Research On Thermal Deformation Error Compensation Technology Of Laser Tracker Orientation In Non-uniform Temperature Field

Throughout the aircraft assembly process, the measurement technology of laser tracker orientation provides an accurate source of data for the aircraft assembly quality testing and evaluation, and also plays an important role in the subsequent maintenance of the assembly system. The accuracy of the laser tracker is determined by the accuracy of the station, however the ERS point position change and the measurement error of the measuring equipment seriously affect the station precision. With the continuous improvement of measurement technology, the measurement error of laser tracker is greatly reduced, ERS point position change has become the main factor affecting the accuracy of station. The ERS point position change caused by the thermal deformation is particularly significant. In the measurement of the station, it is very important to control the change of ERS point position with the temperature and to suppress the adverse effect of ERS position change on the station precision. In this paper, the calculation methods of ERS point position change with the temperature change for two common tooling models in non-uniform temperature field are studied. On this basis, thermal deformation error compensation technology is further studied and analyzed in non-uniform temperature field station.Chapter 1 describes the digital assembly technology of aircraft, and discusses in detail the development of digital measurement technology at home and abroad, and then describes the measurement technology of laser tracker orientation and the orientation error. The research status of the thermal deformation error in the orientation measurement is analyzed, and the research content and structure frame of the paper are given according to the engineering practice.Chapter 2 mainly introduces the theoretical basis of mechanical thermal deformation, and expounds the basic theory of the heat conduction and its related concepts. The basic theory of thermo-elasticity is introduced in detail. The thermal expansion coefficient is introduced, and the relationship between the linear expansion coefficient and the body expansion coefficient is analyzed.In Chapter 3, the long-type tooling which is common in practice is simplified as a one-dimensional model, and the thermal deformation model of the long-type tooling in non-uniform temperature field is established,by using thermal deformation theory. Taking aluminum as an example, the non-uniform temperature field and the parameters are set reasonably. ABAQUS is used to simulate and verify the method of calculating the variation of ERS points on long-type tooling. The calculation method of ERS point change on long-type tooling is analyzed and summarized.In Chapter 4, based on the thermal deformation model of the one-dimensional long-type tooling, the common plane frame type tooling is simplified as the truss tooling, and the thermal deformation modeling of the common four-bar truss tooling is practiced. The method of ABAQUS was used as the verification method, and the calculation method of ERS point change on truss tooling is analyzed and summarized.In Chapter 5,for the ERS points on the long-type tooling and truss tooling in the non-uniform temperature field, the initial theoretical and post-deformation measurements of the ERS points are obtained using the ABAQUS software. The uniform temperature compensation method and the method in this paper are used to carry out the transfer station, and the station errors are compared and analyzed. The results show that the proposed method has higher accuracy.Chapter 6 summarizes the research contents of this paper, and makes the prospect of further research.