Saturated Adaptive Hierarchical Fuzzy Attitude-Tracking Control of Rigid Spacecraft with Modeling and Measurement Uncertainties

The problem of the attitude-tracking control of spacecraft subject to additive measurement uncertainty, control saturation, parametric uncertainty, and unknown external disturbances is studied in this paper. Because of the mismatched disturbance generated by measurement uncertainty in attitude kinematics, the normwise adaptive estimations for the bounds of the mismatched disturbance are involved in the kinematical controller; then, a saturated adaptive hierarchical fuzzy controller for attitude dynamics is developed in the backstepping design, where an antiwindup compensator is used to deal with the effect of control saturation, elementwise adaptive estimations are used to compensate parametric uncertainty, and direct adaptive hierarchical fuzzy control is designed to compensate the lumped disturbances in attitude dynamics. It is proved via Lyapunov analysis that the attitude-tracking errors eventually converge to adjustable small neighborhoods of zero. Simulation results validate the effectiveness and performance of the proposed control approach.