Adaptive robust control: A piecewise Lyapunov function approach

The problem of output tracking control for a class of multi-input multi-output uncertain systems is considered. A novel adaptive robust controller is proposed, which incorporates a variable-structure radial basis function (RBF) network to approximate unknown system dynamics. The RBF network can determine its structure on-line dynamically, where radial basis functions are added or removed to ensure the desired tracking accuracy and to prevent the network redundancy simultaneously. The structure variation of the RBF network is taken into account in the stability analysis of the closed-loop system. This is accomplished by using the piecewise continuous quadratic Lyapunov function typically for the analysis of switched and hybrid systems.