GKYP-Based Finite Frequency Control for Relative Motion of Drag-Free Satellite

Drag-free control technology plays a key role in space science tasks such as microgravity science, space basic physics verification, Earth observation, and spacecraft high-precision navigation. At present, a drag-free controller is designed in the time domain aimed at the full frequency band by many scholars, which cannot meet some of the high-precision task requirements under specific frequency constraints. Therefore, some scholars use robust control and quantitative feedback control to design a controller in the frequency domain indirectly, but the design process is complicated. Moreover, the satellite tracking test mass strategy is generally used, and it limits the control capability of a drag-free satellite with double test masses. For these problems, a design method of a finite frequency domain controller based on Generalized Kalman-Yakubovich-Popov (GKYP) lemma combined with frequency separation control strategy is presented in this paper, which covers the dynamic model, design of the finite frequency H∞ controller, proof of stability, and performance analysis. Finally, the numerical simulation analysis is carried out. The simulation results show that the controllers are effective.