Dynamic Behaviour Analysis of Optical Linear Encoder under Mechanical Vibrations

Donatas Gurauskis,Artūras Kilikevičius

doi:10.5755/j01.mech.26.1.23070

Abstract

Mechanical vibrations are probably inevitable and occur in more or less all machine tools and other technological equipment. In case the linear encoder is used for moveable parts positioning in such machines, vibrations could cause additional errors. This paper investigates the dynamic behavior of the optical linear encoder under mechanical vibrations. Potentially the most harmful frequencies are determined experimentally, and the corresponding mode shapes are simulated by using finite element method (FEM). Obtained results describe tested encoder`s construction dynamic response to external excitation and could be used to improve its design.

Highlights

Optical linear encoders play noticeable role in performance of computer numerical controlled machines (CNC) [1], coordinate measuring machines (CMM), robotics [2], positioning stages [3], tracking systems [4] and other precision positioning applications [5]
The optical linear encoder analysed in this work is incremental
In case, when the reading head is mounted in fixed position as well as the aluminum extrusion, generated output signals are presented as a circumference arc of the Lissajous curve

Summary

Introduction

Optical linear encoders play noticeable role in performance of computer numerical controlled machines (CNC) [1], coordinate measuring machines (CMM), robotics [2], positioning stages [3], tracking systems [4] and other precision positioning applications [5]. Resonance in measuring device parts like aluminium extrusion or reading head, either in supporting elements of the application could cause additional undesirable motion of a scanning carriage (cursor) along a measuring scale. There are developed methodologies to evaluate optical encoders performance under vibration [9] or compensate vibration caused errors [10], but in order to have a good understanding of ongoing processes in mechanical construction of each encoder, more detailed investigation such as modal analysis is required. In order to establish how the encoder elements, behave at these resonances, the modal analysis is done

Experimental details

Results and discussion

Conclusions

Summary