Research On Drive Control Technology Of Linear Voice Coil Motor For IC Package

The positioning system of CNC machine tools for IC packaging field mostly uses linear motor,which plays an important role in the field of industrial control because of its fast running speed and high positioning accuracy.In view of the inability of linear voice coil motors to establish accurate mathematical models and the characteristics of repetitive motion,iterative learning control is adopted as the feedforward term of the linear voice coil motor controller;In order to improve the robustness of the system,the PID feedback controller is added,and the feedback feedforward iterative learning controller is constructed for the position servo control of linear voice coil motor.In this paper,the linear voice coil motor motion platform of the wire bonder is taken as the research object.Aiming at the problems of inaccurate modeling and the existing sample signal disturbance,a feedforward and feedback composite controller is proposed for the servo control of the linear voice coil motor.Firstly,according to the dynamic characteristics of the linear voice coil motor and the related parameters of the motor,the mathematical model is established;Secondly,the iterative learning control theory as the feedforward term of the controller is analyzed,and the PD-type closed-loop learning rate with forgetting factor is further studied and improved,so that the algorithm is optimized in terms of convergence,convergence speed,etc.because the system will be affected by the measurement noise during operation,The Q filter in the iterative learning controller is designed as a low-pass filter to filter out measurement noise;the digital incremental PID control algorithm with integral separation is used to enhance the control robustness of the system.In order to achieve the optimal control of the incremental PID controller in the simulation experiment,the particle swarm optimization algorithm based on the optimization of the number of particles plus the decrease of the piecewise weight is proposed to optimize the control parameters of the PID controller.Based on this,a composite controller with an iterative learning control algorithm as the feed-forward term and a PID controller as the feedback term is constructed.Finally,the linear voice coil motor experimental platform is designed and built,and bipolar reversible PWM converter is used as the driving mode of the linear voice coil motor.The design of two drive hardware circuits based on analog drive and PWM drive is given.The position information is obtained by using the designed serial communication software,and the positioning accuracy of the motor is calculated by experiment.The accuracy of the two-way repetitive positioning is 0.013 mm,which meets the expected control requirements.