{'fraction_non_alphanumeric': 0.01498751040799334, 'fraction_numerical': 0.0016652789342214821, 'mean_word_length': 5.462365591397849, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Satellite vibration control using frequency selective feedback

This paper addresses the problem of actively attenuating the vibration of plates on satellites. A pure feedback controller is demonstrated which operates at a set of dominant frequencies in a disturbance spectrum, where the control path model is estimated on-line. A new feature of the frequency selective feedback is the use of the inverse Hessian to improve adaptation speed. The control scheme also incorporates a frequency estimation technique to determine the relevant disturbance frequencies with higher precision than the standard fast Fourier transform (FFT). The controller is implemented on a test rig to demonstrate the practical feasibility of the method. A disturbance with three rational dominant frequencies is introduced. If FFT were used instead of the frequency estimation method proposed, then a large number of samples would be required to accurately estimate the disturbance frequencies, and, most importantly, FFT-estimated frequencies could lead to an unstable control system due to their granularity. Using the proposed frequency estimation method, the total achieved attenuation is 26 dB on the experimental rig.