Abstract
Many methods have been proposed for the unknown disturbance estimation. However, these methods are mainly for minimum phase systems but a few methods can be applied to non-minimum phase systems. Moreover, it is difficult to improve unknown disturbance estimation performances because of the phase lags of non-minimum phase systems. In the present paper, a new design procedure of an unknown disturbance observer by using a parallel feedforward mode is proposed and the effectiveness of the proposed method is verified by numerical simulations.
