Development of Space Photographic Robotic Arm based on binocular vision servo

A Space Photographic Robotic Arm (SPRA) system for astronautical application is introduced in this paper. This system is designed for the taking photo task of some small size equipments in orbit in future. Considering of the system reliability, a 5-DOF movement platform is utilized to carry and drive the observed equipment to move and rotate in appointed directions so that the cameras of SPRA can capture its full surface pictures only with simple motions. When implementing the control and positioning function: first, a 5-DOF robotic arm with three cameras installed in its end joint is developed. The kinematics model, the camera calibration techniques, and the eye-in-hand calibration method are all employed to solve the control and positioning problem of SPRA system. Then a 5-DOF movement platform, which can make the line movement in 4 axes and a rotation movement in 1 axis, is designed. Finally, when our system works, all the three cameras will compute the feature information and estimate posture of the observed equipment, and then it will sent the control signal to both the robotic arm and the movement platform to implement the automatic taking picture tasks. By using the combinatorial work mode, the control complexity of SPRA will decrease effectively. Many experiment results have shown the correctness and validity of our proposed system.