An approach to investigate moire patterns of a reflective linear encoder with application to accuracy improvement of a machine tool

作者：Zhao, Lei; Cheng, Kai^*; Chen, Shijin; Ding, Hui; Zhao, Liang

来源：Proceedings of the Institution of Mechanical Engineers - Part B: Journal of Engineering Manufacture , 2019, 233(3): 927-936.

DOI：10.1177/0954405417752506

• Moire patterns
• reflective linear encoder
• three-grating system
• geometric errors
• machine tool accuracy

The accuracy of a machine tool is based on the direct position feedback from its built-in encoders which accurately measure displacements of motion axes by moire patterns. However, the posture of an encoder is altered by errors from the machine tool, resulting in six geometric deviations. A comprehensive analysis and scientific understanding on the influences of these deviations on moire patterns are necessary. To investigate the influences, a simulation model of a reflective encoder is constructed to obtain moire patterns, and four new methods are developed to identify characteristic parameters of the patterns. Variations in characteristic parameters caused by four geometric deviations are simulated and experiments are designed and performed. The results prove that the approach is able to assess the influences of geometric deviations. The approach can be used as a powerful aid for estimating impacts of geometric deviations and external errors on encoders to improve the accuracy of a machine tool.

• 出版日期2019-2
• 单位哈尔滨工业大学