Research On Factors Of The Accuracy Of Photoelectric-angular Encoder Influenced By Coupling

With the rapid development of aviation technology, the requirements of photoelectric-angular encoder accuracy is more and more demanding, this would make it can measure angle precisely in real time either in tough environment or complex conditions. However, the existence of coupling and installation error of photoelectric encoder will affect angle measurement precision when it is loaded into the overall machine. At present, in our country high accuracy axial angle encoder designed cant not meet the request due to the limitation of the accuracy of coupling itself.So it is necessary to study photoelectric encoder coupling in order to meet high accuracy operational requirements.Firstly, considering the basic principle and structure characteristics of photoelectric-angular encoder, this paper analyzes factors that influence the measurement accuracy of photoelectric-angular encoder, and analyzes detailedly the impact of coupling on the measurement accuracy of the encoder. Besides, the geometric model is established which is used for analyzing the coupling's effects on the measurement accuracy of encoder, and a method is proposed for calculating the angle error that coupling alone produces. The design idea of coupling in this article is that the angle error is minimized in the actual condition and a limit of the strength criteria. Then, analyze statically the original coupling by using the finite element analysis, including the axial compensation performance and radial compensation performance of coupling, simulating the shock deformation. What's more, sensitivity analysis on angle error is made for thickness, diameter, fan angle and width of the structure of the ear coupling parameters. According to the results of the sensitivity analysis, a new design of the coupling is proposed.Finally, a test is designed to measure the encoder error that produced by coupling only, and the test result is basically consistent with the calculated results, which prove that the mathematical models and computational methods in this article is correct.