| With the advantages of non-contaction, automation, objective, high precision, as well as being easy to combine with automatic control and communication technologies to improve the efficiency and automation level of industrial production and manufacturing, machine vision technology has been studied deeply and applied widely in worldwide.In this paper, based on the requirement of controlling the initial electrochemical machining gap, as well as being adapt to the development of manufacturing technology, machine vision technology was used in the measurement of initial electrochemical machining gap, and the measurement system based on machine vision was built.After studying the composition of machine vision system as well as the performance parameters and selection methods of the needed devices, a hardware system for image acquisition was designed and built. By setting the background, adjusting the light sources and camera, ideal experiment images can be captured with the system.Based on the analysis of the gap images and the associated image processing algorithms, the appropriate image processing methods was selected, a function for gap distance measure was written, which can get the pixel distance of the gap in the image. For the non-linear distortion of machine vision system, an image rectification processing was conducted, which significantly reduced the distortion level of the image. And by use of system calibration, the pixel size of the gap detected first was transformed to the the actual size in millimeters. A software system which realize the algorithms and functions in use was developed in VC++6.0 enviroment.In order to validate the system, experiments were carried on the initial gap of both electrochemical turning with line tool electrode and multi-axis electrochemical machining with spherical electrode, and the experimental data shows that the test results are basically consistent with the actual size and meet the expectations. |
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