristic of free chattering thanks to the filter function of the AFLS. A numerical simulation example illustrates the effective of the designed control law.