Research On Rapid Response And Temperature Evaluation Of Voice Coil Motor Servo System

Fast response and thermal reliability are two important indicators of the voice coil motor servo system.This paper studies the voice coil motor servo system from these two perspectives.Aiming at the requirement of rapid position response,a control structure with time-optimized control and self-interference resistance is proposed,which realizes the rapid response of the position of the voice coil motor and has good steady-state performance.It has high requirements for thermal reliability.In this paper,the temperature of the voice coil motor is evaluated from the perspective of theoretical calculation and experiment,and an equivalent temperature evaluation method is proposed to obtain the safe working range of the voice coil motor.First,the model of the voice coil motor is analyzed for the demand.The state space model and the thermal network model of the voice coil motor are analyzed separately.Propose the state space model of voice coil motor based on its working principle.The series integration model of the voice coil motor combining the anti-interference control structure given by this paper to eliminate the system disturbance and improve the anti-interference ability.The thermal network model and the model parameters are determined to calculate the temperature under the motor operating conditions.Then,for the fast response demand of voice coil motor,a control structure that can realize time optimal control and has self-interference resistance is proposed.Since the time optimal control law of high-order system cannot be solved directly and the discretization is difficult,the neural network is used to obtain the control law through data learning.In order to transform the complex voice coil motor control system into a series integral model and improve the anti-disturbance capability of the system,a disturbance observer is designed to estimate and compensate the total disturbance of the system.The voice coil motor position servo control system is constructed,and its rapidity and immunity are simulated and verified.In order to reduce system cost further,improve system reliability,and optimize the control system,a control structure without current sensor is proposed.The core of the structure is to obtain the high-order differential signals of the location accurately.This paper proposes four solutions and their performance is verified by experiments.Finally,evaluate the temperature of the voice coil motor.A temperature evaluation method that does not rely on models is proposed.The temperature response under any operating conditions can be obtained by analyzing the situation of short periods,and small excitations,which avoids the risk of motor damage when large excitation applied.The correctness of the method is evaluated from the perspective of theoretical calculation and experiment.Calculation includes the equivalent thermal path method and the finite element method.According to the method,the safe working range of the voice coil motor is obtained.The accuracy is improved and the algorithm is optimized by analyzing the error of the proposed method.