Robust Tracking Guidance for Zero Propellant Maneuver, Part 1: Background and Approach

The Zero Propellant Maneuver (ZPM) rotates the space station by large angle, utilizing the Control Momentum Gyroscopes (CMGs) only. The traditional tracking guidance for the ZPM lacks robustness and depends heavily on the accuracy of the initial states and the dynamic modeling. To enhance its performance, a robust tracking guidance strategy is proposed. This approach is distinguished from the traditional manner in that the reference attitude trajectory is adjusted on-line, which aims to eliminate the risky CMGs momentum error. The Lyapunov controller is developed to adjust the attitude trajectory and further redesigned for a better performance based on an interesting physical phenomenon, which is taken advantage of by coupling the components of the error momentum vector. With a feedback linearization controller, the adjusted trajectory is tracked to reach the target states of the maneuver. Examples which show the effectiveness of the robust tracking guidance are provided in Part 2 of the paper.