Model Free Adaptive Control with Disturbance Observer

This paper considers the problem of model free adaptive control (MFAC) for nonlinear systems subject to disturbances. It is shown that the robust stability of MFAC systems with disturbances can be guaranteed, and the bound on tracking error depends on the bound on the disturbance. To attenuate disturbance, an improved MFAC is also developed using disturbance observer based control techniques, where the disturbance observer design is established by radial basis function (RBF) neural network. The stability analysis of proposed MFAC algorithm is given, and the effectiveness is also illustrated by simulations.