Adaptive fuzzy attitude tracking control of spacecraft with input magnitude and rate constraints

A new adaptive feedback controller for attitude tracking of uncertain spacecraft is developed, based on the dynamic inversion theory and fuzzy logic technology. The objective is to control the spacecraft subject to parametric uncertainties, external disturbances, and control input constraints so that its attitude follows a prescribed path. First, a controller which consists of the dynamic inversion algorithm and a linear control law is designed for the nominal spacecraft. Then, the fuzzy logic system is added to approximate the unknown parametric uncertainties. To deal with the effect of input constraints, an auxiliary block is used to adjust the control strategy to ensure the system stability and performance. Furthermore, the robust feedback is applied to attenuate the effect of external disturbances. The stability and performance is guaranteed by Lyapunov analysis. Numerical examples show that the whole system, using the proposed control law, has good performance and robustness to uncertainties, even when the inputs are in saturation.