Research On Dynamic Error Control Of Servo Drive Joint Based On Full Closed Loop Control

Driven by practical needs for high dynamic output precision of servo driven joints in the industrial field,this thesis investigates dynamic error control based on external sensors.The contents cover a wide range of spectrum in terms of dynamic error control strategy based on cascade full closed-loop control and full state feedback control,the full state feedback compensation control strategy based on active disturbance rejection,and experimental verification.The following contributions have been made.According to joint elasticity,servo tracking properties and disturbance properties,a dynamic error modeling method of servo drive joint based on dynamic error coefficient method is proposed,a dynamic error equation with explicit analytical expression is established,and the influence law of control parameters on dynamic error in typical cascade control structure is revealed.In order to overcome the strict limitation on the position loop gain of traditional full-closed loop P-PI control to improve the dynamic error suppression capability,a full closed-loop P-P-PI control strategy is proposed.Based on the full state feedback control theory,according to the typical state space form of the driving joint,control collocated and non-collocated control strategies are proposed,the full state feedback regulators are designed,the dynamic error equations of the driving joint in the full state feedback control are established,and the formation and suppression mechanism of the dynamic error in this control mode are revealed.Compared with the cascade full closed-loop control,the control strategies further improves the dynamic output accuracy of the servo drive joint.A full-state feedback compensation control strategy based on active disturbance rejection is proposed to suppress the dynamic error caused by external disturbance and modeling uncertainty.Corresponding to control collocated and non-collocated control,two kinds of compensators are designed based on reduced order extended state observer.On this basis,a friction feedforward compensator is designed based on Stribeck friction model to suppress the dynamic error caused by friction during low-speed commutation.The experimental results show that the compensation control strategy significantly improves the dynamic output accuracy of the servo drive joint.The outcomes of this thesis not only offer a complete theoretical package for the research of servo drive joint dynamic error.And it also demonstrate its potential application to other servo control systems.