A low-cost pose-measuring system for robot calibration

摘要

To maintain robot accuracy, calibration equipment is needed. In this paper we present a self-calibrating measuring system based on a camera in the robot hand plus a known reference object in the robot workspace. A collection of images of the reference object is obtained. Using image-processing, image-recognition and photogrammetric techniques, the positions and orientations of the camera are computed. The essential geometrical and optical camera parameters can be derived from the redundancy in the measurements. From each image the positions of markers on the reference object are extracted and the individual markers are identified. The camera positions for all images plus the parameters of the camera are solved together in a non-linear least-squares fitting procedure. Experimental results for this low-cost measuring system are presented.