An Analysis of the Optical System of a Length Measurement Comparator

Rimantas Lazdinas,Eugenijus Jurkonis,Vladas Vekteris,Vytautas Turla,Mindaugas Jurevicius

doi:10.5755/j01.mech.26.6.24554

Abstract

In the paper, the optical system of a precise bar length measuring comparator is analysed. The requirements for such a system are determined and systematized. The impact of the resolution, signal discretization frequency, image blurring, bar edge measurement indeterminacy and camera noise on measuring the bar width and establishing the bar position is discussed upon. Various algorithms have been analysed and finally a bar edge identification algorithm oriented to the scale calibration accuracy and the high processing speed was proposed. In the end of the paper, conclusions are provided.

Highlights

The increasingly growing level of industry robotization causes a need in high accuracy bar length measures and the latter, in its turn, stimulates an acceleration of the processes of manufacturing such measures
Upon striving to ensure the required efficiency, new measurement system and methods that would enable to achieve a high accuracy of dynamic calibration upon non-ideal metrological conditions are being developed
The accuracy of detecting the bar position upon using a length or angle measurement comparator [1, 2] is considerably affected by the optical system of the comparator

Summary

Introduction

The increasingly growing level of industry robotization causes a need in high accuracy bar length measures and the latter, in its turn, stimulates an acceleration of the processes of manufacturing such measures. Upon striving to ensure the required efficiency, new measurement system and methods that would enable to achieve a high accuracy of dynamic calibration upon non-ideal metrological conditions are being developed. The interferometer enables to compensate elongations and deflections of the granite base If such deformations appear during a measurement, they can cause Abbe errors while detecting the position of the line under calibration. For bar detection (edge identification) in length calibration systems, a photoelectric microscope with CCD (charge-coupled device) or CMOS (complementary metal oxide semiconductor) sensors is used. In the further calculations, the values of the directional factor β are considered the same for all edges of the signal approximated by straight lines [4]

The object under investigation

An analysis of the optical system

Results and discussion

Summary