CMOS Based Measuring Technique And Apparatus For Wheel Hub Pitch Circle

Aluminum wheel hubs are the important parts of vehicle for safety. In modern vehicle manufacturing, the installing parameters of wheel hubs have direct impacts on the performance of vehicle. As the social economy develops, the production of wheel hubs becomes more and more intelligent and accurate.This paper introduces a CMOS based measuring technique and apparatus for wheel hub pitch circle. As a new measuring method, it makes use of CMOS imaging technique and computer image processing technique to carry out the pitch circle measurement. With the combination of certain algorithms in image processing and camera calibration, an effective measuring system for pitch circle is formed. Besides, this measuring system can be further developed to contain integrated measuring functions for wheel hub in the future.Computer image processing is an advanced measuring method that works in a non-contact way. It can overcome the disadvantages of simplex function, lower efficiency, and intricate operations with traditional measuring methods, and has good flexibility to different-shaped hubs. This is very meaningful for quality assurance of hubs and reduction of production cost. Therefore, this new measuring technique is of high research value and application value.The paper first introduces the background of wheel hub measuring techniques, and then brings forward the main scheme for pitch circle measurement. Two crictical techniques, image processing and camera calibration, are discussed and implemented. Meanwhile, the hardware and software development of measuring system is also explained. Finally, the measuring results for pitch circle are listed out.