MEMS GYRO

• US 20170268879A1
• Filed: 12/17/2015
• Published: 09/21/2017
• Est. Priority Date: 12/18/2014
• Status: Active Grant

• Current Assignee: RISE Acreo AB (Government of Sweden)
• Original Assignee: RISE Acreo AB (Government of Sweden)
• Inventors: ANDERSSON, Gert, SVENSSON, Erik, STOEW, Borys, HEDENSTIERNA, Nils
• Granted Patent: US 9,976,858 B2
• Time in Patent Office: Days
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• 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

Abstract

A sensor is disclosed for detecting a rotational motion about a resulting sensitivity axis. The sensor includes at least two dual mass gyroscope units, each of the gyroscope units are adapted to detect a rotational motion about a sensitivity axis of the respective gyroscope unit. The sensitivity axes being parallel to each other and to the resulting sensitivity axis. The gyroscope units are interconnected at the inertial masses of the gyroscope units which cause the gyroscope unit to operate synchronously.

Claims

1. A sensor for detecting a rotational motion about a resulting sensitivity axis, said sensor comprising:

at least two dual mass gyroscope units, each of said at least two dual mass gyroscope units being adapted to detect a rotational motion about a sensitivity axis of the respective gyroscope unit of said at least two dual mass gyroscope units, said sensitivity axes being parallel to each other and to said resulting sensitivity axis, each of said at least two dual mass gyroscope units comprising;

a total inertial mass comprising a first inertial mass and a second inertial mass physically attached to each other, each of said first inertial mass and second inertial mass being arranged spaced apart from and facing a respective first and a respective second electrode, wherein a rotation of said first inertial mass about a detection axis of said respective gyroscope unit, said detection axis being perpendicular to said sensitivity axis and said rotation being caused by a coriolis force when said respective gyroscope unit is subjected to a rotation about said sensitivity axis, results in a positive change of the capacitance between said total inertial mass and one of said first electrode and said second electrode and a negative change of the capacitance between said total inertial mass and the other one of said first electrode and said second electrode;

first excitation means for causing the first mass to oscillate in a rotational motion about a first excitation axis substantially perpendicular to said sensitivity axis of said respective gyroscope unit; and

second excitation means for exciting the second mass to oscillate in a rotational motion about a second excitation axis substantially perpendicular to said sensitivity axis of said respective gyroscope unit and parallel with said first excitation axis, said oscillation of said second mass being in anti-phase with said oscillation of said first mass;

wherein the first mass of a first gyroscope unit of said at least two dual mass gyroscope units is connected by a connecting element to the first mass of a second gyroscope unit of said at least two dual mass gyroscope units such that a rotation of said first mass of said first gyroscope unit in a first direction about said excitation axis causes said first mass of said second gyroscope unit to rotate about its respective excitation axis in an opposite direction compared to said first direction; and

wherein each of said first and second mass of each respective gyroscope unit of said at least two dual mass gyroscope units comprises a first half portion and a second half portion, said first and said second half portion being defined by opposite sides of an axis parallel to said sensitivity axis and intersecting the excitation axis of the respective mass, and

wherein said connecting element is connected to said first half portion of said first mass of said first gyroscope unit and to said second half portion of said first mass of said second gyroscope unit.

2. The sensor according to claim 1, wherein said connecting element is connected to a first side of said first mass of said first gyroscope unit, and to a second side of the first mass of the second gyroscope unit, wherein said first side and said second side face each other.

3. The sensor according to claim 1, wherein said connecting element is self-supporting.

4. The sensor according to claim 1, wherein said connecting element is S-shaped or Z-shaped.

5. The sensor according to claim 1, wherein said oscillation of said first mass of said first gyroscope unit and said first mass of said second gyroscope unit is synchronous and in anti-phase with respect to each other about said respective excitation axis.

6. The sensor according to claim 1, wherein said gyroscope unit is provided with drive frames comprising said first excitation means and second excitation means, said drive frames are arranged external to said first and second mass, each of said drive frames being connected to a respective mass with a coupling member.

7. The sensor according to claim 6, wherein each of said first excitation means and second excitation means is configured to alternatingly move each of said drive frames along a direction substantially parallel to said sensitivity axis in order to cause each of said first mass and said second mass to oscillate in a rotational motion about said first excitation axis and said second excitation axis respectively.

8. The sensor according to claim 1, wherein said at least two gyroscope dual mass units are further connected via a second connecting element,

wherein the second mass of a first gyroscope unit is connected by said second connecting element to the second mass of a second gyroscope unit such that a rotation of said second mass of said first gyroscope unit in a first direction about the corresponding excitation axis causes said second mass of said second gyroscope unit to rotate about its respective excitation axis in an opposite direction compared to said first direction.

9. The sensor according to claim 1, wherein said sensor is a planar sensor.

10. The sensor according to claim 1, wherein said sensor is formed in a single unit.

11. The sensor according to claim 1, comprising an even number of gyroscope units.

12. The sensor according to claim 1,

wherein said connecting element is a resilient connection.

13. The sensor according to claim 1, wherein said first and second inertial masses are physically connected via an elongated connector, wherein said first and second masses are symmetrically arranged with respect to the elongated connector.

14. The sensor according to claim 1, wherein a shape of said first mass is substantially the same as the shape of said second mass.

15. The sensor according to claim 1, wherein said connection element forces a rotational motion of said first mass of a first gyroscope unit about said detection axis to be synchronous with a rotational motion of said first mass of a second gyroscope unit about the respective detection axis.