Research On Key Technology Of Line Laser On-machine Measurement

It is an important process to realize the high precision and high precision machining of large aerospace complex surface.Because of its non-contact,good directionality,stable precision and large wide scan,it has become one of the most important methods for on-machine environment measurement.However,the accuracy of line laser measurement is affected by the sensor manufacturing accuracy,the laser beam incident attitude,the measurement environment and the surface quality of the workpiece,and the each point error of the laser beam projection line is different,so the measurement accuracy cannot be guaranteed.At the same time,the line laser measurement data points are redundancy,and the measured values are noisy.If the data processing operations such as surface modeling and singular feature analysis are carried out directly,it is not only tedious,inefficient,but also large in data storage and memory consuming.Therefore,with the support of the national 973 project,the key technologies such as error traceability,measurement modeling,data processing and system development are carried out for the problem of high precision measurement of line laser on-machine measurement.In view of the influence of laser beam incident attitude,measurement environment and workpiece surface quality on the measurement accuracy of line laser.Starting with the principle of line laser measurement,the variation process of the line laser Gauss light beam intensity diffuse reflection onto the photosensitive array is analyzed.The influence of the angle of incidence of laser beam?the measured surface parameters?external environment and exposure time on the accuracy of line laser measurement is analyzed emphatically,quantify the influence of the above factors on the precision of line laser measurement.Aiming at the problem of line laser in machine measurement modeling,the general mathematical model of line laser on-machine measurement is established,which realizes the unification of line laser measuring coordinate system?workpiece coordinate system?machine tool coordinate system,and ensures the reliability of geometric information precision extraction.Aiming at the problem that the direction of the line laser on-machine measurement system is difficult to be guaranteed line laser on machine measurement,a calibration method of the line laser measurement coordinate system is proposed,and the line laser measurement coordinate system calibration and adjusting experiments were carried out.Aiming at the problem of redundant data and noise points in line laser measurement,Starting with line laser data acquisition mode,the line laser data preprocessing algorithm is studied.A data denoising method based on Gaussian filtering and median filtering is designed.And a data reduction algorithm based on angle chord is designed.The experiment results verify the feasibility of data preprocessing algorithm.A line laser on-machine measurement system based on conventional CNC machine tools is established.The communication architecture of line laser in computer measurement system is established.And the laser data acquisition and processing software based on Labview software is developed.According to the research content of this paper,the line laser on-machine measurement experiment is carried out,which provides reference and thought for using the line laser on-machine measurement technology in practical engineering.