Output feedback control of Lorentz-augmented spacecraft rendezvous

A Lorentz spacecraft is an electrostatically charged space vehicle that could modulate the surface charge to induce Lorentz force as propellantless electromagnetic propulsion for orbital maneuvering. Modeling the Earth's magnetic field as a tilted dipole corotating with Earth, a dynamical model of Lorentz-augmented spacecraft relative motion about arbitrary elliptic orbits is developed, based on which the optimal open-loop trajectory of Lorentz-augmented rendezvous is solved by Gauss pseudospectral method. To track the open-loop trajectory in the presence of external perturbations and without velocity measurements, a reduced-order observer and an output feedback controller are designed, ensuring the stability of the closed-loop system by a Lyapunov-based approach. Numerical simulations verify the validity of both the open-loop and closed-loop controllers.