Gyroscopic sensor and method for operating a gyroscopic sensor

Abstract

A gyroscope (100) with a substrate having a principal extension plane (103) for detecting a gyroscope rate about a first axis (X) extending parallel to the principal extension plane (103), wherein the gyroscope (100) has a first rotation element (101) and a second rotation element (102), wherein the first rotation element (101) is driveable about a first axis of rotation, wherein the second rotation element (102) is driveable about a second axis of rotation, wherein the first axis of rotation is arranged perpendicular to the principal extension plane (103), wherein the second axis of rotation is arranged perpendicular to the principal extension plane (103), wherein the first rotation element (101) and the second rotation element (102) are driveable in opposite directions to each other, wherein the first rotation element (101) is configured as an outer ring, and wherein the second rotation element (102) is configured as an inner ring.wherein the second rotating element (102) is arranged inside the first rotating element (101), wherein the first axis of rotation passes through the second axis of rotation.

Description

Prior ArtThe invention relates to a rotation rate sensor and a method for operating a rotation rate sensor (DRS).Such rotation rate sensors and such methods for operating a rotation rate sensor are generally known.Rotation rate sensors are known from the prior art. For example, the publication WO 2003 / 064 975 A1 discloses a rotation rate sensor having two oscillating mass elements. Micromechanical rotation rate sensors for rotation rates about an axis parallel to the sensor plane (Z' or the rotation rate Qy) are usually designed as planar-vibrating masses or as masses that execute rotational vibrations in the plane, which experience a Coriolis force perpendicular to the plane when a rotation occurs. This force is determined either by the electrostatic counterforce (closed-loop control) required for position feedback control or by the change in capacitance due to the change in distance from the substrate (open-loop operation). In addition to the target measured variable Coriolis force, there are further medial forces which act on the sensors and can produce a signal, such as linear accelerations and rotational accelerations. The occurrence of these accelerations can lead to incorrect signals during operation. By differential evaluation of the forces acting on two masses moving in opposite directions, it is possible to distinguish between the Coriolis force and the force by linear acceleration (e.g. two masses that oscillate towards each other or a mass that carries out rotational oscillations in the plane), in which the capacitance is evaluated at two opposite positions.These sensors are not sensitive to rotational acceleration about the y-axis, but also to rotational acceleration about the z-axis. However, a differentiation between the Coriolis force and the force that arises due to rotational acceleration about the x-axis is disadvantageously not possible with the conventional sensors. This is extremely problematic because rotational accelerations occur as disturbance variables.Further rotation rate sensors are known from the publications US 2004 / 0 211 257 A1, U.S. Pat. No. 5,869,760 A and DE 10 2009 027 897 A1.It is therefore an object of the present invention to provide a rotation rate sensor and a method for operating a rotation rate sensor, which do not have the disadvantages of the prior art and are insensitive to rotational accelerations and linear acceleration.Disclosure of the InventionThe rotation rate sensor according to the present invention and the method according to the present invention for operating a rotation rate sensor according to the independent claims have the advantage over the prior art that they are insensitive to rotational accelerations and linear acceleration.This advantage is achieved according to the invention by a rotation rate sensor having a substrate having a main plane of extension for detecting a rotation rate about a first axis extending parallel to the main plane of extension, wherein the rotation rate sensor has a first rotation element and a second rotation element, wherein the first rotation element can be driven about a first rotation axis, wherein the second rotation element can be driven about a second rotation axis, wherein the first rotation axis is arranged perpendicular to the main plane of extension, wherein the second rotation axis is arranged perpendicular to the main plane of extension, wherein the first rotation element and the second rotation element can be driven in opposite directions to one another.Advantageous embodiments and developments of the invention can be derived from the dependent claims and from the description with reference to the drawings.According to a preferred development, it is provided that the first rotation element and the second rotation element are connected to one another via at least one coupling element. This advantageously allows an increase in the frequency splitting between parallel drive mode and detection mode to be achieved with respect to the antiparallel drive mode and detection mode.According to another preferred development, it is provided that the coupling element is connected to the substrate via at least one spring. As a result, it is advantageously possible in a particularly simple manner for an increase in the frequency splitting between parallel drive mode and detection mode to be achievable with respect to the antiparallel drive mode and detection mode.According to another preferred development, it is provided that the coupling element has a rocker structure with a rocker rotational axis, wherein the rocker rotational axis runs parallel to the first axis. This advantageously allows a comparatively particularly strong increase in the frequency splitting between parallel drive and detection modes to be achieved with respect to the antiparallel drive and detection mode.According to the present invention, it is provided that the first rotation element is formed as an outer ring, wherein the second rotation element is formed as an inner ring, wherein the second rotation element is arranged in the interior of the first rotation element, wherein the first axis of rotation runs through the second axis of rotation. In this way, while achieving a particularly compact design, it is advantageously possible for an increase in the frequency splitting between parallel drive mode and detection mode to be achievable with respect to the antiparallel drive mode and detection mode.According to another preferred development, it is provided that at least one first mass element and one second mass element is arranged between the first rotation element and the second rotation element, wherein the first mass element is connected to the first rotation element and the second mass element is connected to the second rotation element, wherein the first mass element is preferably coupled to the second mass element. This advantageously allows both a particularly interference-insensitive arrangement to be realized and an increase in the frequency splitting between parallel drive mode and detection mode to be achieved in relation to the antiparallel drive mode and detection mode.According to another preferred development, it is provided that the first rotation element is plate-shaped and the second rotation element is plate-shaped. As a result, it is advantageously possible in a particularly simple manner for an increase in the frequency splitting between parallel drive mode and detection mode to be achievable with respect to the antiparallel drive mode and detection mode.According to another preferred development, it is provided that the rotation rate sensor has a third rotation element with a third axis of rotation and a fourth rotation element with a fourth axis of rotation, wherein the third axis of rotation and the fourth axis of rotation are arranged perpendicular to the main plane of extension, wherein the third rotation element and the first rotation element can be driven in opposite directions to one another, wherein the third rotation element and the fourth rotation element can be driven in opposite directions to one another. As a result, it is advantageously possible, while increasing the redundancy, for an increase in the frequency splitting between parallel drive mode and detection mode to be achievable with respect to the antiparallel drive mode and detection mode.According to another preferred development, it is provided that the first rotation element is coupled to the second rotation element and that the third rotation element is coupled to the fourth rotation element. This advantageously allows an increase in the frequency splitting between parallel detection mode and antiparallel detection mode to be achievable.A further subject matter of the present invention relates to a method for operating a rotation rate sensor having a substrate having a main extension plane for detecting a rotation rate about a first axis extending parallel to the main extension plane, wherein a first rotation element and a second rotation element are arranged, wherein the first rotation element is driven about a first rotation axis, wherein the second rotation element is driven about a second rotation axis, wherein the first rotation axis is arranged perpendicular to the main extension plane, wherein the second rotation axis is arranged perpendicular to the main extension plane, wherein the first rotation element and the second rotation element are driven in opposite directions to one another. According to a preferred development, it is provided that a first, second, third and fourth rotation element are arranged, wherein the first, second, third and fourth rotation element are driven about a first, second, third and fourth rotation axis, respectively, wherein the first, second, third and fourth rotation axes are arranged perpendicular to the main extension plane, wherein in each case two rotation elements are driven in opposite directions to one another and the remaining two rotation elements are driven in the same direction to one another. This advantageously allows an increase in the frequency splitting between parallel drive mode and detection mode to be achieved with respect to the antiparallel drive mode and detection mode.According to a preferred development, it is provided that the rotation elements are driven parallel to a third axis (y) perpendicular to the first axis (x) and to the second axis (z), wherein the rotation elements are preferably mounted rotatably (in the sense of a rotational oscillation), wherein a first and second detection signal is generated by the deflection of the first rotation element, wherein a third and fourth detection signal is generated by the deflection of the second rotation element, wherein the first to fourth detection signals are individually evaluated, wherein a fifth and sixth detection signal is preferably generated by the deflection of a third rotation element, wherein a seventh and eighth detection signal is generated by the deflection of a fourth rotation element, wherein the first to eighth detection signals are individually evaluated in order to measure the rotational acceleration about the x- or y-axis and linear acceleration along the z-axis.According to another preferred development, it is provided that the first and the third detection signal and / or the first, the third, the fifth and the seventh detection signal are added to a first sum signal, wherein the second and the fourth and / or the second, the fourth, the sixth and the eighth detection signal are added to a second sum signal. This advantageously allows a differential evaluation to be carried out in a simple manner.According to another preferred development, it is provided that a difference signal is formed from the first sum signal and the second sum signal, wherein the rotation rate is determined as a function of the difference signal. This advantageously allows the method to be insensitive to disturbing and in particular rotational accelerations.According to another preferred development, the quadrature can be compensated for by surface electrodes below the rotation elementsAccording to another preferred development, the detection mode can be coupled together by surface electrodes below the rotation elements, so that a fully resonant operation of the sensor is possibleAccording to another preferred development, the decoupling of forces during operation can be prevented by balancing the masses. The coupling structures mentioned above can additionally serve for balancingExemplary embodiments of the present invention are illustrated in the drawings and explained in more detail in the following description.Brief Description of the DrawingsThey show FIGS. 1 to 13 schematically show exemplary embodiments of the rotation rate sensor according to the invention.Embodiment(s) of the InventionIn the various figures, identical parts are always provided with the same reference numerals and are therefore generally also designated or mentioned only once in each case.FIGS. 1 aand 1 bschematically show an exemplary embodiment of the rotation rate sensor 100 according to the invention comprising two rotors 101, 102 (dual-rotary DRS) lying one inside the other and having an opposite direction of rotational oscillation and its drive and detection movement (wherein the curved arrows represent the movement of a half-phase). The first axis X denotes the axis of rotation of the rotation to be detected and runs parallel to the main plane of extension 103 of the substrate. The second axis Y extends perpendicular to the first axis X and parallel to the main plane of extension 103 of the substrate. The third axis Z extends perpendicular to the main plane of extension 103 of the substrate. The deflections to be detected are measured in the direction of the third axis Z. The surface areas which are used for differential capacitance measurement when the signals are detected are denoted by 1 and 2. Differential capacity evaluation of the regions designated by 1 compared to the regions designated by 2 makes it possible to distinguish between Coriolis force and linear acceleration or rotational acceleration.FIGS. 2 aand 2 b show a side view of the rotation rate sensor from FIGS. 1 aand 1 b. The detection deflection of the dual-rotational rate sensor with two planar masses oscillating in opposite directions in rotation due to Coriolis force (dΩx) (FIG. 2 a) and rotational acceleration (dΩx / dt) (FIG. 2 b) differ, so that a sensor of this type of construction can distinguish between the two forces.FIGS. 3 aand 3 b show plan views of a further embodiment of the rotation rate sensor according to the invention and of a coupling structure 305 for the dual-rotational rotation rate sensor 100 for increasing the frequency splitting between parallel drive mode and detection mode and antiparallel drive mode and detection mode. Rotation rate sensor 100 has coupling structures 305, 305'. The coupling structures 305, 305' connect the rotation elements 101, 102 to one another. Arrows 300 and 301 indicate the directions of movement of the rotors. The coupling structure 305 is connected to the substrate via substrate anchors 302, 302'. The coupling structure 305 has compensating springs 303, 304, which are provided for opposing tension to the left and right (with respect to the plane of the drawing) or out of the plane.FIGS. 4 aand 4 bschematically show a further exemplary embodiment of the rotation rate sensor 100 according to the invention. FIG. 4 ashows the driving movement and FIG. 4 bshows the detection movement. The rotation rate sensor has two masses which carry out rotational oscillations in opposite directions and are arranged next to one another. The areas which are used for differential capacitance measurement when the signals are detected are denoted by 1 and 2. Differential capacity evaluation of the regions designated by 1 compared to the regions designated by 2 makes it possible to distinguish between Coriolis force and rotational acceleration.FIG. 5 schematically shows a further exemplary embodiment of the rotation rate sensor 100 according to the invention. Rotation rate sensor 100 has a third rotation element 503 and a fourth rotation element 504. FIG. 5 shows a top view of the drive movement of the rotation rate sensor. The rotation rate sensor has four masses that execute rotational oscillations in opposite directions. The surface areas which are used for differential capacitance measurement when the signals are detected are denoted by 1 and 2. Differential capacity evaluation of the regions designated by 1 compared to the regions designated by 2 makes it possible to distinguish between Coriolis force and rotational acceleration.FIGS. 6 aand 6 bschematically show a further exemplary embodiment of the rotation rate sensor 100 according to the invention. The rotation rate sensor 100 has two frames 101, 102 which execute concentrically opposite rotational oscillations and to which masses 600, 600', 600", 600"', 601, 601', 602", 603"' are fastened alternately. The areas which are used for differential capacitance measurement when the signals are detected are denoted by 1 and 2. Differential capacity evaluation of the regions 1 and 2 makes it possible to distinguish between Coriolis force and rotational acceleration. The surfaces 1, 2 can move / tilt out of the plane.FIGS. 7 a, 7 b, 7 c, 7 d, 7 e, 7 fschematically show a further exemplary embodiment of the rotation rate sensor 100 according to the invention. FIG. 7 ashows a top view of a coupled drive movement of the rotation rate sensor 100 having two masses 101, 102 executing rotational oscillations in opposite directions. The rotational elements 101, 102 are connected to one another via coupling structures 700, 700', 700" (optional element). The rotation elements 101, 102 are connected to the substrate via connecting structures 799, 799', 799''799'''. With the coupling structure. 700" is advantageously possible to balance. The coupling structure 700 has springs 701, 701', a rocker 703 and connecting elements 702, 702' which connect the rocker 703 to the substrate. The surface areas which are used for differential capacitance measurement when the signals are detected are denoted by 1 and 2. FIG. 7 cshows the antiparallel detection movement (relevant mode for signal detection). FIG. 7 d shows the parallel detection movement (interference mode) FIG. 7 b shows a micromechanical, rocker-like structure 700 for canceling the degeneracy between parallel and antiparallel detection mode, i.e. displacement of the parallel detection mode to higher frequencies. This advantageously achieves a lower sensitivity to interference. Micromechanical structure 700 has masses executing rotational oscillations at the connection points between rocker and rotational oscillations, in order to be able to balance the drive movement. Figure 7f shows an enlarged view of the connecting structure 799'. The connecting structures 799, 799', 799''799''' advantageously lead to symmetrization of the sensor, which thus has a lower susceptibility to faults. FIG. 7 e outlines a further disturbing movement which is shifted, i.e. suppressed, to higher frequencies by the rocker structures.FIG. 8 schematically shows a further exemplary embodiment of the rotation rate sensor 100 according to the invention, the drive movement being illustrated. The rotation rate sensor has four masses 101, 102, 800, 801 that execute rotational oscillations in opposite directions. The surface areas which are used for differential capacitance measurement when the signals are detected are denoted by 1 and 2. In each case two rotation elements are connected to one another via coupling structures 802, 802', 803, 803', 804, 805, 806, 807, which are designed, for example, as rocker structures; these coupling structures couple regions 1 and 2 in each case and lead to mode degeneration between parallel and antiparallel detection mode and between parallel and antiparallel drive mode, i.e. the parallel detection mode or drive mode is shifted to higher frequencies.FIG. 9 schematically shows a further exemplary embodiment of the rotation rate sensor 100 according to the invention, the drive movement being illustrated. The rotation rate sensor differs from the embodiment from FIG. 6 ain that coupling structures 900 are additionally arranged between the masses 600, 601. The rotation rate sensor 100 has two concentric frames rotating in opposite directions (or executing rotational oscillations), to which masses ( 1 and 2) are fastened alternately. The areas which are used for differential capacitance measurement when the signals are detected are denoted by 1 and 2. Micromechanical rocker structures 900 preferably couple regions 1 and 2, respectively, and lead to a cancellation of the mode degeneracy between parallel and antiparallel detection mode, i.e. the parallel detection mode is shifted to higher frequencies.FIG. 10 schematically shows a further exemplary embodiment of the rotation rate sensor 100 according to the invention, the drive movement being illustrated. Rotation rate sensor 100 has two masses 101, 102 that execute rotational oscillations in opposite directions and are connected to one another via a coupling element 1001. On the rotational elements 101, 102, drive structures 1000, 1000' are shown, which are firmly connected to the masses carrying out rotational oscillations. With the aid of electrostatic forces between the comb structures of these drive structures and matching counter structures (not shown) which have a connection to the substrate, the driving of the masses which carry out two rotational oscillations is possible. Due to the rotational movement shape, the combs are preferably aligned tangentially curved both on the rotor (actuator combs) and on the substrate (stator combs).FIG. 11 schematically shows a further exemplary embodiment of the rotation rate sensor 100 according to the invention, the drive movement being illustrated. FIG. 11 shows the coupled drive movement of the rotation rate sensor 100 having two masses 101, 102 which execute rotational oscillations in opposite directions and are connected to one another via a coupling element 1101. Arranged on the rotational elements 101, 102 are drive structures 1100, 1100' which are connected to the masses carrying out rotational oscillations via stiff elements in the direction of movement of the drive structures (see curved arrows) and elastic elements perpendicular to their direction of movement. With the aid of electrostatic forces between the comb structures of these drive structures and matching counter structures (not shown) which have a connection to the substrate, the driving of the masses which carry out two rotational oscillations is possible.FIGS. 12 aand 12 bschematically show a further exemplary embodiment of the rotation rate sensor 100 according to the invention, wherein the driving movement is illustrated. FIG. 12 ashows the coupled drive movement of the rotation rate sensor 100 comprising two masses 101, 102 that execute rotational oscillations in opposite directions and that are connected to one another via a coupling element 1204. Micromechanical drive structures 1200, 1200' are arranged on the rotational elements 101, 102, which are connected via stiff elements 1201 and resilient elements 1202 to the masses carrying out rotational oscillations. The up-and-down movement (along the Y direction) of the drive structures is rotated by 90° (along the x direction) via deflection frames (see detailed diagram in FIG. 12 b) in order to ensure the required drive movement of the masses. By means of electrostatic forces between the comb structures of these drive structures and matching counter structures (not shown) which have a connection 1203 to the substrate, the driving of the masses carrying out the two rotational oscillations is possible.FIG. 13 shows a detailed illustration of the rotation rate sensor 100 according to the invention from FIGS. 7 a- 7 f. The rotation rate sensor 100 has the drive means 710, 710' with comb electrodes which excite the masses 101, 102, which are connected to one another via a coupling element 700", to counter-clockwise rotational oscillations of the drive movement. The coupling element 700" consists of a mass 742, Phi springs for stress compensation, which connect the mass of the coupling element 700" to the masses 101, 102. Furthermore, 700" contains symmetrically arranged detection means 741 with comb electrodes and springs including substrate connection 740. The driving motion is due to the central torsion springs 720, which are present twice in both the center of the masses 101 and 102. The springs 720 include stress balancing structures 722 and substrate interconnects 721. Quadratures that occur can be compensated for by electrodes located under the symmetrically arranged quadrature structures 730.

Claims

Rotation rate sensor (100) having a substrate having a main plane of extension (103) for detecting a rotation rate about a first axis (X) extending parallel to the main plane of extension (103), wherein the rotation rate sensor (100) has a first rotation element (101) and a second rotation element (102), wherein the first rotation element (101) can be driven about a first rotation axis, wherein the second rotation element (102) can be driven about a second rotation axis, wherein the first rotation axis is arranged perpendicular to the main plane of extension (103), wherein the second rotation axis is arranged perpendicular to the main plane of extension (103), wherein the first rotation element (101) and the second rotation element (102) can be driven in opposite directions to one another, wherein the first rotation element (101) is designed as an outer ring, wherein the second rotation element (102) is designed as an inner ring, wherein the second rotational element (102) is arranged in the interior of the first rotational element (101), wherein the first rotational axis extends through the second rotational axis.Rotation rate sensor (100) according to Claim 1, characterized in that the first rotation element (101) and the second rotation element (102) are connected to one another via at least one coupling element (305).Rotation rate sensor (100) according to Claim 2, characterized in that the coupling element (305) is connected to the substrate via at least one spring (303).Rotation rate sensor (100) according to Claim 3, characterized in that the coupling element (305) has a rocker structure having a rocker rotation axis, the rocker rotation axis running parallel to the first axis (X).Rotation rate sensor (100) according to one of the preceding claims, characterized in that at least one first mass element (600) and one second mass element (601) are arranged between the first rotation element (101) and the second rotation element (102), wherein the first mass element (600) is connected to the first rotation element (101) and the second mass element (601) is connected to the second rotation element (102), wherein preferably the first mass element (600) is coupled to the second mass element (601).Rotation rate sensor (100) according to one of the preceding claims, characterized in that the first rotation element (101) is of plate-shaped design and the second rotation element (102) is of plate-shaped design.Rotation rate sensor (100) according to one of the preceding claims, characterized in that the rotation rate sensor (100) has a third rotation element (503) with a third axis of rotation and a fourth rotation element (504) with a fourth axis of rotation, wherein the third axis of rotation and the fourth axis of rotation are arranged perpendicular to the main plane of extent, wherein the third rotation element (503, 800) and the first rotation element (101) can be driven in opposite directions to one another, wherein the third rotation element (503, 800) and the fourth rotation element (504, 801) can be driven in opposite directions to one another.Rotation rate sensor (100) according to Claim 7, characterized in that the first rotation element (101) is coupled to the second rotation element (102), and in that the third rotation element (503, 800) is coupled to the fourth rotation element (504, 801).Method for operating a rotation rate sensor (100) having a substrate having a main extension plane (103) for detecting a rotation rate about a first axis (X) extending parallel to the main extension plane (103), wherein a first rotation element (101) and a second rotation element (102) are arranged, wherein the first rotation element (101) is driven about a first rotation axis, wherein the second rotation element (102) is driven about a second rotation axis, wherein the first rotation axis is arranged perpendicular to the main extension plane (103), wherein the second rotation axis is arranged perpendicular to the main extension plane (103), wherein the first rotation element (101) and the second rotation element (102) are driven in opposite directions to one another, wherein the first rotation element (101) is designed as an outer ring, wherein the second rotation element (102) is designed as an inner ring, wherein the second rotational element (102) is arranged in the interior of the first rotational element (101), wherein the first rotational axis extends through the second rotational axis.Method according to claim 9, characterised in that the rotation elements (101, 102) are tilted parallel to a second axis (Y), wherein a first and second detection signal is generated by the deflection of the first rotation element (101), wherein a third and fourth detection signal is generated by the deflection of the second rotation element (102), wherein the first to fourth detection signal is individually evaluated, wherein a fifth and sixth detection signal is preferably generated by the deflection of a third rotation element (503, 800), wherein a seventh and eighth detection signal is generated by the deflection of a fourth rotation element (504, 801), wherein the first to eighth detection signal is individually evaluated.Method according to claim 10, characterised in that the first and the third detection signal and / or the first, the third, the fifth and the seventh detection signal are added to a first sum signal, wherein the second and the fourth and / or the second, the fourth, the sixth and the eighth detection signal are added to a second sum signal, wherein preferably a difference signal is formed from the first sum signal and the second sum signal, wherein the rotation rate is determined as a function of the difference signal, wherein further preferably a grid electrode is arranged.

Images