Carbon nanotube tape vibrating gyroscope

• US 9,523,577 B1
• Filed: 02/27/2014
• Issued: 12/20/2016
• Est. Priority Date: 02/27/2014
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Tucker, Dennis Stephen
• Primary Examiner(s): West, Paul
• Assistant Examiner(s): Zhong, Xin
• Application Number:
  US14/192,350
• Time in Patent Office: 1,027 Days
• Field of Search: 735/143.2, 735/041.2
• US Class Current: 1/1
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/5656 the devices involving a micromechanical structure

Abstract

A vibrating gyroscope includes a piezoelectric strip having length and width dimensions. The piezoelectric strip includes a piezoelectric material and carbon nanotubes (CNTs) substantially aligned and polled along the strip'"'"'s length dimension. A spindle having an axis of rotation is coupled to the piezoelectric strip. The axis of rotation is parallel to the strip'"'"'s width dimension. A first capacitance sensor is mechanically coupled to the spindle for rotation therewith. The first capacitance sensor is positioned at one of the strip'"'"'s opposing ends and is spaced apart from one of the strip'"'"'s opposing faces. A second capacitance sensor is mechanically coupled to the spindle for rotation therewith. The second capacitance sensor is positioned at another of the strip'"'"'s opposing ends and is spaced apart from another of the strip'"'"'s opposing faces. A voltage source applies an AC voltage to the piezoelectric strip.

Claims

1. A vibrating gyroscope, comprising:

a piezoelectric strip having a length dimension and a width dimension, wherein said piezoelectric strip defines opposing ends along said length dimension and wherein said piezoelectric strip defines opposing faces spanning said length dimension and said width dimension, said piezoelectric strip including a piezoelectric material and carbon nanotubes (CNTs) substantially aligned and polled along said length dimension of said piezoelectric strip;

a spindle having an axis of rotation, said spindle coupled to said piezoelectric strip wherein said axis of rotation is parallel to said width dimension of said piezoelectric strip;

a first capacitance sensor mechanically coupled to said spindle for rotation therewith, said first capacitance sensor positioned adjacent to and spaced apart from one of said opposing faces in proximity to one of said opposing ends of said piezoelectric strip wherein said first capacitance sensor generates a first capacitance measurement based on a first distance between said first capacitance sensor and said one of said opposing faces;

a second capacitance sensor mechanically coupled to said spindle for rotation therewith, said second capacitance sensor positioned adjacent to and spaced apart from another of said opposing faces in proximity to another of said opposing ends of said piezoelectric strip wherein said second capacitance sensor generates a second capacitance measurement based on a second distance between said second capacitance sensor and said another of said opposing faces; and

a voltage source for applying an AC voltage to said piezoelectric strip wherein said piezoelectric strip vibrates along said length dimension and wherein, when said spindle rotates about said axis of rotation, a Coriolis force acts on said piezoelectric strip wherein said one of said opposing faces of said piezoelectric strip is pushed towards said first capacitance sensor and said another of said opposing faces of said piezoelectric strip is pushed towards said second capacitance sensor.

2. A vibrating gyroscope as in claim 1, wherein said piezoelectric strip comprises:

a layer of said piezoelectric material having a first face and a second face;

a first layer of CNTs disposed on said first face of said layer; and

a second layer of CNTs disposed on said second face of said layer.

3. A vibrating gyroscope as in claim 1, wherein said CNTs are embedded in said piezoelectric material.

4. A vibrating gyroscope as in claim 1, wherein said axis of rotation of said spindle is approximately centered between said opposing ends of said piezoelectric strip.

5. A vibrating gyroscope as in claim 1, wherein said spindle is electrically conductive and wherein said voltage source is electrically coupled to said spindle for applying said AC voltage thereto.

6. A vibrating gyroscope as in claim 1, wherein said piezoelectric material is selected from the group consisting of polyvinilydene fluoride (P(VDF)) and polyvinilydene trifluoroethylene (P(VDF-TrFE)).

7. A vibrating gyroscope as in claim 1, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO₃).

8. A vibrating gyroscope as in claim 2, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO₃).

9. A vibrating gyroscope, comprising:

a piezoelectric strip having a length dimension and a width dimension, wherein said piezoelectric strip defines opposing ends along said length dimension and wherein said piezoelectric strip defines opposing faces spanning said length dimension and said width dimension, said piezoelectric strip including a piezoelectric material and carbon nanotubes (CNTs) substantially aligned and polled along said length dimension of said piezoelectric strip;

an electrically-conductive spindle having an axis of rotation, said spindle coupled to said piezoelectric strip wherein said axis of rotation is parallel to said width dimension of said piezoelectric strip and is approximately centered between said opposing ends of said piezoelectric strip;

a first capacitance sensor mechanically coupled to said spindle for rotation therewith, said first capacitance sensor positioned adjacent to and spaced apart from one of said opposing faces in proximity to one of said opposing ends of said piezoelectric strip wherein said first capacitance sensor generates a first capacitance measurement based on a first distance between said first capacitance sensor and said one of said opposing faces;

a second capacitance sensor mechanically coupled to said spindle for rotation therewith, said second capacitance sensor positioned adjacent to and spaced apart from another of said opposing faces in proximity to another of said opposing ends of said piezoelectric strip wherein said second capacitance sensor generates a second capacitance measurement based on a second distance between said second capacitance sensor and said another of said opposing faces; and

a voltage source for applying an AC voltage to said spindle wherein said piezoelectric strip vibrates along said length dimension and wherein, when said spindle rotates about said axis of rotation, a Coriolis force acts on said piezoelectric strip wherein said one of said opposing faces of said piezoelectric strip is pushed towards said first capacitance sensor and said another of said opposing faces of said piezoelectric strip is pushed towards said second capacitance sensor.

10. A vibrating gyroscope as in claim 9, wherein said piezoelectric strip comprises:

a layer of said piezoelectric material having a first face and a second face;

a first layer of CNTs disposed on said first face of said layer; and

a second layer of CNTs disposed on said second face of said layer.

11. A vibrating gyroscope as in claim 9, wherein said CNTs are embedded in said piezoelectric material.

12. A vibrating gyroscope as in claim 9, wherein said piezoelectric material is selected from the group consisting of polyvinilydene fluoride (P(VDF)) and polyvinilydene trifluoroethylene (P(VDF-TrFE)).

13. A vibrating gyroscope as in claim 9, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO₃).

14. A vibrating gyroscope as in claim 12, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO₃).

15. A vibrating gyroscope, comprising:

a piezoelectric strip having a length dimension and a width dimension, wherein said piezoelectric strip defines a first end and a second end along said length dimension and wherein said piezoelectric strip defines a first face and a second face, each of said first face and said second face spanning said length dimension and said width dimension, said piezoelectric strip including a piezoelectric material and carbon nanotubes (CNTs) substantially aligned and polled along said length dimension of said piezoelectric strip;

a spindle having an axis of rotation, said spindle coupled to said piezoelectric strip wherein said axis of rotation is parallel to said width dimension of said piezoelectric strip;

a first capacitance sensor mechanically coupled to said spindle for rotation therewith, said first capacitance sensor positioned adjacent to and spaced apart from said first face in proximity to said first end for generating a first capacitance based on a distance from said first capacitance sensor to said first face;

a second capacitance sensor mechanically coupled to said spindle for rotation therewith, said second capacitance sensor positioned adjacent to and spaced apart from said second face in proximity to said second end for generating a second capacitance based on a distance from said second capacitance sensor to said second face;

a voltage source for applying an AC voltage to said piezoelectric strip wherein said piezoelectric strip vibrates along said length dimension and wherein, when said spindle rotates about said axis of rotation, a Coriolis force acts on said piezoelectric strip wherein said first face of said piezoelectric strip is pushed towards said first capacitance sensor and said second face of said piezoelectric strip is pushed towards said second capacitance sensor; and

a processor coupled to said first capacitance sensor and said second capacitance sensor for generating an angular velocity of said piezoelectric strip rotating about said axis of rotation as said AC voltage is applied to said piezoelectric strip, wherein said angular velocity is based on said first capacitance and said second capacitance.

16. A vibrating gyroscope as in claim 15, wherein said piezoelectric strip comprises:

a layer of said piezoelectric material having a first face and a second face;

a first layer of CNTs disposed on said first face of said layer; and

a second layer of CNTs disposed on said second face of said layer.

17. A vibrating gyroscope as in claim 15, wherein said CNTs are embedded in said piezoelectric material.

18. A vibrating gyroscope as in claim 15, wherein said axis of rotation of said spindle is approximately centered between said first end and said second end of said piezoelectric strip.

19. A vibrating gyroscope as in claim 15, wherein said spindle is electrically conductive and wherein said voltage source is electrically coupled to said spindle for applying said AC voltage thereto.

20. A vibrating gyroscope as in claim 15, wherein said piezoelectric material is selected from the group consisting of polyvinilydene fluoride (P(VDF)) and polyvinilydene trifluoroethylene (P(VDF-TrFE)).

21. A vibrating gyroscope as in claim 15, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO₃).

22. A vibrating gyroscope as in claim 20, further comprising additives mixed in said piezoelectric material, said additives being selected from the group consisting of magnesium niobate-lead titanate (PMN-PT), lead zirconium titanate (PZT), and barium titanate (BaTiO₃).