The Research Of6D Precision Laser Tracking Measurement Techniques

The laser tracker is a new large-size space measuring instrumentswhich was developed in recent decades, It can not only make high-precision3D measure for space stationary target，but also track and measure thespace position and pose of the moving target. Easy installation,real-time scanning measurement and high measurement accuracy are itsadvantages. Therefore, it has been rapidly developed in recent yearsbecause it is the primary means of large-size industrial measurement andscientific measurement.Laser tracking head combined high-precision laser ranging technologywith the precise angle measurement of the theodolite. It adopts thepoint-measuring way to carry out the error measurement of the size andshape of the large size target workpiece and provides real-timemeasurement benchmark for assembly and inspection of larger part. Inaddition, the laser tracking and measurement head can implement rapidfacial measurements on flat and curved surface by scanning measurement.6Dmeasurement system can monitor the information of the distance and poseof the target, which has a vital role in the docking process of theinstallation of large systems. The laser tracking head features rapidand dynamic measurement without rail, high accuracy, convenient forinstallation and moving. Thus, it has very high value in the assemblyand inspection of larger part of installation and detection in scienceprojects, large-scale equipment construction, aerospace, ships, cars,track laying process, and so on.Based on the measuring principle of the polar coordinates, This paperdesigned a six-dimensional precise laser tracking head measuring systemthat was composed of laser tracker and collaborative targets, that ismeasuring the target‘s space coordinates (x, y, z) and attitude (pitchangle, yaw angle, roll angle).Laser tracking head structural elements including the interference laser ranging units, the absolute laserranging unit, two-dimensional precise tracking theodolite, servo controlunit, the refractive index of air compensation unit, the instrumentsupport, management computer unit, electrical control box and the targetsof cooperation.This subject is based on the project of3D portable, multi-functionalprecision laser tracking head, using the spherical coordinatemeasurement principle, designed a six-dimensional information measuringsystem that was composed of a single laser tracker and cooperative target.The thesis focuses on the study of designing cooperative targets andtheodolite, the main duties include:1.The technique of6D laser tracking and measurement system. The keymeasurement system technology, that is how to extend3D measurement to6D measurement, convert the data acquired by cooperative target to thepitch angle, yaw angle and roll angle. At the same time obtain thetransformation matrix from the tracker coordinate, rotating mirrorcoordinate of this system to world coordinate.2.The overall design of the laser tracking head. Including the designof the horizontal shaft, vertical shaft, tracking reflection mirror. Thefocus of this paper is the design of the cooperative target, through themodification of the target reflection mirror, manually measure the yawangle, pitch angle and roll angle of the target point.3.Analyze the accuracy and calculate the error of the laser trackinghead systematically.Including angle measurement accuracy of the trackingtheodolite, measurement distance, the measurement error of thecooperative target that was induced by the tilt sensor and PositionSensing Detector.It is proved that all errors can be reduced to the indexrange which was set previously via computing.