Study On Strategies Of Anti-disturbance For AC Servo Drive System Based On Lowpass Disturbance Observer

High-performance AC servo drive systems demand for good dynamic performance and strong anti-disturbance ability to against parametric uncertainties and external disturbances. In practice, regular PID controller possesses the advantages of simple structure and easy to implement. However, the robustness of the controlled system cannot be guaranteed in the presence strong unknown disturbances. Therefore, a strategy of antidisturbance based on disturbance observer is designed to estimate the nominal disturbances and then mitigate the effect by feedforward compensation straightforwardly. The main contents of this thesis can be summarized as follows:The control framework and principle of disturbance observer are investigated, followed by the studies of performance evaluation. Then, the overall disturbance observed-based control scheme of servo system can be developed.Based on lowpass filtering, disturbance observer is proposed: Considering of the nominal model of servo system, the mathematical model of traditional disturbance observer are derived; Moreover, the lowpass filter is designed to improve the control dynamic performance and anti-disturbance ability; Finally, disturbance observerbased control strategy is presented on the basis of lowpass filter.Anti-disturbance simulations on stiff system and flexible system are carried out to verify the validity and disturbances attenuation ability of the proposed disturbance observer.Servo experimental platform is built. According to the identified accurate model, continuous speed tracking performance of the disturbance observer-based system is analyzed. The results validate that stronger anti-disturbance ability and dynamic performance can be obtained under the proposed method.