Dual Motor Drive Servo System Backlash And Synchronization Control Method

Dual motor drive gear transmission system has the advantages of large output power,compact structure,high efficiency and low cost,so it has been widely used in heavy load industrial applications.For high-precision,high-speed system,the servo motors drive the load frequently to change,it is difficult to overcome the backlash influence,which seriously affects the precision and performance of servo system.In addition,the actual motor parameters are inconsistent,the load disturbance is different and so on,which will lead to speed difference between drive motors.It easily leads to differential oscillation,even cause a single motor overload or mechanical shaft broken.So a control strategy must be taken to ensure drive motors speed synchronization.In order to eliminate the backlash influence,this paper established the dynamics model of dual permanent magnet synchronous motor drive servo system with backlash,designed the dual motor anti-backlash control strategy based on variable bias torque.By controlling the output torque of two motors to ensure that at least one small gear meshing with the big gear,so the big gear can not swing freely in the backlash,the torque,speed and displacement can be accurately transmitted.In traditional dual PI parallel control strategy,when one motor is under load disturbance,there will be a large speed synchronization error between the two motors.Since the two motors are rigidly connected,it is very easy to cause differential oscillation,even cause a single motor overload or mechanical shaft broken.Aiming at this problem,a speed synchronous control strategy is proposed based on sliding mode control algorithm and cross coupling control structure.It uses an integral sliding mode speed controller to improve anti-load disturbance performance of motors.Then it enhances the coupling between the two motors,by feeding the speed difference information to the current loop of two motors to compensate the speed error quickly.At the same time,the influence of the value of the synchronous coupling coefficient on the synchronization performance is studied.Finally,the optimal value is selected by simulation and experiment,the anti-load disturbance ability is enhanced,and the synchronous performance of the system is improved.Finally,the experimental platform is built,and the traditional dual PI parallel control and speed synchronous control strategy are verified.The experimental results show that the speed synchronous control strategy can not only reduce the speed tracking error and synchronization error of the system,but also reduce the recovery time of the system,effectively improve the synchronization performance of the system and reduce the risk of differential oscillation.