A controlled deployment method for flexible deployable space antennas

Abstract

A decoupling control method is presented for the controlled deployment of flexible deployable space antennas. The deformable antenna bodies are discretized with a hypothesized displacement field structured according to the Rayleigh-Ritz method. Combined with the Lagrange method, the deployable antenna's flexible multi-body dynamic model is established. Based on the result of a dynamic analysis and an Fast Fourier Transform (FFT) spectrum analysis of the deployment trajectory, a filter is used to decouple the movement feedback signal into two separate parts: the rigid movement and the vibration caused by flex factors. Based on the instantaneous structure modal analysis of the mechanism, the eigenfrequency affiliation between the mechanism and the structure is discussed, thus the cut-off frequency of the low-pass filter is determined. The rigid and lex controllers are designed according to the characteristics of the decoupled feedback respectively. The rigid controller ensures that the antenna deploys along a specified trajectory and the flex controller restrains the flex vibration. The coupling relationship of the gain parameters between the two controllers is discussed and a guideline for the proper parameter selection is proposed based on an energy correlation analysis. Numerical simulations of a practical application for an Astromesh-type antenna are carried out below, and these simulations demonstrate the rationality and feasibility of the proposed methodology. © 2012 Elsevier Ltd. All rights reserved.