Rotational speed sensor having substrate and method for producing and / or operating rotational speed sensor

Abstract

The invention relates to a rotational speed sensor and to a method for producing and / or operating a rotational speed sensor, in which the substrate has a main extension plane having an X-direction and a Y-direction, the Y-direction extending perpendicular to the X-direction and likewise parallel to the main extension plane, the X-direction, the Y-direction and the Z-direction extend perpendicularly to the main extension plane, and wherein the rotational speed sensor is configured in such a way that an applied rotational speed about each of the directions can be detected in such a way that not only the X-direction, but also the Y-direction and the Z-direction are sensitive directions or axes.

Description

Field of the Invention

[0001] The present invention starts from a rotational speed sensor having a substrate and a dual rotor. Background Art

[0002] Rotational speed sensors of this type having a substrate and multiple sensitive directions or axes - especially microelectromechanical rotational speed sensors (MEMS) - are well known.

[0003] Such MEMS rotational speed sensors are subject to certain interferences on their output signals, especially due to external influences such as temperature variations, humidity, mechanical stress (such as the bending of a circuit board to which the sensor is soldered), aging effects, or linear and rotational accelerations or vibrations and mechanical shocks. These effects lead to changes in performance parameters, which are mainly the cross-axis sensitivity (CAS). The paths of action of these interferences within the micromechanical structure and the corresponding application-specific integrated circuit (i.e., ASIC) are partially known. However, the methods known to date are insufficient to study the path of action of the CAS and to measure the level of the CAS, especially the level of orthogonality of the measurement axes. In particular, in typical MEMS rotational speed sensors, axis-individual excitation is not used.

[0004] It is known for a mode separation, open-loop MEMS rotational speed sensor, and the MEMS rotational speed sensor generally has a so-called orthogonal electrode. Orthogonality is the axis for detecting the mode in a vibrating, amplitude-modulated rotational speed sensor that is separate and (undesired) motion offset by 90° relative to the motion generated by the Coriolis force. Mode separation means that the drive mode and the detection mode are at separate frequencies, for example with a spacing of 1 to 5 kHz. Open-loop refers to a system concept in which an adjustment loop is not used for the orientation adjustment of the micromachined device for detection. A known variant is that the micromachined device for detection is still operated without orientation adjustment (i.e., "open-loop"), but the orthogonal motion is reset via an adjustment circuit. By changing the voltage on such an orthogonal electrode - but for one axis or direction - usually all three detection modes of all three spatial measurement axes are simultaneously stimulated. For cost reasons and space reasons, in the rotation speed sensors known so far, no separate orthogonal electrodes are provided for each axis. In the known systems or methods, the voltage change on the orthogonal electrode is implemented as two different, constant levels. Recently, not only such two levels are considered, but systematic recognition of other parameters (such as the frequency split between the drive mode and the detection mode) can be achieved from the step dynamics. Instead of a single step (voltage value) on the orthogonal electrode (of only one direction or axis), excitation can also be performed by a tone or noise sequence in a certain frequency range and thus information about the system characteristics can be obtained. In addition, for a closed-loop, mode-matching MEMS rotational speed sensor, a method has been developed: how sensitivity and frequency split can be obtained via a pilot tone or the noise inherently present in the adjustment loop; however, these methods are not used to determine the coupling between the CAS or the axes.

[0005] In addition, according to the current state of the art, when manufacturing such a rotational speed sensor, it is mandatory to measure or determine the cross-axis sensitivity CAS in a complex manner (especially by applying or generating motion stimuli). Summary of the Invention

[0006] In this context, the following task is proposed: to provide a rotational speed sensor having a substrate and a method for manufacturing and / or for operating such a rotational speed sensor, which rotational speed sensor or method does not have the above-mentioned disadvantages.

[0007] One subject matter of the present invention is a rotational speed sensor having a substrate, wherein the substrate has a main extension plane having an X direction and a Y direction, the Y direction being perpendicular to the X direction and extending parallel to the main extension plane as well, wherein a Z direction extends perpendicular to the main extension plane, and wherein the rotational speed sensor is configured such that it is possible to detect an applied rotational speed about each of these directions in such a way that not only the X direction, but also the Y direction and the Z direction are sensitive directions or axes.

[0008] Wherein the rotational speed sensor has at least one vibrating mass, and wherein the rotational speed sensor is configured such that the at least one vibrating mass can be driven or is driven to perform a driving movement along a driving direction for detecting the rotational speed, and wherein the rotational speed sensor is furthermore configured such that by detecting the deflection of an element of the rotational speed sensor that can be deflected in a detection direction perpendicular to the driving direction, the action of the Coriolis force or a Coriolis force component on the driven at least one vibrating mass can be detected, and for this purpose, the rotational speed sensor has a first detection device for detecting the rotational speed about the X direction, a second detection device for detecting the rotational speed about the Y direction, and a third detection device for detecting the rotational speed about the Z direction, wherein the first detection device has at least a first and a second detection electrode (11, 12) and a first and a second orthogonal electrode (21, 22), the second detection device has at least a third and a fourth detection electrode (13, 14) and a third and a fourth orthogonal electrode (23, 24), and the third detection device has at least a fifth and a sixth detection electrode (15, 16) and a fifth and a sixth orthogonal electrode (25, 26), characterized in that in order to determine at least the cross-axis sensitivity, one or more pre-given and at least partially varying voltages or voltage profiles are applied to the orthogonal electrodes (21, 22, 23, 24, 25, 26) of the first, second, and / or third detection device, and at least the cross-axis sensitivity is determined or improved by means of the system response.

[0009] Compared with the prior art, the rotational speed sensor having a substrate according to the present invention has the following advantages: it is possible to separately stimulate each individual axis in an advantageous manner by means of the orthogonal electrodes. Advantageously, it is thereby possible to identify or determine the cross-axis sensitivity (CAS) (i.e., the cross-coupling of the measurement signal of one axis into another axis ) and in particular the orthogonality of the measurement axes in a significantly better manner than in the prior art.

[0010] In particular, according to the invention, it is advantageously possible, in the case of using orthogonally separate electrodes for the axes, to perform axis-separate excitation of the MEMS rotational speed sensor. This allows for the identification inside the sensor of signal over-coupling (i.e., components of the CAS) or orthogonality from one axis to another. By omitting the motion excitation, significant cost savings are achieved in the test facility and higher productivity is achieved in production. In addition, this method is suitable for verifying the sensor function. Thus, this method can be used as an additional component, for example, when starting the sensor, in safety-critical products (airbags, ESP).

[0011] In particular, according to the invention, it is advantageously possible to determine the sensitivity of the transverse axis by means of self-calibration, which can also be carried out without motion excitation, for example, during the production of the rotational speed sensor.

[0012] Advantageous configurations and refinements of the invention can be gathered from the dependent claims and the description with reference to the drawings.

[0013] According to an advantageous configuration of the invention, the rotational speed sensor comprises a dual rotor, which comprises a first rotor and a second rotor, wherein the first rotor and the second rotor, spaced apart along the X direction, are elastically connected to the substrate via respective suspensions and are furthermore elastically connected to each other via a coupling element such that the two rotors can be excited to perform anti-phase rotational vibrations. Thereby, a three-axis rotational speed sensor can be realized in a relatively simple manner.

[0014] Another subject matter of the invention is a method for manufacturing and / or for operating a rotational speed sensor having a substrate, wherein the substrate has a main extension plane having an X direction and a Y direction, the Y direction being perpendicular to the X direction and also extending parallel to the main extension plane, wherein a Z direction extends perpendicular to the main extension plane, and wherein the rotational speed sensor is configured such that it is possible to detect the applied rotational speed about each of these directions such that not only the X direction but also the Y direction and the Z direction are sensitive directions or axes.

[0015] Among them, the rotational speed sensor has at least one vibrating mass, and the rotational speed sensor is configured such that the at least one vibrating mass can be driven or driven to perform a driving motion along the driving direction for detecting the rotational speed. In addition, the rotational speed sensor is configured such that by detecting the deviation of the deflectable element of the rotational speed sensor in the detection direction perpendicular to the driving direction, the action of the Coriolis force or the Coriolis force component on the at least one driven vibrating mass can be detected. For this purpose, the rotational speed sensor has a first detection device for detecting the rotational speed around the X direction, a second detection device for detecting the rotational speed around the Y direction, and a third detection device for detecting the rotational speed around the Z direction. The first detection device has at least a first and a second detection electrode (11, 12) and a first and a second orthogonal electrode (21, 22), the second detection device has at least a third and a fourth detection electrode (13, 14) and a third and a fourth orthogonal electrode (23, 24), and the third detection device has at least a fifth and a sixth detection electrode (15, 16) and a fifth and a sixth orthogonal electrode (25, 26). It is characterized in that, in order to determine at least the transverse axis sensitivity, one or more pre-given and at least partially varying voltages or voltage variation curves are applied to the orthogonal electrodes (21, 22, 23, 24, 25, 26) of the first, second, and / or third detection devices, and at least the transverse axis sensitivity is determined or improved by means of the system response.

[0016] Compared with the prior art, the method for manufacturing and / or operating a rotational speed sensor according to the present invention is advantageous because separate stimulation of each individual axis can be achieved in an advantageous manner. Thereby, it is advantageously possible to determine or identify the transverse axis sensitivity in a significantly better manner than in the prior art. According to the present invention, this can be achieved by using orthogonally electrodes separately arranged for each axis. Thereby, it is advantageously possible to achieve axis-separate excitation of the MEMS rotational speed sensor by means of the orthogonal electrodes (by applying one or more pre-given and at least partially varying voltages or voltage variation curves to the orthogonal electrodes), and to allow identification inside the sensor of signal over-coupling from one axis to another axis. In addition, the method is suitable for verifying the sensor function.

[0017] The advantages and configurations described in the context of an embodiment of a rotational speed sensor according to the present invention having a substrate can be used for the method for operating a rotational speed sensor having a substrate and a dual rotor.

[0018] According to another advantageous configuration of the invention, the micromechanical structure is excited in a defined manner such that in particular the lateral axis sensitivity (or the multiple (matrix) components of the lateral sensitivity) can be inferred or the lateral axis sensitivity can be determined. For this purpose, in particular, it is provided that by means of the excitation coupled into the sensor structure via at least one of the sensitive axes (or sensitive directions) among the sensitive axes (or sensitive directions), the (one or more) lateral sensitivities can be well detected or measured. This is achieved in particular by the following way: a pre-given or multiple pre-given voltages or voltage change curves are applied to the first and second orthogonal electrodes (with reference to the first detection device with respect to the X direction as the sensitive direction or axis), where referring to the first and second orthogonal electrodes (and thus referring to the X direction) does not mean a limitation of generality, but rather it could also and according to the invention could also be done in the same way with reference to the third and fourth orthogonal electrodes (with reference to the Y direction) or alternatively with reference to the fifth and sixth orthogonal electrodes (with reference to the Z direction). Thus, it is applicable that for the case of observing the first and second orthogonal electrodes, a pre-given or multiple pre-given voltages or voltage change curves are applied to the first and second orthogonal electrodes such that

[0019] -- starting from the first voltage level on the first orthogonal electrode and the second voltage level on the second orthogonal electrode at the observed first time point -- in particular stepwise or with a pre-given time change curve --

[0020] -- at the observed second time point, a voltage difference is applied, another first voltage level is applied to the first orthogonal electrode, a voltage difference of the other second orthogonal electrode is applied to the second orthogonal electrode, and -- in particular before, during, or after the observed second time point -- the system response, in particular the system response on the other orthogonal electrodes and / or the Coriolis electrodes, is determined.

[0021] Thereby, according to the invention, it is advantageously possible to determine the system response of such an excitation under controlled conditions and in particular to do so in such a way that this can be carried out separately for each of the three sensitive directions or axes.

[0022] According to another advantageous configuration of the invention, differential excitation is carried out, in which case the other first voltage level is changed by a first voltage difference with respect to the first voltage level, while the second voltage level and the other second voltage level are not changed, or vice versa, in which case the other second voltage level is changed by a second voltage difference with respect to the second voltage level, while the first voltage level and the other first voltage level are not changed -- where in particular the first voltage level and the second voltage level are the same.

[0023] Thus, according to the present invention, it is advantageously possible to have various possibilities to couple different excitations or different types of excitations and their different temporal profiles into the micromechanical structure of the rotational speed sensor such that multiple parameters of the micromechanical structure can be determined.

[0024] In particular, according to the present invention, it is advantageously possible that

[0025] - the first and second orthogonal electrodes (21, 22) are loaded with a voltage profile (differential or common mode) such that a voltage step between two constant levels is thereby generated, and / or

[0026] - the first and second orthogonal electrodes (21, 22) are loaded with a voltage profile such that a common mode step between two constant levels on the first and second orthogonal electrodes (21, 22) is thereby generated, and / or

[0027] - instead of a single stepwise voltage change, multiple such voltage changes to different voltage levels and / or repeated steps and / or tones and / or tone sweep profiles and / or noise sequences, in particular pseudo-noise sequences, are carried out, especially at a frequency near the drive frequency.

[0028] According to a further advantageous configuration of the present invention, the method is used to perform a safety check, especially at the start of sensor operation or during sensor operation.

[0029] Embodiments of the present invention are shown in the drawings and are explained in more detail in the following description. Description of the Drawings

[0030] Figure 1 A rotational speed sensor according to the present invention with a substrate and a dual rotor is shown in a schematic diagram.

[0031] Figure 2 A flowchart for showing a method according to the present invention is shown in a schematic diagram, wherein in particular a possibility for self-calibrating the lateral axis sensitivity of the rotational speed sensor after measuring the lateral axis sensitivity by means of a motion stimulus during production is shown.

[0032] Figure 3 A flowchart for showing a method according to the present invention is shown in a schematic diagram, wherein in particular a possibility for self-calibrating the lateral axis sensitivity of the rotational speed sensor without measuring the lateral axis sensitivity based on a motion stimulus is shown.

[0033] Figure 4The mechanical transfer functions of the first axis (upper schematic) and the second axis (lower schematic) of the rotational speed sensor are shown in the schematic diagram (the right axis corresponds to the frequency; the vertical axis corresponds to the signal amplitude).

[0034] Figure 5 In the schematic diagram, a schematic illustration of the method according to the invention is shown exemplarily for excitation via the first and second orthogonal electrodes, i.e., via the first axis or the X direction. Detailed Description

[0035] In the different figures, the same components are always provided with the same reference numerals and are thus generally only named or mentioned once each.

[0036] In Figure 1 a rotational speed sensor according to the invention or a sensor assembly according to the invention is shown in a top view, i.e., in a manner having a projection direction perpendicular to the main extension plane of the substrate of the rotational speed sensor (in other words, the drawing plane corresponds to the main extension plane or a parallel plane of the substrate).

[0037] Exemplarily, the rotational speed sensor has a dual-rotor structure or dual rotors that can be excited to vibrate in antiphase; the dual rotors include a first rotor 1 and a second rotor 2. The first and second rotors 1, 2 - spaced apart along the X direction - are elastically connected to the substrate via respective suspension portions (centrally arranged for each of the rotors 1, 2 but not specifically denoted by reference numerals), and are furthermore elastically connected to each other via a coupling element such that the two rotors 1, 2 can be excited or driven to rotate in antiphase vibration (indicated by the two curved arrows in Figure 1 ). A driver (not shown in Figure 1 ) can cause these driving vibrations (rotational vibrations) of the rotors 1, 2 such that, in a manner known per se, based on the substantially linear (driving) motion of the (radially spaced-apart) sub-regions of the rotors 1, 2, and in the presence of a rotational speed or a rotational speed component about a rotational axis perpendicular to the direction of motion of these linear driving motions, a Coriolis force acts on the rotors 1, 2 or their sub-regions. In the case of an open-loop system concept, the Coriolis force causes the deviation of an element of the sensor structure that can be deflected (a part of the rotors 1, 2 themselves or a deflectable element coupled thereto), or at least causes a force action on such a deflectable element (the force action can also be determined or detected without deviation by causing an orientation adjustment of the deflectable element by means of an adjustment loop (closed loop) such that at most a minimum actual deviation is achieved).

[0038] In order to detect these deviations or the action of these forces, a detection device is provided for each sensitive axis, said detection device comprising at least two detection electrodes, said detection electrodes being arranged opposite the element to be deflected on both sides in the deflection direction of the element to be deflected respectively observed and thus serving as double differential detection electrodes (i.e., a first detection device (including a first and a second detection electrode) is provided for the first sensitive axis - for example, the X direction - a second detection device (including a third and a fourth detection electrode) is provided for the second sensitive axis - for example, the Y direction - and a third detection device (including a fifth and a sixth detection electrode) is provided for the third sensitive axis - for example, the Z direction). In Figure 1 only schematically - and for each of the rotors 1, 2 - (in terms of detecting the rotational speed component in the X direction) the first detection electrode 11 and the second detection electrode 12 are shown and (in terms of detecting the rotational speed component in the Y direction) the third detection electrode 13 and the second detection electrode 14 are shown. According to the invention, in addition to the detection electrodes, the corresponding detection devices (i.e., separately for each sensitive axis) also have orthogonal electrodes - in the form of axis-separate orthogonal electrodes, i.e., for the first sensitive axis (or X direction), the first detection device includes a first and a second orthogonal electrode; for the second sensitive axis (or Y direction), the second detection device includes a third and a fourth orthogonal electrode; and for the third sensitive axis (or Z direction), the third detection device includes a fifth and a sixth orthogonal electrode (however, for simplicity, the fifth and sixth orthogonal electrodes are not shown in Figure 1 . Also applicable to the orthogonal electrodes is that in Figure 1 only schematically - and for each of the rotors 1, 2 - the first orthogonal electrode 21 and the second detection electrode 22 (as part of the first detection device) and the third orthogonal electrode 23 and the fourth orthogonal electrode 24 are shown.

[0039] Hereinafter, the excitation of the sensor structure by means of the orthogonal electrodes is mainly shown by taking the excitation by the first and second orthogonal electrodes 21, 22 as an example, but it has been mentioned that this should be understood only exemplarily and any other pair of orthogonal electrodes in the existing pairs of orthogonal electrodes can also be used; the first detection electrode 11 is hereinafter also referred to as CN1, the second detection electrode 12 is also referred to as CP1, the first orthogonal electrode 21 is also referred to as QN1, the second orthogonal electrode 22 is also referred to as QP1, the third orthogonal electrode 23 is also referred to as QN2, and the fourth orthogonal electrode 24 is also referred to as QP2.

[0040] According to the invention, the excitation of the sensor structure by means of the orthogonal electrodes is achieved in the following manner:

[0041] Orthogonal electrodes for one direction - i.e., for example, QN1 and QP1 for the first direction or QN2 and QP2 for the second direction, or, more generally, QN and QP for any direction - are initially at the same potential during ongoing sensor operation and thus generate forces that cancel each other out. Figure 4 Exemplarily shown is the mechanical transfer function of axes 1 and 2 of a rotational speed sensor in the case of simultaneous excitation of all orthogonal channels. For excitation, a very fine frequency sweep is used differentially on the QN and QP electrodes. The detection mode (right dashed line in the upper schematic; left dashed line in the lower schematic) at the corresponding part of the resonance frequency couples into the respective other axis. This principle enables the recognition of mode coupling via the excitation of the orthogonal electrodes. In addition, the (orthogonal) coupling shown between the two axes has a correlation with the CAS.

[0042] (In the case of a rotational speed sensor according to the prior art) The disadvantage of simultaneously exciting all axes is the superposition of the system responses of the individual axes. The analysis in the case of coupled orthogonal electrodes is only possible for a very fine frequency sweep.

[0043] According to the present invention, there are separate orthogonal electrodes for each axis. If now a step voltage difference is applied between QP1 and QN1, the detection mode vibrates (especially at its resonance frequency) and then decays again. Alternatively, a step from an existing difference to a difference of 0 V can also be applied. Now, by overcoupling (electrically and / or mechanically), axes 2 and 3 are also excited (i.e., the (usually other) deflectable elements assigned to these axes or these sensitive directions are excited), or the output signal (orthogonal and / or rotational speed) is measured. The recognized overcoupling value can be used for adapting the CAS compensation of the sensor.

[0044] In addition, directly after a step on axis 1, i.e., on the electrodes QN1 and QP1 (but also on the second and / or third axes - i.e., in principle in the same way on other orthogonal electrodes), information about further system parameters can be obtained, for example, by means of suitable mathematical methods of system recognition. The further system parameters are, for example, phase characteristics, gain related to rotational speed output, quality, frequency, common coupling ability etc., and in particular also information about the change of the further system parameters relative to other measurements. This is schematically shown in Figure 5 and is discussed below and further below. Figure 5 .

[0045] Depending on the system model used as a basis, the values or changes can also be used to calculate the parameters of the mechanical device and the production changes. Examples of the mechanical device parameters include mass, stiffness, internal pressure, etc., and examples of the production changes include the edge loss and layer thickness of the structure being moved. The absolute values and / or changes allow for the adaptation of the CAS, sensitivity compensation, or offset compensation of the sensor, for example, in order to improve the characteristics regarding temperature, humidity, mechanical stress, or service life. In addition, instead of performing compensation afterwards, the operating state of the sensor can also be changed, for example, to become similar to the initial state.

[0046] According to the present invention, in particular, the following variants and embodiments are provided:

[0047] -- Apply a step to the orthogonal electrodes of axis 1 between two constant levels and evaluate the amplitude and phase in all axes. Here, in terms of the attenuation characteristics, in particular, the transition of the resonant frequency from axis 1, for example, to axis 2 is observed. See Figure 5 Through the orthogonal electrodes of each axis, the transition of the excitation from axis 1 to axis 2 can be seen significantly better because the resonant mode of axis 2 is not (or as little as possible) excited by the orthogonal electrodes of axis 1. Thus, it becomes possible to separate the unwanted common excitation from the transition between the axes to be identified;

[0048] -- Apply a step between two constant levels (see the previous indent) and perform system identification from the step response;

[0049] -- Apply a common-mode step to the Q electrodes between two constant levels (resulting in a change in common coupling), and evaluate the amplitude and phase or perform system identification from the step response;

[0050] -- Excite with a single tone at a determined frequency, evaluate the amplitude and phase in the tone, and then compare between the axes;

[0051] -- Excite with a tone sweep, evaluate the amplitude and phase in the tone, and then compare between the axes;

[0052] -- Excite with a noise or pseudo-noise sequence and then perform system identification (possibly with appropriate filtering);

[0053] -- Apply a step between two constant levels and analyze the attenuation characteristics, and then change the common-mode voltage, and repeatedly apply a step between two constant levels and analyze the attenuation characteristics. By comparing the subsequent attenuation characteristics, it is possible to identify possible changes in the common coupling ability (for example, due to a change in the gap);

[0054] --A step is applied between two constant levels and a common-mode step occurs in a short time interval during the decay. With this excitation form, the decay characteristics in different common coupling cases can be recognized;

[0055] --This method is particularly suitable for open-loop systems, but can also be used in a similar form for closed-loop orthogonal regulators, in such a way that, for example, a step is given to the guiding parameter. Then, the result parameter obtained with the described excitation form is associated with the process regarding CAS and other sensor parameters described in Figure 3 . This usually occurs in the rest position while the sensor is not in use. If the demodulation phase error is well adjusted, the proposed method can also be used to recognize signal drift and system parameters during normal sensor operation.

[0056] Figure 2 A flowchart for showing the method according to the invention is shown in the schematic; in particular, a possibility for self-calibrating the lateral axis sensitivity of a rotational speed sensor after measuring the lateral axis sensitivity with a motion stimulus during production is shown.

[0057] The method starts in the first method step 101.

[0058] During the production of the rotational speed sensor, the first block 110 of the method steps is carried out:

[0059] In the second method step 111, the measurement of the lateral axis sensitivity (CAS) is carried out with a motion stimulus, i.e., the defined motion of the rotational speed sensor to be produced - especially rotation - is carried out in a relatively complex way; here, the cross-axis sensitivity is measured and thus a compensation matrix is determined or created. In the third method step 112, the CAS compensation matrix is stored. In the fourth method step 113, other parameters are especially measured. In the fifth method step 114, the other parameters and the parameters derived therefrom are stored in the sensor. In the sixth method step 115, the second to fifth method steps 111 - 114 are repeated several times if necessary, especially with different motion stimuli, such as with different loads, such as temperature or the like. In the seventh method step 116, especially a sensor-specific calculation rule is created and stored in the sensor.

[0060] In the eighth method step 117, further production steps are carried out, in particular tape & reel, transportation and soldering into the final product and, if necessary, conditioning (Konditionierung). As a result or for this reason, in the ninth method step 118, a change in the CAS occurs, i.e., the CAS compensation (based on the previously created CAS compensation matrix) no longer fits as well at least.

[0061] After producing the rotational speed sensor, i.e., in the final product or in the rotational speed sensor itself, a further block 130 of method steps is carried out:

[0062] Self-calibration is carried out in the first sub-block 131:

[0063] In its first method step 132, excitation is carried out on one or more orthogonal electrodes, for example one or more orthogonal electrodes in the X direction - for example a voltage change as described above.

[0064] In the second method step 133, the over-coupling onto other axes (for example the second and third axes) is measured and qualitatively determined. In the third method step 134, further parameters (especially in all three axes) are identified from the resulting system response to the excitation of the first axis. In the fourth method step 135, the first, second and third method steps 132, 133, 134 are repeated by means of the excitation of the second or third axis.

[0065] In an (optional) fifth method step 136, further parameters are measured. In a (likewise optional) sixth method step 137, the sensor memory is read. In the seventh method step 138, calculation rules are executed. The self-calibration 131 is completed by means of the seventh method step 138, and the CAS compensation matrix is adapted in the eighth method step 139. In the ninth method step, this results in an improvement of the CAS or the CAS compensation matrix (compared to the CAS compensation matrix existing before the self-calibration).

[0066] Therefore, Figure 2 A possible process plan for the parameter CAS is described for the case of measuring and correcting the CAS on-site during production.

[0067] Figure 3 A flow chart for showing the method according to the invention is shown in the schematic diagram; in particular, a possibility for self-calibrating the lateral axis sensitivity of a rotational speed sensor without measuring the lateral axis sensitivity based on a motion stimulus is shown here.

[0068] The method starts in the first method step 201.

[0069] During the production of the rotational speed sensor, the first block 210 of method steps is carried out:

[0070] In the first sub-block 211, the cross-axis sensitivity (CAS) is identified without motion stimulation, i.e., self-calibration is carried out:

[0071] In its first method step 212, excitation is carried out on one or more orthogonal electrodes, for example on one or more orthogonal electrodes in the X direction - for example a voltage change as described above.

[0072] In the second method step 213, the over-coupling to other axes (for example the second and third axes) is measured and qualitatively determined. In the third method step 214, other parameters (especially among all three axes) are identified from the resulting system response to the excitation of the first axis. In the fourth method step 215, the first, second, and third method steps 212, 213, 214 are repeated by means of the excitation of the second or third axis.

[0073] In the fifth method step 216, the CAS compensation matrix is stored. In the sixth method step 217, other parameters are especially measured. In the seventh method step 218, the other parameters and the parameters derived therefrom are stored in the sensor. In the eighth method step 219, the second to seventh method steps 212 - 218 may be repeated several times if necessary, especially for different measurement points by means of, for example, different loads, such as temperature or the like. In the ninth method step 220, especially a separate calculation rule for the sensor is created and stored in the sensor.

[0074] In the tenth method step 221, further production steps are carried out, especially tape reel mounting, transportation, and welding into the final product and conditioning if necessary. As a result or therefore, in the eleventh method step 223, a change in CAS occurs, i.e., the CAS compensation (based on the previously created CAS compensation matrix) no longer fits as well at least.

[0075] After the production of the rotational speed sensor, i.e., in the final product or in the rotational speed sensor itself, another block 230 of method steps is carried out:

[0076] Self-calibration is carried out in the first sub-block 231:

[0077] In its first method step 232, excitation is carried out on one or more orthogonal electrodes, for example on one or more orthogonal electrodes in the X direction - for example a voltage change as described above.

[0078] In a second method step 233, the overcoupling to other axes, for example the second and third axes, is measured and qualitatively determined. In a third method step 234, further parameters (especially in all three axes) are identified from the resulting system response to the excitation of the first axis. In a fourth method step 235, the first, second and third method steps 232, 233, 234 are repeated with the excitation of the second or third axis.

[0079] In an (optional) fifth method step 236, further parameters are measured. In a (likewise optional) sixth method step 237, the sensor memory is read. In a seventh method step 238, the calculation rules are executed. With the aid of the seventh method step 238, the self-calibration 231 is completed and the CAS compensation matrix is adapted in an eighth method step 239. In a ninth method step, this results in an improvement of the CAS or the CAS compensation matrix (compared to the CAS compensation matrix existing before the self-calibration).

[0080] therefore, Figure 3 It is shown that with the aid of the method according to the invention, CAS can be identified in a cost-effective manner even in production without motion stimulation.

[0081] Figure 4 The diagram shows the mechanical transfer function of a first axis (upper diagram) and a second axis (lower diagram) of a rotational speed sensor (right axis corresponds to frequency; vertical axis corresponds to signal amplitude). The axes have a mode coupling (CAS) at the location of the corresponding resonant frequencies: for the schematically shown first axis (upper diagram), the resonant frequency corresponds to the right dashed line in the diagram, and for the schematically shown second axis (lower diagram), the resonant frequency corresponds to the left dashed line in the diagram. In particular, the excitation is carried out simultaneously at all orthogonal electrodes, i.e., QN and QP electrodes, by means of a very fine frequency sweep.

[0082] Figure 5 In the schematic diagram, a schematic diagram of the method according to the invention is shown by way of example for excitation via the first and second orthogonal electrodes 21 , 22 , ie via the orthogonal electrode of the first axis or the X direction:

[0083] In method step 132 or 212 or 232, an excitation is performed (see Figure 5The reference numeral 20) in the figure, the excitation is performed on the first and second orthogonal electrodes 21, 22 (see the "step function" schematically shown in the time-varying curve), but not on the other orthogonal electrodes 23, 24, 25, 26 (see the time-constant curve). Due to the coupling 27 existing in the micromechanical structure of the rotational speed sensor (especially the coupling 251 of the mechanical device based on the first axis (or X direction), the coupling 252 of the mechanical device based on the second axis (or Y direction), or the coupling 253 of the mechanical device based on the third axis (or Z direction)), different system responses are generated on and / or in the corresponding orthogonal electrodes and / or detection electrodes (see reference numeral 30) and different time-varying curves (and especially different amplitudes) of the system responses assigned to the corresponding axes or directions; for example, it is schematically shown that there is less coupling in the second axis than in the third axis. In method steps 133, 213 or 233, the system response is detected or analyzed.

[0084] According to the present invention, in particular, the following are performed in additional method steps:

[0085] -- performing, in particular based on a neural network (reference numeral 255), amplitude evaluation and phase evaluation and / or system identification; this particularly relates to (reference numeral 256) the CAS coupling coefficient, different frequencies, qualities, phases, common coupling capabilities, gains, mechanical device parameters or production parameters or the like;

[0086] -- in particular (see reference numeral 257), performing an algorithm for calculating a compensation rule or adapting the operating state;

[0087] -- In addition, according to the present invention (see reference numeral 258), trimming is performed or improvements are made to CAS, offset, sensitivity, noise, etc. due to environmental influences and / or aging.

[0088] The present invention is not limited to the above-described embodiments, but can be used in a variety of applications for object navigation, orientation, and stabilization based on inertial sensors. The computing unit in the sensor can be used to control the operation of the inertial sensor (e.g., power-saving mode, measurement range), check the credibility of the sensor signal and its tolerances (e.g., for internal sensor monitoring), perform signal processing (e.g., calculate position or orientation, filter data), and select communication protocols. Different, also self-learning KI-based algorithms can be used in the calculator unit for analyzing and processing and signal processing of inertial sensor data, temperature sensor data, and external data (e.g., GPS data, odometer data). It is also possible to consider applications for: two-wheeler applications, such as motorcycle applications, bicycle applications, scooter applications (e.g., ESP / airbag, tilt recognition, balance); three-wheeler applications (e.g., TucTuc); aviation applications (e.g., flight stabilization and flight control); industrial robot applications (e.g., control of the position of an excavator bucket, drilling, image stabilization, flight control, orientation of a satellite antenna, fine motor device of a grasping robot); household and gardening applications (e.g., navigation of a lawn mower, monitoring the position of a door,...); medical applications (e.g., fall recognition, motion recognition and posture recognition,...); sports activities and leisure activities (e.g., motion recognition and posture recognition in a golf club, tennis racket, snowboard); numerous CE applications (e.g., in smartphones, tablets, wearable devices, ear-wearable devices, drones, toys). In addition, in the context of smartphones and tablets, the present invention can be used for the following applications: screen orientation, significant motion, appliance orientation, activity recognition, gesture recognition and context recognition, image stabilization, SLAM (simultaneous localization and mapping) in an interior space, recognition of impacts and free falls, motion control. In the context of wearable devices, ear-wearable devices, AR, and VR, the present invention can be used for the following applications: display information; step counting; activity recognition, gesture recognition and context recognition; calorie counting; ear-in recognition; sleep monitoring; elderly care; indoor navigation; position tracking; low-power sensing, real-time motion recognition, head motion tracking; precise sensor data fusion. In the context of drones, games, and toys, the present invention can be used for the following applications: orientation; Gimbal; altitude stabilization; flight control; motion tracking, motion control, balance; activity recognition and gesture recognition. In the context of robots, the present invention can be used for the following applications: navigation; boundary recognition; dynamic path planning; SLAM in an interior space; monitoring of air quality; recognition of blockages. In the context of smart homes, the present invention can be used for the following applications: burglary control, air quality monitoring, mold recognition, climate control, floor water bottle recognition, navigation in an interior space.In an industrial context, the present invention can also be used in the following applications: water level identification; asset tracking; navigation and control; motion tracking and position tracking; energy management; predictive maintenance. In addition, numerous modifications, variations, designs, arrangements and embodiments are possible, all of which fall within the scope of application of the present invention.

Claims

1. A rotational speed sensor, the rotational speed sensor having a substrate, wherein, The substrate has a main extension plane having an X direction and a Y direction, the Y direction being perpendicular to the X direction and also extending parallel to the main extension plane, wherein a Z direction extends perpendicular to the main extension plane, wherein the rotational speed sensor is configured such that the applied rotational speed about each of the directions can be detected such that not only the X direction but also the Y direction and the Z direction are sensitive directions or axes. Wherein the rotational speed sensor has at least one vibrating mass, wherein the rotational speed sensor is configured such that the at least one vibrating mass can be driven or is driven to perform a driving movement along a driving direction for detecting the rotational speed, wherein the rotational speed sensor is furthermore configured such that by detecting the deviation of an element of the rotational speed sensor that can be deflected in a detection direction perpendicular to the driving direction, the action of the Coriolis force or a Coriolis force component on the at least one driven vibrating mass can be detected, wherein, for this purpose, the rotational speed sensor has a first detection device for detecting the rotational speed about the X direction, a second detection device for detecting the rotational speed about the Y direction, and a third detection device for detecting the rotational speed about the Z direction, wherein the first detection device has at least first and second detection electrodes (11, 12) and first and second orthogonal electrodes (21, 22), the second detection device has at least third and fourth detection electrodes (13, 14) and third and fourth orthogonal electrodes (23, 24), and the third detection device has at least fifth and sixth detection electrodes (15, 16) and fifth and sixth orthogonal electrodes (25, 26), characterized in that, in order to determine at least the lateral axis sensitivity, one or more pre-given and at least partially varying voltages or voltage variation curves are applied to the orthogonal electrodes (21, 22, 23, 24, 25, 26) of the first, second, and / or third detection devices, and at least the lateral axis sensitivity is determined or improved by means of the system response.

2. The rotational speed sensor according to claim 1, wherein The rotational speed sensor includes a dual rotor, the dual rotor including a first rotor (1) and a second rotor (2), wherein the first and second rotors (1, 2) - spaced apart along the X direction - are elastically connected to the substrate via respective suspension portions and are furthermore elastically connected to each other via a coupling element such that the two rotors (1, 2) can be excited to perform anti-phase rotational vibrations.

3. A method for manufacturing and / or for operating a rotational speed sensor, the rotational speed sensor having a substrate, wherein, The substrate has a main extension plane having an X direction and a Y direction, the Y direction being perpendicular to the X direction and also extending parallel to the main extension plane, wherein a Z direction extends perpendicular to the main extension plane, wherein the rotational speed sensor is configured such that the applied rotational speed about each of the directions can be detected such that not only the X direction but also the Y direction and the Z direction are sensitive directions or axes. The rotational speed sensor has at least one vibrating mass, and the rotational speed sensor is configured such that the at least one vibrating mass can be driven or is driven to perform a driving movement along the driving direction for detecting the rotational speed. In addition, the rotational speed sensor is configured such that by detecting the deviation of the deflectable element of the rotational speed sensor in the detection direction perpendicular to the driving direction, the action of the Coriolis force or the Coriolis force component on the at least one driven vibrating mass can be detected. For this purpose, the rotational speed sensor has a first detection device for detecting the rotational speed around the X direction, a second detection device for detecting the rotational speed around the Y direction, and a third detection device for detecting the rotational speed around the Z direction. The first detection device has at least a first and a second detection electrode (11, 12) and a first and a second orthogonal electrode (21, 22), the second detection device has at least a third and a fourth detection electrode (13, 14) and a third and a fourth orthogonal electrode (23, 24), and the third detection device has at least a fifth and a sixth detection electrode (15, 16) and a fifth and a sixth orthogonal electrode (25, 26). It is characterized in that in order to determine at least the transverse axis sensitivity, one or more pre-given and at least partially variable voltages or voltage change curves are applied to the orthogonal electrodes (21, 22, 23, 24, 25, 26) of the first, second, and / or third detection devices, and at least the transverse axis sensitivity is determined or improved by means of the system response.

4. The method according to claim 3, wherein One pre-given or a plurality of pre-given voltages or voltage change curves are applied to the first and second orthogonal electrodes (21, 22) such that -- starting from the first voltage level on the first orthogonal electrode and the second voltage level on the second orthogonal electrode at the observed first time point -- in particular stepwise or with a pre-given time change curve --, -- at the observed second time point, a voltage difference is applied, another first voltage level is applied to the first orthogonal electrode, another second orthogonal electrode is applied to the second orthogonal electrode, and -- in particular before, during, or after the observed second time point -- the system response is obtained, in particular the system response on the other orthogonal electrodes (23, 24, 25, 26) and / or the detection electrodes (13, 14, 15, 16).

5. The method according to claim 3 or 4, characterized in that Differential excitation is performed. In the case of the differential excitation, the other first voltage level is changed by a first voltage difference relative to the first voltage level, while the second voltage level and the other second voltage level are not changed, or vice versa. In the case of the differential excitation, the other second voltage level is changed by a second voltage difference relative to the second voltage level, while the first voltage level and the other first voltage level are not changed -- where in particular the first voltage level and the second voltage level are the same.

6. The method according to any one of claims 3 to 5, characterized in that - a voltage change curve is applied to the first and second orthogonal electrodes (21, 22) such that a voltage step between two constant levels is thereby generated, and / or - a voltage change curve is applied to the first and second orthogonal electrodes (21, 22) such that a common-mode step between two constant levels is thereby generated on the first and second orthogonal electrodes (21, 22), and / or - instead of a single stepwise voltage change, a plurality of such voltage changes to different voltage levels and / or repeated steps and / or tones and / or tone sweep change curves and / or noise sequences, in particular pseudo-noise sequences, are carried out, especially at a frequency near the drive frequency.

7. The method according to any one of claims 3 to 6, characterized in that The method is carried out during the ongoing operation of the rotational speed sensor or in parallel with the ongoing operation of the rotational speed sensor.

8. The method according to any one of claims 3 to 7, characterized in that The method is used to perform a safety check, especially at the start or during the sensor operation.

Images