COMPLIANT STRUCTURES WITH TIME-VARYING MOMENT OF INERTIA

• US 20140208848A1
• Filed: 04/01/2012
• Published: 07/31/2014
• Est. Priority Date: 03/31/2011
• Status: Active Grant

• Current Assignee: Ramot at Tel Aviv University Limited (Tel Aviv University)
• Original Assignee: Ramot at Tel Aviv University Limited (Tel Aviv University)
• Inventors: Krylov, Viacheslav, Ya'Akobovitz, Assaf
• Granted Patent: US 9,354,061 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• CPC Class Codes: B81B 3/0048 Constitution or structural means for controlling angular deflection not provided for in groups B81B3/0043 - B81B3/0045
• CPC Class Codes: G01C 19/06 Rotors
• CPC Class Codes: G01C 19/5705 using masses driven in reciprocating rotary motion about an axis

Abstract

A rotation sensor system is presented. The system comprises a rotating frame configured to be mounted on a gimbal and adapted for controllable rocking motion about a predetermined axis of said frame, and a proof mass assembly mounted on said rotating frame. The proof mass assembly comprises one or more proof mass elements each mounted for controllable movement with respect to the predetermined axis along a certain path, a distance of each proof mass element from said axis corresponding to a direction of the rocking motion of said frame, thereby affecting a moment of inertia of said rotating frame.

Claims

1. A rotation sensor system comprising a rotating frame configured to be mounted on a gimbal and adapted for controllable rocking motion about a predetermined axis of said frame, and a proof mass assembly mounted on said rotating frame, said proof mass assembly comprising one or more proof mass elements each mounted for controllable movement with respect to said predetermined axis along a certain path, a distance of the proof mass elements from said axis corresponding to a direction of the rocking motion of said frame, thereby affecting a moment of inertia of said rotating frame.

2. The rotation sensor system of claim 1, wherein each of said one or more proof mass elements is elastically connected to said rotating frame.

3. The rotation sensor system of claim 2, comprising a springing assembly for providing said elastic connection of the one or more proof mass elements to the rotating frame.

4. The rotation sensor system of claim 1, comprising an electrode assembly controllably operable to create and maintain a predetermined electric field within a field region, said proof mass assembly being located in the field region, thereby providing said controllable movement of the one or more proof mass elements.

5. The rotation sensor system of claim 1, said proof mass assembly comprises two or more of said proof mass elements arranged in a symmetric fashion around said predetermined axis of rotation defined by said rotating frame.

6. The rotation sensor system of claim 5, wherein the proof mass elements are arranged in a circular array around said predetermined axis.

7. The rotation sensor system of claim 1, wherein the system is configured as a planar system extending within a plane intersecting with said predetermined axis.

8. The rotation sensor system of claim 1, wherein the system is configured as a planar system extending within a plane parallel to said predetermined axis.

9. The rotation sensor system of claim 1, wherein said rotating frame carries a light deflection assembly, different angular position of the frame during the rocking motion thereof corresponding to a different deflection direction of light incident on said deflection assembly.

10. The rotation sensor system of claim 1, wherein said system is configured such that frequency of rotation of said rocking frame and frequency of movement of said proof mass assembly correspond to thereby provide the system with non zero angular momentum.

11. The rotation sensor system of claim 1, comprising an electrode arrangement providing an electric field configured to vary stiffness of connectors connecting said one or more proof mass elements to said rocking frame.

12. The rotation sensor system of claim 1, comprising a control unit configured and operable to provide drive force to thereby force at least one of said one or more proof mass elements of the proof mass assembly and rotation of said rocking frame with a predetermined frequency.

13. The rotation sensor system of claim 12, wherein said control unit is configured and operable to force movement of said one or more proof mass elements at a frequency being equal to twice the rotation frequency of said rocking frame, thereby actuating rotation of said rocking frame.

14. The rotation sensor system of claim 12, wherein said control unit is configured and operable to control a relative phase between rotation of said rocking frame and movement of said one or more proof mass elements.

15. The rotation sensor system of claim 14, wherein said control unit is configured to force rotation of said rocking frame and movement of said one or more proof mass elements with a predetermined frequency and phase to thereby provide the system of a certain non zero angular momentum.

16. The rotation sensor system of claim 14, wherein said control unit operates to control said relative phase to thereby vary moment of inertia of said rocking frame at a frequency corresponding to a natural frequency of a gimbal holding said rocking frame, thereby enabling coupling of said variation of the moment of inertia with tilting of said gimbal in accordance with external angular rotation.

17. The rotation sensor system of claim 14, wherein said control unit operates to control said relative phase to vary moment of inertia of said rocking frame to thereby enable tuning of rotation frequency of said frame.

18. The rotation sensor system of claim 1, wherein said system is configured as a micro rotation sensor system.

19. A structure comprising a rotatable frame and one or more movable proof mass elements elastically connected to said frame, the structure is configured to enable displacement of said one or more proof mass elements along a predetermined path thereby varying a mass distribution of the structure with respect to an axis of rotation of said frame.

20. The structure of claim 19, comprising one or more electrode arrangements generating electric field configured to control at least one of rotation of said frame and displacement of said one or more proof mass elements with certain frequency.

21. The structure of claim 19, wherein a resonance frequency of displacement of said proof mass elements and a resonance frequency of rotation of said rotatable frame being selected to enable parametric amplification of said rotation of the rotatable frame by periodic displacement of said one or more proof mass elements.