Research On Motion Control System Of 3D Precision Workbench

It has been shown that the digital channel transmission delay is the main cause of the error of the measurement result of the integrated circuit AC parameters.This error has great influence on the high speed device,which can lead to misjudgment of the test result.In order to calibrate the digital channel transmission delay,all digital channels of the integrated circuit test system are required to be calibrated.There are hundreds of digital channels in the integrated circuit test system,each digital channel has a smaller size,therefore,it is necessary to design a set of precision coordinate table automatic switching measurement device to realize accurate automatic switching measurement of each digital channel.In this paper,the motion control system of the coordinate table is used as the object,and the two DOF PID control strategy based on BP network is used to replace the conventional PID control strategy.The system step response overshoot phenomenon and the hysteresis of the sinusoidal input are studied.The BP network is improved in order to solve the overshoot problem and the lag problem in the process of coordinate table movement.The main contents of this paper are as follows:According to the technical requirements design the motion control system of the coordinate table,using the "PC + motion controller" closed-loop motion control system.And on this basis,the corresponding hardware is selected to build the model of the motion control system which studied in this paper,so as to facilitate the subsequent simulation analysis and system implementation.Modeling and simulating the motion control system in Simulink,it shows that: the use of step input overshoot is more serious,the use of sinusoidal input is not only overshoot larger,the output and input there is still a certain lag.In order to solve these problems,we can use the two DOF PID to replace the conventional PID which can ensure the immunity and follow ability in the process of motion.The neural network can be combined with the two DOF PID to ensure that the parameters can be adjusted online when the controlled object changes,it is also possible to improve the convergence rate and suppress the local convergence by changing the excitation function,giving specific hidden layer node number selection method and segmented learning rate.After the realization of the coordinate table system,analyzing the location accuracy and movement precision through the experiment,the experimental data shows that: the single axis,the three axis location accuracy and the movement precision of the two DOF PID motion control system based on the improved BP network is high,the stability of the repeated measurement is good,the precision is high,thus the design of the motion control system meet the technical requirements of the subject.