Method for acquiring angular velocity of gyro sensor and device for doing the same

Patent metadata

Field	Value
Publication number	US-2016298966-A1
Application number	US-201514848344-A
Country	US
Kind code	A1
Filing date	Sep 9, 2015
Priority date	Apr 10, 2015
Publication date	Oct 13, 2016
Grant date	—

Abstract

According to one embodiment, a method of acquiring angular velocity of a gyro sensor, includes sensing a predetermined physical quantity which depends upon an amplitude of a vibration in a second direction, the vibration in the second direction being based on Coriolis force that is applied to a movable body which is vibrating in a first direction, and calculating angular velocity of the movable body based on the sensed predetermined physical quantity, wherein the predetermined physical quantity is sensed when the vibration in the second direction based on the Coriolis force is in a non-stationary state.

First claim

What is claimed is:

1 . A method of acquiring angular velocity of a gyro sensor, comprising:
sensing a predetermined physical quantity which depends upon an amplitude of a vibration in a second direction, the vibration in the second direction being based on Coriolis force that is applied to a movable body which is vibrating in a first direction; and calculating angular velocity of the movable body based on the sensed predetermined physical quantity, wherein the predetermined physical quantity is sensed when the vibration in the second direction based on the Coriolis force is in a non-stationary state.

2 . The method of claim 1 , wherein the predetermined physical quantity is based on capacitance between a fixed electrode portion and a movable electrode portion included in the movable body.

3 . The method of claim 1 , further comprising stopping a vibration in the first direction of the movable body after the predetermined physical quantity is sensed.

4 . The method of claim 3 , wherein the vibration in the first direction of the movable body is stopped before the vibration in the second direction based on the Coriolis force reaches a stationary state.

5 . The method of claim 3 , wherein the vibration in the first direction of the movable body is stopped by catching the movable body.

6 . The method of claim 5 , wherein catching the movable body is performed by applying an electrostatic force between the movable body and a drive electrode.

7 . The method of claim 3 , wherein the vibration in the first direction of the movable body is stopped by catching the movable body when an amplitude of the vibration in the first direction reaches a peak.

8 . The method of claim 3 , wherein the vibration in the first direction of the movable body is stopped by catching the movable body using a stopper.

9 . The method of claim 1 , further comprising starting a vibration in the first direction of the movable body before the predetermined physical quantity is sensed.

10 . The method of claim 9 , wherein the vibration in the first direction of the movable body is started by releasing the movable body.

11 . The method of claim 10 , wherein releasing the movable body is performed by reducing an electrostatic force between the movable body and a drive electrode.

12 . The method of claim 1 , wherein a forced vibration in the first direction is not applied to the movable body after the movable body starts to vibrate in the first direction.

13 . The method of claim 1 , wherein after a forced vibration in the first direction is applied to the movable body for a fixed period of time, the forced vibration to the movable body is stopped.

14 . The method of claim 1 , wherein a resonant frequency in the first direction of the movable body and a resonant frequency in the second direction of the movable body are different from each other.

15 . The method of claim 1 , wherein the angular velocity is calculated based on the predetermined physical quantity sensed when the amplitude of the vibration in the second direction of the movable body reaches a peak.

16 . The method of claim 1 , wherein the angular velocity is calculated based on the predetermined physical quantity sensed at specific timing after the movable body starts to vibrate in the first direction.

17 . The method of claim 1 , wherein the movable body starts to vibrate in the first direction from a state in which the movable body is displaced forcibly in the first direction.

18 . The method of claim 1 , wherein the vibration in the second direction of the movable body has a transient beat in the non-stationary state.

19 . The method of claim 1 , wherein a period of time for which the movable body continues to vibrate in the first direction is shorter than a period corresponding to a reciprocal of an output data rate of the gyro sensor.

20 . The method of claim 1 , wherein a difference between a resonant frequency in the first direction of the movable body and a resonant frequency in the second direction of the movable body is 1 kHz or more.

21 . The method of claim 1 , wherein (f x +f y )/2 is 5 kHz or more, where a resonant frequency in the first direction of the movable body is f y and a resonant frequency in the second direction of the movable body is f x .

22 . The method of claim 1 , wherein γ x is 100 Hz or less, where an attenuation coefficient of the vibration in the second direction of the movable body is b x , a mass in the second direction of the movable body is m x , and y x =b x /m x .

23 . The method of claim 1 , wherein a Q value of the vibration in the second direction of the movable body is 345 or more.

24 . A device of acquiring angular velocity of a gyro sensor, comprising:
a sensing unit sensing a predetermined physical quantity which depends upon an amplitude of a vibration in a second direction, the vibration in the second direction being based on Coriolis force that is applied to a movable body which is vibrating in a first direction; and an angular velocity calculating unit calculating angular velocity of the movable body based on the predetermined physical quantity sensed by the sensing unit, wherein the predetermined physical quantity is sensed when the vibration in the second direction based on the Coriolis force is in a non-stationary state.

25 . The device of claim 24 , wherein the predetermined physical quantity is based on capacitance between a fixed electrode portion and a movable electrode portion included in the movable body.

26 . The device of claim 24 , further comprising a vibration stopping portion stopping a vibration in the first direction of the movable body after the predetermined physical quantity is sensed.

27 . The device of claim 26 , wherein the vibration stopping portion stops the vibration in the first direction of the movable body before the vibration in the second direction based on the Coriolis force reaches a stationary state.

28 . The device of claim 26 , wherein the vibration stopping portion stops the vibration in the first direction of the movable body by catching the movable body.

29 . The device of claim 24 , wherein a resonant frequency in the first direction of the movable body and a resonant frequency in the second direction of the movable body are different from each other.

30 . The device of claim 24 , wherein the angular velocity calculating unit calculates the angular velocity based on the predetermined physical quantity sensed when the amplitude of the vibration in the second direction of the movable body reaches a peak.

31 . The device of claim 24 , wherein the angular velocity calculating unit calculates the angular velocity based on the predetermined physical quantity sensed at specific timing after the movable body starts to vibrate in the first direction.

Assignees

• Toshiba Kk

Inventors

• Ikehashi Tamio

Classifications

• G01C19/5762

  the sensing mass being connected to a driving mass, e.g. driving frames · CPC title

• G01C19/5621 Primary

  the devices involving a micromechanical structure · CPC title

• G01C19/5719

  using planar vibrating masses driven in a translation vibration along an axis · CPC title

• G01C19/5726 Primary

  Signal processing · CPC title