Rotation rate sensor and method for calibrating a rotation rate sensor

Patent metadata

Field	Value
Publication number	US-9372097-B2
Application number	US-201214008835-A
Country	US
Kind code	B2
Filing date	Feb 24, 2012
Priority date	Mar 30, 2011
Publication date	Jun 21, 2016
Grant date	Jun 21, 2016

Abstract

A rotational rate sensor is provided having a substrate and a Coriolis element, the rotational rate sensor having a drive means for exciting the Coriolis element to a Coriolis oscillation, and the rotational rate sensor having a detection device for producing a sensor signal as a function of a deflection of the Coriolis element relative to the substrate on the basis of a Coriolis force acting on the Coriolis element, and in addition the rotational rate sensor being configured to carry out a self-calibration when a rotational acceleration signal produced as a function of the sensor signal falls below a specified threshold value.

First claim

What is claimed is:

1. A rotational rate sensor, comprising:
a substrate;
a Coriolis element;
a driver to excite the Coriolis element to a Coriolis oscillation;
a detection device to produce a sensor signal as a function of a deflection of the Coriolis element relative to the substrate based on a Coriolis force acting on the Coriolis element;
wherein the rotational rate sensor is configured to carry out a self-calibration when a rotational acceleration signal produced as a function of the sensor signal falls below a threshold value; and
a difference value formation unit configured to produce the rotational acceleration signal from a difference between at least two sensor values of the sensor signal.

2. The rotational rate sensor as recited in claim 1 , further comprising:
a comparator to compare the rotational acceleration signal to the threshold value.

3. The rotational rate sensor as recited in claim 1 , further comprising:
a differentiator that is configured to produce the rotational acceleration signal from a mathematical derivative of the sensor signal.

4. The rotational rate sensor as recited in claim 1 , further comprising:
an intermediate storage device configured to store a multiplicity of sensor values of the sensor signal during execution of the self-calibration, the intermediate storage device being configured to store a sum of the multiplicity of sensor values of the sensor signal during the execution of the self-calibration.

5. The rotational rate sensor as recited in claim 4 , further comprising:
a mean value formation unit configured to produce a new sensor offset value from a mathematical mean value of the sensor values stored in the intermediate storage device; and
an offset storage device configured to store a sensor offset calculated as a function both of the new sensor offset value and of an earlier sensor offset value.

6. The rotational rate sensor as recited in claim 1 , further comprising:
an interrupt interface, the rotational rate sensor being configured to produce an interrupt signal at the interrupt interface at least one of during and at a time after the execution of the self-calibration.

7. A method for calibrating a rotational rate sensor, the rotational rate sensor including a substrate, a Coriolis element, a driver to excite the Coriolis element to a Coriolis oscillation, a detection device to produce a sensor signal as a function of a deflection of the Coriolis element relative to the substrate based on a Coriolis force acting on the Coriolis element, wherein the rotational rate sensor is configured to carry out a self-calibration when a rotational acceleration signal produced as a function of the sensor signal falls below a threshold value, and a difference value formation unit configured to produce the rotational acceleration signal from a difference between at least two sensor values of the sensor signal, the method comprising:
exciting the Coriolis element to the Coriolis oscillation;
producing the sensor signal as a function of a deflection of the Coriolis element relative to the substrate on the basis of a Coriolis force acting on the Coriolis element;
producing the rotational acceleration signal as a function of the sensor signal,
wherein the rotational acceleration signal is the difference between the at least two sensor values of the sensor signal; and
carrying out a self-calibration of the rotational rate sensor when it is detected that the rotational acceleration signal has fallen below a specified threshold value.

8. The method as recited in claim 7 , wherein the self-calibration is started when the rotational acceleration signal falls below the threshold value for a specified time span.

9. The method as recited in claim 7 , wherein the rotational acceleration signal is produced from a mathematical derivative of the sensor signal.

10. The method as recited in claim 7 , wherein for the self-calibration of the rotational rate sensor, a multiplicity of sensor values of the sensor signal are recorded, a sum of the sensor values being stored, and a new sensor offset value being calculated from the sensor values as a function of a mathematical mean value, a sensor offset being calculated both as a function of the new sensor offset value and as a function of an old sensor offset value.

11. The method as recited in claim 10 , wherein the self-calibration is terminated when, during the self-calibration, it is detected that the rotational acceleration signal has exceeded the specified threshold value.

Assignees

• Kohn Oliver
• Claus Thomas
• Bennini Fouad
• Bosch Gmbh Robert

Inventors

• Kohn Oliver
• Claus Thomas
• Bennini Fouad

Classifications

• G01C25/005

  initial alignment, calibration or starting-up of inertial devices · CPC title

• G01C19/56

  Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces · CPC title

• G01C19/5747

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

• G01C19/5726 Primary

  Signal processing · CPC title

• G01C25/00 Primary

  Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass (testing, calibrating or compensating compasses G01C17/38) · CPC title