Passivity-based adaptive tracking control for spacecraft elliptical orbital proximity operations

Passivity-based adaptive tracking control of spacecraft proximity between chief and deputy spacecraft is explored in this paper. Tschauner-Hempel equations are employed to describe the relative motion between two spacecraft, exclusively considering that the chief spacecraft operates in an arbitrary elliptical orbit. The linear periodical time-varying property of Tschauner-Hempel equations is affixed with zero dynamic theory to build an almost strictly passive system, which facilitates a passivity-based adaptive controller to guarantee the closed-loop stability via Lyapunov theory as well as LaSalle's invariance principle. The proposed control scheme is implemented without requiring specific model information of the relative motion dynamics. It hence exhibits robustness to model uncertainties, benefiting from the application of passivity theory. Numerical simulations are illustrated to validate the performance of the proposed adaptive control scheme.