CN-119087907-B - High-precision calibration method for measurement control field in long time domain assembly process

CN119087907BCN 119087907 BCN119087907 BCN 119087907BCN-119087907-B

Abstract

A high-precision calibration method for measuring a control field in a long time domain assembly process includes the steps of firstly, obtaining actual measurement coordinates of ERS points and coordinates before and after an additional orientation point moves in the measurement control field by means of laser networking measurement, calculating conversion parameters between nominal benchmarks and actual calibration benchmarks of the measurement control field through current actual measurement coordinates of series of identical ERS points in the measurement control field and the original calibration nominal coordinates, aligning the ERS points and the orientation point coordinates under the actual measurement benchmarks to the nominal benchmarks, obtaining coordinate deviations of the ERS points under the nominal benchmarks, setting coordinate deviation thresholds according to requirements, constructing an additional orientation point-based orientation constraint, introducing a solution model with the minimum sum of the ERS point coordinate deviations as a target to form a new conversion parameter optimization solution model with the minimum sum of the ERS point coordinate deviations, and carrying out global assignment on the ERS points in the measurement control field again based on the conversion parameters to achieve calibration of the measurement control field precision in the long time domain assembly process, and guaranteeing high-precision transmission of quality data.

Inventors

ZHANG YANG
Yan Ruidi
LU YONGKANG
WANG JIAWEI
LI JUNQING
WANG SHOUCHUAN
WEI HONGYANG
LIU WEI

Assignees

大连理工大学

Dates

Publication Date: 20260508
Application Date: 20240829

Claims (1)

1. A high-precision calibration method for measuring a control field in a long time domain assembly process is characterized by comprising the following specific steps: first step, ERS point and directional point networking measurement in measurement control field Firstly, adding movable orientation points in an assembly site measurement control field, placing a plurality of laser trackers in the measurement control field, obtaining actual measurement coordinate values of ERS points in the measurement control field through laser networking measurement, and constructing a Data set Data, wherein the Data set Data is shown in a formula (1): (1) in the formula, For the measured coordinates of the ith ERS point under the measured reference, M is the number of ERS points in the measurement control field; secondly, obtaining initial measured coordinates of the additional movable orientation point Then controlling the additional movable orientation point to perform orientation movement, and obtaining the actual measurement coordinates of the end point of the additional movable orientation point ; Second, solving coordinate deviation of ERS point under nominal reference of measurement control field Is provided with The nominal coordinates of the ith ERS point under the known nominal reference are calculated by the nominal coordinates of the ERS point in the nominal reference and the actual measured reference based on the least square principle Measured coordinates Solving conversion parameters between a nominal reference and an actual measurement reference, namely a rotation matrix and a translation vector, wherein the conversion parameters are shown in a formula (2); (2) in the formula, And A rotation matrix and a translation vector for the measured reference to the nominal reference, as shown in (3); (3) In the formula, 、、 C and s respectively represent a sine function and a sine function; actual measurement coordinates of ERS points in actual measurement reference Attaching initial measured coordinates of movable orientation points Adding movable orientation point end point actual measurement coordinates Converting to a nominal reference as shown in formula (4); (4) in the formula, For measuring the measured coordinates of the ith ERS point of the control field at nominal reference, For the origin coordinates of the movable orientation point to be appended at the nominal reference, Then, calculating the deviation between the actual measurement coordinates of the series of the same-name ERS points under the nominal reference and the nominal coordinates and the displacement before and after the movement of the orientation points through a formula (5); (5) in the formula, For the i-th ERS point, the measured coordinate is offset from the nominal coordinate at the nominal reference, thus , Displacement of the orientation point before and after movement under the nominal reference; third, solving conversion parameters based on nominal coordinate iteration correction Firstly, establishing a conversion parameter optimization solving model with the minimum sum of ERS point coordinate deviations as a target, wherein the parameters to be optimized are conversion parameters between an ERS point name coordinate deviation value and a nominal reference and an actual measurement reference, and setting an ERS point name coordinate deviation threshold value by considering the actual measurement process requirement in the assembly process and avoiding the occurrence of an overfitting condition, wherein an objective function is shown as a formula (6), and a constraint function is shown as a formula (7): (6) (7) in the formula, , As a conversion parameter between the nominal reference and the measured reference, The nominal coordinate deviation value obtained by the jth optimization of the ith ERS point, N is optimized for the number of times, , And Respectively an upper limit and a lower limit of a coordinate deviation threshold value, and passing through the nominal coordinates of the ERS point under the nominal reference Measured coordinates Displacement of orientation point before and after movement under nominal reference Carrying out optimization solution by adopting a particle swarm algorithm, wherein an fitness function in the algorithm is an objective function, carrying out iterative correction on nominal coordinate values of ERS points, and finally obtaining conversion parameters between nominal references and actual measurement references , And finally, nominal coordinate deviation value of ERS point obtained by nth optimization As shown in formula (8); (8) Secondly, based on the conversion parameters, obtaining the actual measurement coordinates of a new group of ERS points in the measurement control field by using a laser tracker Wherein K is the number of ERS points in the acquired measurement control field, then based on the acquired conversion parameters, converting the measured coordinates of the ERS points under the measured reference to the nominal reference, as shown in (9), (9) In the formula, The ith ERS point solved based on the conversion parameters is converted into coordinate values under a nominal standard; then, the actual measurement coordinates of the new set of ERS points converted to the nominal reference are calculated Nominal coordinates from nominal reference Coordinate deviation of (2) As shown in (10); (10) 。

Description

High-precision calibration method for measurement control field in long time domain assembly process Technical Field The invention belongs to the field of digital measurement and assembly, and relates to a high-precision calibration method for a measurement control field in a long time domain assembly process. Background In-situ assembly driven by digital measurement has become one of the mainstream manufacturing modes of large-scale aerospace components, wherein accurate measurement and transmission of geometric information are the core for realizing high-precision assembly of aerospace equipment. At present, observation data of each local measurement system in an aerospace assembly site, pose data of an execution tool/device and the like are all required to be taken as a bridge, and the data are transmitted to a global coordinate system, so that the accuracy and reliability of the measurement control field directly influence the assembly quality of a final product. However, the factors such as the loading effect of the ground of the aerospace assembly workshop and the natural settlement of the foundation are easy to generate non-uniform deformation, so that the original calibration information in a measurement control field is misaligned, and the temperature difference in the long-time-domain cross-season assembly process causes thermal expansion and cold contraction of the ground. Together, these factors result in significant shifts in the measurement control field at each control point (also known as ERS point), with consequent failure of the global information (nominal coordinate values) carried by it. At this time, if conversion parameters between different references are solved by using the nominal coordinates of the control points in the measurement control field, a large unified error of the references is easily caused, so that the quality data transmission precision is seriously reduced in the assembly process. In conclusion, aiming at the problem that the measurement control field has poor accuracy and reliability due to foundation settlement, temperature difference, large load and other factors, a high-accuracy calibration method of the measurement control field in the long-time-domain assembly process is provided, and accurate transmission of quality data in the assembly process is ensured. The invention discloses an aircraft assembly measurement field point position calibration method, which comprises the steps of collecting data of an orientation point and a measurement site through a laser tracker, calculating ERS point and TB point coordinates according to the orientation point coordinates and the measurement site coordinates through a adjustment algorithm, converting the ERS point and TB point coordinates into a coordinate system of a measurement field to finish point position calibration, and in an automatic calibration method, a device, equipment and a medium of a measurement reference network and a patent number CN202410080738.7, converting the ERS point coordinates into ERS point theoretical coordinates in the measurement reference network by adopting a conversion station comprehensive error assessment method through obtaining the ERS point coordinates and adopting a unified space measurement network technology. The method only considers retesting the ERS point and TB point coordinates of the assembly site so as to finish point position calibration in the assembly measurement site, does not correct the ERS point coordinates under the nominal reference, solves the obtained conversion parameters of the nominal reference and the actual measurement reference, is still inaccurate, and has larger reference unification error. Therefore, the invention provides a high-precision calibration method for a measurement control field in a long-time-domain aviation assembly site, when the actual measurement coordinates of ERS points of the measurement control field are obtained, movable orientation points are added to form orientation constraint, and further, the nominal coordinates of the ERS points are subjected to iterative correction, a rotation matrix and a translation vector between the nominal reference and the actual measurement reference are solved, and global assignment is carried out on all ERS points in the measurement control field again, so that the calibration of the precision of the measurement control field in the long-time-domain aviation assembly process is realized, the unified reference errors caused by foundation settlement and other factors are reduced, the high-precision transmission of quality data in the assembly process is ensured, and the method has good universality and wide application prospect. Disclosure of Invention The invention aims to provide a high-precision calibration method for a measurement control field in a long time domain assembly process. The technical scheme of the invention is as follows: A high-precision calibration method for measuring a control field