Time-varying modal parameters identification of large flexible spacecraft using a recursive algorithm

Abstract

In existing identification methods for on-orbit spacecraft, such as eigensystem realization algorithm (ERA) and subspace method identification (SMI), singular value decomposition (SVD) is used frequently to estimate the modal parameters. However, these identification methods are often used to process the linear time-invariant system, and there is a lower computation efficiency using the SVD when the system order of spacecraft is high. In this study, to improve the computational efficiency in identifying time-varying modal parameters of large spacecraft, a faster recursive algorithm called fast approximated power iteration (FAPI) is employed. This approach avoids the SVD and can be provided as an alternative spacecraft identification method, and the latest modal parameters obtained can be applied for updating the controller parameters timely (e.g. the self-adaptive control problem). In numerical simulations, two large flexible spacecraft models, the Engineering Test Satellite-VIII (ETS-VIII) and Soil Moisture Active/Passive (SMAP) satellite, are established. The identification results show that this recursive algorithm can obtain the time-varying modal parameters, and the computation time is reduced significantly.

Large-scale flexible spacecraft mass properties determination using torque-generating control

“…24 Zhiyu et al (2016) employed a recursive algorithm called fast approximated power iteration to improve the computational efficiency in identifying time-varying model parameters of a large spacecraft. 25 Yong et al ( 2018) presented an onorbit frequency identification method for spacecrafts directly using attitude maneuver data. 26 These works mainly focus on the identification of flexible parameters, but the result of flexible parameter identification can be used as the input condition of mass properties identification.…”

Multi-objective integrated robust H∞ control for attitude tracking of a flexible spacecraft

“…Besides, the problem of spacecraft parameter uncertainties has been widely addressed, and a commonly-used methodology is to assume that the uncertain parameters, typically the moments of inertia, always consist of the nominal component and the uncertain one [4, 6, 12-16, 18, 25, 27]. Sometimes, spacecraft mass and modal parameters are uncertain and occasionally time-varying due to on-orbit maneuvers such as solar array and antenna re-orientation [32]. Spacecraft sensors and actuators are not placed at the same locations exactly [33].…”