Development Of Measuring System For Smooth Gauge’s External Diameter Based On Machine Vision

As widely used of tube and hole parts in automotive industry,aerospace industry and other batch manufacturing industries,the requirement of high precision and high efficiency is put forward for the detection of such parts.In order to ensure the reliable operation of the equipment and reduce the hazard caused by the match problem,it is important that the detection of tube and hole parts.It is efficient method that use smooth gauge for testing processing quality of this kind part,however,the measurement with smooth gauge is a kind of contact measurement,it is easy to wear and tear,so this needs often to measure the smooth gauge.The traditional measurement method of the smooth gauge is not high efficiency and single measuring parameter,therefore,it is very urgent and necessary to develop a high efficient,high precision measuring instrument for the smooth limit gauge.In this paper,the main contents researched in this thesis are as follows:(1)The measuring system for the external diameter of smooth gauge based on machine vision is developed.The system is consisted of mechanical system,electrical system and optical system and it set up a test bench which can realize the test need of smooth gauge combing with the grating and the Labview software;Positioning of the platform is by the grating and control is by the Labview program.(2)The measuring system for the external diameter of smooth gauge is using the machine vision technology and the image got in the measurement is processed by the digital image processing technique.A set of precessing methods is designed for the image threshold segmentation which is the key in digital image processing technique and the image of edge is effectively extracted.(3)The calibration of measurement system is done precisely and the calibration method and steps are researched and given;Under the condition of professional measurement,the experiment is done through the designed method of the digital image processing and the relationship between the threshold and diaphragm or light intensity are preliminary obtained.(4)The error analysis of the measuring system is presented,including seven source of error to the system:the error of the mechanical parts of the test bench,the imaging error of image sensor,the error of lens distortion,the error caused by temperature,the error of image system calibration,the error caused by the workbench movement and the error caused by the grating ruling and the aspect is effected by these errors;The calculation formulas of these errors are given through the theoretical analysis and the comprehensive precision is carried on using the error theory.Through the experimental analysis and validation,the measurement system has the characteristics of efficient and fast measurement for smooth gauge which can realize the purpose of obtain multiple parameters by one measurement and it is easy to realize high precision measurement of smooth gauge;By testing a single complete measuring time is not more than 200 seconds and the repeat accuracy is not greater than one micron.