Vibration-testing system

Abstract

Horizontal vibration shakers 21a and 21b are disposed opposite to each other on both sides of a vibration table 4, and either of the horizontal vibration shakers, e.g. 21a is arranged vertically movable so as to produce a positional difference (offset) with respect to a horizontal vibration axis 63 of the other horizontal vibration shaker 21b. When it is supposed that an accelerated velocity appears upwards on the left side of the vibration table 4, while another accelerated velocity appears downwards on the right side of the vibration table 4 as a result of generation of a rotational mode M, one of the horizontal vibration shakers, e.g. 21a, is elevated to produce the positional difference (offset) with respect to the horizontal vibration axis 63 of the other opposed horizontal vibration shaker 21b. In addition, vibration forces of the horizontal vibration shakers 21a and 21b are controlled at the same time to produce a moment towards the reverse direction, whereby the rotational mode M is suppressed so as to balance the right and left moments.

Dependencies are inferred from the claim text.