Double-axis rotation rate sensor

• US 8,794,067 B2
• Filed: 03/11/2010
• Issued: 08/05/2014
• Est. Priority Date: 03/11/2009
• 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, Sivaraman, Ramnath
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US13/255,321
• Publication Number:
  US 20120048016A1
• Time in Patent Office: 1,608 Days
• Field of Search: 735/041.2, 735/041.4
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion

Abstract

A micromechanical rotation rate sensor, comprising at least one substrate, wherein the rotation rate sensor has at least a first and a second seismic mass which are coupled to one another by means of at least one coupling beam, and wherein the rotation rate sensor is embodied in such a way that it can detect rotation rates about at least a first and a second sensitive axis, wherein each seismic mass is assigned at least one actuator unit with which the deflection behavior of the seismic mass can be influenced.

Claims

1. A micromechanical rotation rate sensor, comprising at least one substrate, wherein the rotation rate sensor has at least a first and a second seismic mass which are coupled to one another by at least one coupling beam, and wherein the rotation rate sensor is embodied in such a way that it can detect rotation rates about at least a first and a second sensitive axis, wherein each seismic mass is assigned at least one actuator unit with which the deflection behavior of the seismic mass can be influenced,

wherein the rotation rate sensor respectively comprises at least a first, a second and a third oscillator configuration with respect to the deflection of the first and second seismic masses, wherein the first oscillator configuration has at least one drive unit which imposes a driving oscillation on said first oscillator configuration, which driving oscillation comprises deflections of the seismic mass in the direction of a first axis, wherein the first oscillator configuration has a defined driving resonant frequency, and

the second oscillator configuration is defined essentially by the deflections of the seismic mass in the direction of a second axis in the form of a first reading out oscillation, which oscillation is caused by the effect and/or detection of a rotational rate about the first sensitive axis, wherein the second oscillator configuration has a defined first reading out resonant frequency,

the third oscillator configuration is defined essentially by the deflection of the seismic mass in the direction of a third axis in the form of a second reading out oscillation which is caused by the effect and/or detection of a rotation rate about the first second sensitive axis, wherein the third oscillator configuration has a defined second reading out resonant frequency,

wherein the at least one coupling beam is embodied and arranged in such a way that it couples the deflections of the first and second seismic masses with respect to the first reading out oscillation within the second oscillator configuration, and the rotation rate sensor additionally has at least a second coupling beam, which is embodied and arranged in such a way that it couples the deflections of third and fourth seismic masses with respect to the second reading out oscillation within the third oscillator configuration.

2. The rotation rate sensor as claimed in claim 1, wherein the at least one actuator unit has an electrode structure or a comb structure and is configured and can be actuated in such a way that an electrical actuator voltage is present between the electrode structure or comb structure of the actuator unit and the seismic mass assigned thereto, which actuator voltage gives rise to an electrical force with which the deflection behavior of the seismic mass can be influenced, and

wherein said rotation rate sensor has at least one actuator unit which is embodied as a combined quadrature trimming resetting actuator unit, and the rotation rate sensor has a quadrature trimming resetting control unit which sets at least one electrical actuator voltage in such a way that the reading out deflections and/or reading out oscillations are reset with respect to the first and/or second sensitive axes of the rotation rate sensor, and that parasitic oscillation components of at least the first and second seismic masses and/or a quadrature signal are suppressed.

3. The rotation rate sensor as claimed in claim 2, wherein at least one quadrature trimming actuator unit has at least one comb structure which is embodied as a quadrature trimming comb structure and which comprises at least one comb structure base element pair which is composed at least of a first and a second comb structure base element which each comprise a first and a second comb back and comprise one or two or more prongs which are each integrally connected thereto, wherein the prongs of these first and second comb backs engage one in the other in a contactless fashion, wherein the second comb structure base element is essentially embodied and arranged in comparison with the first comb structure base element in such a way that, with respect to the geometric consideration starting from the first comb structure base element, said second comb structure base element is rotated through 180°

with respect to a normal to the surface of the substrate and is shifted in a translatory fashion within the plane of the substrate.

4. The rotation rate sensor as claimed in claim 2, wherein at least one combined quadrature trimming resetting actuator unit comprises a combined comb structure which comprises a quadrature trimming comb structure,

which comprises at least one comb structure base element pair which is composed at least of a first and a second comb structure base element which each comprise a first and a second comb back and one or two or more prongs which are each integrally connected thereto, wherein the prongs of these first and second comb backs engage one in the other in a contactless fashion, wherein the second comb structure base element is essentially embodied and arranged in comparison with the first comb structure base element in such a way that, with respect to the geometric consideration starting from the first comb structure base element, said second comb structure base element is rotated through 180°

with respect to a normal to the surface of the substrate, and is shifted in a translatory fashion within the plane of the substrate,

wherein the combined comb structure additionally has a comb structure which is configured as a resetting comb structure,

wherein this resetting comb structure comprises a comb structure base element pair which is composed at least of a first and a second comb structure base element, which each comprise a first and a second comb back and one or two or more prongs which are each integrally connected thereto, wherein the prongs of these first and second comb backs engage one in the other in a contactless fashion, wherein the second comb structure base element is essentially embodied and arranged in comparison with the first comb structure base element in such a way that, with respect to the geometric consideration starting from the first comb structure base element, this second comb structure base element is mirrored along a straight line, parallel to at least one of the first or second comb backs, and is shifted in a translatory fashion within the plane of the substrate.

5. The rotation rate sensor as claimed in claim 1, wherein the rotation rate sensor has at least one actuator unit which is embodied as a quadrature trimming actuator unit, and the rotation rate sensor has a quadrature trimming control unit which sets at least one electrical actuator voltage in such a way that parasitic oscillation components of at least the first and the second seismic masses and/or a quadrature signal are suppressed.

6. The rotation rate sensor as claimed in claim 1, wherein said rotation rate sensor has at least one actuator unit which is embodied as a resetting actuator unit, and the rotation rate sensor has a resetting control unit which sets at least one electrical actuator voltage in such a way that the reading out deflections and/or reading out oscillations are reset, with respect to the first and/or second sensitive axes.

7. The rotation rate sensor as claimed in claim 1, wherein said rotation rate sensor has at least one actuator unit which is embodied as a resonant frequency shift actuator unit, and the rotation rate sensor has a resonant frequency shift control unit which sets at least one electrical actuator voltage in such a way that the driving resonant frequency and/or the first reading out resonant frequency and/or the two resonant frequencies, of the corresponding oscillator configuration or configurations are changed by a defined value and/or are set to a defined value.

8. The rotation rate sensor as claimed in claim 1, wherein the second and third oscillator configurations are embodied and/or operated in such a way that the difference between the first reading out resonant frequency and the driving resonant frequency and the difference between the second reading out resonant frequency and the driving resonant frequency are both greater than zero or are both smaller than zero, wherein, the absolute value of the difference between the first reading out resonant frequency and the second reading out resonant frequency is greater than 0.1 Hz.

10. The rotation rate sensor as claimed in claim 1, wherein the second and third oscillator configurations are embodied and/or operated in such a way that the difference between the first reading out resonant frequency and the driving resonant frequency is essentially equal to zero or the difference between the second reading out resonant frequency and the driving resonant frequency is essentially equal to zero, or that the difference between the first reading out resonant frequency and the driving resonant frequency and the difference between the second reading out resonant frequency and the driving resonant frequency are respectively essentially equal to zero.

11. The rotation rate sensor as claimed in claim 1, wherein said rotation rate sensor comprises at least one drive unit and at least a first and a second detection unit with respect to at least the first seismic mass, wherein this drive unit and/or the first and/or the second detection units are/is connected to the seismic mass via at least one spring element.

12. The rotation rate sensor as claimed in claim 11, wherein the drive unit and/or the first and/or the second detection units are part of the seismic mass with respect to the first and/or second and/or third oscillator configurations.

13. The rotation rate sensor as claimed in claim 1, wherein the first and second seismic masses each have at least a first rotation-rate-sensitive component mass which is connected, by at least one spring element, to at least one other component unit of the respective seismic mass, wherein this first rotation-rate-sensitive component mass is embodied and configured in such a way that it is part either of the second or of the third oscillator configuration.

9. The rotation rate sensor as claimed in 1, wherein the second and third oscillator configurations are embodied and/or operated in such a way that the difference between the first reading out resonant frequency and the driving resonant frequency is greater than zero and the difference between the second reading out resonant frequency and the driving resonant frequency is smaller than zero, or vice versa, wherein, the absolute value of the difference between the first reading out resonant frequency and the second reading out resonant frequency is greater than 0.1 Hz.