Auxiliary Positioning Method And System Implementation Of Nuclear Reactor Pressure Vessel Inspection Platform

Nuclear reactor pressure vessels are important equipment for nuclear power plants.According to the requirements of the pre-service in-service inspection program for nuclear power plants,automatic inspection technology must be used to implement regular inspections of pressure vessels.Aiming at the problems that the nuclear reactor vessel inspection platform cannot achieve automatic positioning and low positioning accuracy at this stage,this paper proposes an auxiliary positioning method based on the combination of binocular vision and line structured light,through program design,hardware selection,platform construction and system calibration The research of algorithms such as,measurement,etc.finally realized the automatic positioning of the nuclear reactor pressure vessel inspection platform.The main research work of the thesis is as follows:First,an auxiliary positioning method based on binocular vision and line structured light is proposed.The hardware of the auxiliary positioning system,such as cameras,lasers,and light shields,was selected.At the same time,the hardware layout of the auxiliary positioning system was optimized according to the actual situation of the nuclear reactor vessel inspection site.Secondly,the calibration of the auxiliary positioning system is completed.Explain the camera imaging model,use Zhang Zhengyou calibration method to complete the calibration of the binocular camera;design auxiliary calibration parts according to the detection probe structure,use the least square method to fit different plane spaces to achieve the calibration of the probe axis;use the absolute articulated arm And based on the method of singular value decomposition of common feature points in space,the camera coordinate system and the coordinate system of the carriage are unified.Subsequently,the auxiliary positioning system was used to collect the image of the structured light on the surface of the penetrating part,and the image was preprocessed and fracture repaired,and the target area was screened by the threshold method.The epipolar line constraint is used to complete the matching of the points of the same name,and the three-dimensional reconstruction of the line structured light is realized;the plane cutting method is used to realize the fitting of the axis of the penetrating piece,and the deviation value of the alignment is calculated,which provides the positioning of the inspection platform in accordance with.Finally,in order to verify the measurement accuracy and positioning error of the auxiliary positioning method in this paper,an experimental platform was built,and the positioning results were evaluated by the high-precision absolute articulated arm.Experimental results show that the measurement accuracy of the auxiliary positioning method can reach 1.7mm,and the positioning deviation can be controlled within 2.6mm,which meets the requirement that the field positioning deviation should be less than5 mm,and has the ability to complete the positioning task of the detection platform.