Micromachined gyroscope including a guided mass system

• US 9,395,183 B2
• Filed: 08/28/2014
• Issued: 07/19/2016
• Est. Priority Date: 09/16/2011
• Status: Active Grant

• Current Assignee: Invensense Incorporated (TDK Corporation)
• Original Assignee: Invensense Incorporated (TDK Corporation)
• Inventors: Seeger, Joseph, Anac, Ozan
• Primary Examiner(s): Patel, Harshad R
• Assistant Examiner(s): Shah, Samir M
• Application Number:
  US14/472,143
• Publication Number:
  US 20140366631A1
• Time in Patent Office: 691 Days
• Field of Search: 735/040.2, 735/040.4, 735/041.2, 735/041.4, 735/10, 735/11
• US Class Current: 1/1
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5733 Structural details or topology
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: G01C 19/5755 the devices having a single sensing mass
• CPC Class Codes: G01C 19/5762 the sensing mass being connected to a driving mass, e.g. driving frames

Abstract

A gyroscope is disclosed. The gyroscope comprises a substrate; and a guided mass system. The guided mass system comprises proof-mass and guiding arm. The proof-mass and the guiding arm are disposed in a plane parallel to the substrate. The proof-mass is coupled to the guiding arm. The guiding arm is also coupled to the substrate through a spring. The guiding arm allows motion of the proof-mass to a first direction in the plane. The guiding arm and the proof-mass rotate about a first sense axis. The first sense axis is in the plane and parallel to the first direction. The gyroscope includes an actuator for vibrating the proof-mass in the first direction. The gyroscope also includes a transducer for sensing motion of the proof-mass-normal to the plane in response to angular velocity about a first input axis that is in the plane and orthogonal to the first direction.

Claims

1. A gyroscope comprising;

a substrate;

a guided mass system, the guided mass system comprising at least one proof-mass and at least one guiding arm;

wherein the proof-mass and the guiding arm are disposed in a plane parallel to the substrate;

the at least one proof-mass being coupled to the at least one guiding arm;

the at least one guiding arm being coupled to the substrate through a coupling comprising at least one flexible member;

wherein the proof-mass vibrates in a first direction in the plane and the guiding arm rotates in the plane;

wherein in response to angular velocity about a first input axis, an end of the guiding arm is able to rotate out of the plane and the proof-mass is able to rotate out of the plane;

an actuator for rotating the guiding arm in the plane; and

a transducer for generating an output in response to the angular velocity of the at least one proof-mass.

2. The gyroscope of claim 1, wherein the transducer comprises a capacitive transducer.

3. The gyroscope of claim 1, wherein the angular velocity generates a Coriolis force on the at least one proof mass.

4. The gyroscope of claim 1, wherein actuator comprises an electrostatic actuator, wherein the electrostatic actuator includes a fixed comb and a moving comb, wherein the moving comb is disposed in the plane and the fixed comb is coupled to an anchor.

5. The gyroscope of claim 1, wherein the at least one guiding arm comprises two guiding arms.

6. The gyroscope of claim 1 wherein the at least one proof-mass comprises at least two proof masses, the at least two proof-masses being coupled to at least one guiding arm, the at least one guiding arm being coupled to the substrate through at least one flexible member;

wherein the two proof masses move in anti-phase along the first direction;

wherein the at least one guiding arm and the two proof-masses are able to rotate out of the plane in response to angular velocity about the first input axis that is in the plane.

7. The gyroscope of claim 1 further comprising:

at least one other proof mass coupled to the at least one proof mass, wherein when the at least one proof mass is vibrating the at least one other proof mass vibrates; and

at least one other transducer for sensing motion of the at least one other proof-mass in response to angular velocity about an axis other than the first input axis.

8. The A gyroscope comprising;

a substrate;

a guided mass system, the guided mass system comprising at least one proof-mass and at least one guiding arm;

the at least one proof-mass being coupled to the at least one guiding arm;

the at least one guiding arm being coupled to the substrate through at least one flexible member;

wherein the proof-mass vibrates in a first direction and the guiding arm rotates;

wherein the at least one guiding arm and the at least one proof-mass are able to rotate about a first sense axis in response to angular velocity about a first input axis;

an actuator for vibrating the at least one proof-mass in the first direction;

a transducer for generating an output in response to the angular velocity of the at least one proof-mass;

wherein the at least one proof-mass comprises at least two proof masses, the at least two proof-masses being coupled to at least one guiding arm, the at least one guiding arm being coupled to the substrate through at least one flexible member;

wherein the two proof masses move in anti-phase along the first direction;

wherein the at least one guiding arm and the two proof-masses are able to rotate out of a plane about the first sense axis in response to angular velocity about the first input axis that is in the plane;

at least one other proof-mass coupled to the at least one proof mass, wherein when the at least one proof mass is vibrating the at least one other proof-mass rotates in plane; and

a second transducer for detecting the rotation of the at least one other proof-mass about a second sense axis orthogonal to the first sense axis responding to angular velocity about a second input axis that is in plane and orthogonal to the first input axis.

9. The A gyroscope comprising:

a substrate;

a guided mass system, the guided mass system comprising at least one proof-mass and at least one guiding arm;

the at least one proof-mass being coupled to the at least one guiding arm;

the at least one guiding arm being coupled to the substrate through at least one flexible member;

wherein the proof-mass vibrates in a first direction and the guiding arm rotates;

wherein the at least one guiding arm and the at least one proof-mass are able to rotate about a first sense axis in response to angular velocity about a first input axis;

an actuator for vibrating the at least one proof-mass in the first direction;

a transducer for generating an output in response to the angular velocity of the at least one proof-mass;

at least one other proof-mass coupled to the at least one proof mass, wherein when the at least one proof mass vibrates, the at least one other proof-mass translates in the first direction and in response to angular rotation of the gyroscope about a second input axis normal to the plane, the at least one other proof-mass translates in the plane orthogonal to the first direction; and

a second transducer for detecting motion of the at least one other proof-mass in the plane orthogonal to the first direction.

10. A gyroscope comprising;

a substrate;

a guided mass system, the guided mass system comprising a first proof-mass and at least one guiding arm;

the first proof-mass being coupled to the at least one guiding arm;

the at least one guiding arm being coupled to the substrate through at least flexible member;

wherein the at least one guiding arm allows for motion of the first proof-mass in a first direction;

wherein the at least one guiding arm and the first proof-mass are able to rotate about a first sense axis, a second proof-mass coupled to the first proof mass, wherein when first proof mass moves in the first direction, the second proof-mass rotates;

a third proof-mass coupled to the first proof mass, wherein when the first proof mass moves in the first direction, the third proof-mass moves in the first direction;

an actuator for vibrating the first proof-mass in the first direction;

a first transducer for sensing motion of the first proof-mass normal to the plane in response to angular velocity about a first input axis;

a second transducer for detecting the rotation of the second proof-mass about a second sense axis orthogonal to the first sense axis responding to angular velocity about a second input axis; and

a third transducer for detecting motion of the third proof-mass in-plane and orthogonal to the first direction in response to angular rotation of the gyroscope about a third input axis.

11. The gyroscope of claim 10 further comprising:

a stress relief frame, wherein the at least one guiding arm is flexibly coupled to the stress relief frame via the at least one flexible member, wherein the stress relief frame is coupled to the substrate, wherein the stress relief frame decouples motion of the substrate coupling points from the at least one flexible member.

12. A gyroscope comprising:

a substrate;

a first guided mass system, the first guided mass system comprising at least one proof-mass and at least one guiding arm;

the at least one proof-mass being coupled to the at least one guiding arm;

the at least one guiding arm being coupled to the substrate through at least one flexible member;

wherein the at least one proof-mass vibrates and the guiding arm rotates in a plane parallel to the substrate;

wherein the at least one guiding arm and the at least one proof-mass rotate out of the plane in response to angular velocity about a first input axis;

a first spring;

a second guided mass system, the second guided mass system coupled by the first spring to the first guided mass system;

the second guided mass system comprising at least one second proof-mass and at least one second guiding arm;

the at least one second proof-mass being coupled to the at least one second guiding arm;

the at least one second guiding arm being coupled to the substrate through at least one second flexible member;

wherein the second proof-mass vibrates in a first direction and the guiding arm rotates in the plane;

wherein the at least one second guiding arm and the at least one second proof-mass rotate out of the plane in response to angular velocity about the first input axis;

wherein the at least one proof-mass rotates about a first axis in response to angular rate, the second proof-mass rotates about a second axis in response to angular rate, and the at least one proof-mass and the second proof-mass rotate in anti-phase in response to angular rate;

an actuator for vibrating the second proof-mass in the first direction; and

a transducer for sensing motion of the at least one proof-mass in response to angular velocity.

13. The gyroscope of claim 12 further comprising:

a stress relief frame, wherein the at least one guiding arm is flexibly coupled to the stress relief frame via the at least one flexible members of the first and second guided mass systems, wherein the stress relief frame is coupled to the substrate;

wherein the stress relief frame decouples motion of the substrate coupling points from the at least one spring to prevent stress on the at least one flexible member.

14. The gyroscope of claim 12 further comprising:

a second spring;

a third guided mass system, the third guided mass system coupled by the second spring to the first guided mass system;

the third guided mass system comprising at least a third proof-mass and at least a third guiding arm;

the third proof-mass being coupled to the third guiding arm;

the third guiding arm being coupled to the substrate through at least one third flexible member;

wherein the third guiding arm allows for motion of the third proof-mass in the first direction;

wherein the third guiding arm and the third proof-mass rotate out of the plane, wherein the second proof mass rotates out of the plane in response to angular rate, the third guided mass system rotates out of the plane in response to angular rate, and the second and third guided mass systems rotate anti-phase in response to angular rate.

15. The gyroscope of claim 14 further comprising:

a stress relief frame, wherein the at least one guiding arm is flexibly coupled to the stress relief frame via one or more of the at least one flexible member of the first, second and third guided mass systems, wherein the stress relief frame is coupled to the substrate, wherein the stress relief frame decouples motion of the substrate coupling points from the at least one flexible member.

16. A gyroscope comprising;

a substrate;

a guided mass system, the guided mass system comprising at least two proof-masses and at least one guiding arm;

the at least two proof-masses being coupled to the at least one guiding arm;

the at least one guiding arm being coupled to the substrate through at least flexible member;

wherein the at least one guiding arm allows for anti-phase motion of the at least two proof-masses;

at least one other proof-mass coupled to the at least two proof masses, wherein when the at least two proof masses move anti-phase in the first direction the at least one other proof-mass rotates; and

an actuator for vibrating the at least two proof-masses antiphase in the first direction; and

a transducer for detecting the rotation of the at least one other proof-mass about a sense axis responding to angular velocity.

17. A gyroscope comprising;

a substrate;

a guided mass system, the guided mass system comprising at least one proof-mass and at least one guiding arm;

wherein the proof-mass and the guiding arm are disposed in a plane parallel to the substrate;

the at least one proof-mass being coupled to the at least one guiding arm;

the at least one guiding arm being coupled to the substrate through a coupling comprising at least one flexible member;

wherein the proof-mass vibrates in a first direction in the plane and the guiding arm rotates in the plane;

wherein in response to angular velocity about a first input axis, a first end portion of the guiding arm is able to rotate out of the plane and the proof-mass is able to rotate out of the plane.

18. The gyroscope of claim 17, wherein a first end portion of the guiding arm is able to rotate out of the plane about a first rotation axis;

and the proof-mass is able to rotate out of the plane about a second rotation axis.

19. The gyroscope of claim 18, wherein the first rotation axis and the second rotation axis are not coincident.

20. The gyroscope of claim 18, wherein the angle between the first rotation axis and the first direction is less than 45 degrees.

21. The gyroscope of claim 17, wherein the first end portion of the guiding arm is coupled to the proof-mass;

the guiding arm further comprises a second end portion;

the second end portion of the guiding arm is coupled to the substrate through the coupling comprising the at least one flexible member; and

the guiding arm is configured so that the first end portion rotates further out of the plane than the second end portion in response to angular velocity about a first input axis.

22. The gyroscope of claim 17, wherein the coupling comprises a direct connection between the substrate and the guide arm via one flexible member and an anchoring point.

23. The gyroscope of claim 17, wherein the flexible member is elongated in a direction parallel to the first direction.

24. The gyroscope of claim 23, wherein the flexible member is doubly folded.

25. A gyroscope comprising;

a substrate;

a guided mass system, the guided mass system comprising at least one proof-mass and at least one guiding arm;

wherein the proof-mass and the guiding arm are disposed in a plane parallel to the substrate;

the at least one proof-mass being coupled to a first end portion of the at least one guiding arm;

a second end portion of the at least one guiding arm being coupled to the substrate through a coupling comprising at least one flexible member;

wherein the proof-mass vibrates in a first direction in the plane and the guiding arm rotates in the plane;

wherein in response to angular velocity about a first input axis, the first end portion of the guiding arm is able to rotate out of the plane and the proof-mass is able to rotate out of the plane; and

wherein the guiding arm is configured so that the first end portion rotates further out of the plane than the second end portion in response to angular velocity about a first input axis.

26. The gyroscope of claim 25, wherein a first end portion of the guiding arm is able to rotate out of the plane about a first rotation axis;

and the proof-mass is able to rotate out of the plane about a second rotation axis.

27. The gyroscope of claim 26, wherein the first rotation axis and the second rotation axis are not coincident.

28. A gyroscope comprising;

a substrate;

a guided mass system, the guided mass system comprising at least one proof-mass and at least one guiding arm;

wherein the proof-mass and the guiding arm are disposed in a plane parallel to the substrate;

the at least one proof-mass being coupled to the at least one guiding arm;

the at least one guiding arm being coupled to the substrate through a coupling comprising a direct connection between the substrate and the guide arm via one flexible member and an anchoring point;

wherein the proof-mass vibrates in a first direction in the plane and the guiding arm rotates in the plane;

wherein in response to angular velocity about a first input axis, a first end portion of the guiding arm is able to rotate out of the plane and the proof-mass is able to rotate out of the plane.

29. The gyroscope of claim 28, wherein a first end portion of the guiding arm is able to rotate out of the plane about a first rotation axis;

and

the proof-mass is able to rotate out of the plane about a second rotation axis.

30. The gyroscope of claim 29, wherein the first rotation axis and the second rotation axis are not coincident.

31. The gyroscope of claim 28, wherein the first end portion of the guiding arm is coupled to the proof-mass;

the guiding arm further comprises a second end portion;

the second end portion of the guiding arm is coupled to the substrate through the coupling comprising the at least one flexible member; and

the guiding arm is configured so that the first end portion rotates further out of the plane than the second end portion in response to angular velocity about a first input axis.

32. The gyroscope of claim 28, further comprising an actuator configured to oscillate the at least one proof-mass in the first direction;

and a transducer for generating an output in response to the angular velocity of the at least one proof-mass.

33. The gyroscope of claim 28, wherein the flexible member is doubly folded.

34. A method of responding to angular velocity about an input axis, comprising:

oscillating an actuator suspended on an actuator mass in a plane parallel to a substrate, wherein the actuator mass oscillates along a first axis in the plane;

rotating a suspended guiding arm that is anchored to the substrate via a flexible element and an anchoring point, wherein the guiding arm is disposed in the plane and the rotating occurs in the plane, wherein the guiding arm has a first end portion that is coupled to a suspended proof-mass via at least a first spring and a second end portion that is coupled to the actuator mass via at least a second spring, wherein the oscillation of the actuator is transmitted via the second spring and causes the rotating;

oscillating the proof-mass along a second axis in the plane, wherein the rotating of the guiding arm is transmitted via the first spring and causes the oscillating of the proof-mass;

in response to an angular velocity about an input axis that is orthogonal to the first direction, rotating the first end portion of the guiding arm out of plane and rotating the proof mass out of plane;

detecting, with a transducer, the motion of the proof-mass normal to the plane; and

generating an output with the transducer based upon the amplitude of the rotation of the proof mass out of the plane.

35. The method of claim 34, wherein the first axis is not coincident with the second axis.

36. A gyroscope comprising,

a substrate

an actuator arm suspended in a plane parallel to the substrate;

an actuator attached to the actuator arm, wherein the actuator is a comb drive;

a guiding arm suspended in the plane, the guiding arm having a first end portion and a second end portion;

a first spring coupling the actuator arm to the first end portion of the guiding arm;

a proof mass;

a second spring coupling the proof mass to the second end portion of the guiding arm;

wherein the actuator is configured to oscillate the actuator arm along an actuation axis in the plane;

wherein oscillation of the actuator arm will cause the guiding arm to rotate in the plane;

wherein the rotation of the guiding arm in the plane will cause the proof mass to oscillate along an oscillation axis;

wherein the oscillation axis is not coincident with the actuation axis; and

wherein in response to angular velocity about an input axis, the second end portion of the guiding arm is able to rotate out of the plane and the proof-mass is able to rotate out of the plane.

37. The gyroscope of claim 36, wherein, the width of the first end portion measured in the plane is greater than the width of the first spring at the connection of the first end portion to the first spring;

and

the width of the second end portion measured in the plane is greater than the width of the second spring at the connection of the second end portion to the second spring.

38. The gyroscope of claim 36, wherein the guiding arm comprises an L-shaped portion.

39. The gyroscope of claim 38, wherein the first end portion is offset from the second end portion at a right angle within the plane.