Active disturbance rejection station-keeping control of cislunar point orbits

A novel active disturbance rejection station-keeping control approach is proposed and analyzed for stabilization of spacecraft flight on cislunar point orbits of the Sun-Earth system. It is an error driven, rather than model-based control law, essentially accounting for the independence of model accuracy and linearization. From the combination of tracking differentiator, extended state observer, and nonlinear state error feedback, the proposed method can estimate the unmodeled spacecraft dynamic and disturbance in real time, and then compensated them for high accurately station-keeping performance. Simulation results show that the proposed method is adequate for station-keeping of unstable halo orbits in presence of system uncertainties, initial injection errors and un-modeled disturbance. Also, the closed-loop system performance is improved significantly using our method in comparison with the general LQR method.