Visual Tracking Control Research Articles

宇宙ロボット作業評価用テストベットの開発と衛星捕捉模擬実験

We developed the Advanced Space Robot Testbed with Redundant Arms (ASTRA) for studying the autonomous control of a space robot. Berthing a satellite that is moving in space is the kind of difficult and dangerous task expected of space robots. This paper describes a robot which berthes a mockup satellite that is moving and rotating in zero gravity. The features of the robot include the capability for an autonomous approach to a moving target satellite on the base of a visual estimation of satellite motion, real-time visual tracking control for tracking satellite handles with two robot arms, and the capability to grasp the satellite handles while exerting minimum mechanical shock because of flexible wrist mechanisms and impedance control. We ran a satellite berthing experiment with ASTRA to check its performance.

Robot Visual Servoing for Curve Tracking

Aiming at high speed visual tracking by integration of vision and control, this paper presents a new control scheme for robot visual tracking of a drawing curve (eye in hand configuration). To track a curve, the control is decomposed into two subfunction, The one is velocity control, which controls the center of CCD camera to move along tangential direction of the curve, The other is position control, which controls the center of CCD camera to move in normal direction approaching to the curve. As the result the center of CCD camera always moves along the curve. The unit tangential vector and the normal tracking deviation can be measured from image within servo sampling time, Hence the visual tracking control is realized on the base of servo cycle (2ms). For integration of vision and control, a Transputer based parallel controller is developed. The tracking speed can reach 25cm/s with a small field of view (2.64cm × 2.64cm), which is about 10 times higher than the conventional method.