Research And Application Of Position Servo Drive System For Voice Coil Motor

The thesis takes the counting machine in enterprise medical packaging machinery as the application background,and uses a voice coil motor(VCM)as the excitation source to improve the electromagnetic vibration feeder.The traditional vibrating feeder basically uses the electromagnetic structure as the excitation source,and is used to disperse and transfer materials in the counting machine.However,the excitation of the electromagnetic structure has the disadvantages of being severely affected by the aging of the spring,susceptible to the environment,and the amplitude cannot be controlled.The stability of the feeding effect and speed is not enough,which is not conducive to the full servo control of the counting machine.The voice coil motor has the characteristics of precise and controllable movement process,strong anti-interference ability and high degree of automation.Using a voice coil motor instead of an electromagnetic structure to design a full servo vibration feeder can accurately control the amplitude and frequency,which is conducive to improving the feeding speed and stability.The main contents of the thesis are as follows:(1)Firstly,the research status of the voice coil motor servo system is introduced,the working process of the electromagnetic vibration feeder is described,the main problems of the electromagnetic structure are analyzed,and the voice coil motor position servo drive system is selected to provide stable and reliable excitation.Improve the vibration feeder.(2)In order to establish the mathematical model of the voice coil motor,the working principle is analyzed,and the transfer function of its low-order model is obtained under the approximate equivalent case.According to the working characteristics of the vibration feeder,the voice coil motor needs to perform high-frequency reciprocating motion.The complex hysteresis characteristics of the voice coil motor are introduced.It shows that the voice coil motor exhibits non-negligible non-linear characteristics under high-frequency motion and is a complex non-linear controlled object.Combined with the dynamic analysis of the vibration feeder,the position servo control requirements for the high frequency reciprocating motion of the voice coil motor are determined.(3)In order to obtain better control results,the necessary analysis of the H-bridge power converter is carried out,and the position servo drive system of the voice coil motor is studied and verified by simulation.In order to further improve the dynamic performance of the current loop,feed-forward compensation control is added to the current loop.The Active Disturbance Rejection Control(ADRC)method is introduced and applied to the position loop to adapt to the complex hysteresis characteristics of the voice coil motor and improve the control accuracy of the position loop.The control algorithm of current loop and position loop is analyzed in detail,and the method of parameter setting is explained.Finally,it is verified by Simulink simulation platform.(4)The hardware platform and software structure of the voice coil motor position servo drive system are introduced,and the main parts are explained.The hardware includes H-bridge power converter,switching power supply,operation panel and control circuit,and the software includes control algorithm module and panel.Communication module and Coordinate Rotation Digital Computer(CORDIC).(5)An experimental platform for a vibration feeder with a voice coil motor as the excitation source was set up.The on-load test of the designed voice coil motor position servo drive system was carried out,and the control performance of ADRC was verified by comparison with the classic PID control.The voice coil motor is controlled to generate high frequency vibration,and continuous platform feeding test is performed to verify the stability of the system.