Study On The Measurement Methods And Predictive Models For Volumetric Errors In Total Stroke Of Machining Centre

High efficiency is the main trend of modern manufacturing industry,and the precision of manufacturing equipment has greatly influenced the development of manufacturing industry.Error compensation technology is one of the main means to improve the precision of nc machine tool.For the most current 21 error compensation models,the practical effect is limited because the measurement items are more than the elastic deformation of the machine itself.Based on this paper,a method for measuring the position error of total travel space of machine tools based on laser interferometer is presented.Compared with the commonly used laser tracker,this method has the advantage of higher position accuracy.This method by two 90°steering mirror,it can realize measurement of laser beam in the full machine stroke space any move,to determine in advance the given space lattice on each point position error.Two kinds of prediction models based on cubic polynomial fitting and minimum unit interpolation algorithm are proposed.In the design of the measurement scheme,the light method of difference control is put forward,and the clamping mode of long connecting rod and magnetic bearing is adopted for each measuring part.In the model,based on the cubic polynomial fitting model,put forward the improvement of local fitting,based on linear interpolation model,put forward the linear interpolation and the interpolation of three combinations of Hermite interpolation algorithm.Final measurement by this method the measured position error on the lattice,validation on the lattice by using a linear interpolation model to predict the location of the error of the measured position error on the lattice,compare the forecast in the difference between the measured values,the mean value and mean square deviation index to evaluate the smallest unit body linear interpolation prediction precision of the model.According to the experimental results,the error measurement method of the total travel space of the machine tool based on laser interferometer can measure the position error of the whole travel space.