Robust Constrained Attitude Control of Spacecraft Formation Flying in the Presence of Disturbances

In this paper, the robust control problem for spacecraft formation flying in virtual structure algorithm is addressed. The effects of external disturbances, model uncertainties, sensor noises, and actuator saturation are taken into account. A robust controller based on μ-synthesis is first designed to overcome the environmental disturbances. To obtain a control law with lower order, an H∞-based linear matrix inequality controller is designed, using the linearized model with uncertainties. Then, a robust adaptive controller, based on the Lyapunov stability theorem, is presented to overcome a broader range of model uncertainties, which also guarantees the stability. From a comparison viewpoint, the numerical results are also demonstrated to show the performance of the robust controllers in tracking the desired attitude and position.