Low frequency folded pendulum and vertical seismic sensor utilizing such a folded pendulum

摘要

A folded pendulum is described. The folded pendulum can be a monolithic pendulum and is positioned in the vertical configuration. The folded pendulum allows for more compact realizations through high decouplings of a vertical degree of freedom from other degrees of freedom as well as optimal mechanical quality factors.

主权项

1. A folded pendulum with tunable oscillation frequency, comprising:
a support; a test mass; a simple pendulum; and an inverted pendulum; wherein the simple pendulum and the inverted pendulum being connected at one of their ends to the test mass and at the other end to the support by means of four corresponding joint systems, the test mass being not connected to the support and being therefore free to oscillate, with reference to an equilibrium static position, the simple pendulum and the inverted pendulum are positioned substantially along a disposition direction perpendicular to a tangent to motion of the test mass in a point of geometrical centering with respect to the support; a first means for applying a first constant external force in one or more points of the simple pendulum, and/or the inverted pendulum and/or the test mass, in a direction of the tangent to the motion of the test mass in the point of geometrical centering with respect to the support; and a second means for applying a second constant external force along said disposition direction in one or more points of the simple pendulum, and/or the inverted pendulum and/or the test mass, to generate a local conservative field of a pre-defined value,an oscillation frequency of the folded pendulum being a function of said second external force.