Out-of-Planar Motion Stabilization for Tethered Interplanetary Maneuver using Multivariable Super-Twist Sliding Mode Control

This paper studies the out-of-planar motion control of the spinning tether system (STS) for interplanetary maneuvers. Through spinning tether, two connected spacecraft in the interplanetary hyperbolic orbit are tossed into an elliptical orbit around the moon and a faster flyby orbit simultaneously without consuming fuel. The main challenge during such an interplanetary maneuver is stabilizing the undesirable perturbing out-of-planar motion to ensure maneuver accuracy. To deal with this problem, the dynamic equations of the STS is established for showing and analyzing the influence of out-of-planar motion during the maneuver firstly. To next, the coupling problem of out-of-planar motion with the spinning in-planar motion, a robust finite-time controller is developed for the out-of-planar motion by using the multivariable super-twist sliding mode control, which can effectively stabilize the perturbing out-of-planar motion. Finally, theoretical analysis and numerical simulations illustrate the effectiveness of the proposed control algorithm.