Vibration Tests of a Spacecraft via a Switched Robust Controller-based Virtual Shaker
Résumé
This paper considers the control of spacecraft’svibration testing system. This test system is used for thequalification of the dynamic behavior of spacecraft under severelaunch environment. The vibration testing system shall cover thelauncher’s vibration frequency band with respect to thespacecraft limitations (notching around the eigen frequencies).Several control strategies were already studied, leading howeverto inaccurate tracking performance and important oscillationsdue to the excitation of the vibrational modes of the spacecraft.An additional difficulty results from the large spectral intervaltracking problem, generally beginning at 5 Hz, and continuingup to 150 Hz. In this paper, a switching control strategy isdeveloped based on several robust controllers, where the switchbetween controllers depends on the reference frequency. Theperformance of this strategy is assessed by means of a model in-the-loop (MIL) architecture introduced for the virtual shakertesting campaign up to 40 Hz, including Monte-Carlosimulations. Moreover, the campaign's security is assuredthrough guaranteed stability margins of the closed-loop system,limiting the testing campaign to a single run vibration testinginstead of the current four-stage one, reducing the testing cost.