A Methodology for Tracking Control for Formation Flight of Satellites

Abstract

Abstract This paper develops a methodology for the tracking control of satellite formation flight in the presence of external disturbances. The control methodology is composed of two steps. In the first step, an exact control strategy is developed for a nominal system model which provides the best assessment of real-life uncertainties. Upon using results from analytical dynamics, a closed-form control input is derived such that the formation configuration requirements are satisfied. In the second step, an additive robust controller is designed to compensate for the external disturbances to which the satellite formation system may be subjected. A gain adaptation law is developed that automatically updates the control gain in real time to adjust for the presence of environmental disturbances while keeping the precision of the tracking to within user-specified bounds. An additive combination of the two controllers enables precision tracking control for the satellite formation without a priori information about the bounds on the uncertainties and disturbances imposed on the formation system. Numerical simulations demonstrate the accuracy and effectiveness of the proposed two-step control methodology in which a desired formation configuration is to be maintained under unknown environmental disturbances.