Micromechanical vibratory gyroscope sensor array

• US 5,465,620 A
• Filed: 06/14/1993
• Issued: 11/14/1995
• Est. Priority Date: 06/14/1993
• Status: Expired due to Term

• Current Assignee: Rensselaer Polytechnic Institute
• Original Assignee: Rensselaer Polytechnic Institute
• Inventors: Maby, Edward W., Sanderson, Arthur C.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): Oda, Christine K.
• Application Number:
  US08/077,345
• Time in Patent Office: 883 Days
• Field of Search: 73/504, 73/505
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

A micromechanical gyroscopic sensor array for detecting rotational movement includes a plurality of vibrational microgyroscopic sensing elements fixedly oriented in a common plane relative to one another such that an in-plane direction and an out-of-plane direction orthogonal thereto are defined. A mechanism for driving each microgyroscopic sensing element at a predetermined in-plane drive frequency is provided. Each sensing element has a predefined out-of-plane resonant frequency selected such that a range of in-plane frequencies and/or out-of-plane resonant frequency differences exist among the sensing elements. A resonant gate transistor is associated with each sensing element for sensing out-of-plane motion and producing a sense signal representative thereof. Signal processing then converts the sense signal to a signal representative of rotational movement experienced by the micromechanical gyroscopic sensor array. A learning function can be added to the sensor array by associating adjustable weights with each sensing element and employing a neural network having feedback control of the adjustable weights.

Claims

1. A micromechanical gyroscopic sensor array for detecting rotational movement, said sensor array comprising:

a plurality of vibrational microgyroscopic sensing elements fixedly oriented in a common plane relative to one another such that an in-plane direction and out-of-plane direction orthogonal thereto are defined, each microgyroscopic sensing element of said plurality of vibrational microgyroscopic sensing elements having an associated predefined out-of-plane resonant frequency;

means for driving said each microgyroscopic sensing element at a predetermined in-plane drive frequency, wherein the respective predetermined in-plane drive frequencies of said plurality of vibrational microgyroscopic sensing elements and the associated predefined out-of-plane resonant frequencies of said plurality of vibrational microgyroscopic sensing elements are such that various frequency differences exist between the respective predetermined in-plane drive frequencies and the associated predefined out-of-plane resonant frequencies amongst said plurality of vibrational microgyroscopic sensing elements;

sensing means, associated with said each microgyroscopic sensing element of said plurality of vibrational microgyroscopic sensing elements, for sensing out-of-plane motion of said each microgyroscopic sensing element and producing a corresponding sense signal therefrom; and

signal processing means coupled to said sensing means for producing a combined signal representative of rotational movement experienced by the micromechanical gyroscopic sensor array based upon said associated sense signals produced by said sensing means from said out-of-plane motion experienced by said plurality of vibrational microgyroscopic sensing elements.

2. The micromechanical gyroscopic sensor array of claim 1, wherein each of said plurality of vibrational microgyroscopic sensing elements has substantially the same predefined out-of-plane resonant frequency and at least two of said plurality of vibrational microgyroscopic sensing means have unique predetermined in-plane drive frequencies such that a range of drive frequency differences exists between associated out-of-plane resonant frequencies and respective in-plane drive frequencies amongst said plurality of vibrational microgyroscopic sensing elements.

3. The micromechanical gyroscopic sensor array of claim 1, wherein at least two of said plurality of vibrational microgyroscopic sensing elements have unique predefined out-of-plane resonant frequencies and said each microgyroscopic sensing element of said plurality of vibrational microgyroscopic sensing elements has substantially the same predetermined in-plane drive frequency, said unique predefined out-of-plane resonant frequencies having frequency differences with respect to one another.

4. The micromechanical gyroscopic sensor array of claim 1, wherein the associated predefined out-of-plane resonant frequencies of at least two of said plurality of vibrational microgyroscopic sensing elements are unique and the respective predetermined in-plane drive frequencies of at least two of said plurality of vibrational microgyroscopic sensing elements are unique such that differences in the out-of-plane resonant frequencies and differences in the in-plane drive frequencies exist among said plurality of vibrational microgyroscopic sensing elements.

5. The micromechanical gyroscopic sensor array of claim 1, wherein said each microgyroscopic sensing element of said plurality of vibrational microgyroscopic sensing elements and said associated sensing means share at least one common electrode.

6. The micromechanical gyroscopic sensor array of claim 5, wherein said each microgyroscopic sensing element comprises a micromechanical tuning fork having two tines.

7. The micromechanical gyroscopic sensor array of claim 6, wherein for said each microgyroscopic sensing element, said at least one common electrode shared by said associated sensing means is disposed adjacent one of said two tines.

8. The micromechanical gyroscopic sensor array of claim 1, wherein said sensing means includes a resonant gate transistor associated with said each microgyroscopic sensing element.

9. The micromechanical gyroscopic sensor array of claim 1, wherein said plurality of vibrational microgyroscopic sensing elements are arranged in a circular ring in said common plane and wherein an inner area of substrate is defined within said circular ring defined by said plurality of vibrational microgyroscopic sensing elements, said inner area containing integrated control circuitry for at least two of said driving means, said sensing means and said signal processing means.

10. The micromechanical gyroscopic sensor array of claim 1, further comprising means for weighing out-of-plane motion sensed by at least two of said plurality of vibrational microgyroscopic sensing elements.

11. The micromechanical gyroscopic sensor array of claim 10, wherein said weighing means is adjustable and said sensor array further includes neural network means and feedback circuitry, said neural network means being connected to receive said sense signals from said sensing means for monitoring said sense signals with references to prestored patterns of motion and for learning new patterns thereof, and said feedback circuitry being coupled between said neural network means and said adjustable weighing means for feedback adjusting the weighing of said weighing-means based on the monitoring of said neural network means.

12. The micromechanical gyroscopic sensor array of claim 1, wherein multiple sense signals from respective sensing means are produced based on said out-of-plane motion experienced by said plurality of vibrational microgyroscopic sensing elements, and wherein said signal processing means constructs said combined signal representative of rotational movement experienced by the micromechanical gyroscopic sensor array through a combination of said multiple sense signals.

13. A micromechanical gyroscope sensor array for detecting rotational movement, said sensor array comprising:

a plurality of rotation detecting means fixedly oriented in a common plane relative to one another such that an in-plane direction and an out-of-plane direction orthogonal thereto are defined, each rotation detecting means of said plurality of rotational detecting means having an associated predefined out-of-plane resonant frequency;

means for driving said each rotation detecting means at an associated predetermined in-plane drive frequency, wherein the respective predetermined in-plane drive frequencies of said plurality of rotation detecting means and the respective predefined out-of-plane resonant frequencies of said plurality of rotation detecting means provide various frequency differences between the respective predetermined in-plane drive frequencies and the corresponding predefined out-of-plane resonant frequencies amongst said plurality of rotation detecting means;

a plurality of sensing means, each sensing means of said plurality of sensing means being associated with one rotation detecting means of said plurality of rotation detecting means for sensing a component of an out-of-plane motion experienced by said associated detecting means and for producing a component sense signal therefrom; and

signal processing means coupled to said plurality of sensing means for producing a combined signal representative of rotational movement experienced by the micromechanical gyroscopic sensor array by combining said component sense signal produced by each sensing means of said plurality of sensing means.

14. The micromechanical gyroscope sensor array of claim 13, wherein said each sensing means comprises a resonant gate transistor associated with said one rotation detecting means of said plurality of rotation detecting means.

15. The micromechanical gyroscope sensor array of claim 14, wherein said each resonant gate transistor and said one rotation detecting means have a common electrode.

16. The micromechanical gyroscope sensor array of claim 13, further comprising means for weighing at least two of said component sense signals produced by said plurality of sensing means.

17. The micromechanical gyroscope sensor array of claim 16, wherein said weighing means is adjustable and said sensor array further includes neural network means and feedback circuitry, said neural network means being connected to receive said component sense signals from said plurality of sensing means for monitoring said sense signals with references to prestored patterns of motion and for learning new patterns thereof, and said feedback circuitry being coupled between said neural network means and said adjustable weighing means for feedback adjusting of said weighing means based upon the monitoring of said neural network means.

18. The micromechanical gyroscope sensor array of claim 13, wherein each of said detecting means includes a micromechanical tuning fork having two tines.

19. A method for detecting rotational movement employing a micromechanical gyroscopic sensor array, said sensor array including a plurality of vibrational sensing elements fixedly oriented in a common plane relative to one another such that an in-plane direction and an out-of-plane direction orthogonal thereto are defined, each vibrational sensing element of said plurality of vibrational sensing elements having an associated predefined out-of-plane resonant frequency, said method comprising the steps of:

(a) driving said plurality of vibrational sensing elements at associated predetermined in-plane drive frequencies, said in-plane drive frequencies of said plurality of vibrational sensing elements and said associated predefined out-of-plane resonant frequencies of said plurality of vibrational sensing elements providing various frequency differences between respective in-plane drive frequencies and corresponding out-of-plane resonant frequencies among the plurality of vibrational sensing elements;

(b) experiencing rotational movement by at least two of said plurality of vibrational sensing elements;

(c) sensing at each vibrational sensing element of said plurality of vibrational sensing elements an out-of-plane motion component and producing therefrom a component sense signal; and

(d) combining said component sense signal of said each vibrational sensing element to produce a signal representative of the rotational movement experienced by the micromechanical gyroscopic sensor array.

20. The method of claim 19, further comprising the step of assigning an associated weight to the out-of-plane motion component sensed at said each vibrational sensing element in said sensing step (c).

21. The method of claim 20, wherein said weight assigning includes assigning adjustable weights to each of said out-of-plane motion components sensed at said sensing elements in said sensing step (c) and wherein said method further includes the step of subsequently intelligently adjusting said assigned weights based on the plurality of component sense signals produced in said sensing step (c).