Research on Measurement Method of Joint Angle for Underwater Manipulator

Abstract

Measurement method of joint angle for underwater manipulator is studied in this paper. The swing of a manipulator can be described as a circular motion in spatial. Therefore this paper proposes a spatial circle fitting algorithm. The points for spatial circle fitting come from multiple stereo vision system. At first, attach the designed target to the robot arm, then proposes algorithm to track the target in real time. Then three-dimensional coordinates of target’s movement in space at each location can be obtained by using stereo reconstruction techniques. At last, the center and radius of the circle can be calculated by spatial circle fitting. Through the theory of analytic geometry, the manipulator’s joint angle can be calculated. Experiments show that the algorithm proposed in this paper is well used in manipulator’s joint angle measurement.