Fuzzy adaptive observer backstepping control for MIMO nonlinear systems

In this paper, a fuzzy adaptive backstepping output feedback control approach is developed for a class of multi-input and multi-output (MIMO) nonlinear systems with unmeasured states. Using fuzzy logic systems to approximate the unknown nonlinear functions, a fuzzy adaptive observer is designed for state estimation as well as system identification. Combining with the backstepping design techniques, a fuzzy adaptive output feedback control is constructed recursively. It is proved that the proposed fuzzy adaptive control approach can guarantee the semi-global uniform ultimate boundedness for all the signals and the tracking error to a small neighborhood of the origin. Simulation studies illustrate the effectiveness of the proposed approach. (C) 2009 Elsevier B.V. All fights reserved.