ROTATIONAL SPEED SENSOR AND OPERATION OF A ROTATIONAL SPEED SENSOR AT VARIOUS FREQUENCIES AND IN VARIOUS DIRECTIONS

Abstract

A rotation rate sensor having a substrate having a principal extension plane and having a structure movable with respect to the substrate. The rotation rate sensor encompasses a first excitation unit for deflecting the structure out of an idle position substantially parallel to a first axis extending parallel to the principal extension plane, in such a way that the structure is excitable to oscillate at a first frequency with a motion component substantially in a direction parallel to the first axis, the rotation rate sensor encompassing a second excitation unit for deflecting the structure out of an idle position substantially parallel to a second axis extending parallel to the principal extension plane and extending perpendicularly to the first axis, in such a way that the structure is excitable to oscillate at a second frequency with a motion component substantially in a direction parallel to the second axis.

Claims

1-10. (canceled)

11. A rotation rate sensor, comprising: a substrate having a principal extension plane; a structure movable with respect to the substrate; a first excitation unit for deflecting the structure out of an idle position parallel to a first axis extending parallel to the principal extension plane, in such a way that the structure is excitable to oscillate at a first frequency with a motion component substantially in a direction parallel to the first axis; a second excitation unit for deflecting the structure out of an idle position parallel to a second axis extending parallel to the principal extension plane and extending perpendicularly to the first axis, in such a way that the structure is excitable to oscillate at a second frequency with a motion component in a direction parallel to the second axis.

12. The rotation rate sensor as recited in claim 11, further comprising: a first detection unit for detecting a force acting on the structure in a direction parallel to a third axis extending perpendicularly to the principal extension plane, at least one of: (i) at the first frequency, and (ii) at the second frequency, at least one of: (i) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the first axis, and (ii) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the second axis.

13. The rotation rate sensor as recited in claim 12, further comprising: a third excitation unit for deflecting the structure out of an idle position parallel to a third axis extending perpendicularly to the principal extension plane, in such a way that the structure is excitable to oscillate at a third frequency with a motion component in a direction parallel to the third axis.

14. The rotation rate sensor as recited in claim 13, further comprising: a second detection unit for detecting a force acting on the structure in a direction parallel to the second axis, at least one of: (i) at the first frequency, and (ii) at the third frequency, at least one of: (i) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the first axis, and (ii) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the third axis.

15. The rotation rate sensor as recited in claim 14, wherein the rotation rate sensor has a third detection unit for detecting a force acting on the structure in a direction parallel to the first axis, one of: (i) at the second frequency, and (ii) at the third frequency, at least one of: (i) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the second axis, and (ii) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the third axis.

16. The rotation rate sensor as recited in claim 13, wherein the rotation rate sensor encompasses at least one of: (i) at least one first suspension component, (ii) at least one second suspension component, and (iii) at least one third suspension component, for suspending the structure movably relative to the substrate, in such a way that at least one of: (i) the structure is excitable to oscillate at the first frequency with a motion component substantially in a direction parallel to the first axis, (ii) the structure is excitable to oscillate at the second frequency with a motion component substantially in a direction parallel to the second axis, and (iii) the structure is excitable to oscillate at the third frequency with a motion component substantially in a direction parallel to the third axis.

17. The rotation rate sensor as recited in claim 15, wherein the first detection unit encompasses at least one first electrode, the first electrode being embodied in substantially plate-shaped fashion, the first electrode extending parallel to a plane encompassing the first axis and the second axis, the second detection unit encompassing at least one second electrode, the second electrode being embodied in plate-shaped fashion, the second electrode extending substantially parallel to a plane encompassing the first axis and the third axis, the third detection unit encompassing at least one third electrode, the third electrode being embodied in plate-shaped fashion, the third electrode extending substantially parallel to a plane encompassing the second axis and the third axis.

18. The rotation rate sensor as recited in claim 13, wherein the rotation rate sensor encompasses a further structure movable with respect to the substrate, the further structure being excitable to oscillate in counter-phase with respect to the structure at least one of: (i) at the first frequency with a motion component in a direction parallel to the first axis, and (ii) at the second frequency with a motion component in a direction parallel to the second axis, and (iii) at the third frequency with a motion component substantially in a direction parallel to the third axis.

19. The rotation rate sensor as recited in claim 18, wherein the rotation rate sensor has a further first detection unit for detecting a force acting on the further structure in a direction substantially parallel to the third axis, at least one of: (i) at the first frequency, and (ii) at the second frequency, at least one of: (i) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the first axis, and (ii) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the second axis, the rotation rate sensor having a further second detection unit for detecting a force acting on the further structure in a direction parallel to the second axis, at least one of: (i) at the first frequency, and (ii) at the third frequency, at least one of: (i) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the first axis, and (ii) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the third axis, the rotation rate sensor having a further third detection unit for detecting a force acting on the further structure in a direction parallel to the first axis, at least one of: (i) at the second frequency, and (ii) at the third frequency, at least one of: (i) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the second axis, and (ii) as a result of a rotation rate of the rotation rate sensor around an axis parallel to the third axis.

20. A method for operating a rotation rate sensor, the rotation rate sensor including a substrate having a principal extension plane, a structure movable with respect to the substrate, a first excitation unit for deflecting the structure out of an idle position parallel to a first axis extending parallel to the principal extension plane, in such a way that the structure is excitable to oscillate at a first frequency with a motion component substantially in a direction parallel to the first axis, a second excitation unit for deflecting the structure out of an idle position parallel to a second axis extending parallel to the principal extension plane and extending perpendicularly to the first axis, in such a way that the structure is excitable to oscillate at a second frequency with a motion component in a direction parallel to the second axis, the method comprising: deflecting the structure out of the idle position of the structure, with the aid of at least one drive signal, in such a way that the structure is excited to oscillate at the first frequency with a motion component in a direction parallel to the first axis; detecting at least one detection signal being detected with the aid of the first detection unit; processing the at least one detection signal with the aid of synchronous demodulation at the first frequency, and with the aid of low-pass filtration; and ascertaining at least one rotation rate associatable with the first frequency from the at least one processed detection signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 schematically depicts a rotation rate sensor in accordance with an exemplifying embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0020] Identical parts are labeled with identical reference characters and are each therefore, generally, also mentioned only once.

[0021] FIG. 1 schematically depicts a rotation rate sensor 1 in accordance with an exemplifying embodiment of the present invention, rotation rate sensor 1 encompassing a substrate 3, indicated with the aid of substrate attachments, having a principal extension plane 100 and having a structure 5 movable with respect to substrate 3. A first excitation unit (not depicted) is provided in order to deflect structure 5, so that structure 5 is excitable to oscillate at a first frequency out of an idle position depicted in FIG. 1 with a motion component in a direction parallel to first axis X. Rotation rate sensor 1 depicted in FIG. 1 furthermore encompasses a second excitation unit (not depicted) for exciting structure 5 to oscillate at a second frequency out of the idle position with a motion component in a direction parallel to second axis Y. Rotation rate sensor 1 depicted in FIG. 1 furthermore encompasses a third excitation unit (not depicted) for exciting structure 5 to oscillate at a third frequency with a motion component in a direction parallel to third direction Z. Structure 5 is preferably excited via capacitive forces. Also preferably, the oscillation amplitudes in the three spatial directions are measured via capacitive measurement sensors, and a constant oscillation amplitude is established with the aid of an electronic system, preferably automatic gain control (AGC) and phased-lock loop (PLL). Preferably, structure 5 is excited via capacitive forces to oscillate at its resonant frequencies in the three spatial directions. For example, the oscillation amplitude in the three spatial directions is determined in this context via capacitive measurement sensors.

[0022] In order for an above-described excitation of structure 5 to be possible, rotation rate sensor 1 depicted in FIG. 1 encompasses a first suspension component 35, a second suspension component 37, and a third suspension component 39. Preferably the suspension components are springs.

[0023] In order to detect a force acting on structure 5, at the first frequency and/or at the second frequency and/or at the third frequency, as a result of a rotation rate of rotation rate sensor 1 around an axis parallel to first axis X and/or around an axis parallel to second axis Y and/or around an axis parallel to third axis Z, rotation rate sensor 1 depicted in FIG. 1 furthermore encompasses a first detection unit 29, a second detection unit 31, and a third detection unit 33. First detection unit 29 encompasses a first electrode 41, second detection unit 31 a second electrode 43, and third detection unit 33 a third electrode 45.

[0024] For example, a rotation rate of rotation rate sensor 1 around an axis parallel to first axis X results in Coriolis deflections of structure 5 in a direction parallel to second axis Y at the third frequency, and in Coriolis deflections of structure 5 in a direction parallel to third axis Z at the second frequency. For example, a rotation rate of rotation rate sensor 1 around an axis parallel to first axis X results in Coriolis accelerations acting on structure 5 in a direction parallel to second axis Y at the third frequency and in a direction parallel to third axis Z at the second frequency.

[0025] A rotation rate of rotation rate sensor 1 around an axis parallel to second axis Y and a rotation rate of rotation rate sensor 1 around an axis parallel to third axis Z results, for example, in corresponding Coriolis deflections of structure 5, and in corresponding Coriolis accelerations acting on structure 5, in the corresponding directions at the corresponding frequencies. The Coriolis deflections or Coriolis accelerations are sensed, for example, capacitively, demodulated at the respective frequencies, and low-pass filtered. The signal thereby processed is an indication of the applied rotation rates. The detected Coriolis deflections or Coriolis accelerations have a different frequency from the signal of the excitation oscillation in that direction. The Coriolis forces and the corresponding rotation rates can be detected by demodulation at the corresponding resonant frequencies.

[0026] The rotation rate sensor depicted in FIG. 1 thus offers the advantage that the same mass can be used to measure rotation rates in different spatial directions. A further advantage is that enhanced robustness in the context of measurement of a rotation rate is furnished thanks to evaluation of the Coriolis accelerations that have been ascertained at two frequencies. If no errors are present, the two ascertained rotation rates must indicate identical values.

[0027] Rotation rate sensor 1 depicted in FIG. 1 encompasses only structure 5. Provision is made in particular, however, for rotation rate sensor 1 additionally to encompass a further structure, preferably coupled mechanically to structure 5. The further structure is excited to oscillate in counter-phase with respect to structure 5 at the first frequency, the second frequency, and the third frequency, in each case with a motion component in the respective directions parallel to first axis X, parallel to second axis Y, and parallel to third axis Z. The further excitation units and further detection units provided for the further structure correspond substantially to the excitation units and detection units provided for structure 5. This makes possible a reduction in the force outcoupling of the oscillating masses, and in an enhancement in robustness with respect to linear accelerations.