On the Use of Multisine Input Signals for Plant Identification of Precision Structures

Abstract

This paper compares the performance of multi-sine input signals for plant identification of mildly non-linear precision structures. In the first approach, the frequency band of interest is divided into octave bands to prevent super-harmonics from corrupting the measurements at the expense of additional testing time. In the second approach, the spacing of the spectral lines is selected to minimize corruption of the measurements. Both approaches give information on the magnitude of the non-linearities. The AFRL Deployable Optical Telescope (DOT) testbed serves as the representative demonstration system. FRFs generated with sine dwell excitation serve as the reference data for the DOT measurements.