Linearization of attitude-control error dynamics

Some useful properties of direction-cosine and quaternion attitude formulations that include specification of attitude error and the inversion of rigid-body rotational dynamics are reviewed. The inversion procedure is then applied to a measure of attitude error to realize a new model-follower control system that exhibits linear attitude-error dynamics. Error analyses and simulation results for spacecraft attitude-control systems are presented to demonstrate the more robust performance obtainable from an exact linear-error formulation over that obtained from either direction-cosine or quaternion formulations with simple linear feedback control laws.<
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