Hub Eccentricity Measurement Based on Machine Vision

Abstract:

In this investigation, a measurement system based on machine vision applied for auto-hubs eccentricity between the center hole and the pitch circle of bolt holes was proposed. The measurement system was integrated by a CCD camera with a telecentric lens, a diffuse bright-field back light illumination system, a rotating platform, a rotating encoder and an industrial computer. The camera was fixed at a suitable location from the rotation center, which ensured that one bolt hole and a part of the center hole could appear in its visual field. All bolt holes were shot when the auto-hub was rotating, while a rotary encoder recorded these angles. Then a global image of the auto-hub could be tiled by these pictures. An image-processing algorithm integrating morphology, circle fitting, affine transformation and edge extracting was used to measure the auto-hubs eccentricity. According to the measurement of a standard block that had 50um-eccentricity and was manufactured by WEDM-LS (Wire Cut Electrical Discharge Machining-Low Speed), the maximum deviation between measuring value and real value was less than 0.013mm, eccentricitys standard deviation was 0.0035mm and the standard deviation of eccentricitys direction angle was 2.37°. Meanwhile the experimental data of real auto-hubs gave an eccentricitys standard deviation less than 0.013mm and a direction angles standard deviation less than 2.1°.

• Periodical: Advanced Materials Research (Volumes 718-720)
• Pages: 409-414
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.718-720.409
• Online since: July 2013
• Authors: Rui Han, Feng Ling Zhang, Shu Xia Guo, Peng Yin, Lei Wang
• Keywords: Auto-Hub, Eccentricity, Machine Vision, Standard Deviation

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