ABSTRACT This work addresses fuzzy

ABSTRACT This work addresses fuzzy adaptive tracking control of uncertain nonlinear systems with unknown control gain signs. Nussbaum functions are used to eliminate the effect of unknown control directions (i.e. unknown control gain signs). In order to make tracking errors approach a predened neighborhood, two controllers are developed by the aid of fuzzy adaptive prescribed performance control (PPC) technique.The controlled system is transformed to an equivalent one by using appropriate transformation function.Under the proposed tracking controllers without accurate initial errors, the boundedness of all involved variables is guaranteed. Moreover, the tracking errors can remain within the small prescribed performance bounds (PPBs). Finally, simulation results show the effectiveness of the proposed methods.

ABSTRACT This work addresses fuzzy adaptive tracking control of uncertain nonlinear systems with unknown control gain signs. Nussbaum functions are used to eliminate the effect of unknown control directions (i.e. unknown control gain signs). In order to make tracking errors approach a predened neighborhood, two controllers are developed by the aid of fuzzy adaptive prescribed performance control (PPC) technique. The controlled system is transformed to an equivalent one by using appropriate transformation function. Under the proposed tracking controllers without accurate initial errors, the boundedness of all involved variables is guaranteed. Moreover, the tracking errors can remain within the small prescribed performance bounds (PPBs). Finally, simulation results show the effectiveness of the proposed methods.

摘要研究控制增益符号未知的不确定非线性系统的模糊自适应跟踪控制问题。Nussbaum函数用于消除未知控制方向（即未知控制增益符号）的影响。为了使跟踪误差逼近预定邻域，采用模糊自适应性能控制（PPC）设计了两个控制器技术通过适当的变换，将被控系统转化为等效系统函数。在无精确初始误差的跟踪控制器，保证了所有相关变量的有界性。此外，跟踪误差可以保持在规定的小性能界限（PPBs）内。最后，通过仿真验证了所提方法的有效性。<br>