带有时滞的未知非仿射非线性系统自适应模糊跟踪控制  

Adaptive Fuzzy Tracking Control for Unknown Nonaffine Nonlinear Systems With Delay

作　　者：李平[1] 金福江[1] 梅小华[1] 

机构地区：[1]华侨大学信息科学与工程学院,厦门361021

出　　处：《北京工业大学学报》2014年第9期1315-1320,1326,共7页Journal of Beijing University of Technology

基　　金：国家自然科学基金资助项目(61273069);福建省高校产学合作科技重大项目(2013H6016);中央高校基本科研业务费资助项目(JB-ZR1204)

摘　　要：应用自适应模糊逼近方法研究了一类带有时滞的未知非仿射非线性系统的跟踪控制问题.系统的实际控制器是按照Backstepping设计过程经逐步反推而得到,在每一步设计中需要用自适应模糊逻辑系统来逼近未知的非线性函数.为了降低控制设计对先验知识的依赖性,取消须事先已知模糊基函数的限制,采用非线性参数化的模糊逻辑系统作为逼近器.由于逼近器中的未知参数彼此之间呈非线性关系,无法直接得到在线估计这些参数的自适应律.为了实现对相关参数的在线调节,先应用Taylor展开式将呈非线性关系的参数分离,使其相互之间具有线性关系,然后再基于Lyapunov第2方法给出相应参数的自适应调节律.最后,通过一个仿真实例来验证所给方法的有效性.结果表明:所得自适应模糊控制器能有效补偿时滞的影响,保证闭环系统中所有信号均有界,而且输出跟踪误差能收敛到原点的任意小邻域内.Tracking control for a class of unknown nonaffine nonlinear systems with delay is studied by using adaptive fuzzy approximation approach. The real controller is recursively obtained through a Backstepping design procedure. In each step, an adaptive fuzzy logic system is used to approximate the unknown nonlinear functions. To reduce the dependence on a priori knowledge and release the limitation that the fuzzy basis functions must be completely known beforehand, some nonlinearly parameterized fuzzy logic systems are used as approximators. As the relationships of the unknown parameters in the approximators are nonlinear, the adaptive laws cannot be directly obtained to estimate these parameters on-line. To realize the on-llne adjusting for corresponding parameters, Taylor expansion is first used to separate the nonlinear parameters, by which the relationships of the unknown parameters become linear. Then, the adaptive laws for estimating the unknown parameters can be designed on the basis of Lyapunov second method. Finally, a simulation example is presented to demonstrate the effectiveness of the approach. Results show that the proposed adaptive fuzzy controller can compensate for the influence of delay and guarantee all closed-loop signals hounded. Besides, the output tracking error converges to an arbitrarily small neighborhood of the origin.

关 键 词：非仿射非线性系统 自适应模糊逼近 反步递推 时滞 

分 类 号：TP273[自动化与计算机技术—检测技术与自动化装置]