Combined Method for the Modal System Identification of the Balloon-Borne Imaging Testbed

AbstractThis paper presents a novel method for the modal system identification of a large mechanical structure by combining results from simulations and physical measurements. Specifically, reconstruction of mode shapes was accomplished by comparing simulated and measured amplitude ratios generated using a Nyquist analysis. The methodology developed in this paper improves upon traditional techniques by allowing for statistically cross-referencing relatively few sensor measurements and a relatively simple simulation model. This methodology was used to identify three major modal frequencies and mode shapes of the main aluminum honeycomb sandwich panel gondola structure of the balloon-borne imaging testbed (BIT). BIT was a stratospheric ballooning project for astronomy that was launched on September 18, 2015, from Timmins, Ontario, Canada. Ensuring that structural vibrations do not adversely affect the pointing accuracy of the on-board telescope is crucial to the success of the project. This paper also highl...