Robot Measurement Planning And Data Processing For Flange Seal Profile Of Nuclear Main Pump

Flange sealing surface is the key bearing boundary of nuclear main pump.It can withstand thermal/mechanical stress impact,heavy water corrosion,etc.In service,it is prone to failure such as profile deformation and surface spalling.The traditional method requires manual carrying of the contact gauge into the nuclear radiation field to complete the size error and surface defect detection,which is harmful to human body and the detection result is unstable.To solve this problem,this paper focuses on the construction of the robot's 3D optical measurement system,the collision-free measurement path,the measurement data processing algorithm,the calculation of size error/surface defect of sealed surface,etc.The main contents include:(1)Research on the generation method of collision-free measurement path of robot threedimensional optical measurement system.Considering the needs of field detection,the robot optical measurement platform was built,and the hand-eye transformation matrix of the robot was built to solve the mathematical model step by step.Considering the constraint parameters of field measurement,such as the depth of field,the range of measurement,and the Angle of measurement of the scanner,an optimization method of robot scanning measurement posture was proposed to complete the calculation of the Angle of the robot's 6 axis joints.The collision avoidance scheme under two modes of automatic measurement and manual measurement is proposed to realize the automatic generation of collision free measurement path for the robot of flange sealing profile.(2)Study the data processing,dimension parameter extraction and defect depth calculation method of flange sealing type point cloud.The point cloud normal vector estimation and realtime display algorithm based on the centroid movement is proposed,and the workpiece coordinate system-robot base coordinate system transformation matrix is used to replace the traditional PCA algorithm to improve the point cloud matching speed.The initial section of the flange ring part was determined through the initial path point of the robot,so as to achieve the circumferential unification of the point cloud coordinate system and the workpiece coordinate system.2D dimensions of the sealing surface were calculated based on the point cloud of each cross-section through the object.The defect depth and defect area calculation method based on three-dimensional point cloud was proposed,and the defect detection experiment was completed with samples containing defect features.The experimental results showed that the calculation error of this method was less than 10%.(3)Develop RobotScan,the robot's 3D optical measurement data acquisition and error calculation software based on the VS2010 platform,It has the main functional modules of data acquisition,data processing,network communication and robot control.The results show that the single measurement accuracy of the system is up to 0.02 mm,and the multi-angle splicing accuracy is up to 0.075 mm.The operation software controls the robot to complete the point cloud data collection,point cloud preprocessing and point cloud model matching process according to the preset path,and USES batch processing function to automatically calculate the 2D dimension of flange sealing surface.The whole measurement process is controlled within 15 minutes,which is more than 80% higher than manual detection efficiency.