A novel continuous finite-time disturbance observer design and its application

In this paper, we will investigate the problem of continuous finite-time disturbance observer (CFTDO) design and its application in the finite-time control (FTC) for systems subject to non-vanishing disturbances. First of all, based on the homogeneous domination approach and state saturation technique, a CFTDO design approach is proposed such that the disturbance can be precisely estimated in finite time. Then, the proposed CFTDO design approach is used to solve the finite-time stabilization problem for a class nonlinear circuit systems subject to non-vanishing disturbance. Finally, a composite controller consisting of a baseline FTC law and a feedforward compensation term based on the estimation of CFTDO is constructed for the nonlinear circuit system. It is shown that under the proposed composite controller the nonlinear circuit system can be stabilised. The proposed CFTDO and control strategy are confirmed by simulation results.