Fuzzy adaptive output feedback control for a class of uncertain nonlinear MIMO systems

In this paper, a tracking-model fuzzy adaptive output feedback control is proposed for a class ofuncertain nonlinear MIMO systems. Unknown nonlinear vector functions are approximated byfuzzy systems based on universal approximation property in which both the premise andconsequent parts of fuzzy rules are tuned by adaptive schemes. Thus prior knowledge andnumber of fuzzy rules to design fuzzy systems are effectively decreased. Under-control Systemstates are not accessible in many practical problems. Advantageously, the proposed controllerdoesn’t need the availability of system states and employs an observer to estimate them. To copewith uncertainties due to fuzzy approximation error and external disturbances, a robust structurewith an adaptive gain is used. Since the gain is adaptive, not only is there no need to know theuncertainties bounds but also the chattering phenomenon is attenuated. All adaptive rules arederived from the Lyapunov designing scheme, thus; asymptotic stability of the closed-loopsystem is guaranteed. The proposed controller is applied to Chen chaotic system accompaniedby uncertain dynamics and external disturbances. Simulation analysis reveals that the proposedmethod is truly effective to cope with uncertainties while assuring asymptotic stability.

کلیدواژه ها:

Nonlinear control ، Fuzzy approximator ، Adaptive control ، Uncertainty ، External disturbances