Dynamics analysis and controller design for maneuverable tethered space net robot

Space robots are considered as a promising solution to active space-debris capture and removal. In this paper, a brand new space robot system called the maneuverable tethered space net robot is proposed. In addition to the advantages inherited from the tethered space net, extra maneuverability in the tethered space net robot allows for wider possibilities for debris capture. The motion equations of the system are derived, and both symmetrical and asymmetrical configurations are analyzed. According to the specific vibration analysis, a modified adaptive supertwisting sliding-mode control scheme is proposed. The proposed adaption law is a function of the disturbance, which is considered as the sum of all the adjacent forces working on the controller plant: that is, the maneuverable unit. Both symmetrical and asymmetrical cases are simulatedtoverify that the tethered space net robot can fly toward active space debris steadily under the proposed control scheme.