The deformed shape of a cylinder provides valuable information that can be used to monitor or control the process. The shape can be used to estimate the von Mises equivalent stress and strain, to estimate foldover and the frictional interface conditions in compression, and to predict and possibly avoid fracture. Shape measurements can also be used in a closed-loop control system to maintain a constant strain rate during nonhomogeneous deformation. A method is described that uses coarse digital camera data to calculate the shape parameters. An assumed form of the deformed shape is used to provide subpixel resolution. Since the method uses moments of the data, which are integrals, the method is insensitive to noise in the data. Because of its simplicity, the moment method is practical for real-time computation and control.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the American Control Conference|
|State||Published - Dec 1 1987|