A Simple Modal Parameter Identification Method for On-Orbit Satellite with Flexible Appendages

Satellites generally have flexible appendages such as solar arrays, and the vibration frequency and damping ratio of the flexible appendages are critical for satellite attitude control system design, but accurate modal parameters cannot be obtained by ground experiments and finite element analysis. In this paper, the relationship between open-loop and closed-loop modal parameters is derived by analyzing the dynamic equations of flexible attitude when the satellite attitude is in the earth-pointing state. A more simple modal parameters identification method based on OKID and ERA algorithm is proposed, and the effectiveness of the method is demonstrated by numerical simulations.