The Study Of Robust Repetitive-Control Of Dual-motor Couping Servo Motor

The servo system is widely used in national defense,industrial and other fields,the control accuracy and robust performance demand constantly to improve.But in practice there are parameters perturbation and external interference,in order to improve the control performance of the servo system,this paper concerns the problem of designing a robust sliding mode variable structure repetitive control system and a H_∞ robust reprtitive control system for the dual motor coupled servo system with aperiodic disturbances and parameter uncertainty.The designed controller can suppress the parameters of uncertainty and aperiodic disturbance,improve the robustness of the system and that the tracking error can converge rapidly to zero.The main research results and innovative points are as follows:(1)Establishment of dual mtor coupled servo system modelConsidered the dual motor coupled servo system(where one motor is used as the controlled object and the other one is used to generate the disturbance signal).By analyzing the structure and mechanism of DC servo motor,the structure of dual servo motor coupling model is deduced and the state space model is given.(2)The method of H_∞ robust repetitive control was proposedWe analyzed the stability of the repetitive control system based on the established dual-motor coupled servo system model.By considering the time delay as a perturbation and introducing the H_∞ control method for the dual-motor coupled servo system with uncertain parameters.Then,the problem of repetitive control system design based on state feedback is transformed into the standard H_∞ state feedback gain design problem and H_∞ robust repetitive control design method is proposed,and the system robust stability condition is deduced by using Lyapunov function.At the same time,a numerical example demonstrates the validity of the method.(3)The method of robust sliding mode variable structure repetitive control was proposedthe problem of designing a robust sliding-mode based modified repetitive-control system fothe dual motor coupled servo system with aperiodic disturbances and parameter uncertainty.An augmentedsystem is first constructed,which contains a repetitive controller,a sliding mode controller,and a feedbackcontroller.And its state-space model is presented.Next,a stability condition for the MRCS is established thatcan be directly used to design the parameters of the repetitive controller and the feedback controller.Then,forthe augmented system,the Lyapunov stability theory is used to derive a linear-matrix-inequality(LMI)basedrobust stability condition.Based on the stability condition,a design algorithm for the gains of the sliding-modecontroller is constructed.Finally,a numerical example demonstrates the validity of the method.