US 4,082,005 A · Spin coupled, angular rate sensitive inertial sensors with mounting structure and method of fabricating and mounting same

Abstract

Spin coupled angular rate sensitive inertial sensors of the tuned suspension system type with mounting structure, and method of fabricating and mounting such sensors whereby the twice spin frequency linear and angular vibration sensitivity characteristic of tuned sensors may be eliminated. The twice spin frequency angular vibration sensitivity characteristic of other tuned inertial sensors is reduced by creating an equal and opposite torque component dependent on the same vibrational input by angularly offsetting the rotor suspension system from a plane orthogonal to the spin axis, and by providing the shaft assembly with an effective product of inertia of controlled magnitude and orientation. Compensation for twice spin frequency linear vibration caused primarily by the spin bearings is achieved either by mounting the spin bearings in a relatively soft mounting, or supporting the instrument case (non-rotating portion) on a suspension tuned to twice spin frequency in the translational mode. Further reduction of twice spin frequency angular vibration sensitivity may also be accomplished by the relatively soft mounting of the spin bearings and/or the support of the instrument case on a suspension system tuned to twice spin frequency angular vibration. Various forms of implementation of the invention and methods of dynamic rebalancing the rotating assemblies are disclosed.

Claims33

Dependent claims

A tuned inertial instrument comprising:

an instrument case;
a shaft means supported on bearings coupled to said instrument case for rotation about a spin axis at a predetermined spin frequency within said instrument case;
a sensitive element;
a suspension means for coupling said sensitive element to said shaft, said suspension means including means for allowing relative oscillation between said sensitive element and said shaft about at least one suspension means axis, said suspension means axis being non-orthogonally disposed with respect to said spin axis by a predetermined angle;
means coupled to said shaft for providing a product of inertia about said spin axis and an axis perpendicular to said spin axis;
and
means for reducing the apparent angular restraint of the nonrotating portion of said bearings about axes generally perpendicular to said spin axis.

4 more elements

An inertial instrument comprising:

a shaft means for rotation about a spin axis at a predetermined spin frequency;
a rotor having first, second and third orthogonal principal axes, said third principal axis being approximately aligned with said spin axis, said rotor having substantially different moments of inertia about said first and second principal axes;
a suspension means for coupling said rotor to said shaft, said suspension means having first and second torsional spring rates about first and second suspension means axes respectively, said suspension means axes being non-orthogonally disposed with respect to said spin axis by a predetermined angle, said rotor having a predetermined pendulosity along said first principal axis with respect to the center of support of said suspension means;
inertia means fastened to said shaft for providing a product of inertia about said spin axis and an axis perpendicular to said spin axis;
and
means for reducing the apparent angular restraint of the nonrotating portion of said bearings about axes generally perpendicular to said spin axis.

3 more elements

Dependencies are inferred from the claim text.

Spin coupled, angular rate sensitive inertial sensors with mounting structure and method of fabricating and mounting same

Life of this patent

Spin coupled, angular rate sensitive inertial sensors with mounting structure and method of fabricating and mounting same

Life of this patent

Abstract

Claims33