Large-scale precision turntable calibration method based on multi-station measurement system of laser tracker

Abstract

The invention discloses a large-scale precision turntable calibration method based on a multi-station measurement system of a laser tracker. The method comprises the following steps of building a laser tracker multi-station measurement system, self-calibrating the laser tracker stations based on the Levenberg-Marquardt algorithm, selecting the parameter mui, optimizing coordinates of the laser tracker stations, fitting the center of circle of the rotating shaft of the turntable, and calibrating the positioning accuracy of the large-scale precision turntable. The method utilizes the Levenberg-Marquardt algorithm and the singular value decomposition transformation method of the covariance matrix to optimize the coordinates of the laser tracker stations, and calibrates the positioning accuracy of the turntable by establishing a geometric relationship model between the optimized coordinates of the laser tracker stations and the rotation angle of the turntable. The proposed method for calibrating the positioning accuracy of the turntable based on the multi-station measurement system of the laser tracker is suitable for the case where the turntable and the three-axis machine tool are notlinked, and is particularly suitable for large-scale high-precision turntables. At the same time, the method can provide a theoretical basis for the calibration of multi-axis machine tools.

Description

technical field [0001] The invention relates to a method for calibrating a large-scale precision turntable, in particular to a method for calibrating a large-scale precision turntable based on a multi-station measurement system of a laser tracker. It belongs to the technical field of precision testing. Background technique [0002] Multi-axis machine tools can realize high-precision, high-efficiency, high-reliability, and high-intelligence processing of complex parts, and are key equipment in modern machinery manufacturing. With the continuous development of the manufacturing industry and the complexity of parts processing, the processing of many parts must use the indexing accuracy of the turntable to meet the position accuracy requirements of the parts at different angles. The indexing accuracy of the turntable directly affects the machining accuracy of the parts. For specific applications, the turntable is separated from the machine tool without linkage, and the turntabl...

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Problems solved by technology

Among them, high-precision optical instruments such as laser interferometers and photoelectric autocollimators need to be built, which takes a long time and cannot meet the requirements of fast and efficient calibration; the method of installing multi-faceted prisms and other optical components on the spindle to realize the calibration of the turntable , not suitable for large-scale turntables, because it is very difficult to install the multi-faceted prism, and it is difficult to ensure the installation accuracy; for the method of laser tracker calibration turntable, due to the small tracking angle range of the laser tracker, full-circle measurement cannot be realized; for the electronic theodolite calibration method, you can Overcome the shortcomings of the difficulty in determining the center of rotation of the eccentric turntable and the small field of view of the autocollimator, but it is difficult to select the observation point and the calibration accuracy is not high

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