Automatic Detection System On Zero Position Of Optical Encoder Based On Machine Vision

The optical encoder has been used widely in the systems of angel position measurement, digital control and automation equipment. With the development of optical encoder’s application field and precision was constantly improved, the accuracy of measurement system of optical encoder, performance and efficiency is also put forward higher requirements. The precision of the incremental encoder is associated with assembly accuracy. A special set of narrow slit in the incremental photoelectric encoder used for generating a set of zero signals. The Accurate alignment of the code disc’s zero position and the radial grating’s zero position can affect the encoder’s accuracy, stability and reliability.In recent years, with the continuous progress of manufacturing industry, in the field of machine vision carried out a large number of application study, obtained the gratifying achievement and gained enormous economic benefits in some important areas. In some field, machine vision can instead of human to work and used in place of any work to human eyes. Even the machine vision can completed the jobs of human eye can’t completed. Similar as in perceptual invisible objects and dangerous scenario, using computer vision this part of the computer industrialization, it fully reveals its advantage.This research combines the actual project of the incremental encoder’s enterprise production. The traditional method is workers completed in visual proofreading before the incremental photoelectric encoder has been leaved factory, Because of lower work efficiency of artificial detection and lower accuracy, the stability and reliability of the incremental photoelectric encoder can’t meet the actual requirements. In this paper we have designed automatic detection system on zero position of optical encoder in installation process based on machine vision. Using the camera and image acquisition card, computer, built a detection system platform of zero position to install the incremental photoelectric encoder. Adopting the NI visual software and write digital image processing program by LabVIWE to realize a series of Image processing and recognition functions to the collected the incremental photoelectric encoder’s images. We used edge detection operator to determine the edge of the optical encoder and used the arc detection principle of hough transform to find the coordinates of the center of a circle, measured the error of the coaxiality between the encoder and revolving axle to fix the disc. Then we detected the zero position in template matching and fixed the radial grating. Finally, we completed the zero position of optical encoder’s automatic detection.The experiment showed that use machine vision technology to achieve automatic detection in the incremental photoelectric encode installation process, it can improve the precision and efficiency of the installation the incremental photoelectric encode, enhance the stability and reliability of the photoelectric encoder, reduce high manual operation workload and judge the inaccurate problems. The system has good man-machine interface, the different types of incremental encoder can be real-time detection.