Research On Numerical Control Application System Of Blade Section Laser Measurement

As an important part of energy equipment,blade has a complex cross-section and higher requirement for detection accuracy.With the rapid development of aviation and energy industries,the demand for different types of blade is increasing day by day.CMM is widely used in the field of detection,but its measurement efficiency can not meet the requirements of large quantities of blade detection,so the non-contact measurement method represented by laser triangle optics is gradually rising,laser measurement has the advantages of high sampling frequency,high measurement accuracy,strong anti-interference ability and so on.Based on laser triangulation principle of optical measurement,for small blade parts between process and final inspection stage,type blade cutter location algorithm is proposed,and the laser probe calibration algorithm,leaf position methods of automatic identification algorithm,blade cutting type numerical control measure application system is developed,and connecting with the four axis measurement calibration specimen platform and independent design,integrated system has been verified.The following is a brief description of the research content of this paper:(1)Before blade measurement,point set coordinates of the cut-off type to be measured should be extracted from the 3D digital model,and the cut-off type of blade is composed of a combination of the back of the blade blade with a large curvature radius and the front and rear edges with a small curvature radius.In this paper,a cut-off point arrangement strategy based on characteristic parameter constraints is designed.The blade cut-off pattern is segmented through "extreme point",and points are arranged in different ways for two groups of cut-off shapes with different curvature,so as to reduce the number of points and ensure the cut-off profile features to the maximum extent.(2)Laser triangulation is a non-contact measurement method.Since the laser beam is a non-physical element,it is difficult to determine the spatial position relationship between the probe and the machine tool shaft system.As a necessary condition of measurement,the probe and machine tool shaft system coordinate system directly affects the accuracy of subsequent measurement work.In this paper,a probe calibration technology based on the principle of laser step mutation characteristics is proposed,which can realize the accurate mapping of the coordinate system of the probe in the transverse and longitudinal installation modes.(3)the installation of the laser measuring head pose error significantly influence the blade cutting type measuring precision,and the laser beam is not easy to detect the position error,therefore,this paper proposes a laser probe installation position correction algorithm,and combine the physical characteristics of correct posture to calibration specimen,realize the fast and efficient laser probe installation correction and calibration.(4)measurement of blade,in order to reduce the blade clamping time,blade detection efficiency as the goal,this paper designed a based on machine vision detection of initial phase Angle of blade and coarse localization algorithm of the deviation of the center position,reduces the searching computation precision positioning process,and the method of laser probe to focus,reduce the depth error of measuring head.(5)Because the blade is not positioned by fixture,the contact between the blade and the upper surface of the machine tool rotation shaft through the bottom datum surface only limits the degree of freedom in Z,A and B directions,which belongs to incomplete positioning.In this paper,a precise positioning algorithm combining the datum probe data with the shafting position data is proposed,which limits the X,Y and C degrees of freedom of the blade,and realizes the 6-DOF full positioning of the blade datum.(6)Taking VS as the software platform,the application system of blade sectional numerical control measurement was developed,which integrated the function of cutting pattern layout,probe calibration,position and pose recognition,and numerical control measurement.The key algorithm,calibration process and measurement function proposed were comprehensively verified.