| In the modern automation production, to ensure the quality of finished products, reliability tests are necessary for the products in the production process. Low voltage circuit breaker is a kind of switch protection devices are widely used in power distribution system, if it did not reach the long delay, reliability and other performance indicators, it will affect the power distribution system work properly, even endanger the safety of power systems and equipments. While the fast and accurate positioning of the tripping screw is the key step to complete the long delay test, the positioning precision of screw is crucial to circuit breaker long time delay test. In the past, long time delay test is usually examined manually, unable to meet the requirements of automatic production line for high speed, high precision, high stability, etc. Therefore, how to solve the problem of accurate, rapid positioning and tracking to screw in breaker long delay test, complete the circuit breaker long delay intelligent testing equipment has become an inevitable trend.Aiming at the problem of automatic fast positioning the tripping screw in long time delay test, and put forward a release screw positioning method based on visual image. CCD camera is used to get image information of the three-phase release screws, OpenCV software is used for image processing to extract the screw center position. Thereby, the position value is transferred to lower machine PLC to control concentric double soft shaft adjustment mechanism for completing lapse adjusting action. In this paper, the main research contents and innovations are as follows:Firstly, according to the MCCB double metal thermal deformation mechanism, and combined screwdriver and screw head adjustment process of stress analysis, the adjusting screw running track models and combined screwdriver dynamic balance model are respectively established. A micro integration adjusting mechanism of release screw is designed, implemented of fast, accurate positioning and real-time dynamic adjustment to screw on the bimetallic sheet breaker in multi degree of freedom, and the circuit breakers long delay testing time reduced more than 30%.Secondly, analyzed the composition and working principle of breaker adjustment mechanism positioning system based on machine vision, analyzed and selected of each part of the system, including the light source, the industrial CCD camera, lens and image acquisition card, and a hardware platform is built.Then, the software system which is the core to release screw vision positioning system is designed. According to the idea of modular design, the image acquisition module, image processing module, software interface module, calibration module, motion control module, and corresponding software program are designed respectively. Each section coordinated operation independently, realized the automatic location detection and adjustment control. According to the image feature, the completion of the gray image and the denoising preprocessing, Focused on the Hough transform and the improved Canny edge detection operator. Zhang Zhengyou calibration method is used for camera calibration, the target localization results converted into corresponding pulse number transmitted to the lower PLC control unit, control the adjustment mechanism to achieve fast tracking and adjusting of screw.Finally, carried out the operation interface design based on MFC, help the operator real-time monitoring, image process and set of monitoring and parameters of the servo motion control system. The interface is clear and simple with good human-computer interaction.This visual positioning system has entered the test stage, it is stable and reliable, achieved a fast and accurate positioning, and the long delay testing time reduced more than 30%, with a very good application value and market prospect. |
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