Coordinated control for free-flyer space robots

Robots exploitation for hazardous space environment is challenging the planetary missions, and will have a special role in the assembly and maintenance of International Space Station. In orbit support of extra vehicular activities (EVA), automatic object recognition and manipulation on planets, will enable space robots more and more to substitute astronauts and time delayed teleoperation. Robust and reliable applications of free-flyer space robots are mainly characterized by the dynamic coupling between the motion of the arm and the drift of the spacecraft. Attitude modification is highly undesirable for tracking or manipulation tasks with accuracy, for directional antennas misalignment and for EVA performed close to manned space vehicles. In order to compensate the spacecraft attitude induced motions or to regulate the attitude at a fixed value, the proposed coordinated control exploits both coupled dynamics of the spacecraft-manipulator system and nonholonomic constraint due to angular momentum