Vibration apparatus for minute vibrations

摘要

An electro-dynamic shaker and a pendulum system which has a resonant frequency lower than the lower limit of the frequency band of ordinary floor vibrations are fixedly mounted on a base plate. The pendulum system comprises a pendulum, damper and a differential transformer for detecting the relative displacement between the pendulum and the output shaft of the shaker. The detected relative displacement is compared in a control device with an input signal, the difference obtained by the comparison being used as a negative feedback signal to correct the input signal to be fed to the shaker to thereby stably produce minute vibration.