An Approach Toward an Automated Object Retrieval Operation with a Two-Arm Flexible Manipulator

The recent developments in space technology demand various services to uncontrollable satellites, such as refueling and repairing, in order to extend their lifespans. However, there has so far been no research on such practical applications with flexible manipulators. In this paper, we address automated object capture with a two-arm flexible manipulator, which is a basic technology for such services in space. This object capturing strategy includes symmetric cooperative control, visual servoing, the resolution of the inverse kinematics problem and the optimization of the configuration of a two-arm redundant flexible manipulator. For the performance improvement on the rise time of the internal forces at the instant of making contact, a transition control strategy is also proposed considering the resultant mechanical compliance associated with the internal forces. Moreover, we present the control system configuration for this task. This control system is based on IBM-compatible personal computers (PCs), and the computational loads for the task execution are distributed to several PCs connected to each other through the Ethernet. The effectiveness of the proposed control system and task sequence is validated with the experiments. KEY WORDS—flexible manipulator, automated object retrieval operation, cooperative control of two arms, structural compliance, redundancy resolution, PC-based manipulator control system