Robust Adaptive Control for a Class of Nonlinear Systems Based on Interval Type-2 Fuzzy Logic System and Small Gain Approach

摘要

In this paper, a novel robust adaptive control scheme for a class of uncertain nonlinear systems based on interval type-2 fuzzy logic system (IT2-FLS) and small gain approach is proposed. An interval type-2 Takagi-Sugeno-Kang fuzzy logic system (IT2-TSK-FLS) is employed to approximate the unknown dynamics of such a system. Based on the small gain theorem, a composite feedback form of the system is then established and a novel robust adaptive control law is developed, which can ensure all the signals in the close-loop system are uniformly ultimately bounded (UUB). Throughout the whole control scheme, only one parameter needs to be adapted online, which is different from most of existing IT2-FLSs. Numerical simulations demonstrate the robustness of our proposed scheme against uncertainties as well as the superiorities of IT2-TSK-FLS.