The invention discloses an ultra-
low frequency modal test gravitational equilibrium
system which comprises a horizontal motivation
modal suspension device, a vertical
servo modal suspension device, an installation base, a support and a movable adjustment base. The horizontal motivation modal suspension device is installed on the installation base. The vertical
servo modal suspension device is arranged above the horizontal motivation modal suspension device through the support. The movable adjustment base is arranged below the installation base. The horizontal motivation modal suspension device comprises a gas floating ring installation board, a proximity switch, a gas floating ring, a floating panel and a
rope-clamping
assembly. The vertical
servo modal suspension device comprises a
machine frame, an installation framework, a movable cross beam, a guiding rod, a main rod, an
air bearing, a limiting device, a
laser displacement sensor, a load sensor, a
floating system and a magnetic
system. Plane motion of the ultra-low modal test gravitational equilibrium
system is not influenced by restriction, a
friction force or an
inertia force basically.