Vibration Tests of a Spacecraft via a Switched Robust Controller-based Virtual Shaker
Abstract
This paper considers the control of spacecraft’s
vibration testing system. This test system is used for the
qualification of the dynamic behavior of spacecraft under severe
launch environment. The vibration testing system shall cover the
launcher’s vibration frequency band with respect to the
spacecraft limitations (notching around the eigen frequencies).
Several control strategies were already studied, leading however
to inaccurate tracking performance and important oscillations
due to the excitation of the vibrational modes of the spacecraft.
An additional difficulty results from the large spectral interval
tracking problem, generally beginning at 5 Hz, and continuing
up to 150 Hz. In this paper, a switching control strategy is
developed based on several robust controllers, where the switch
between controllers depends on the reference frequency. The
performance of this strategy is assessed by means of a model in-
the-loop (MIL) architecture introduced for the virtual shaker
testing campaign up to 40 Hz, including Monte-Carlo
simulations. Moreover, the campaign's security is assured
through guaranteed stability margins of the closed-loop system,
limiting the testing campaign to a single run vibration testing
instead of the current four-stage one, reducing the testing cost.