Research On Noise And Disturbance Suppression Method Of Servo System Based On Compound Observer

The permanent magnet synchronous machine(PMSM)servo system has been widely applied in military systems like artillery,radar,and industrial systems like robots and various precision machine tools.However,PMSM is a nonlinear system which has multiple variables,and PMSMs’ s coupling is strong.The dynamic performance of PMSM servo system is affected by many factors.For example,the white noise interference in the feedback signal of the speed sensor,the periodic harmonics of the current loop,the error and deviation of the current sensor,the uncertainty of the motor parameters,the load mutation and other factors.The above factors will cause the speed chattering of the motor,and the dynamic tracking ability will become worse.Therefore,it is of great significance to study the control algorithm to suppress noise and interference when the feedback signal of motor drive system contains noise and disturbance.This paper shows that the double loop of PMSM servo system is filted and compensated based on observer and disturbance compensator,the composite observer composed of observation and compensation is used to estimate the load of sensor noise,offset and external mutation,the disturbance compensator is fed back in real time to improve the anti-interference ability of PMSM servo system.The simulation and the joint experiment platform of RT-LAB and d SPACE are used to verify the results.The main contents of this paper are as follows:(1)Aiming at the application scenario and research development of permanent magnet synchronous motor control system,this paper analyzes the problems existing in the current servo control system in detail,and for the existing problems,the corresponding solution strategy is put forward.At the same time,the system model of permanent magnet synchronous motor is simplified by the change matrix of static coordinate and rotation coordinate.(2)Aiming at the problem that the bandwidth of PMSM servo system is reduced due to the filtering link in current loop and speed loop sampling,a control method using lead network is proposed.Firstly,the controller parameters are analyzed and adjusted according to the system model and transfer function,an adaptive extended sliding mode disturbance observer is designed to estimate the disturbances.Secondly,according to the designed current loop and speed loop,the loop bandwidth and phase margin are analyzed,and the design or improvement is carried out according to the system requirements.Finally,the bandwidth of current loop and speed loop is improved according to the phase advance characteristic of lead network,and the dynamic response performance of the system is improved.(3)Due to the white noise interference of the sensors and the harmonic of the current loop in the speed tracking of PMSM servo system,a double loop compensation strategy with Kalman filter is proposed in this paper.Firstly,the disturbance of current loop and speed loop is analyzed,and the motor model with disturbance is established;Secondly,Kalman observer is used to filter the white noise of the speed sensor,and combined with the compensation link to form a composite observer for compensation.Then,the Kalman filter is improved to reduce the adjustment time of the system.(4)Aiming at the problems of load mutation and parameter uncertainty in speed tracking of PMSM servo system,a control strategy of uncertain disturbance estimation control method(UDE control)based on backstepping algorithm is proposed.Firstly,the PMSM servo system with external load torque mutation and parameter mutation is modeled;Secondly,the disturbance of velocity loop and current loop is estimated by using the uncertain disturbance estimator through low pass filter,and the velocity current controller is designed based on the inverse step and uncertainty disturbance estimator.In the backstepping control of speed loop and current loop,the estimation of disturbance is import to controller by uncertain disturbance estimator.