Libration Control of Tethered Satellites in Elliptical Orbits

摘要

A strategy for the control of the librations of a tethered satellite system in elliptic orbits using tether length control, which drives the system to controlled periodic libration trajectories, is suggested. There is a range of eccentricities up to about 0.4453 for which no length variations are needed for the system to follow the periodic trajectory. Above this eccentricity, it is necessary to vary the length of tether to maintain a periodic trajectory. The method for finding these trajectories to minimize the control input utilizes a collocation solution. Closed-loop stability is provided by a linear feedback control law, whose feedback gains are also periodic. Consequently, Floquet theory demonstrates the stability of the closed-loop system.