Systematic Design Method of Disturbance Observer Guaranteeing Closed-loop System's Robust Stability
保证闭环系统鲁棒稳定性的干扰观测器系统性设计方法

The sufficient condition on the robust stability against model uncertainties in the feedback system with disturbance observer(DOB) is studied.Weighting functions satisfying this condition are consequently selected such that robust stability to plant s parameters variation is guaranteed by the disturbance observer designed with standard H∞ disturbance observer design method.Selection methods of frequency weighting functions are proposed concerning about the robustness design specifications and structural restrictions in designing the H∞ DOB.Trade-off between peek magnitude in cut-off frequency of Q-filter and disturbance depressing performance is optimized in designing low-pass filter of disturbance observer via selections of the weighting functions.Therefore,the resultant disturbance observer has the optimal disturbance rejection performance with satisfactory peak magnitude.Experimental results show the proposed method could guarantee robust stability of closed-loop system while providing design freedom for other available design specifications.