Continuous output-feedback finite-time control for a class of second-order nonlinear systems with disturbances

In this paper, a solution to the continuous output-feedback finite-time control problem is proposed for a class of second-order MIMO nonlinear systems with disturbances. First, a continuous finite-time controller is designed to stabilize system states at equilibrium points in finite time, which is proven correct by a constructive Lyapunov function. Next, because only the measured output is available for feedback, a continuous nonlinear observer is presented to reconstruct the total states in finite time and estimate the unknown disturbances. Then, a continuous output-feedback finite-time controller is proposed to track the desired trajectory accurately or alternatively converge to an arbitrarily small region in finite time. Finally, proposed methods are applied to robotic manipulators, and simulations are given to illustrate the applicability of the proposed control approach. Copyright (C) 2015 John Wiley & Sons, Ltd.