MICROMACHINED GYROSCOPE INCLUDING A GUIDED MASS SYSTEM

• US 20130068018A1
• Filed: 09/16/2011
• Published: 03/21/2013
• 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
• Granted Patent: US 8,833,162 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• 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 at least one proof-mass and the at least one 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 at least one spring;

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

wherein the at least one guiding arm and the at least one proof-mass are able to rotate out of the plane about a first sense axis, the first sense axis being in the plane and parallel to the first direction;

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

a transducer for sensing motion of the at least one 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.

2. 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 spring;

wherein the at least one guiding arm allows for anti-phase motion of the at least two proof-masses along a first direction and anti-phase motion of the at least two proof-masses normal to the plane.

3. 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.

4. The gyroscope of claim 2 which includes:

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.

5. The gyroscope of claim 1 which includes:

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.

7. The gyroscope of claim 2 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 spring, wherein the stress relief frame is coupled to the substrate, wherein the stress relief frame is not driven by the actuator;

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 spring.

6. A gyroscope comprising;

a substrate;

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

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

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 one spring;

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

wherein the at least one guiding arm and the first proof-mass are able to rotate out of the plane about a first sense axis, the first sense axis being in the plane and parallel to the first direction;

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 in plane;

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 that is in the plane and orthogonal to the first direction;

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 that is in plane and orthogonal to the first 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 normal to the plane.

8. 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;

wherein the at least one proof-mass and the at least one guiding arm are disposed 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 at least one spring;

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

wherein the at least one guiding arm and the at least one proof-mass rotate about a first sense axis, the first sense axis being in-plane and parallel to the first direction;

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 proof-mass and at least one guiding arm;

wherein the at least one proof-mass and the at least one guiding arm are disposed 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 at least one spring;

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

wherein the at least one guiding arm and the at least one proof-mass rotate about a second sense axis, the second sense axis being in-plane and parallel to the first direction;

wherein the first guided mass system rotates about the first axis in response to angular rate, the second guided mass system rotates about the second axis in response to angular rate, and the first and second guided mass systems rotate anti-phase in response to angular rate;

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

a transducer for sensing at least one proof-mass motion normal to the substrate in response to angular velocity that is parallel to the substrate and orthogonal to the first direction.

9. The gyroscope of claim 8 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 springs of the first and second guided mass systems, wherein the stress relief frame is coupled to the substrate, wherein the stress relief frame is not driven by the actuator;

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 spring.

10. The gyroscope of claim 8 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 one proof-mass and at least one guiding arm;

wherein the at least one proof-mass and the at least one guiding arm are disposed 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 at least one spring;

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

wherein the at least one guiding arm and the at least one proof-mass rotate about a third sense axis, the third sense axis being in-plane and parallel to the first direction;

wherein the second guided mass system rotates about the first axis in response to angular rate, the third guided mass system rotates about the second axis in response to angular rate, and the second and third guided mass systems rotate anti-phase in response to angular rate;

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 spring of the first, second and third guided mass systems, wherein the stress relief frame is coupled to the substrate, wherein the stress relief frame is not driven by the actuator;

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 spring.

12. 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;

wherein the at least two proof-masses and the at least one guiding arm are disposed in a plane parallel to the substrate;

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 one spring;

wherein the at least one guiding arm allows for anti-phase motion of the at least two proof-masses along a first direction in the plane;

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 in plane; 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 in the plane and orthogonal to the first direction responding to angular velocity about an input axis that is in plane and parallel to the first direction.