Measurement reference deviation correction method based on thermal expansion coefficient reverse solution

Abstract

The invention discloses a measurement reference deviation correction method based on thermal expansion coefficient reverse solving, belongs to the field of geometric quantity measurement, and relates to the measurement reference deviation correction method based on the thermal expansion coefficient reverse solving. The method comprises the following steps: firstly, synchronously measuring temperature and reference point coordinates under a local active temperature control condition of a tool; secondly, reconstructing a temperature field function, and reversely solving the optimal thermal expansion coefficient based on the mapping relation between the temperature and the reference point coordinate offset; secondly, correcting the coordinates of the reference point by adopting a scaling method; and finally, establishing a conversion relation between the measurement reference and the digital-analog reference by using a least square method, and solving a conversion error before and after reference correction. By means of the method, field calibration of the thermal expansion coefficient of the tool can be achieved, and reference deviation correction in the non-uniform temperature environment is completed. The method can improve the reliability and consistency of the measurement reference, and can be applied to the engineering fields of measurement reference and digital-analog reference matching, laser tracker transfer error correction and the like in the field non-uniform temperature condition large-scale component manufacturing.

Description

technical field [0001] The invention belongs to the field of geometric quantity measurement, and relates to a measurement reference deviation correction method based on inverse thermal expansion coefficient. Background technique [0002] With the advancement and implementation of major aerospace strategies such as long-range wide-body passenger aircraft and manned space stations in my country, the manufacturing requirements for large-scale component products are also getting higher and higher. In the process of machining and assembling large components, the measurement datum is used to match the measurement data with the digital model of the component, and then guide the manufacturing process. Therefore, its accuracy and stability are the prerequisites to ensure manufacturing quality and process consistency. This type of datum consists of several datum points on the component tooling, and there is a known conversion relationship with the digital-analog datum. However, affec...

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Problems solved by technology

This method substitutes the material thermal expansion coefficient obtained from the look-up table into the finite element model for calculation, but due to factors such as the composition difference of the tooling material and the error transmission of the measurement system, there is a large gap between the real thermal expansion coefficient and the theoretical value of the tooling material under field conditions. The thermal deformation calculation method based on the look-up table method has low accuracy; while the current thermal expansion coefficient verification of materials needs to be carried out in a constant temperature measurement room, the steps are cumbersome and the cost is high

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