Image Number 6 for United States Patent #5012428.
A vibration control system for generating desired random vibration environment with a given reference Power Spectral Density (P.S.D.) using a vibration generator on which a test object is fixed is disclosed. A detected signal representing vibration of a test object is converted into a response spectrum by Fast Fourier Transform (FFT) and the response spectrum is compared with the reference spectrum to determine a drive spectrum. Random drive signal having the determined drive spectrum amplitude is then generated continuously, and the signal is applied to a vibration generator on which the test object is fixed. This signal must be random i.e. nonperiodic, and therefore consisting of continuous spectral components with sufficient statistical independence. Method and facility to generate above mentioned signal are the principal of the present invention.