Research And Application Of End Runout Measurement Technologies Of DD Motor Based On Linear Structured Light

DD(Direct Driver)motor is widely used in semiconductor,LCD engraving machine and other high-precision positioning occasions,which is the core component of highprecision manufacturing.It has the advantages of direct drive,no transmission error,and high positioning accuracy.The deviation in end-face runout of the DD motor has a direct impact on the transmission accuracy and motion smoothness of the manufacturing equipment.To guarantee that the end-face runout of each DD motor satisfies the highprecision requirements of the manufacturing equipment,end face runout inspection must be carried out before leaving the factory.At present,the end-face runout detection of DD motors in China is commonly performed by workers using a dial indicator for contacttype detection,which not only poses a risk of surface damage to the measured component,but also can only measure the end face runout value of one circumference at a time,and needs to be measured multiple times in multiple radial directions In order to get more accurate results,the efficiency is low.Many parts cannot use contact measurement methods due to the existence of mounting holes on the end faces.The industry urgently needs to adopt non-contact measurement methods based on machine vision to achieve end face runout evaluation while improving detection efficiency.Aiming at the engineering application of the non-contact measurement of DD motor runout,research on key technologies such as the design of the end face runout measurement system based on line structured light,the collection,simplification and segmentation of DD motor point clouds,and the fitting of measurement benchmarks are carried out.It is of great significance to measure and evaluate the runout and flatness of rotating parts.The main research content and results are as follows:(1)The mainstream three-dimensional measurement schemes are analyzed and compared,and the end-face runout measurement scheme based on line structured light is designed in combination with the DD motor end-face runout engineering application scenario.By integrating vertical incidence line lasers,CCD cameras and other 3D visual measurement components and motion controllers,a fully automatic measurement test bench for end face runout of rotating parts is constructed to collect point cloud data of the parts to be tested.(2)To simplify the point cloud,the research on point cloud simplification algorithm is carried out.Analyzing the shortcomings of the traditional point cloud reduction algorithm that may destroy the measurement accuracy,a point cloud reduction algorithm based on uniform down-sampling is designed,an experiential equation was also developed to determine the key parameters for implementing the algorithm;the algorithm based on curvature and density is proposed to accurate acquisition of the point cloud of the DD motor target measurement surface,which solves the shortcomings of oversegmentation and mis-segmentation of the point cloud that are prone to occur in traditional methods.(3)A fitting model of the survey datum level is constructed.A point cloud plane fitting algorithm based on ICook-WTLS is designed to address the issues of low precision and limited noise immunity.The algorithm effectively optimizes the fitting accuracy of the point cloud plane while resisting noise by improving the Cook distance,adaptively setting the threshold,and introducing weighted total least squares(WTLS).(4)Based on Qt framework,PCL point cloud library,SQLite database,multi-thread programming and other technologies,the overall structure and functional modules of the DD motor end face runout measurement system were designed and developed.And the effectiveness of the algorithm and software system was demonstrated through comparative experiments using a dial indicator,which laid the foundation for further promoting the engineering application of end face runout measurement of rotating parts.