Real-time part position sensing

A light-stripe vision system is used to measure the location of polyhedral features of parts from a single frame of video camera output. The geometric conditions which assure location of the feature when the light plane intersects three of the feature's faces are given. Issues such as accuracy in locating the line segments of intersection in the image and combining redundant information from multiple measurements and multiple sources are addressed. It was found that in 2.5 s, the prototype sensor was capable of locating a 2-in cube to an accuracy (one standard deviation) of 0.002 in (0.055 mm) in translation and 0.1 degrees (0.0015 radians) in rotation. When integrated with a manipulator, the system was capable of performing high-precision assembly tasks.<
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