Research On The Error Compensation Technology Of The Large Size Three Coordinate Measuring Orientation

As a three coordinate measuring instrument widely used in the field of aircraft digital assembly, the Laser Tracker has the advantages of high precision and high efficiency. In aircraft assembly process, enhanced reference system is frequently used to orient Laser Tracker and get the conversion between measured and theoretical coordinate so that the measurement results are unified to the assembly coordinate system.This paper relies on a key scientific research project of the model digital assembly. Expand research on technology of improving the Laser Tracker orientation measurement accuracy. The paper focuses on ERS-points thermal deformation compensation technology in Laser Tracker orientation.Chapter 1 introduces the development of digital measurement technology at home and abroad, the laser tracker system and its application in the field of digital assembly.. Discuss the background of Laser Tracker orientation measurement and the significance improving orientation precision. The research content is given at last.Chapter 2 introduces the Leica Laser Tracker measurement system, assembly coordinate system, device coordinate system in the digital assembly system. Explain the principle of laser tracker transfer station. Introduce SVD method to solve the orientation parameters.Chapter 3 introduces the solution to solve transformation parameters, analyzes the source counting for orientation error, and gives the measures to reduce the measurement error and registration error, offers a evaluation method of the transfer station.In chapter 4, the thermal deformation compensation coefficient matrix is used to compensate the ERS point according to the different thermal deformation of each ERS point in different directions. Establish a multi-objective optimization function of compensated ERS points and use Levenberg-Marquardt (LM) to optimize the solution. The experiment results showed that the compensation effect can be achieved.In chapter 5, the three methods of solving the thermal deformation coefficient matrix are analyzed. Compare registration error, the change of registration parameters relative to the non compensated orientation and the change of the thermal deformation coefficient matrix with the number of ERS points. The use occasions and conditions of the three methods are introduced.Chapter 6 summarizes the research content of the paper. The prospects for further improvement and research work are also discussed.