Tethered Robot Casting Using a Spacecraft-Mounted Manipulator

Abstract

A space robot attached to the far end of a tether deployed from a spacecraft is considered. Such a robot can be made to translate freely in space without the need of jet thrust, using tether tension. The tethered robot can be applied to perform a variety of tasks such as grappling a remote object, transporting supplies, servicing a satellite, and so on. A casting strategy is described that is accomplished by means of a manipulatormounted on the spacecraft. The tether is attached to the endpoint of this manipulator. The spacecraft-mounted manipulator generates the necessary initial momentum for the tethered robot and adjusts its trajectory by controlling tether tension. The desired Ž nal state of the tethered robot includes accurate positioning at the destination point with zero momenta.To achieve such a state, a cooperative control scheme for translation and linkmotion of the tethered robot is proposed. The effectiveness of the proposed control approach is conŽ rmed by computer simulations.