Nutation damping and spin orientation control of tethered space debris

摘要

As a preliminary of an active debris removal process, the attitude motion control of the debris need to be carried out to ensure security of following operations. The tethered space system is one of the most attractive methods for active debris removal missions. However, the tether tension becomes the only input to manipulate the attitude motion of the debris, causing a highly underactuated problem. Fortunately, the fully attitude stabilization of the debris is not a prerequisite for a secure deorbit operation. As long as the nutation of the debris is not so violent that makes the tether winds, the towing process can be applied continually, which is a significant advantage of the tether method. In this paper, a switched tension control law is presented to damp the nutation of the debris. Only two constant tension values are needed in the control method. Under the assumption that the tether direction is fixed in the inertia frame, the bounded stability of the control algorithm is proved based on the Barbalat's Lemma, and an asymptotic stability can be achieved for an asymmetrical debris symmetrically captured. Numerical simulations with tether libration considered are carried out to show the capability of the control method.