Research Of Deformation Detection And Application Of Roll Forming Based On CCD

Roll forming is a new craft and new technology, which is a kind of materials saving, energy saving and highly efficiency in metal forming. In the roll forming process, due to the different distribution of stress caused by the Edge wave, bag-shaped wave defects. It has practical significance to calculate the stress and strain values of forming regions to avoid the emergence of a variety of defects. Coordinate grid method is one of the most widespread methods to study the distribution of plastic deformation of metal. Through printed coordinate grids in the sheet metal surface, Analysis the change of grid size before and after deformation, then you can get the size and distribution of sheet metal strain.For overcoming the traditional grid strain measurement techniques restriction,at the same time, because of the widely use of computer and optical sensor technology, non-contact measurement technology based on computer vision has been rapid development, this paper Research and develop a kind of strain measurement system for roll forming based on CCD technique, it synthetically utilizes the computer measuring principle of binocular vision, optical and related technology, image processing technology to complete the strain and stress measurement of roll forming material.According to the principle of measurement system, this paper has designed and build hardware system, which takes the CCD camera, the image acquisition card and the computer as the core. The software system using Visual C++6.0 for development, In general, the whole software system contains three modules: pre-processing, computer vision technology and post-processing. Pre-processing is the process of image processing and identification, this paper designed the image processing approach, which includes of image binarization, dilation, erosion, contour tracking and so on, selected the appropriate image processing algorithms, established the corresponding procedures, realized the grid node identification. The computer vision measurement technology module includes three parts: camera calibration, image matching and three-dimensional reconstruction, this paper introduces the related principle and realization method. The post-processing is mainly sample's stress and strain calculation and the results of the output, which is according to the grid node three-dimensional coordinates before and after deformation and the stress and strain calculation methods. Finally, I makes the experiment by using the measurement system to roll forming simple section, detailed describes four measurement steps of the grid made, roll forming, camera calibration, strain calculation. Compared with finite element simulation software marc simulation results, the results is validity. According to contrast the results, analysis of the factors that affect measurement precision.In this paper, the research and development of the strain measurement system in the small deformation strain measurement has a certain practical value, at the same time, this study for measuring sheet metal three-dimensional strain and large deformation has provided a good theoretical foundation.