Multisensor with directly coupled rotors

• US 5,932,805 A
• Filed: 08/01/1997
• Issued: 08/03/1999
• Est. Priority Date: 08/01/1997
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Litton Systems Incorporated
• Inventors: Stewart, Robert E.
• Primary Examiner(s): Oda, Christine K.
• Application Number:
  US08/904,927
• Time in Patent Office: 732 Days
• Field of Search: 73/510, 73/511, 73/504.03, 73/504.04, 73/504.12
• US Class Current: 73/510
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces

Abstract

A multisensor includes direct rotor coupling. A pair of rotors is mechanically coupled by a torsion bar whose stiffness largely determines the resonant frequency of the counteroscillating rotor pair. The axis of the torsion bar is coincident with the common axis of rotation of the rotors. Piezo bimorphs are fixed to opposed surfaces of radial vanes of the rotors which suspend the torsionally-coupled rotor pair with the case, isolating it from external angular vibration that could interfere with the resonant frequency of the rotor pair subassembly. The bimorphs receive signals for driving the oscillations of the rotors. Taken together, the stiffnesses of the vanes and the torsion bar substantially determine the common resonant frequency of the counteroscillating pair of rotors.

Claims

1. A multisensor comprising, in combination:

a) a pair of rotors, each of said rotors including a plurality of radially-directed rotor arms;

b) an accelerometer being fixed to each of said rotor arms;

c) each of said rotors being arranged to oscillate about a common axis;

d) means associated with each of said rotors for oscillating said rotors substantially 180 degrees out-of-phase with respect to one another; and

e) means for directly coupling said rotors to one another along said common axis, said means for coupling having an axis of symmetry coincident with said common axis and comprising (i) a cylindrical central member of a first diameter and (ii) cylindrical end members of a second, larger diameter.

2. A multisensor as defined in claim 1 wherein each of said rotors further comprises:

a) a central hub;

b) said rotor arms being joined to and extending radially from said hub;

c) a plurality of assemblies; and

d) each of said assemblies comprising a single radially-directed vane fixed to and extending from said hub and having a pair of piezoelectric elements fixed to opposed sides of said vane.

3. A multisensor as defined in claim 2 wherein each of said assemblies further includes a peripheral mount fixed to the end of said vane opposite said hub.

4. A multisensor as defined in claim 3 further including:

a) a case;

b) each of said rotors being located within said case; and

c) said peripheral mounts being fixed to said case.

5. A multisensor as defined in claim 4 further including:

a) said case comprising a body having a cylindrical internal cavity for accommodating said rotors;

b) a pair of rotor support plats fixed to opposed ends of said cavity; and

c) said peripheral mounts being fixed to said plats.

6. A multisensor as defined in claim 5 further including:

a) a pair of hybrid substrates; and

b) said substrates being fixed to the rotor arms of said rotors.

7. A multisensor as defined in claim 2 further including:

a) said central hub has a central aperture;

b) said central aperture is aligned with said common axis; and

c) an end member of said means for coupling being fixed to each of said rotors at said aperture.

8. A multisensor as defined in claim 7 wherein said end member is fixed to each of said rotors by means of an adhesive.

9. A multisensor as defined in claim 8 wherein said adhesive is a resinous catalytic adhesive.

10. A multisensor as defined in claim 7 wherein a laser weld fixes said end member to each of said rotors.