Coordination control of a free-flying manipulator and its base attitude to capture and detumble a noncooperative satellite

Abstract

This paper focuses on the guidance of a robot manipulator to capture a tumbling satellite and then bring it to state of rest (detumbling). First, a coordination control for combined system of the space robot and the target satellite, which acts as the manipulator payload, is presented so that the robot tracks the optimal path while regulating the attitude of the chase vehicle to a desired value. Subsequently, two optimal trajectories for the pre-and post-capture phases are designed. In the pre-capturing phase, the manipulator maneuvers are optimized by minimizing a cost function which includes the time of travel and the weighted norms of the end-effector velocity and acceleration, subject to the constraint that the robot end-effector and a grapple fixture on the satellite arrive at the rendezvous point with the same velocity. In the postgrasping phase, the manipulator dumps the initial velocity of the tumbling satellite in minimum time subject to the constraint that the magnitude of the torque applied to the satellite remains below a safe value. Simulation and experimental results are appended.

Modeling and observer-based augmented adaptive control of flexible-joint free-floating space manipulators

“…The traditional singular perturbation approach is thus applicable to robots whose joint stiffness is large enough [29]. But the joint stiffness of the actual space robot is always not large enough, a flexibility compensator proposed by Liu et al [30] is introduced here.…”

“…where χ 2 is reasonably defined to ensure the first line of (29). Then the dynamic behavior s is given by (see Appendix B for details)…”

A Review of Robotics Technologies for On-Orbit Services

“…The proposed control strategy was verified by numerical simulation with a space manipulator model, which has a 7 DOFs and three reaction wheels. References [185,186] address an optimal control of a space manipulator in the post-capture phase to bring the tumbling non-cooperative satellite to rest in minimum time while ensuring that the magnitude of the interaction torque between the manipulator and the target remains below a prescribed threshold.…”

Optimal detumbling of defunct spacecraft using space robots

“…Velocities of manipulator joints are non-zero at the moment of capture of a tumbling target satellite and must be safely reduced to zero. Various methods are proposed for control of the satellite-manipulator system in this phase (e.g., [27,28]). …”