Research on Benchmark Ruler Measurement Method based on Cluster Analysis

In order to improve the accuracy of the traditional laser tracking interferometric length measurement method and make the traceability of the datum ruler more reliable, a datum ruler measurement optimization method under multi-attitude is proposed in the paper. The method firstly constructs a multi-attitude datum ruler layout on the basis of traditional laser tracking interferometric length measurement, and collects the measurement information in different datum ruler directions under the layout by a laser tracker, and then adopts the weight-based optimization strategy to optimize the combination of measurement data, and then outputs the measurement results and carries out the analysis of the error source and the evaluation of the uncertainty, and finally conducts experimental analysis on the datum ruler with an accuracy of 1000mm based on the optimization scheme. Finally, based on this optimization scheme, an experimental analysis is carried out on the 1000mm datum ruler, and compared with the CMM method with higher accuracy, the En value is 0.1, which verifies the reasonableness of the uncertainty assessment, and it is found through experimental comparisons that the reference lengths output from the measurement optimization scheme with multiple postures are more reliable than those with single postures. The optimization method provides a new calibration scheme for achieving the traceability of the measurement value of high-precision large-size reference ruler, which has good practicality and certain guiding significance.