Adaptive robust control of MIMO nonlinear systems with guaranteed transient performance

This paper deals with adaptive robust control of a class of multi-input multi-output (MIMO) nonlinear systems, with parametric uncertainties, unknown nonlinear functions, modelling error and external disturbances. The idea of adaptive robust control Lyapunov functions (ARCLF) is introduced to formulate a general framework of the adaptive robust control. Specific ARCLFs are sought out for different applications, including MIMO nonlinear systems with arbitrary known relative degrees transformable to a semi-strict feedback form, in which unknown parameters are also allowed to enter control channels. The method bridges the gap between adaptive control and deterministic robust control by preserving their advantages, i.e. the asymptotic stability of adaptive control in the presence of parametric uncertainties and guaranteed transient performance with prescribed precision of deterministic robust control in the presence of both parametric uncertainties and unknown nonlinear functions and, at the same time, eliminating drawbacks of each. Simulation results verify the effectiveness of the suggested method