Nonlinear stability control of tethered sub-satellite attitude in deployment

This paper studies the impact of tether deployment on the attitude dynamics of the tethered sub-satellite. The dynamics model of the tethered sub-satellite is derived from the Newton - Euler equation of motion and the stability of tethered sub-satellite's attitude motion is studied with the consideration of tether attachment offset from the symmetric axis of the satellite. Based on the dynamic analysis, a Lyapunov type nonlinear attitude controller is derived for the attitude motion of the tethered sub-satellite, which is disturbed by the unwanted offset of tether attachment. Simulation results and their analysis demonstrated preliminarily that the newly proposed controller is effective and efficient.