Three-axis angular rate sensor with a substrate and a double rotor

Abstract

A three-axis angular rate sensor with a substrate and a A double rotor is proposed, wherein the double rotor has a first and a second rotor (1, 2) which are elastically connected to one another via a first coupling element (8) in such a way that the two rotors (1, 2) can be excited to antiphase torsional vibrations, wherein the first rotor (1) has a first and a second second seismic mass (3, 4) which are mounted so as to be deflectable relative to the first rotor (1) and the second rotor (2) has a third and a fourth seismic mass (5, 6) which are mounted so as to be deflectable relative to the second rotor (2), wherein the first mass (3) is connected to the third mass (5) via a first rocker element (9) is connected in such a way that the third mass (5) at a lateral deflection of the first mass (3) is deflected in an opposite lateral direction, wherein the second mass (4) is connected to the fourth mass (6) via a second rocker element (9') such that the fourth mass (6) is deflected in an opposite lateral direction upon a lateral deflection of the second mass (4).

Description

State of the art

[0001] The invention is based on a three-axis yaw rate sensor according to the preamble of claim 1.

[0002] Numerous designs of yaw rate sensor arrangements are known from the prior art. In a simple variant, for example, a rotor is arranged in a MEMS functional plane (XY plane) parallel to a substrate and excited to oscillate. If an external yaw rate in the X or Y direction is applied to the MEMS component, the rotor is deflected in the Z direction by the Coriolis force. This deflection can in turn be determined via a change in capacitance relative to fixed detection electrodes. It is advantageous to use two detection electrodes arranged symmetrically to the rotation axis, whose differential signal is used as the yaw rate signal. In this arrangement, an externally applied linear acceleration generates an equal change in capacitance for both detection electrodes, whereby the differential signal remains unchanged. The yaw rate signal cannot therefore be disturbed by an externally applied acceleration.

[0003] Furthermore, arrangements with two symmetrical rotors are known, which are excited to an antiphase oscillation and which are equipped with four symmetrical detection electrodes in each detection direction. The capacitances are cross-coupled, and the resulting differential signal is measured. If an external torsional vibration with the frequency of the drive vibration is applied to a single rotor, this torsional vibration generates a deflection of the rotor that cannot be distinguished from a yaw rate signal. In a system with two rotors oscillating in antiphase, however, the signal from the first rotor is exactly compensated for by the signal from the second rotor oscillating in antiphase when an external torsional vibration is applied. A further advantage of this arrangement is that the antiphase oscillation of the two rotors does not decouple any torque from the MEMS system.Regardless of the installation conditions, no rotational energy can be dissipated from the system to the environment. Furthermore, it is advantageous to mount the rotors spring-loaded at their center.

[0004] The suspension of the moving structures and the coupling between the antiphase oscillating Coriolis masses are always a critical consideration in the design of gyroscopes. External disturbances such as vibrations, electrical measurement pulses, or electronic noise from the evaluation circuit can lead to the excitation of unwanted oscillation modes, which, depending on the oscillation mode, can result in a false signal or an additional noise component in the signal. Experience has shown that the simpler and more compact the sensor's design, the lower its susceptibility to interference. Therefore, even a gyroscope comprising only two centrally suspended rotors and possibly a coupling structure can form a very robust and robust system.

[0005] The disadvantage of such an arrangement is that one can only measure the yaw rate in the X and Y directions, while a measurement in the Z direction is not possible. An arrangement for three-axis measurement using a single rotor with additional seismic masses for the Z direction is known, for example, from EP 1 832 841 A1. There are various approaches to detecting the Z direction based on the dual-rotor arrangement, but these always require additional elements that are coupled to the movement of the two rotors. Due to the additional elements and their coupling structures, the three-axis yaw rate sensors are usually very complex, have a large number of spring elements, in particular very soft ones, and are therefore very sensitive to interference from external vibrations or electrical measuring pulses. Disclosure of the invention

[0006] Against this background, it is an object of the present invention to provide an arrangement of a three-axis yaw rate sensor which is vibration-robust, couples out as little energy as possible during operation, is insensitive to electrical measuring pulses, can be realized in a small area and has a high sensitivity and good area utilization.

[0007] The yaw rate sensor according to claim 1 allows the detection of external yaw rates in all three spatial directions, with the drive movement consisting of the torsional vibrations of the rotors. Without an external yaw rate, the two rotors are initially arranged parallel to the XY plane. If an external rotation is applied to the sensor, the axis of rotation of which is parallel to the XY plane, Coriolis forces act on the rotors, tilting them relative to the plane. In contrast, with an external yaw rate whose axis of rotation is perpendicular to the main plane of extension, a rigid rotor is subjected to only radial expansion or compression forces, which cannot cause any overall movement of the rotor.However, the rotors of the sensor according to the invention themselves have deflectable seismic masses that rotate with the rotors' rotational vibration, so that the radial Coriolis forces cause a displacement of the seismic masses in the radial direction of the rotor, which can be detected accordingly. Due to the first and second coupling elements according to the invention, both the drive vibrations of the two rotors and the detection movements of the seismic masses are in antiphase, so that the deflection of the seismic masses can be precisely determined via a differential measurement.

[0008] The rotors in the sensor according to the invention therefore fulfill a dual function, acting as detection mass in the X and Y directions as well as in the Z direction, thus enabling a particularly compact sensor to be realized without the need for additional elements. A double rotor can advantageously be designed to be particularly space-saving with very good area utilization and can be easily adapted to different external conditions. Compared to other three-axis sensors, the inventive concept requires very few mass and coupling elements, so that the sensor exhibits far fewer spurious modes at higher frequencies and is less susceptible to external interference. Furthermore, the sensor according to the invention requires fewer springs overall and can be realized, in particular, with harder springs than known concepts.This makes the sensor significantly less sensitive to variations in the manufacturing process, which can result in very inaccurate representation of particularly soft springs. This advantageously allows for the production of angular rate sensors with a narrower frequency distribution than conventional sensors.

[0009] The following geometric description of the sensor's electromechanical structure is based on the substrate's main plane of extension. The directions parallel to the substrate are referred to as lateral directions, and the direction perpendicular to the substrate is referred to as the vertical direction. The lateral directions are spanned by an X direction and a Y direction perpendicular to the X direction. The X and Y directions, together with the vertical Z direction, form a rectangular coordinate system, whereby the relative position of individual components with respect to the Z direction is also referred to as "above" and "below," and vertical movements are referred to as "up" and "down."

[0010] The two rotors of the double rotor can, for example, be spaced from one another in the X direction and are coupled in such a way that they can be excited by the drive, in particular an electrostatic drive, to anti-phase torsional oscillations relative to the substrate. The axes of rotation of both rotors run in the Z direction, whereby two directions of rotation can be distinguished, one of which is referred to as clockwise (i.e. running clockwise with respect to the top view of the substrate) and the other as anti-clockwise (running counterclockwise). The axis of rotation preferably runs through the center, particularly preferably through the center of gravity, of the respective rotor. The anti-phase oscillations of the double rotor are understood to be movements in which the first and second rotor rotate in opposite directions at all times.In other words, the first rotor reaches its maximum deflection with respect to clockwise rotation when the second rotor reaches its maximum deflection with respect to counterclockwise rotation, and vice versa. To distinguish rotations of the entire sensor from rotations of the rotors, rotations of the sensor as a whole are referred to below as external or externally applied rotations or rotation rates. Each of the two rotors now has two seismic masses, which are elastically coupled to the respective rotor in such a way that lateral deflection relative to the rotor is possible. The lateral deflection direction of the first mass runs parallel to the lateral deflection direction of the second mass, and the deflection direction of the third mass runs parallel to that of the fourth mass.If the two rotors are in their non-deflected rest position with respect to rotation, the lateral deflection directions of all four seismic masses run parallel to each other, for example in the Y direction.

[0011] The seismic masses can in particular be separate segments of the rotors, which are separated from the rest of the respective rotor by one or more recesses and connected to it by springs. For example, the rotors can have a rectangular or square shape with regard to their lateral extent, while the seismic masses can be rectangular, square or trapezoidal, for example. In order to enable the lateral deflections, the springs are designed to be particularly soft in the deflection direction, i.e. they have a lower spring constant or stiffness in this direction than in the directions perpendicular to it. Preferably, the spring constant in the lateral deflection direction is at most half as large as in the perpendicular lateral direction and / or the vertical direction.Preferably, leaf springs with a high aspect ratio in the Z direction are used for this purpose, whereby the height (extension in the Z direction) is at least twice as large as the width (extension in the lateral direction) of the spring. If the lateral deflection runs, for example, in the Y direction, an advantageously high sensitivity in the X direction is achieved in this way, whereby sensitivity remains almost unchanged compared to a pure double rotor without Z detection. According to the invention, the seismic masses are coupled via the rocker elements in such a way that the lateral deflections of the first and third masses and of the second and fourth masses are each in antiphase. In particular, the rocker elements tilt parallel to the substrate during this movement, so that, for example, one end piece of the first rocker element follows the lateral deflection of the first mass, while the opposite end piece follows the lateral deflection of the third mass.These antiphase movements are now in turn coupled according to the invention via the second coupling element in such a way that the lateral deflections of the seismic masses have the following phase relationships: Seismic masses belonging to the same rotor (first and second mass or third and fourth mass) move in antiphase and seismic masses that are connected by a rocker element (first and third, or second and fourth mass) also move in antiphase.

[0012] The sensor according to the invention is preferably suspended from the substrate at only four points, which are arranged relatively centrally and symmetrically to one another. This ensures that the sensor reacts significantly less sensitively to bending, such as that caused by mechanical stresses during further processing. Each of the two rotors preferably has a single anchor point, whereby the anchor points of both rotors can lie, for example, on a line parallel to the X-direction. Each of the two rocker elements preferably also has a single anchor point, which is particularly preferably arranged centrally with respect to a main extension direction of the rocker element, such that each rocker element is divided longitudinally into two subsections that form lever arms of equal length with respect to the anchor point.The anchor points of the two rocker elements can, for example, lie on a line parallel to the Y-direction and be spaced from each other in the Y-direction. The first coupling element is preferably designed such that it not only couples the drive oscillation of the two rotors, but also couples the tilting movements of the two rotors caused by an external rotation rate in the X-direction. The first coupling element preferably extends in the X-direction between the two rotors and is elastic with respect to stretching or compressing in this direction. In particular, the first coupling element can have two or more partial sections running in the Y-direction for this purpose, which bend when the first coupling element is stretched or compressed in the X-direction, thus producing the desired elasticity.If an external rotation rate is applied in the X direction, each rotor rotates around an axis in the Y direction due to the tilting caused by the Coriolis forces, with the tilting of the two rotors occurring in antiphase due to the opposite directions of rotation. The first coupling element then generates, in particular, a restoring force directed such that the two rotors are retracted into the non-tilted position parallel to the substrate, so that the antiphase oscillations of the tilting are accordingly supported by the coupling. Furthermore, the two rocker elements can preferably be designed such that they couple the vertical movements of the seismic masses particularly well, whereby the main extension direction of the rocker elements can run, in particular, parallel to the X direction.The first rocker element preferably couples the vertical movement (relative to the substrate) of the first and third seismic masses such that, upon a vertical deflection of the first mass, the third mass is deflected in a direction opposite to the vertical deflection of the first mass, and vice versa. In other words, an upward movement of the first mass is associated with a downward movement of the second mass (and vice versa). During these movements of the first and third masses, the rocker element tilts, in particular from its rest position parallel to the substrate, so that a first end piece of the rocker element, connected to the first mass, moves upwards, while the opposite end piece, connected to the third mass, moves downwards (and vice versa). The second and fourth seismic masses are coupled in a similar manner via the second rocker element.The paired mass elements are in turn coupled to each other via the second coupling element. It is conceivable that the second coupling element, for example in the form of a torsion spring, can provide a restoring force between antiphase tilts of the rocker elements.

[0013] In the system according to the invention, all detection masses are coupled to one another in all detection directions by the first and second coupling elements and the two rocker elements. The coupling of all individual detection masses results in them oscillating at exactly the same frequency. This prevents unwanted beats in the detection movement, unlike in uncoupled systems. Furthermore, it is possible to shift the frequencies of the detection movements using additional electrodes so that they have the same value as the frequency of the drive movement. This achieves a quality enhancement in the detection, which enables particularly sensitive sensors. Furthermore, it also enables the realization of sensors operated with a particularly cost-effective closed-loop concept.

[0014] Advantageous embodiments and further developments of the invention can be found in the dependent claims and the description with reference to the drawings.

[0015] Preferably, the two rotors are connected to the substrate at their center, in particular at their center of gravity, via at least one spring.

[0016] Particularly preferably, the axis of rotation of the rotors also runs through the center, or center of gravity. The connection of a rotor to the substrate can be realized, for example, via an anchor point at which one, two, or more springs are arranged, running parallel to the substrate and connected to the rotor. The at least one spring can, in particular, be designed as a hard spring, so that it can be manufactured with less process variation than softer springs (i.e., in particular, springs with a smaller width).

[0017] The arrangement and geometric shape of the double rotor, the seismic masses, and the coupling elements can advantageously be designed symmetrically so that the forces and torques caused by the detection elements moving in antiphase are precisely compensated. In this way, the transfer of kinetic energy to the substrate and an offset in the measurement signal generated by the corresponding detection movement can be advantageously prevented. The following information on symmetry always refers to the lateral arrangement, shape, and extent of the individual elements, i.e., the symmetry relationships are described as two-dimensional symmetries with respect to the main extension plane. In the three-dimensional arrangement, the respective axes of symmetry correspond to planes of symmetry spanned by the symmetry axis and the Z direction.The entire sensor structure is preferably designed symmetrically so that disturbances of any kind are compensated for simply by virtue of the symmetry. According to a preferred embodiment, the double rotor is designed to be axially symmetrical to a first and / or a second axis of symmetry, the first axis of symmetry running in the Y direction and being arranged centrally between the two rotors, and the second axis of symmetry running in the X direction through a center, in particular a center of gravity, of the first rotor and a center, in particular a center of gravity, of the second rotor. The two rotors are spaced apart in the X direction in particular and are mirror images of one another with respect to the first axis of symmetry running between them.

[0018] Each of the two rotors can, in particular, be designed to be mirror-symmetrical to the second axis of symmetry running through its center. Preferably, the first and second masses, or the third and fourth masses, are also mirror images of the second axis of symmetry. Particularly preferably, the spring arrangements connecting the seismic masses to the respective rotors are also designed to be correspondingly symmetrical.

[0019] According to one embodiment, the first rotor is axially symmetrical to a third axis of symmetry and / or the second rotor is axially symmetrical to a fourth axis of symmetry, wherein the third axis of symmetry runs in the Y direction through a center, in particular a center of gravity, of the first rotor, and the fourth axis of symmetry runs in the Y direction through a center, in particular a center of gravity, of the second rotor. Preferably, both rotors are each mirror-symmetrical with respect to their central axis running in the Y direction.

[0020] Preferably, the seismic masses arranged on the rotors are also mirror-symmetrical with respect to the third and / or fourth axis of symmetry, i.e., each of the masses is preferably symmetrical with respect to the axis of symmetry of the respective rotor running in the Y direction. Particularly preferably, the spring arrangements of the seismic masses also exhibit the corresponding symmetry.

[0021] Preferably, the first coupling element is a first spring element arranged centrally between the rotors, wherein the first spring element is formed in particular by at least one leaf spring, which is preferably oriented predominantly in the Y direction. Particularly preferably, the first spring element has one or more sections that run in the Y direction and bend accordingly in the X direction when the spring element is loaded in the X direction. The first spring element can, for example, have one or more U- or O-shaped sections that are spread open in the X direction when loaded. Alternatively, a meandering sequence of sections is also conceivable. Preferably, the first spring element is at least twice as stiff with respect to bending in the Z direction as in the Y direction. A leaf spring with a high aspect ratio in the Z direction is preferably used for this purpose, e.g.with a height that is at least twice the width of the spring.

[0022] According to a preferred embodiment, the rocker elements each have a lever element that is connected to a seismic mass of the first rotor via a second spring element and to a seismic mass of the second rotor via a third spring element, wherein the second and third spring elements are preferably each arranged centrally on a seismic mass and / or the lever element is anchored to the substrate via a fourth spring element, wherein the fourth spring element is particularly preferably arranged centrally on the lever element and / or extends from the lever element towards a center of the double rotor. Preferably, the connection of the spring elements to the respective seismic mass is arranged in the center (with respect to the X direction) of the mass. Preferably, a leaf spring with a high aspect ratio is used for this purpose, in particular a leaf spring whose height is at least twice as large as the width of the spring.The lever element is anchored to the substrate via at least a fourth spring element, with the fourth spring element and the anchorage aligned toward the center of the double rotor to enable a compact design. It is advantageous to design each of the two rocker elements mirror-symmetrically with respect to the first axis of symmetry, and to use two identical rocker elements that are mirror images of each other with respect to the second axis of symmetry. This, in turn, prevents energy extraction and an offset in the measurement signal.

[0023] According to a preferred embodiment, the second coupling element has a first and a second additional arm and a bending element, the first additional arm being arranged on the first rocker element and the second additional arm being arranged on the second rocker element, the bending element connecting the first additional arm to the second additional arm. The additional arms are preferably attached to the lever element of the respective rocker element symmetrically and centrally between the two rotors in order to avoid an offset. The bending element that connects the two additional arms is preferably designed as a leaf spring, and a leaf spring with a high aspect ratio can be used for this purpose, in particular a leaf spring whose height is at least twice as large as its width.The length of the leaf spring is preferably chosen to be shorter than the length of the additional arms, i.e. shorter than the Y-section of the additional arms between the lever element and the bending element, so that a parallel deflection of the seismic masses is particularly strongly suppressed.

[0024] Preferably, the second coupling element is arranged above or below the first coupling element, at least in one partial region, or has two parallel partial elements, at least in one partial region, wherein one partial element is arranged above the first coupling element and the other partial element is arranged below the first coupling element. In other words, the first coupling element, which runs in particular in the X direction, and the second coupling element, which runs in particular in the Y direction, intersect in a region between the rotors, and the second coupling element is guided in the intersection region in a plane below or above (or below and above) the first coupling element.

[0025] In particular, it is advantageous to realize the connection between the additional arms and the flexure element via a mechanical bridge that bridges part of the first coupling element. For this purpose, for example, the flexure element can be connected to a bridge element in a second functional layer that is vertically spaced from the functional layer of the rotors. If only a thin second functional layer can be produced in the manufacturing process, it is advantageous to prevent kinking between the two lever arms by means of an additional spring element that is designed to be soft in the X direction but stiff in the Z direction and that is connected on one side to the substrate and on the other side to the lever element. The bridge element can be arranged below or above the first coupling element or branch into two parallel sub-elements, one of which is arranged above and the other below the first coupling element.The bridge element is then guided through a section below or above the first coupling element and connected to a lever arm in each case. A bridge element that is connected both below and above the first coupling element is advantageous, so that bending between the two lever arms in the area of ​​the bridge element can be avoided under load.

[0026] Preferably, a first detection electrode arrangement arranged below and / or above the first rotor is designed symmetrically to the second and / or third axis of symmetry and / or a second detection electrode arrangement arranged below and / or above the second rotor is designed symmetrically to the second and / or fourth axis of symmetry. The first detection electrode arrangement is used, in particular, to detect a tilt of the first rotor, such as that caused by the effect of an external rotation with a rotation axis in the X or Y direction. Preferably, the first and second detection electrode arrangements each have at least four electrode surfaces, wherein the four electrodes of the first rotor are each arranged mirror-symmetrically with respect to the second and third axes of symmetry, while the four electrodes of the second rotor are arranged mirror-symmetrically to the second and fourth axes of symmetry.Both the arrangement and the lateral shape of the individual electrode surfaces (e.g., trapezoidal) adhere to double mirror symmetry. Tilts whose rotational axis lies in the X direction can thus be realized by a differential measurement between the two electrode surfaces facing each other in the Y direction. Similarly, perpendicular tilts can be determined using the other pair of electrodes. A symmetrical electrode arrangement advantageously prevents asymmetric forces caused by electrical pulses on the electrodes. The detection electrodes for X and Y detection can, for example, be located below (or above, or below and above) the rotors. It is particularly advantageous if the X detection electrodes can also be located below the seismic masses, so that these surfaces are not lost but can be used for dual purposes.

[0027] According to a preferred embodiment, a third detection electrode arrangement is configured to detect a lateral deflection of the first and second seismic masses, and a fourth detection electrode arrangement is configured to detect a lateral deflection of the third and fourth seismic masses, wherein the third and fourth detection electrode arrangements have an electrode surface arranged perpendicular to the substrate. The detection of a rotation rate directed in the Z direction can be realized in a particularly advantageous manner via vertically arranged detection surfaces, which are provided in particular on the lever elements or coupled to the lever elements. In this way, it is advantageously achieved that the lever elements are moved during the detection movement but do not follow the drive movement, and thus a particularly low-interference rotation rate signal can be achieved.It is advantageous to provide at least four electrode surfaces in the X and Y directions and to arrange and connect them in pairs in such a way that an external torsional vibration in the differential signal is just compensated so that no interference signal is produced.

[0028] According to a preferred embodiment, the third and fourth detection electrode arrangements are designed such that they detect rotational movements of the rocker elements whose axes of rotation run perpendicular to the main extension plane. During an external rotation whose axis of rotation runs parallel to the Z direction, the seismic masses are deflected in the lateral direction, and the rocker elements follow this movement by rotating about the Z direction (i.e., by tilting parallel to the substrate). In particular, for example, one end piece of the first rocker element follows the lateral deflection of the first mass, while the opposite end piece follows the lateral deflection of the third mass. The associated deflection of the seismic masses can be determined via the rotation of the rocker elements.The rotational movement of the rocker elements can be detected in particular by the third and fourth detection electrode arrangements each having electrodes that are firmly connected to the substrate and further electrodes that are firmly connected to the rocker elements. The rotation of the rocker elements relative to the substrate can thus be capacitively determined via the relative displacement of the associated electrodes.

[0029] In a symmetrical setup with the detection electrode arrangements described above, the sensor is insensitive to external acceleration or rotational acceleration in all directions. An exception is acceleration in the X direction, which can cause deflection of the lever elements, corresponding to an apparent Z rotation rate.

[0030] It is advantageous to choose the mass distribution of the lever elements including additional arms and bending element as well as the suspension of the lever elements in such a way that during acceleration in the X direction the lever elements are balanced in such a way that they do not perform a rotational movement but a pure displacement in the X direction.

[0031] Embodiments of the present invention are illustrated in the drawings and explained in more detail in the following description. Short description of the drawings Fig. 1 schematically shows an embodiment of the yaw rate sensor according to the invention. Fig. 2 schematically shows an embodiment of the yaw rate sensor according to the invention including a bending element between the two second coupling elements. Fig. 3 shows schematically the drive movement of the embodiment of the yaw rate sensor according to the invention. Fig. Figure 4 schematically shows the detection movement for an external rotation rate oriented in the Y direction. Fig. Figure 5 schematically shows the detection movement for an external rotation rate oriented in the X-direction. Fig. Figure 6 schematically shows the detection movement for an external rotation rate oriented in the Z direction. Fig. 7 schematically shows another embodiment of the yaw rate sensor according to the invention. Fig. Figure 8 illustrates a preferred design of the rocker structure. Embodiments of the invention

[0032] In Fig. 1, the sensor arrangement according to the invention is shown schematically. The basic element is formed by a double rotor oscillating in antiphase. In each of the two rotors 1, 2, two seismic masses 3, 4, 5, 6 are separated, which are softly mounted via springs 7 in a direction perpendicular to the oscillation axis of the rotors. The two rotors are coupled to one another via a first coupling element 8, which in the illustrated embodiment has a centrally arranged O-shaped section that is spread open when loaded in the X direction. One of the two separated masses (3 to 5 and 4 to 7) of a rotor 1, 2 is coupled to one another via a rocker element 9 or 9', respectively. The rocker elements 9, 9' enforce an antiphase lateral deflection of the masses 4 and 6 or 3 and 5 (cf. Fig. 5).

[0033] The illustrated arrangement has several axial symmetries, which can advantageously prevent the transfer of kinetic energy to the substrate and an offset in the measurement signal generated by the corresponding detection movement. The two rotors 1, 2, their seismic masses 3, 4, 5, 6, the rocker elements 9, 9', and the coupling elements 8, 10 are each designed to be mirror-symmetrical to the central axes of the double rotor, which run in the X and Y directions. The axis of the illustrated right-left mirror symmetry of the arrangement is referred to as the first axis of symmetry, while the second axis of symmetry is assigned to the mirror symmetry between the lower and upper halves. In addition, each rotor 1, 2 has its own mirror axis oriented in the Y direction, which are referred to as the third and fourth axes of symmetry, respectively.Preferably, the springs 7 of the seismic masses 3, 4, 5, 6 and the anchoring elements 13, 14 of the rotors 1, 2 (cf. . Fig. 3) have the same symmetry as the rotors.

[0034] Fig. 2 shows an embodiment of the sensor arrangement according to the invention as in Fig. 1, wherein the two rocker elements 9, 9' are additionally connected via a second coupling element 10, which consists of two additional arms 11, 11', which in turn are connected to one another via a bending element 12. In the illustrated, particularly advantageous arrangement, the coupling structure 8 of the two rotors 1, 2 and the coupling structure 10 of the two rocker elements 9, 9' are arranged between the two rotors, wherein in the central region where the two coupling elements 8 and 10 intersect, a mechanical bridge 30 is realized, which allows independent movement of both structures in this region. For this purpose, the coupling element has two partial sections 30 (bridge elements) that run below the O-shaped section of the first coupling element 8.

[0035] In the Fig. 3 shows the drive movement of the double rotor. To clearly show the movement, the second coupling element 10, which does not participate in this movement, is not shown. As indicated by the arrows in Fig. As indicated in Figure 3a, the rotors 1, 2 are set into antiphase torsional vibrations by a drive (not shown). Fig. At the time shown in Figure 3a, both rotors 1, 2 are in their zero position (cf. the rest state of the double rotor in Fig. 3c), and the left rotor 1 performs a left rotation, while the right rotor 2 performs a right rotation. In the Fig. 3b shows the corresponding maximum deflection, while in Fig. 3d shows the maximum deflection of the counter-rotating oscillation phase (clockwise rotation of rotor 1, counterclockwise rotation of rotor 2). To enable the torsional oscillation of rotors 1, 2, each rotor 1, 2 has a central recess in the area of ​​their center of gravity, in which they are connected to an anchor point 13 via spring elements 14.

[0036] Fig. Figure 4 schematically shows the movement of the seismic masses 3, 4, 5, 6, which are used to detect an external rotation parallel to the Y-axis. To clearly illustrate the movement, the second coupling element 10, which does not participate in this movement, is not shown. Due to the antiphase torsional oscillation of the rotors 1, 2, the masses 3, 4, 5, 5, 6 move in the positive or negative X-direction during the illustrated passage through the zero position. Due to the Coriolis forces acting due to the external rotation, the two masses 3 and 6 are each deflected in the negative Z-direction (i.e., downwards) during their drive movement in the negative X-direction. The antiphase moving masses 4 and 5 are correspondingly deflected in the positive Z-direction (upwards).The detection movements of masses 3, 4, 5, and 6 are coupled via the two rocker elements 9, 9', each consisting of a lever element 15 connected to masses 4, 6 and 3, 5 via two springs 16 (second and third spring elements) and connected to anchor point 18 via a spring 17 (fourth spring element). Due to the tilting movement of the levers 15 connected to the seismic masses 3, 4, 5, and 6, the detection movements of masses 3, 4, 5, and 6 are coupled in such a way that 3 and 5, or 4 and 6, are each deflected in antiphase in the Z direction. The Z-deflection is measured by the detection electrode arrangements 19 and 29 arranged above and / or below the double rotor, whereby the difference in the capacitance change of the electrode pair 19 and 29 is included in the measurement signal.It is particularly advantageous to provide the X-detection electrodes 19, 29 below the separated masses 3, 4, 5, 6, so that these areas are not lost but can be used twice.

[0037] Fig. Figure 5 schematically shows the movement of the seismic masses 3, 4, 5, 6, which are used to detect an external rotation parallel to the X-axis. To clearly illustrate the movement, the first coupling element 8, which does not participate in this movement, is not shown. The coupling of the detection movement is achieved via the two rocker elements 9, 9'. Due to the Coriolis forces, the right side of the rotor 1 (which moves in the positive Y-direction) is tilted upwards, while the left side (which moves in the negative Y-direction) is tilted downwards. The tilting of the second rotor 2 is a mirror image of this. The first coupling element 8 is advantageously designed such that it not only couples the drive vibration of the two rotors 1, 2, but also couples the tilting movements of the two rotors 1, 2.The O-shaped section of the coupling element 8 forms an elastic connection between the rotors 1, 2, through which the rotors 1, 2 are retracted into the non-tilted position. Detection occurs analogously to . Fig. 4 via the detection electrode arrangements 19' and 29'.

[0038] Fig. Figure 6 shows schematically the movement of the seismic masses 3, 4, 5, 6, which are used to detect an external rotation parallel to the Z-axis. As in Fig. As shown in Figure 6a, the masses 3, 4 of the first (left-rotating) rotor 1 are displaced by the Coriolis forces toward the center of the rotor 1, while the masses 5, 6 of the second rotor 2 are displaced away from the center of the rotor 2. These anti-phase movements of the masses 3, 4, 5, 6 are supported by the second coupling element 10, which, on the one hand, couples the lateral detection movements of the masses 3 and 5 and the lateral detection movements of the masses 4 and 6, and, on the other hand, couples these paired movements to each other via the spring element 12 arranged between the additional arms 11, 11'. Fig. 6a and Fig. 6b shows the lateral deflections of the seismic masses when the left rotor 1 performs a left rotation and the right rotor 2 a right rotation. Fig. 6d, the left rotor 1 performs a right rotation and the right rotor 2 a left rotation and Fig. For comparison, Figure 6c shows the resting state of the double rotor.

[0039] In Fig. Figure 7 shows a particularly advantageous implementation of the sensor concept according to the invention. The high surface area utilization resulting from the large surface area of ​​the rotors 1, 2 can be seen. The drive electrodes 23 are implemented in the form of comb electrodes that are firmly connected to the rotors 1, 2 and electrostatically couple to comb electrodes fixed to the substrate. This complete integration of the drive combs 23 into the rotors 1, 2 is advantageous in this embodiment, particularly with regard to the very large rotors. In this embodiment, surfaces 24 are also provided for quadrature compensation in all three spatial directions, although these cannot be actively operated in this design.

[0040] If only a thin second functional layer can be produced in the manufacturing process, it is advantageous to prevent the bending between the two lever arms 11, 11' by means of an additional spring element 20 which is designed to be soft in the X direction but stiff in the Z direction and which is connected on one side to the substrate and on the other side to the respective lever arm 15.

[0041] The detection of the Z-rotation rate is realized here via vertically arranged detection surfaces 21, 21', which are arranged on the lever arms 15 or, alternatively, can be coupled to the lever arms. This is particularly advantageous because the lever arms 15 follow the detection movement but do not execute the drive movement, so that a particularly low-interference rotation rate signal can be achieved. It is also advantageous to provide at least four detection surfaces 21, 21' in the X and Y directions and to arrange and connect them in pairs in such a way that an externally applied rotational oscillation is just compensated in the differential signal, thus preventing any interference signal.

[0042] Fig. Figure 8 illustrates the correct design of the suspension of the lever element 15. The lever elements 15 are each anchored to the substrate via a spring element 17 connected to an anchor point 18. The figures Fig. 8a, Fig. 8b and Fig. Figure 8c shows how the rocker structure can be symmetrical with respect to an acceleration applied in the X direction, so that an external acceleration cannot cause a false signal in the Z yaw rate signal. Symmetrization is achieved by appropriately selecting the length of spring 17 and the corresponding positioning of anchor point 18. Fig. 8a shows an undercompensated arrangement, Fig. 8b shows the correctly compensated arrangement and Fig. Figure 8a shows an overcompensated arrangement.

[0043] In a symmetrical configuration with the arrangement of the detection electrodes described above, the sensor is insensitive to external acceleration or rotational acceleration in all directions. An exception is acceleration in the X direction, which can lead to a deflection of the lever arms 15 corresponding to an apparent Z rotation rate (see Fig. 8a and Fig. 8c). It is advantageous to choose the mass distribution of the lever elements 15 including the additional arms 11, 11' and the bending element 12 as well as the suspension 18 of the lever elements 15 in such a way that, during acceleration in the X-direction, the lever elements 15 are balanced in such a way that they do not perform a rotational movement, but a pure displacement in the X-direction (see Fig. 8b). QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 1 832 841 A1

[0005]

Claims

[1] Three-axis rotation rate sensor with a substrate and a double rotor, wherein the substrate has a main extension plane with an X and a Y direction, wherein the double rotor has a first and a second rotor (1, 2), which are each elastically connected to the substrate via a suspension (13, 14) and which are elastically connected to one another via a first coupling element (8) such that the two rotors (1, 2) can be excited to antiphase torsional oscillations, wherein the axes of rotation of the rotors (1, 2) run in a vertical Z direction perpendicular to the substrate, characterized bythat the first rotor (1) has a first and a second seismic mass (3, 4) which are mounted so as to be deflectable relative to the first rotor (1), wherein a lateral deflection direction of the two masses (3, 4) of the first rotor (1) runs parallel to the substrate, wherein the second rotor (2) has a third and a fourth seismic mass (5, 6) which are mounted so as to be deflectable relative to the second rotor (2), wherein a lateral deflection direction of the two masses (5, 6) of the second rotor (2) runs parallel to the substrate, wherein the first mass (3) is connected to the third mass (5) via a first rocker element (9) in such a way that the third mass (5) is deflected in a direction opposite to the lateral deflection of the first mass (3) upon a lateral deflection of the first mass (3), wherein the second mass (4) is connected to the fourth mass (6) via a second rocker element (9') in such a way,that the fourth mass (6) is deflected in a direction opposite to the lateral deflection of the second mass (4) upon a lateral deflection of the second mass (4). [2] Rotation rate sensor according to claim 1, wherein the first and second rocker elements (9, 9') are elastically connected to one another via a second coupling element (10) in such a way that the lateral deflections of the first and second masses (3, 4) occur in antiphase and the lateral deflections of the third and fourth masses (5, 6) occur in antiphase. [3] Rotation rate sensor according to claim 1 or 2, wherein the two rotors (1, 2) are connected to the substrate in their center, in particular in their center of gravity, via at least one spring (14). [4] Rotation rate sensor according to claim 1 or 2 or 3, wherein the double rotor is designed axially symmetrical to a first and / or a second axis of symmetry, wherein the first axis of symmetry runs in the Y direction and is arranged centrally between the two rotors (1, 2) and the second axis of symmetry runs in the X direction through a center, in particular a center of gravity, of the first rotor (1) and a center, in particular a center of gravity, of the second rotor (2). [5] Rotation rate sensor according to one of the preceding claims, wherein the first rotor (1) is designed to be axially symmetrical to a third axis of symmetry and / or the second rotor (2) is designed to be axially symmetrical to a fourth axis of symmetry, wherein the third axis of symmetry runs in the Y direction through a center, in particular a center of gravity, of the first rotor (1) and the fourth axis of symmetry runs in the Y direction through a center, in particular a center of gravity, of the second rotor (2). [6] Rotation rate sensor according to one of the preceding claims, wherein the first coupling element (8) is a first spring element arranged centrally between the rotors (1, 2), wherein the first spring element is formed in particular by at least one leaf spring, which is preferably oriented predominantly in the Y direction. [7] Rotation rate sensor according to one of the preceding claims, wherein the rocker elements (9, 9') each have a lever element (15) which is connected to a seismic mass (3, 4) of the first rotor via a second spring element (16) and to a seismic mass (5, 6) of the second rotor (2) via a third spring element (16), wherein the second and third spring elements (16) are preferably each arranged centrally on a seismic mass (3, 4, 5, 6) and / or the lever element (15) is anchored to the substrate via a fourth spring element (17), wherein the fourth spring element (17) is particularly preferably arranged centrally on the lever element (15) and / or extends from the lever element (15) in the direction of a center of the double rotor. [8] Rotation rate sensor according to one of the preceding claims, wherein the second coupling element (10) has a first and second additional arm (11, 11') and a bending element (12), wherein the first additional arm (11) is arranged on the first rocker element (9) and the second additional arm (11') is arranged on the second rocker element (9'), wherein the bending element (12) connects the first additional arm (11) to the second additional arm (11'). [9] Rotation rate sensor according to one of the preceding claims, wherein the second coupling element (10) is arranged at least in a partial area above or below the first coupling element (8) or at least in a partial area has two parallel partial elements, wherein one partial element is arranged above the first coupling element (8) and the other partial element is arranged below the first coupling element (8). [10] Rotation rate sensor according to one of the preceding claims, wherein a first detection electrode arrangement (19, 19') arranged below and / or above the first rotor (1) is designed symmetrically to the second and / or third axis of symmetry and / or a second detection electrode arrangement (29, 29') arranged below and / or above the second rotor (2) is designed symmetrically to the second and / or fourth axis of symmetry. [11] Rotation rate sensor according to one of the preceding claims, wherein a third detection electrode arrangement (21) is configured to detect a lateral deflection of the first and second seismic masses (3, 4) and a fourth detection electrode arrangement (21') is configured to detect a lateral deflection of the third and fourth seismic masses (5, 6), wherein the third and fourth detection electrode arrangement (21, 21') has an electrode surface that is arranged perpendicular to the substrate. [12] Rotation rate sensor according to claim 11, wherein the third and fourth detection electrode arrangements (21, 21') are designed such that they detect rotational movements of the rocker elements (9, 9') whose axes of rotation run perpendicular to the main extension plane.

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