Type-2T-S Fuzzy Control for Nonlinear Systems with Niche Equality Index Function

In this paper, a novel Type-2T-S fuzzy control scheme is proposed for a class of nonlinear systems with uncertain parameters. In this scheme, the fuzzy controller with biological characteristics is firstly constructed by taking the niche equality index function as the consequent of type-2 fuzzy rules, which combines the adaptive characteristics of biological evolution with type-2 fuzzy control. Then, the gradient descent method is used to optimize the parameters of the consequent and adaptive laws are obtained. Furthermore, the stability and convergence of the system are analyzed. Finally, the simulation results from an example show the effectiveness of the proposed method. Obviously, the proposed method is better than the Type-1. This method can reflect the organism being adaptive, self-development ability, the degree of development, and the utilization of biological environment (i.e., a physical background of fuzzy control is given).