Research On Servo System Control Strategy With Friction Characteristic And Its Application

As the driving joint of the delta parallel robot,the control performance of the servo system directly affects the control effect of the robot.The friction exists in the servo system,which shows the nonlinear characteristics of friction memory,variable static friction and so on,which results the servo system has the problems of low speed creeping,steady state error and reducing control precision,Therefore,the effect of delta parallel robot position control is not good.In this thesis,the BackStepping control algorithm is used to compensate the nonlinear friction of friction servo system,and presents a new method based on BackStepping-integral compound control to compensate the friction nonlinearity.First of all,it is necessary to study and analyze the controlled object in the control system,The formation mechanism and the form of the friction are analyzed,and choose the suitable friction model as the nonlinear system.The mathematic model of PMSM and in-depth discussions,in-depth understanding and clear the principle and Realization of vector control mode,and combined with the commonly used algorithm simplified the mathematical model of PMSM,ready to work for the further study.Secondly,the BackStepping control method is chosen as the control strategy of the friction servo system,Based on PMSM mathematical model and friction model,constructing subsystem and the Lyapunov energy function,deriving the BackStepping control rate.Through the change of friction parameters,it is found that the servo system has a steady state error,Through in-depth analysis and discussion,the source of steady-state error is defined.In order to eliminate the steady-state error,the compound control strategy of BackStepping-integral is proposed by using the integral function of PID control strategy,On the basis of the ability to rapidly compensate the friction nonlinearity and the good robustness,the steady-state error caused by the change of the system parameters is eliminated,The effectiveness of the proposed control strategy is verified by simulation,And the design method of the adaptive friction compensation controller based on the dynamic friction model and the hardware and software design of the servo control system are presented in this thesis.Finally,taking the Delta parallel robot platform as the background,the simulation results verify the effectiveness of the proposed control strategy in practical application,The effectiveness of the proposed control strategy and the good application effect in Delta robot are verified.