Rotation rate sensor and method for operating a rotation rate sensor with a first Coriolis element and a second Coriolis element

Abstract

A gyroscope (1) comprising a first Coriolis element (100) and a second Coriolis element (200), wherein the gyroscope (1) has a substrate with a principal extension plane, wherein the gyroscope (1) has a first drive element (102) for driving the first Coriolis element (100) parallel to a second axis (Y), wherein the gyroscope (1) has a second drive element (202) for driving the second Coriolis element (200) parallel to the second axis (Y), wherein the gyroscope (1) has detection means (140, 240) for detecting deflections of the first Coriolis element (100) and the second Coriolis element (200) parallel to a first axis (X) due to a Coriolis force, wherein the first axis (X) is arranged perpendicular to the second axis (Y), wherein the first axis (X) and the second axis (Y) are parallel to the are arranged in the main extension plane,wherein the first drive element (102) and the second drive element (202) are mechanically coupled to each other via a drive coupling element (301, 302), wherein the drive coupling element (301, 302) is mechanically coupled to the substrate, wherein the drive coupling element (301, 302) is designed to be more flexible with respect to rotation about a third axis (Z) than with respect to rotation about the first axis (X), wherein the third axis (Z) is arranged perpendicular to the principal extension plane, and wherein the drive coupling element (301, 302) is designed to be stiffer in the second axis (Y) than in the first axis (X).

Description

State of the art

[0001] The invention relates to a gyroscope according to the preamble of claim 1.

[0002] Such angular rate sensors are generally known. For example, a angular rate sensor is known from German patent application DE 10108196 A1, wherein the angular rate sensor has Coriolis elements surrounded by drive elements, which are perforated on their respective facing sides. The Coriolis elements and the drive elements are connected by springs. The drive elements are connected to bearing blocks by means of springs. Furthermore, movable electrodes, fixed electrodes, and bearing blocks for the fixed electrodes are provided. The two Coriolis elements are connected by means of a coupling spring. For the detection of the deflection of the Coriolis elements, a frame-shaped detection element is provided inside each frame-shaped Coriolis element. The detection elements are also designed as rectangular frame structures, which are connected to the substrate by means of spring elements and bearing blocks.The spring elements are flexible in the X-direction and rigid in the Y-direction, essentially allowing only deflection of the detection frames in the X-direction. The detection frames are connected to the corresponding Coriolis elements via spring elements. These spring elements are flexible in the Y-direction and rigid in the X-direction, transmitting the Coriolis forces in the X-direction. Grid-shaped detection electrodes are arranged inside the detection frames. A rotation rate with an axis of rotation perpendicular to the substrate (Z-direction) results in a force that causes an antiparallel and collinear detection oscillation of the Coriolis elements along the X-axis. The Coriolis elements participate in this oscillation and transmit their motion to the detection oscillators (detection elements); the drive elements do not participate in the detection oscillation. The two detection elements are coupled to each other by means of an interposed structure.This structure couples both the drive movement and the detection movement of the Coriolis elements. In addition to the so-called useful modes (drive mode and detection mode), the gyroscope, according to the state of the art, also exhibits further vibration modes, so-called interference modes. These adversely lead to superposition of the useful modes and can result in false signals.

[0003] It is therefore the object of the present invention to provide a gyroscope that does not have the disadvantages of the prior art and in which, in particular, the interference modes are largely suppressed or the interference modes are at comparatively high frequencies. Disclosure of the invention

[0004] The gyroscope and the method according to the invention for operating a gyroscope according to the dependent claims have the advantage over the prior art that the interference modes are largely suppressed or lie at comparatively high frequencies, thereby enabling a comparatively clear separation of useful modes and interference modes in the frequency domain. This advantageously allows for a comparatively low excitation of the interference modes, so that the operation of the gyroscope is comparatively stable.

[0005] The angular rate sensor is preferably designed as a microelectromechanical system (MEMS). The substrate is preferably a semiconductor substrate and particularly preferably made of a silicon material. The excitation of the Coriolis elements' vibration is preferably achieved by means of electrostatic comb drives on the drive elements. Detection of the Coriolis force is preferably achieved by the Coriolis element and / or a detection element having movable electrodes arranged relative to stationary electrodes.

[0006] Advantageous embodiments and further developments of the invention can be found in the dependent claims and in the description with reference to the drawings.

[0007] According to a preferred embodiment, the drive coupling element comprises a first drive coupling sub-element and a second drive coupling sub-element, wherein preferably the first drive coupling sub-element and / or the second drive coupling sub-element has a beam structure and particularly preferably a T-shaped structure and / or a V-shaped structure. This advantageously allows for a comparatively good separation of disturbance and desired modes. The use of two drive coupling sub-elements, which are preferably arranged symmetrically to the longitudinal axis of rotation, enables comparatively stable operation.

[0008] According to another preferred embodiment, the drive coupling element is mechanically coupled to the substrate. This enables a comparatively good separation of interference and useful modes, as well as a comparatively stable operation of the gyroscope. The mounting on the substrate allows the interference modes to be shifted to comparatively high frequencies.

[0009] According to another preferred embodiment, the drive coupling element is designed to be more flexible with respect to rotation about a third axis than with respect to rotation about the first axis, wherein the third axis is arranged perpendicular to the principal extension plane, and wherein the drive coupling element is stiffer in the second axis than in the first axis. This advantageously shifts the antiparallel useful mode to lower frequencies and the parallel disturbance mode to higher frequencies.

[0010] According to another preferred embodiment, the detection means comprises a first detection element and a second detection element, wherein the first detection element and the second detection element are mechanically coupled to each other via a detection coupling element. The coupling of the detection elements advantageously shifts the antiparallel desired mode to lower frequencies and the parallel interference mode to higher frequencies.

[0011] According to another preferred embodiment, the detection coupling element is mechanically coupled to the substrate. This attachment to the substrate allows the interference modes to be shifted to comparatively high frequencies.

[0012] According to another preferred embodiment, the detection coupling element comprises at least one first detection coupling sub-element and one second detection coupling sub-element, wherein the first detection coupling sub-element and / or the second detection coupling sub-element preferably has a beam structure and, more preferably, an L-shaped structure and / or a T-shaped structure. The use of multiple detection coupling sub-elements advantageously shifts the antiparallel desired mode to lower frequencies and the parallel interference mode to higher frequencies.

[0013] According to another preferred embodiment, the detection coupling element is designed to be more flexible with respect to rotation about the third axis than with respect to rotation about the first axis, and stiffer in the second axis than in the first axis. This advantageously shifts the antiparallel desired mode to lower frequencies and the parallel interference mode to higher frequencies.

[0014] Another object of the present invention relates to a method for operating a gyroscope with a first Coriolis element and a second Coriolis element and with a substrate having a principal extension plane, wherein the first Coriolis element is excited to a first oscillation parallel to a second axis by a first excitation means, wherein the second Coriolis element is excited to a second oscillation parallel to the second axis by a second excitation means, wherein the first excitation means is connected to a first drive element, wherein the second excitation means is connected to a second drive element, wherein deflections of the first Coriolis element and the second Coriolis element parallel to a first axis are detected by detection means, wherein the second axis is arranged perpendicular to the first axis, and wherein the first axis and the second axis are arranged parallel to the principal extension plane.wherein the first oscillation and the second oscillation are mechanically coupled to each other via a drive coupling element.

[0015] Exemplary embodiments of the present invention are shown in the drawings and explained in more detail in the following description. Brief description of the drawings

[0016] They show

[0017] Fig. 1 a gyroscope according to an exemplary embodiment of the present invention,

[0018] Fig. 2a, Fig. 2b, Fig. 2c a gyratory rate sensor according to a further embodiment of the present invention,

[0019] Fig. 3a, Fig. 3c a gyroscope according to two further embodiments of the present invention,

[0020] Fig. 3b a detailed view of a further embodiment of the present invention,

[0021] Fig. 4 a gyratory rate sensor according to a further embodiment of the present invention,

[0022] Fig. 5a, Fig. 5b, Fig. 5c Detailed views of further embodiments of the present invention,

[0023] Fig. 6a a gyratory rate sensor according to a further embodiment of the present invention and

[0024] Fig. 6b, Fig. 6c Detailed views of further embodiments of the present invention. embodiment(s) of the invention

[0025] In the various figures, identical parts are always marked with the same reference symbols and are therefore usually only named or mentioned once.

[0026] Fig. 1 shows a gyroscope. 1 according to an exemplary embodiment of the present invention. In Fig. Figure 1 shows a top view of a substrate not shown in detail with a principal extension plane (XY plane) in which a first Coriolis element is located. 100 and a second Coriolis element 200 are arranged. The first and second Coriolis elements 100 , 200 They are designed as frame-like structures that are perforated on their facing sides. The Coriolis elements 100 , 200 are of drive elements 102 , 202 surrounded by perforations on their respective facing sides. The gyroscope is symmetrically constructed, so for the sake of simplicity, only the left side of the gyroscope will be described below. The right side is symmetrically constructed relative to the left side. The Coriolis element 100 and the drive element 102 are equipped with bending springs 103 connected. The bending springs 103They are designed to be flexible in the X direction and rigid in the Y direction. The drive element 102 is by means of springs 107 with bearing blocks 106 connected, which are firmly attached to the substrate. The springs 107 are designed to be flexible in the Y direction and flexible in the X direction. On the drive elements 102 , 202 are movable electrodes 104 , 204 arranged in a comb-like manner that engage with fixed electrodes (not shown) which are firmly connected to the substrate by bearing blocks (not shown).

[0027] By applying electrical voltages between the movable electrodes 104 , 204 and the fixed electrodes become the drive elements 102 , 202 They are excited to vibrate. The Coriolis elements are also affected accordingly. 100 , 200set into vibration. The center of gravity of the Coriolis elements 100 , 200 Each element then moves along an axis parallel to the Y-axis. The movements of the two Coriolis elements 100 , 200 The movements thus occur along axes that are parallel to each other. The centers of gravity move along parallel lines without the influence of a Coriolis force (i.e., without rotation of the substrate around an axis perpendicular to the substrate). If the substrate rotates around the Z-axis, i.e., around the axis perpendicular to the substrate, then each of the Coriolis elements is subject to a force. 100 , 200 Coriolis forces, which are perpendicular to the axis of rotation Z and perpendicular to the axis of motion Y. These forces then act in the X direction.

[0028] The movable electrodes 104 , 204, together with the stationary electrodes and the drive elements 102 , 202 They thus form excitation media through which the Coriolis elements 100 , 200 They are excited to vibrations in which the axes of vibration of the centers of gravity are aligned parallel to each other. The drive elements 102 , 202 They are driven linearly and out of phase in the XY plane.

[0029] For the detection of the deflection of the Coriolis elements 100 , 200 In the Z-direction (perpendicular to the XY plane) there is a frame-shaped detection means in each direction. 140 , 240 inside the frame-shaped Coriolis elements 100 , 200 provided. The detection means 140 , 240 are designed as rectangular frame structures, which are connected by means of spring elements 141 with bearing blocks 106' are connected to the substrate. The spring elements 141are designed with flex in the X-direction and rigidity in the Y-direction. The verification frameworks 140 , 240 are through spring elements 142 with the corresponding Coriolis elements 100 , 200 connected. The spring elements 142 They are designed to be flexible in the Y-direction and rigid in the X-direction, thus transmitting Coriolis forces in the X-direction particularly well. Inside the detection frames 140 , 240 are grid-shaped detection electrodes 143 arranged, which are only indicated. The grid-shaped detection electrodes 143 are arranged between stationary electrodes (not shown) which are attached to the substrate by bearings and do not move relative to the substrate.

[0030] According to the invention, the first drive element 102 and the second drive element 202 via a drive coupling element with the drive coupling elements 301 , 302connected to each other. In this embodiment, the drive coupling elements are 301 , 302 It is symmetrically constructed, therefore only the drive coupling element is used. 301 The drive coupling element is described in detail. 301 features a rigid beam 312 and three flexible beams 311 , 314 , 316 up, which are located at storage facilities 313 , 315 are firmly attached to the substrate. The beam 312 is over the beams 311 , 316 firmly attached to the drive elements 102 , 202 connected. Through the coupling via the drive coupling elements 301 , 302 It is advantageously achieved that the antiparallel vibration mode (useful mode) is lower in frequency than the parallel vibration mode.

[0031] Frame-shaped detection devices are preferred. 140 , 240 via a detection coupling element 400with four identical detection coupling elements 31 , 31' (hereinafter also referred to as deflection structures) are interconnected, arranged symmetrically to each other with respect to two axes of symmetry, and described in detail in the following figures. Through the coupling of the detection means 140 , 240 via the detection coupling element 400 It is advantageously achieved that the antiparallel vibration mode (useful mode) is lower in frequency than the parallel vibration mode.

[0032] A preferred embodiment is a gyroscope in which the Coriolis frames are open and the detection elements are interconnected by means of a special coupling structure (coupling cross). This coupling structure has four (L- or T-shaped) deflection angles and a central substrate connection. This embodiment suppresses interference modes in the sense that their frequency is higher than that of the desired modes. This improved separation of desired and interference modes in the frequency domain leads to reduced excitation of the interference modes and thus to stable operation. The coupling of the drive movement of the two sub-oscillators is achieved via separate (T-shaped) coupling structures between the Coriolis oscillators.

[0033] Preferably, the gyroscope has at least two drive oscillators with comb structures that move linearly and out of phase in the plane and are coupled by means of coupling structures, such that the antiparallel oscillation mode is lower frequency than the parallel mode. Preferably, at least two Coriolis oscillators are moved linearly in the plane. Further preferred are at least two detection oscillators that move linearly in the plane and / or are coupled by means of a coupling cross, which has at least one substrate connection, such that the antiparallel oscillation mode is lower frequency than the parallel mode (useful modes = antiparallel oscillation modes).

[0034] The drive oscillators are preferably coupled to each other by means of deflection / coupling structures. These structures comprise bending beams, rigid beams, and a substrate connection. The detection oscillators are preferably directly coupled to each other by means of an interposed structure (coupling cross). The coupling cross, in turn, is preferably composed of four deflection structures, each of which performs a rotational movement. The deflection structures (T- or L-shaped) are preferably suspended from U-springs or simple bending beams that meet in the middle and are anchored to the substrate. The detection oscillators move linearly towards or away from each other. Due to the specific shape of the coupling cross, the antiparallel vibration mode has a lower frequency than the parallel vibration mode.

[0035] Preferably, the gyroscope has coupling structures for collinear (i.e., oscillating towards or away from each other) antiphase movements (so-called coupling cross). Preferably, the gyroscope also has coupling structures for non-collinear (i.e., passing by each other) antiparallel (antiphase) movements. Alternatively, the drive and detection movements can be reversed (inverse operation). Preferably, the Coriolis elements are configured as frames, with the frames being particularly preferably open and the drive elements being mechanically coupled by means of a T-shaped structure.

[0036] In the Fig. 2a, Fig. 2b, Fig. Figure 2c shows a gyroscope according to the invention in three different vibration positions of the drive movement. The dashed arrows indicate the direction of movement of the drive structures. An optional detection coupling element, which is not described further here, is indicated by a dashed circle. At time t = 0, the gyroscope is in the position shown in Fig. 2a. At time t = T / 4 (T represents one oscillation period), the gyroscope is located in the position shown in Fig. The position shown in 2b. At time t = T / 2, the gyroscope is located in the position shown in Fig. Position shown in 2c.

[0037] Fig. Figure 3a shows a gyroscope according to a further embodiment of the present invention. An optional detection coupling element, which is not described further here, is indicated by a dashed circle. In comparison to the embodiment from Fig. 1 are the drive coupling components 301 , 302 They are smaller, meaning the distance between the mounting points on the drive elements is comparatively small. This allows for a relatively compact design of the drive coupling components. 301 , 302 possible. In this embodiment, the drive coupling elements are 301 , 302 essentially located outside the area controlled by the drive elements 102 , 202 is surrounded. Fig. Figure 3c shows a gyracy rate sensor according to a further embodiment of the present invention. In comparison to the embodiment shown in Fig. 3a are the drive coupling components 301 , 302 essentially arranged within the area covered by the drive elements 102 , 202is surrounded. This advantageously allows for a comparatively compact design of the gyroscope. Preferably, the T-shaped coupling structures are arranged relatively close together and particularly preferably between the drive elements.

[0038] Fig. Figure 3b shows a detailed view of the drive coupling element. 301 according to an exemplary embodiment. The T-shaped elements 301 consist of a bending beam 21 , which has an anchor point 7 is attached to the substrate. At the other end of the bending beam 21 A stiff beam lies centrally and transversely. 22 on, at the ends of which bending beams are attached 23 located on the drive elements.

[0039] Fig. Figure 4 shows a gyroscope according to a further embodiment of the present invention. An optional detection coupling element, which is not described further here, is indicated by a dashed circle. In this embodiment, the drive coupling elements are 301 , 302 V-shaped.

[0040] Fig. 5a, Fig. 5b, Fig. Figure 5c shows detailed views of further embodiments of the present invention. Fig. Figure 5a shows a detection coupling component. 31 (Deflection structure) e.g. of the detection coupling element 400 out of Fig. 1. Detection coupling component 31 features an L-shaped rigid isosceles beam 32 up. The beam 32 is via two U-springs 33 , which meet in the middle, firmly attached to the substrate (storage area) 7 ). At the ends of the beam 32 close bending beams 34on, which are in rigid beams 35 terminate. Through these detection coupling components. 31 A rotational movement around the pivot point is performed. 40 mediated ( Fig. 5b). Fig. Figure 5c shows an alternative embodiment of the detection coupling element. 400 , where the detection coupling element 400 Detection coupling elements with non-equal-sided beams 32 exhibits.

[0041] Fig. 6a shows a gyroscope according to a further exemplary embodiment. In comparison to the embodiment from the Fig. 1 is the detection coupling element made up of detection coupling sub-elements 31 formed, which – as shown in the detailed view from Fig. 6b shows – a straight, rigid beam 32 have and are centered over a bending beam 36 are anchored to the substrate (storage location) 7Alternatively, the rigid beam may be L-shaped ( Fig. 6c). QUOTES INCLUDED IN THE DESCRIPTION

[0042] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0043] DE 10108196 A1

[0002]

Claims

[1] Gyro sensor ( 1 ) with a first Coriolis element ( 100 ) and a second Coriolis element ( 200 ), where the gyroscope ( 1 ) a substrate with a principal extent plane, wherein the gyroscope ( 1 ) a first drive element ( 102 ) to drive the first Coriolis element ( 100 ) parallel to a second axis (Y), wherein the gyroscope ( 1 ) a second drive element ( 202 ) to drive the second Coriolis element ( 200 ) parallel to the second axis (Y), wherein the gyroscope ( 1 ) Detection means ( 140 , 240 ) for the detection of deflections of the first Coriolis element ( 100 ) and the second Coriolis element ( 200) parallel to a first axis (X) due to a Coriolis force, wherein the first axis (X) is arranged perpendicular to the second axis (Y), wherein the first axis (X) and the second axis (Y) are arranged parallel to the principal extension plane, characterized by , that the first drive element ( 102 ) and the second drive element ( 202 ) via a drive coupling element ( 301 , 302 ) are mechanically coupled to each other. [2] Gyro sensor ( 1 ) according to claim 1, characterized in that the drive coupling element ( 301 , 302 ) a first drive coupling element ( 301 ) and a second drive coupling element ( 302 ) exhibits. [3] Gyro sensor ( 1 ) according to one of the preceding claims, characterized in that the first drive coupling element ( 301 ) and / or the second drive coupling element ( 302 ) exhibits a beam structure. [4] Gyro sensor ( 1 ) according to one of the preceding claims, characterized in that the drive coupling element ( 301 , 302 ) is mechanically coupled to the substrate. [5] Gyro sensor ( 1 ) according to one of the preceding claims, characterized in that the drive coupling element ( 301 , 302 ) is designed to be softer with respect to a rotation about a third axis (Z) than with respect to a rotation about the first axis (X), wherein the third axis (Z) is arranged perpendicular to the principal extension plane, wherein the drive coupling element ( 301 , 302 ) is stiffer in the second axis (Y) than in the first axis (X). [6] Gyro sensor ( 1 ) according to one of the preceding claims, characterized in that the detection means comprises a first detection element ( 140 ) and a second detection element ( 240) has, wherein the first detection sub-element ( 140 ) and the second detection sub-element ( 240 ) via a detection coupling element ( 400 ) are mechanically coupled to each other. [7] Gyro sensor ( 1 ) according to claim 6, characterized in that the detection coupling element ( 400 ) is mechanically coupled to the substrate. [8] Gyro sensor ( 1 ) according to claim 6 or according to claim 7, characterized in that the detection coupling element ( 400 ) at least one first detection coupling element ( 31 ) and a second detection coupling element ( 31' ) exhibits, wherein preferably the first detection coupling element ( 31 ) and / or the second detection coupling element ( 31' ) has a beam structure. [9] Gyro sensor ( 1 ) according to one of claims 5, 6, 7 or 8, characterized in that the detection coupling element (400 ) is designed to be softer with respect to a rotation about the third axis (Z) than with respect to a rotation about the first axis (X), wherein the detection coupling element ( 400 ) is stiffer in the second axis (Y) than in the first axis (X). [10] Method for operating a gyroscope ( 1 ) with a first Coriolis element ( 100 ) and a second Coriolis element ( 200 ) and with a substrate having a principal extension plane, wherein the first Coriolis element ( 100 ) by a first drive element ( 102 ) is excited to a first oscillation parallel to a second axis (Y), whereby the second Coriolis element ( 200 ) by a second drive element ( 202 ) is excited to a second oscillation parallel to the second axis (Y), with deflections of the first Coriolis element ( 100 ) and the second Coriolis element ( 200) parallel to a first axis (X) by detection means ( 140 , 240 ) are detected, wherein the second axis (Y) is arranged perpendicular to the first axis (X), wherein the first axis (X) and the second axis (Y) are arranged parallel to the main extension plane, characterized in that the first oscillation and the second oscillation are transmitted via a drive coupling element ( 301 , 302 ) mechanically coupled together.

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