Design Method for Servo-System Based on Disturbance Observer

The stribeck curve of friction is used for the friction model of the servo-system in this paper. The design method by using disturbance observer to compensate for influence of friction, which taken place when servo-system is run as low speed, is presented.The disturbance observer and the feedback controller can be designed independently as long as the nominal model is correct. For low frequencies the resulting system behaves like the nominal plant, robustness for paramenter uncertainty is therefore guaranteed in theory. As the same time, the influence of friction to servo-system output is equal to zero.The simulation results show the effectiveness of the proposed scheme.