Study On Control System In Special Precision Measurement And Grinding Machine

Thin wall revolving body made by fragile material is a kind of baroque workpiece which is used in some domain such as aviation,spaceflight and radar communication,its precision influences the equipments' performance in these fields.Because of its special materials and high grinding precision,it is a hard object to machine these workpiece at home and abroad.The radome of high speed aircraft is a good example of this kind ofworkpiece,and will be treated as a sample in this article.This kind of workpiece requests high-level electrical properties of its sidewall,and it has different machine way from General machine tools.Firstly,the machining datum surface is actual inner surface of the semi-finished radome,which is a three-dimensional complicated surface.Secondly,the grinding removals at different points on the radome vary from each other. Has been in this field of research for many years,Radome inner surface precision grinding machine tool was developed successfully by Dalian University of Technology.But previous machine tools' machining precision and Level of automation are not high enough for new demands,it is necessary to develop a new precision and grinding machine based on the technology available.According to the machining accuracy(≤5μm) and speed of the new precision grinding machine in the ground of the machine tool based on 'double station in one body' structure,we develop a kind of Open CNC System based on IPC+GALIL structure,analyze the method of data processing briefly,analyze and design the part of measure,grinding and tool presetting detailedly.Aiming at the high precision process demands,we develop a high performance control strategy which combine three-loop feedback PID control and forward feedback compensation, where besides current,speed and position loop with PID feedback controller,append speed forward feedback,acceleration forward feedback and notch filter.The control precision is improved dramatically.To settle with the errors of the machine structure and measuring equipments,we analyze and design the compensation method based on "error table",the precision of the servo-axis is improved remarkably.Aiming at the errors of data processing,coordinate transformation and several times back to zero,we study the error and design the compensation methods,for example radius compensation method and tool presetting compensation method,and get a satisfactory result for improving the precision of the whole system.In order to improve the machining quality,we design the automatic control system to achieve an accurate level of speed based on spindle motor.Through this system,we can keep the value of Vw/Vs.after designing the program in IPC,we complete the debug experiment.At last,we complete the joined debug and synthesis experiment,detect and analyze special exact grinding equipment's servo axis' orientation precision and repetitive orientation precision, achieve the tool presetting and grinding process experimentation,also check up the process precision.The experiment results validates special exact grinding machine tool run stably,has fast response and satisfactory control precision,can grind the rigid fragile material in high precision.