Sensor for detecting a rotation rate of an object

• US 9,689,675 B2
• Filed: 12/13/2013
• Issued: 06/27/2017
• Est. Priority Date: 12/20/2012
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Schmid, Bernhard, Gnthner, Stefan, Lohmann, Jasmin
• Primary Examiner(s): Kwok, Helen
• Application Number:
  US14/653,461
• Publication Number:
  US 20150345948A1
• Time in Patent Office: 1,292 Days
• Field of Search: 7350412, 7350402, 7350404
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 19/5726 Signal processing

Abstract

A sensor for detecting a rotation rate of an object, including: a sensor element, which is designed to vibrate at an angle to the rotation axis of the rotation rate to be detected at an excitation frequency on a resetting element fastened in a spatially fixed manner to the object, such that the sensor element is deflected at a reaction frequency in a reaction direction at an angle to the rotation axis and at an angle to the vibration direction owing to the Coriolis force; and a measuring transducer, which is designed to detect the vibration in the reaction direction wherein the vibratable sensor element is formed in such a manner that a comparison of a temperature-dependent displacement of a frequency spacing between the excitation frequency and the reaction frequency and a temperature-dependent position of the sensor element on the object satisfies a predefined condition.

Claims

1. A sensor for detecting a rotation rate of an object comprising:

a capacitive encoder element configured to oscillate at an angle to an axis of rotation of the rotation rate to be detected at an excitation frequency on a restoring element fastened in a stationary manner on the object, so that the capacitive encoder element is deflected, as a result of a Coriolis force, at the angle to the axis of rotation and at an angle to an oscillation direction in a reaction direction at a reaction frequency,

a capacitive readout plate positioned in proximity to the capacitive encoder element, the capacitive readout plate exerting an electrostatic force on the capacitive encoder element so that the capacitive encoder element is further deflected at the angle to the axis of rotation, the electrostatic force generated by a readout voltage applied to the capacitive readout plate, and

a measurement pickup, which is configured to detect an oscillation in the reaction direction,

wherein the readout voltage is generated to have a value based on a comparison of a temperature-dependent differential frequency between the excitation frequency and the reaction frequency.

2. The sensor as claimed in claim 1, wherein the predetermined condition comprises an observation of the comparison in an approximation.

3. The sensor as claimed in claim 2, wherein the predetermined condition comprises an error interval, in which the approximated comparison must fall within a predetermined temperature range.

4. The sensor as claimed in claim 1, wherein the encoder element is a capacitance electrode, which oscillates in the reaction direction in relation to a further capacitance electrode, wherein the measurement pickup is configured to detect the oscillation in the reaction direction based on a capacitance between the two capacitance electrodes.

5. The sensor as claimed in claim 4, wherein the restoring element has a spring constant, which is dependent on an electrical voltage between the two capacitance electrodes.

6. The sensor as claimed in claim 5, wherein the electrical voltage is set such that the comparison meets the predetermined condition.

7. The sensor as claimed in claim 4, wherein the reaction oscillation induces a change Δ

Ĉ

of the capacitance between the two capacitance electrodes with Δ

f as the frequency interval, Ω

as the rotation rate, x₀ as the amplitude of the oscillation at the excitation frequency, d as the spacing of the capacitance electrodes, and C_s(0) as the open-circuit capacitance between the two capacitance electrodes, which meets the following condition in a first approximation

10. The sensor as claimed in claim 5, wherein the reaction oscillation induces a change Δ

Ĉ

of the capacitance between the two capacitance electrodes with Δ

f as the frequency interval, Ω

as the rotation rate, x₀ as the amplitude of the oscillation at the excitation frequency, d as the spacing of the capacitance electrodes, and C_s(0) as the open-circuit capacitance between the two capacitance electrodes, which meets the following condition in a first approximation

11. The sensor as claimed in claim 6, wherein the reaction oscillation induces a change Δ

Ĉ

of the capacitance between the two capacitance electrodes with Δ

f as the frequency interval, Ω

as the rotation rate, x₀ as the amplitude of the oscillation at the excitation frequency, d as the spacing of the capacitance electrodes, and C_s(0) as the open-circuit capacitance between the two capacitance electrodes, which meets the following condition in a first approximation

8. A method for detecting a rotation rate of an object using a capacitive encoder element, which is configured to oscillate at an angle to an axis of rotation of the rotation rate to be detected at an excitation frequency on a restoring element, which is fastened in a stationary manner on the object, so that the capacitive encoder element is deflected, as a result of a Coriolis force, at the angle to the axis of rotation and at an angle to an oscillation direction in a reaction direction at a reaction frequency, comprising:

exerting, by a capacitive readout plate positioned in proximity to the capacitive encoder element, an electrostatic force on the capacitive encoder element so that the capacitive encoder element is further deflected at the angle to the axis of rotation, the electrostatic force generated by a readout voltage applied to the capacitive readout plate,

detecting an oscillation in the reaction direction,

determining the rotation rate based on the detected oscillation, and

wherein the readout voltage is generated to have a value based on a comparison of a temperature-dependent differential frequency between the excitation frequency and the reaction frequency.

9. A control device for carrying out a method for detecting a rotation rate of an object using a capacitive encoder element, which is configured to oscillate at an angle to an axis of rotation of the rotation rate to be detected at an excitation frequency on a restoring element, which is fastened in a stationary manner on the object, so that the capacitive encoder element is deflected, as a result of a Coriolis force, at the angle to the axis of rotation and at an angle to an oscillation direction in a reaction direction at a reaction frequency, comprising:

exerting, by a capacitive readout plate positioned in proximity to the capacitive encoder element, an electrostatic force on the capacitive encoder element so that the capacitive encoder element is further deflected at the angle to the axis of rotation, the electrostatic force generated by a readout voltage applied to the capacitive readout plate,

detecting an oscillation in the reaction direction,

determining the rotation rate based on the detected oscillation, and

wherein the readout voltage is generated to have a value based on a comparison of a temperature-dependent differential frequency between the excitation frequency and the reaction frequency.