Micro/nano multiaxial inertial sensor of movements

• US 9,176,166 B2
• Filed: 12/20/2012
• Issued: 11/03/2015
• Est. Priority Date: 12/22/2011
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Walther, Arnaud
• Primary Examiner(s): McCall, Eric S
• Assistant Examiner(s): Megna Fuentes, Anthony W
• Application Number:
  US13/722,427
• Publication Number:
  US 20140060184A1
• Time in Patent Office: 1,048 Days
• Field of Search: 7350413-50414, 737/74, 737/67, 7350402-50403, 735/041.2
• US Class Current: 1/1
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01P 15/097 by vibratory elements
• CPC Class Codes: G01P 15/123 by piezo-resistive elements, e.g. semiconductor strain gauges
• CPC Class Codes: G01P 15/14 by making use of gyroscopes gyroscopes per se G01C19/00
• CPC Class Codes: G01P 15/18 in two or more dimensions

Abstract

The multiaxial inertial sensor of movements is a micro/nano sensor that makes it possible to couple at least one accelerometer with other structures, either accelerometers or gyroscopes, by an oscillating disk structure. The oscillating disk also forms an inertial sensor such as a gyrometer. This single-chip structure associating both gyroscopes and accelerometers makes it possible to achieve detections and measurements in up to 6 axes, in other words 3 accelerometer axes and 3 gyroscope axes, and to exert control by a single and unique electronic unit, thus permitting a single automatic control loop in excitation and a single electronic reading chip.

Application to technologies known as MEMS.

Claims

1. A multiaxial inertial sensor of movements, comprising:

a first sensor;

a second sensor;

a coupling structure coupled in rotation around a Z axis and configured to induce transmission of movement between, respectively;

the first sensor with a first excitation mass having a first degree of freedom in translation along a first excitation axis in a plane XY perpendicular to the Z axis, and

the second sensor with a second excitation mass having a second degree of freedom in translation along a second excitation axis of the plane XY, the second excitation axis of the second excitation mass being different from the first excitation axis of the first excitation mass,

wherein the coupling structure is provided with an oscillating element, the oscillations of which in the XY plane around the Z axis are transmitted thereto by the kinetic energy of excitation of an exciter; and

an oscillating disk gyroscope in the XY plane with one degree of freedom in rotation around the Z axis and comprising;

a central ring coupled with an outer excitation ring forming the coupling structure at least partly, the central ring having at least one degree of freedom in rotation around a first axis of the XY plane and transmitting a Coriolis force at least partly in order to measure a rotational movement around a second axis of the XY plane, perpendicular to the first axis,

wherein the outer excitation ring is laterally coupled with the excitation masses of the first sensor and of the second sensor to transmit linear excitation movements in the XY plane to them.

2. The inertial sensor according to claim 1, wherein the oscillating disk gyroscope in the XY plane additionally comprises:

an intermediate ring subjected to the Coriolis force and configured to transmit a Coriolis force at least partly to the central ring without transmitting the oscillations of the outer excitation ring at least partly, in order to assure decoupling between excitation and detection.

3. The inertial sensor according to claim 2, wherein the first sensor is a dynamic accelerometer comprising:

the first excitation mass coupled with the coupling structure;

a first detection mass integral with the movement of the first excitation mass and mobile along a direction perpendicular to the first excitation axis; and

a detector configured to detect an acceleration during displacements of the first detection mass along the direction perpendicular to the first excitation axis.

4. The inertial sensor according to claim 3, wherein the detector comprises a transmission element integral with the movement of the first detection mass along the direction perpendicular to the first excitation axis but not along the first excitation axis, and a gauge for measuring forces to which the transmission element is subjected.

5. The inertial sensor according to claim 3, wherein the first detection mass comprises two individual inertial masses configured to filter the movements due to a Coriolis force resulting from a rotation.

6. The inertial sensor according to claim 5, wherein the inertial masses are coupled so as to exhibit movements in phase along the first excitation axis.

7. The inertial sensor according to claim 1, wherein the second sensor is a gyroscope comprising:

the second excitation mass coupled with the coupling structure;

a second detection mass mobile along a direction perpendicular to the second excitation axis; and

a detector configured to detect a Coriolis force resulting from displacements of the second detection mass along the direction perpendicular to the second excitation axis.

8. The inertial sensor according to claim 7, wherein the detector comprises a transmission element integral with the movement of the second detection mass along the direction perpendicular to the second excitation axis but not along the second excitation axis, and at least one gauge for measuring forces to which the transmission element is subjected.

9. The inertial sensor according to claim 7, wherein the second detection mass comprises two individual inertial masses configured to filter the acceleration movements.

10. The inertial sensor according to claim 9, wherein the inertial masses are coupled so as to exhibit movements in phase opposition along the second excitation axis.

11. The inertial sensor according to claim 1, wherein the coupling structure is provided with at least two oscillating disks in rotation around a Z axis and coupled with one another by their circumferences.

12. The inertial sensor according to claim 1, comprising at least one additional sensor, the coupling structure being configured to induce transmission of movement with the additional sensor.

13. The inertial sensor according to claim 1, wherein the coupling structure is provided, for each of the first and second sensors, with a link configured to transform the rotational movement around the Z axis of the coupling structure into a translational movement in the XY plane.

14. The inertial sensor according to claim 1, comprising a single electronic circuit using a single automatic control loop in excitation and a single element for reading the first and second sensors for all axes.

15. The inertial sensor according to claim 1, wherein the exciter comprises electrodes for excitation of the first excitation mass and/or electrodes for excitation of the second excitation mass and/or electrodes for excitation of the coupling structure.

16. The inertial sensor according to claim 1, wherein the exciter is configured to excite at least two among:

the coupling structure, the first excitation mass and the second excitation mass, and wherein the exciter is provided with an automatic control circuit.