Universal control for a class of nonlinear systems based on finite-time parametric estimation

In this paper, a universal control scheme is investigated for a class of nonlinear systems with unknown parameters and nonlinearities like friction, dead-zone, etc. First of all, an adaptive finite-time update law is developed to estimate the unknown parameters by introducing the auxiliary filtered variables for the system states and regressor matrix. Then, a universal controller is proposed based on the finite-time parameter estimation to guarantee the globally asymptotic stability of the system. Finally, a motor servo control system with nonlinear friction is given as an example to show the effectiveness of the proposed method.