Method for the precise measurement operation of a micromechanical gyroscope

Abstract

Method for the precise measurement operation of a micromechanical angular rate sensor, comprising at least one deflectably suspended seismic mass (1, 15, 20), at least one drive device for driving the seismic mass (1, 15, 20) and at least one first (2, 11, 18) and one second (3, 12, 19) trim electrode element, which are directly or indirectly jointly assigned to the seismic mass (1, 15, 20), wherein a first electrical trim voltage (U) is applied between the first trim electrode element (2, 11, 18) and the seismic mass (1, 15, 20). TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) and a second electrical trim voltage (U) between the second trim electrode element (3, 12, 19) and the seismic mass (1, 15, 20) TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V) are set, whereby the first and second electrical trim voltages depend at least on a quadrature parameter (U). T ) and a resonance parameter (U f ) are set, characterized by the fact that the first (U TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) and the second (U TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V ) electrical trim voltage is set so that the sum of the square of the first electrical trim voltage (U) TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) multiplied by a first constant factor (α) and from the square of the second electrical trim voltage (U) TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V) multiplied by a second constant factor (β), is kept constant and / or is based on a first reference value of the resonance parameter (U) f ) is set to the square.

Description

[0001] The invention relates to a method for the precise measurement operation of a micromechanical yaw rate sensor according to the preamble of claim 1, a micromechanical yaw rate sensor according to the preamble of claim 11, and the use of the yaw rate sensor in motor vehicles.

[0002] It is known that micromechanical springs used to suspend seismic masses in angular rate sensors can, even due to relatively minor manufacturing inaccuracies—leading in particular to undesirable flank angles of the respective structures—cause deflections in the readout direction in drive mode, even without a angular rate being present. This generates interference signals which can be unintentionally interpreted as angular rate signal components, thus distorting the angular rate signal or causing a measurement error with respect to the angular rate signal.

[0003] Such undesirable flank angles or tilting of springs are process-related and can only be avoided to a limited extent. The interference signals described above, which do not arise from a detected rotation rate but from erroneous deflections in the readout direction as a function of the deflection of the seismic mass and its springs in the drive direction, are also referred to as quadrature or quadrature signals.

[0004] Document WO 03 / 010492 A1 proposes a method for suppressing quadrature signals in a gyroscope. This method comprises two trim electrode arrangements associated with a seismic mass, in which the quadrature of the gyroscope is suppressed by means of the voltage applied to the trim electrodes. However, this quadrature suppression can undesirably influence the resonance frequency of the gyroscope's readout mode, thereby also altering the difference frequency between the resonance frequencies of the drive mode and the readout mode of the gyroscope. This is particularly detrimental because the voltage applied to the trim electrodes contributes quadratically to the shift in the resonance frequency of the readout mode.

[0005] US 6,067,858 A and US 2008 / 0282833 A1 describe methods in which the first and second electrical trim voltages are set at least as a function of a quadrature parameter and a resonance parameter.

[0006] It is common for the quadrature of rotation rate sensors of a wafer to vary considerably due to process fluctuations, or to differ considerably from rotation rate sensor to rotation rate sensor of a wafer.

[0007] The object of the present invention is to propose a method in which an undesirable influence on the frequency / resonance frequency of the readout mode of the gyroscope can be avoided in the course of quadrature suppression and, in particular, a desired resonance frequency can be set with simultaneous quadrature suppression.

[0008] This problem is solved according to the invention by the method according to claims 1 and 2 and the micromechanical gyroscope according to claim 11.

[0009] The invention is based in particular on the idea of ​​setting, applying, or adjusting a first and a second trim voltage at a first and a second trim electrode of a gyroscope at least essentially as a function of a quadrature parameter and a resonance parameter.

[0010] The adjustment of the trim voltages is also appropriately understood as a control process.

[0011] The quadrature parameter is preferably understood as a measure of the quadrature of the yaw rate sensor or with respect to the deflection behavior of the at least one seismic mass. In particular, the quadrature parameter depends on the quadrature signal or quadrature signal component of the output signal of the yaw rate sensor, which is phase-shifted by essentially 90° or 270° relative to the component of the output signal representing the yaw rate. Furthermore, the quadrature signal is phase-shifted by 0° or 180° relative to the primary signal or the drive mode. The quadrature parameter is particularly preferably a manipulated variable in a control system used to control an actuator of the seismic mass in order to suppress or avoid the quadrature or quadrature signal of the seismic mass.The quadrature parameter is particularly preferably defined via the electrical voltage to be applied to the actuator as a control variable and has the same unit.

[0012] The resonance parameter is preferably understood as a measure of the frequency or natural frequency of the readout mode, or alternatively, preferably as a measure of the frequency difference between the frequency or natural frequency of the readout mode and the frequency of the drive mode. The resonance parameter is determined, in particular, as a function of, or dependent on, the resonance frequencies of the gyroscope with respect to its drive and readout modes. Most preferably, the gyroscope is operated such that the frequency difference between the resonance frequency of the readout mode and the resonance frequency of the drive mode has a substantially defined value, or is regulated to a defined value, or alternatively, preferably, is substantially zero, or is regulated to zero. The resonance parameter is most preferably defined by the electrical voltage applied to the actuator as a control variable and has the same unit.

[0013] It is advantageous for the resonance parameter to be a control parameter in order to adjust the readout frequency to a defined value or to a defined value in relation to the excitation frequency, in particular defined by a frequency difference.

[0014] The frequency of the readout mode is preferably understood to be the frequency of the readout or secondary mode, or the natural frequency of the readout or secondary oscillator, and the frequency of the excitation signal or excitation frequency is understood to be the frequency of the drive mode or primary mode, or the natural frequency of the drive / primary oscillator.

[0015] A drive mode or primary mode is understood to be a natural mode of a gyroscope, preferably its natural oscillation, and more preferably its oscillation with a resonant frequency, at least one seismic mass in which the seismic mass of the gyroscope, in particular, constantly oscillates. Most preferably, the gyroscope has at least two coupled seismic masses which oscillate out of phase or are deflected in the same direction with inverse orientation to each other during the drive mode.

[0016] A selection mode or secondary mode is understood to be a eigenmode which arises preferably due to a rotation rate and the associated effect of the Coriolis force.

[0017] The angular rate sensor preferably comprises a substrate which is connected to the system or inertial system whose angular rate is to be detected or measured. This connection is particularly rigid and / or stiff. It is especially preferred that the at least one seismic mass is suspended from the substrate and that the at least two trim electrode elements are rigidly connected to the substrate.

[0018] The gyroscope preferably comprises a substrate whose base is oriented substantially parallel to the xy-plane of a Cartesian coordinate system. In particular, the drive mode is defined in the x-direction and the readout mode in the y- or z-direction, or the drive mode is defined in the y-direction and the readout mode in the x- or z-direction. The gyroscope is expediently configured accordingly.

[0019] A substrate is understood to be a base and / or support body and / or housing part of the angular rate sensor, which is preferably a substantially unstructured part of the wafer from which the angular rate sensor is formed. The substrate particularly preferably consists of crystalline or polycrystalline, especially conductive, silicon or one or more layers of semiconductor material and / or metal(s) and / or electrically insulating layers.

[0020] The gyroscope advantageously includes at least one drive unit or drive means for driving the seismic mass and one or more readout devices for directly or indirectly detecting the deflection of the seismic mass.

[0021] It is preferred that the angular rate sensor is designed and arranged with respect to a Cartesian xyz coordinate system such that the drive direction is in the x-direction and it can detect angular rates about the z-axis and / or x-axis.

[0022] It is preferred that the gyroscope is designed in such a way that it can detect gyroscope rates about at least two different axes, i.e., that the gyroscope is designed to be “multi-axis”.

[0023] A seismic mass preferably comprises at least partially one or more drive devices and / or at least partially one or more readout devices and / or one or more additional micromechanical elements of the gyroscope.

[0024] The angular rate sensor is preferably manufactured using at least one micromechanical process. In this process, the structures are etched into a membrane material, particularly silicon, by anisotropic dry etching, preferably essentially perpendicular to the membrane. The plane of the membrane base extends essentially parallel to the substrate surface. Anchor points are formed at the locations where the membrane is rigidly bonded to the underlying substrate. These anchor points are then used to attach either spring elements or stationary structures. This allows for the implementation of freely oscillating rigid bodies suspended from springs. The anchor points are most preferably electrically insulated from one another by insulating layers and are accessible for external contact.

[0025] It is preferred that the first and second trim electrode elements, particularly with regard to their respective electrode surface, are essentially immobile and arranged in such a way as to be electrically insulated and spaced apart from the seismic mass.

[0026] The trim electrode elements are expediently insulated from each other and are particularly preferably designed identically.

[0027] The first and second trim electrode elements are preferably arranged above or below, or one above and one below, the seismic mass and / or in front of or behind, or one in front of and one behind, the seismic mass.

[0028] The gyroscope conveniently incorporates two seismic masses which are coupled together.

[0029] The at least one seismic mass is preferably assigned two additional trim electrode elements.

[0030] The first and second trim tensions are preferably adjusted additionally in a mutually dependent manner.

[0031] The first and second trim voltages are preferably set by means of a control system. This control system, or the control method, is performed during operation of the gyroscope, particularly at defined times, periodically, or continuously. The control system is especially preferably designed as a closed-loop control system.

[0032] The method is preferably extended by determining the quadrature parameter at defined times, periodically or continuously, depending on or from the quadrature signal, and by determining the resonance parameter at defined times, periodically or continuously, depending on or from the frequency of the readout mode or from the frequency difference between the readout mode and the drive mode.

[0033] The first and second trim voltages are set / adjusted so that the sum of the square of the first electrical trim voltage multiplied by a first constant factor and the sum of the square of the second electrical trim voltage multiplied by a second constant factor is kept constant and / or adjusted to a first reference value of the resonance parameter squared. In particular, the difference between the square of the first electrical trim voltage multiplied by a third constant factor and the square of the second electrical trim voltage multiplied by a fourth constant factor is also kept constant and / or adjusted to a first reference value of the quadrature parameter squared.It has been found that the above control / regulation of the first two trim electrode elements by means of the first two trim voltages is particularly suitable for quadrature suppression and simultaneous defined setting of a resonance parameter or the resonance frequency of the seismic mass with respect to the readout mode in the particularly preferred case that the trim electrode elements with their electrode surface jointly assigned to the seismic mass are arranged essentially parallel to the trim surface of the seismic mass in the undisplaced state and these electrode surfaces are essentially planar.

[0034] Alternatively, the first and second electrical trim voltages are set / adjusted so that the sum of the first electrical trim voltage multiplied by a first constant factor and the second electrical trim voltage multiplied by a second constant factor is kept constant and / or adjusted to a first reference value of the resonance parameter, in particular where the difference of the first electrical trim voltage multiplied by a third constant factor and the second electrical trim voltage multiplied by a fourth constant factor is kept constant and / or adjusted to a first reference value of the quadrature parameter.

[0035] The first electrical trim voltage U T01 as well as the second electrical trim voltage U T02 are preferably calculated essentially according to the following equations depending on the quadrature parameter UT and the resonance parameter U f adjusted and / or regulated: Uf2=α*UTO12+β*UTO22 and UT2=(γ*UTO12−δ*UTO22)*sgn(QS)*ε or U2TO1=(ß*U2T*sgn(QS)*ε+δ*U2f) / (α*δ+ß*γ) U2TO2=(γ*U2f−α*U2T*sgn(QS)*ε) / (α*δ+ß*γ) α, β, γ, and δ are the first, second, third, and fourth constant factors, respectively. The expression sgn(QS) symbolizes or represents the signum function of the quadrature signal QS. The parameter ε is a constant, specifically 1, whose sign depends on the following conditions: when an increase in the quadrature parameter U T If the square of the term leads to a reduction of the quadrature signal, then the constant is positive, or if the term Y * U is increased. T01 2 - δ*U TO2 2 If the quadrature signal QS becomes smaller, then ε = 1; when an increase in the quadrature parameter U T If the square of the term leads to an increase in the quadrature signal, then the constant is negative, or if the term δ*U is increased... TO2 2 - Y *U TO1 2 If the quadrature signal QS becomes smaller, then ε = -1.

[0036] According to the relationship shown in these equations, the resonance frequency of the readout mode is preferably set independently of the quadrature suppression, or the resonance parameter is set independently of the quadrature parameter.

[0037] It is advantageous that the first, second, third and fourth constant factors have a positive value, each of which depends at least on a first and a second trimming capacity, wherein the first trimming capacity depends at least on the respective design of the first trimming electrode element and the seismic mass as well as their arrangement and relative motion behavior to each other, and wherein the second trimming capacity depends at least on the respective design of the second trimming electrode element and the seismic mass as well as their arrangement and relative motion behavior to each other.

[0038] The method preferably comprises a control procedure by which the resonance parameter is specified as a function of time based on at least one additional parameter of the gyroscope and / or an additional parameter that influences the operation of the gyroscope, or is replaced by at least a second reference value of the resonance parameter. In particular, this additional parameter is a temperature prevailing in the gyroscope and / or in its immediate vicinity, since the resonance parameter is a temperature-dependent quantity.

[0039] It is preferred that, within the framework of the procedure, information regarding the operating behavior of the gyroscope as a function of temperature is available or provided in the form of at least one function and / or data.

[0040] It is preferred that at least the first trim electrode element is connected to a first electrical voltage source and that the second trim electrode element and / or the seismic mass is / are connected in particular to a second electrical voltage source.

[0041] It is advantageous for the first and second trim electrode elements to each have at least one electrode surface which is arranged substantially parallel to a trim surface of the seismic mass, and wherein the electrode surfaces of the first and second trim electrode elements are always assigned to an opposite region of the trim surface and / or overlap this region, particularly regardless of the displacement state of the seismic mass, at least up to a defined amplitude / displacement, and especially preferably also at maximum displacement of the seismic mass. Advantageously, the electrode surfaces always project beyond the opposite region of the trim surface. The electrode surfaces and the trim surface are most preferably substantially planar.

[0042] It is preferred that the gyroscope has four or a multiple of four trim electrode elements, of which two or a multiple of two each have an electrode surface parallel to the xy-plane and two or a multiple of two each have an electrode surface parallel to the xz-plane and / or yz-plane. These trim electrode elements are jointly assigned to two or more seismic masses. In particular, eight such trim electrode elements are assigned to each of two or more seismic masses of the gyroscope.

[0043] Advantageously, the gyroscope is designed as a 2-axis gyroscope or alternatively preferably as a 3-axis gyroscope, wherein as a 3-axis gyroscope it has at least two, in particular exactly two, trim electrode elements parallel to the xy, xz, and yz planes.

[0044] The gyroscope advantageously comprises at least two seismic masses which are coupled to each other via at least one coupling element, in particular a coupling spring and / or a coupling beam, and in particular are driven in opposite phase by means of at least one drive device or have an opposite-phase drive mode, whereby the common center of mass of these seismic masses remains essentially at rest.

[0045] The angular rate sensor is preferably made at least partially of silicon, in particular single-crystal silicon, wherein the at least one seismic mass and / or at least one suspension element of the seismic mass is / are particularly preferably made of conductive polycrystalline silicon or alternatively preferably of crystalline or single-crystal silicon.

[0046] The invention also relates to the use of the yaw rate sensor in motor vehicles, in particular in a motor vehicle control system.

[0047] The method and the gyroscope according to the invention can be used in various fields to detect one or more gyroscope rates and / or, by means of appropriate signal processing, to detect one or more gyroscope accelerations. Use in vehicles, particularly motor vehicles and aircraft, in automation technology, in navigation systems, in image stabilizers of cameras, in industrial robotics, and in game consoles is preferred, especially in the respective corresponding control systems. The use of the method and the gyroscope as a yaw rate and / or yaw acceleration sensor(s) in a motor vehicle control system, such as ESP, is particularly preferred.

[0048] Further preferred embodiments are described in the dependent claims and in the following descriptions of exemplary embodiments with reference to figures.

[0049] They show in schematic representation Fig. 1 to 3 Exemplary embodiments for suppressing unwanted deflections of the seismic mass perpendicular to the direction of drive and perpendicular to the plane of vibration, Fig. 4, Fig. 5 exemplary rotation rate sensors for suppressing unwanted deflections of the seismic mass perpendicular to the drive direction and within the plane of vibration, Fig. 6 an exemplary angular rate sensor with a cylindrical seismic mass suspended from a torsion spring, Fig. 7, Fig. 8 exemplary trim voltage settings on a gyroscope with a seismic mass, Fig. 9, Fig. 10 exemplary trim voltage settings on a gyroscope with two coupled seismic masses, and Fig. 11 to 13 exemplary diagrams to illustrate the control of the trim voltages.

[0050] The in the Fig. 1 to 10 exemplary embodiments of at least partially illustrated micromechanical angular rate sensors are each aligned with a Cartesian xyz coordinate system of an inertial system whose angular rate is to be detected. With respect to this coordinate system, the drive direction of the at least one seismic mass is in the x-direction, and the respective exemplary angular rate sensor is designed to detect angular rates at least about the z-axis and / or y-axis. Furthermore, these angular rate sensors have a manufacturing direction or structuring direction in the z-direction, with respect to which they are formed from a silicon wafer. In these exemplary embodiments, the trim electrode elements are each arranged immovably and are electrically insulated from each other and from the seismic mass. The trim electrode elements are each, by way of example, symmetrically or...Formed in pairwise symmetrical proportions to the associated seismic mass, which is why the first to fourth constant factor can each be assumed to be 1.

[0051] In Fig. Figures 1 a) and b) illustrate an exemplary angular rate sensor comprising a first and a second trim electrode element 2, 3, which are jointly assigned to seismic mass 1. Seismic mass 1 is driven in the x-direction and always exhibits two overlapping areas 4 and 5 of a trim surface 8 of the seismic mass parallel to the xy-plane, each of which is assigned to an electrode surface 6, 7 of a trim electrode element. This is also the case at maximum displacement d. max seismic mass 1 in the x-direction is the case, as shown in Fig. 1 b) is illustrated.

[0052] A first trimming capacitance C is determined by the trimming surface 8 of seismic mass 1 and the respective electrode surfaces 6, 7 of the first and second trimming electrode elements 2 and 3, wherein these surfaces 6, 7, 8 are formed parallel to the xy-plane. TO1 and a second trimming capacity C TO2 formed. The first and second trim voltage U T01 and U T02 are like in Fig. 2 shown attached to these capacities.

[0053] Fig. Figure 3 shows an embodiment of a gyroscope which has trim electrode elements 2, 3, 9, 10 in the z-direction above and below seismic mass 1, each of which is assigned in pairs to a trim surface 8a and 8b of seismic mass 1, parallel to the xy-plane and each of which has the trim capacitances C TO1 , C TO2 C TU1 , C TU2 form, to which the trimming voltages U TO1 , U TU2 as first trimming voltages and U TO2 , UTU1 as second trimming voltages.

[0054] The exemplary implementations, which are based on the Fig. Figures 1 to 3 are illustrated to suppress unwanted deflections of the seismic mass in the readout direction, perpendicular to the drive direction (x-direction) and perpendicular to the xy-plane.

[0055] In Fig. Figure 4 shows an exemplary angular rate sensor with four trim electrode elements 11, 12, 13, and 14, whose electrode surfaces are parallel to the xz-plane. The trim electrode elements 11, 12, 13, and 14, as well as the seismic mass 1, are designed and arranged such that the seismic mass 1, even at its maximum displacement in the xz-plane, always has a common overlap area with each of its associated electrode surfaces. The trim electrode elements 11, 12, 13, and 14 are each arranged a defined length in the y-direction of the seismic mass 1 relative to its undisplaced state and, together with the seismic mass 1, form four trim capacitances C. T1H , C T2H , C T1V and C T2V from which electrical trim voltages U T1H , U T2V as first trimming voltages and U T2H , U T1V as second trimming voltages.

[0056] Fig. Figure 5 shows an embodiment of the gyroscope. Fig. 4, in which trim electrode elements 11, 12, 13 and 14 are configured as comb structures, of which seismic mass 1 has corresponding counterparts, wherein trim electrode elements 11, 12, 13, 14 are each suspended on substrate S. The trim capacitances C are formed between these comb structures of the trim electrode elements and the comb structures of the seismic mass 1. T1H , C T2H , C T1V , C T2V from which the trimming voltages U T1H , U T2V as first trimming voltages and U T2H , U T1V as second trimming voltages.

[0057] The exemplary implementations, which are based on the Fig. 4 and Fig. Figure 5 illustrates that the devices are designed to suppress unwanted deflections of the seismic mass perpendicular to the driving direction (x-direction) and within the plane of vibration (xy-plane) which is spanned by the driving and readout modes.

[0058] In an embodiment of the gyroscope (not shown), a 2-axis gyroscope sensitive to gyroscope angular rates around two axes, it comprises eight trim electrode elements. Four of these elements have electrode surfaces parallel to the xy-plane, two above and two below the seismic mass, and four have electrode surfaces parallel to the xz-plane, two in front of and two behind the seismic mass. These trim electrode elements are all associated with a single seismic mass.

[0059] In Fig. Figure 6 illustrates an embodiment of a gyroscope sensor comprising a cylindrical seismic mass 20 suspended from a torsion spring 21 so as to be rotatably deflected about the z-axis. The torsion spring 21 also allows rotational deflections of the seismic mass 20 about the x-axis. In this embodiment, the drive mode oscillates about the z-axis, and the readout mode oscillates about the x-axis, with the opposite edges of the seismic mass 20 being deflected out of phase in the z-direction. Trim electrode elements 22, 23, 24, and 25 are suspended from the substrate S or the inertial frame, arranged below the seismic mass 20 in the z-direction, and associated with it, forming trim capacitances C. T1H , C T2H , C T1V , C T2V from which the trimming voltages U T1H , U T2V as first trimming voltages and U T2H , U T1Vas second trimming voltages.

[0060] In an embodiment not shown, four trim electrode elements are arranged according to the trim electrode elements made of Fig. 6 in the z-direction above the seismic mass. In a further, alternative embodiment not shown, eight trim electrode elements are jointly assigned to the seismic mass, four below and four above the seismic mass with respect to the z-direction.

[0061] The in Fig. The exemplary angular rate sensor 7 has only a first and a second trim electrode element 2, 3, which are jointly assigned to seismic mass 1 and thus have trim capacities C TO1 and C To2 develop, at which the first electrical trim voltage U TO1 and the second trim voltage U TO2These two trim voltages are each set as a function of at least one quadrature parameter and one resonance parameter within the framework of an exemplary procedure. Trim voltages U T01 and U TO2 are expressed as DC voltages, independent of any possible quadrature of trim capacitances C TO1 and C To2 For this purpose, trim electrode elements 2, 3 are each connected to an electrical voltage source, and seismic mass 1 is connected to the electrical ground. According to the equation Uf2=UTO12+UTO22 Trimming voltages U TO1 and U T02 depending on the resonance parameter U f This adjusts the resonant frequency of the yaw rate sensor. If the yaw rate sensor does not exhibit quadrature or a quadrature signal, the trim voltages U are adjusted. TO1 and U TO2 set to the same values. Therefore, the following applies: UTO1=UTO2 and Uf2=2 U2TO1

[0062] However, if the gyroscope exhibits quadrature or a quadrature signal, this is additionally eliminated by the trim voltages. Quadrature parameter U T is a measure of the electrical voltage required to eliminate the quadrature. It depends on the quadrature parameter U. T Trimming voltages U TO1 and U TO2 according to the equation UT2=UTO12−UTO22 adjusted, thereby eliminating the squaring.

[0063] In the case that the gyroscope has a maximum trimmable quadrature, the trim voltages are set at the limit according to the following relationships: UT2=UTO22 and UTO12=0

[0064] The maximum achievable trim voltage depends on the maximum available electrode area and the maximum expected quadrature signal. In the case of an inverse quadrature signal compared to the example, the trim voltages are applied in reverse order. According to equations (1) and (3), the trim voltages are set as follows. UTO12=(UT2+Uf2) / 2 and UTO22=(Uf2−UT2) / 2.

[0065] The in Fig. The embodiment shown in 8 is based on the one described in Fig. The embodiment shown in Figure 7 is, however, supplemented by two additional trim electrode elements 9 and 10, which are arranged in the z-direction below seismic mass 1. These provide additional trimming capacities C. TU1 and C TU2 with seismic mass 1. Trim capacity C is also present. TU1 Trim voltage U TU1 = U TO2 , i.e., the same trim voltage as at trim capacitance C TO2installed and connected to trim capacity C TU2 Trim voltage U TU2 = U TO1 , i.e., the same trim voltage as at trim capacitance C TO1 The trimming voltages U TO1 , U TO2 , U TU1 , and U TU2 are chosen as defined by equations (5) and (6), for example, and thus depending on the quadrature parameter U T and the resonance parameter U f to eliminate the squaring of the gyroscope while simultaneously setting a defined resonant frequency of the gyroscope's readout mode.

[0066] In Fig. 9 and Fig. Figure 10 shows an embodiment of a gyroscope sensor comprising two seismic masses 1 and 15 coupled to each other via a coupling element 16, for example, designed as a spring. Seismic masses 1 and 15 are driven in opposite phases and thus exhibit an opposite-phase drive mode, which keeps their common center of gravity at rest and causes the two seismic masses 1 and 15 to share a common resonant frequency with respect to both the drive mode and the readout mode. The suspension spring elements 17 of the seismic masses 1 and 15 are, for example, tilted in the same direction. The trim voltages at the respective trim capacitances C TLO1 , C TL02 , C TRO1 and C TR02 The first trim voltages at C are set identically in pairs between trim electrode elements 2, 3 and seismic mass 1, as well as between trim electrode elements 18, 19 and seismic mass 15. TLO1and C TR01 , U TLO1 , U TR01 as well as the second trim voltages at C TLO2 and C TR02 , U TLO2 , U TRO2 are set identically in pairs. This is based on the Fig. The illustrated embodiment 10 additionally features two trim electrode elements 31, 32, 33 and 34 each in the z-direction below the seismic masses 1 and 15. The first and second trim voltages are set as follows: First trim tension: UTLO1=UTRO1=UTLU2=UTRU2, second trim tension: UTLO2=UTRO2=UTLU1=UTRU1.

[0067] In Fig. 11 and Fig. Figure 12 shows two exemplary diagrams illustrating the control of the first and second trim voltages using the quadrature parameter U. T and the resonance parameter U f To illustrate: At the beginning, in function block A, the quadrature parameter U is "Start". Tand the resonance parameter U f defined. By means of the in Fig. 11 and Fig. In the 12 described regulations, only quadrature trimming / control is performed, and the resonance frequency / frequency of the readout mode remains essentially unaffected by the method. Fig. 11 indicates the resonance parameter U f a defined constant value on and in Fig. 12 changes U f as a function of temperature. The quadrature parameter U TThe initial value, which depends on the quadrature signal of the gyroscope, has a constant starting value, which can also be 0, for example. Subsequently, in function block B, the quadrature signal QS is measured. This signal is a component of the readout signal that is phase-shifted by 180° or 0° relative to the drive mode, or a component of the readout signal that is phase-shifted by 90° or 270° relative to the gyroscope signal component or the useful signal of the readout signal. The signal is then acquired accordingly. In function block C, an assessment is made as to whether the measured quadrature signal QS is greater than, less than, or equal to a threshold value, for example, 0. Depending on this assessment, the quadrature parameter U is then determined in function block D. TThe value is increased, decreased, or left unchanged, for example, by addition and / or multiplication with a function and / or a defined value. Subsequently, in function block E, the trimming voltages U are calculated according to the formulas shown, where sgn is defined as the signum function. T01 and U T02 each depending on the quadrature parameter U T and the resonance parameter U f The control functions are applied to the trim capacitances of the gyroscope. These control functions then serve as manipulated variables for the control system. Subsequently, function block B is executed again, and the following control loop begins.

[0068] In the schematic, exemplary process diagram from Fig. 13 start both parameters U f and U Twith a defined value in function block A. Subsequently, in function block B, the quadrature signal QS and the frequency difference Δf between the readout mode and the drive mode are measured. These values ​​QS and Δf are then compared with defined threshold values ​​in function block C, after which quadrature parameter U is determined in function block D. T and resonance parameter U f The parameters will be adjusted according to the respective comparison results a), b), c), d), e), f), as illustrated in function block D. This adjustment includes increasing, decreasing, or not affecting the parameters U. T and U f , where, for example, one or more additions / subtractions and / or multiplications are performed with one or more defined constants and / or functions. Following this, in function block E, the trimming voltages U are calculated according to the formulas shown, where sgn is defined as the signum function. T01 and UT02 each depending on the quadrature parameter U T and the resonance parameter U f Applied to the trimming capabilities of the gyroscope. This allows, depending on the adjustment of the parameter U, T and U f Both quadrature suppression and frequency adjustment or frequency shifting of the readout mode are performed simultaneously using the same trim electrode elements and trim voltages. Function block B is then executed again, and the subsequent control loop begins.

[0069] In the Fig. In the embodiments shown in 11 to 13, it is assumed or presupposed that an increase in the quadrature parameter U T that the squared result in a reduction of the quadrature signal QS and that the exemplary gyroscope is designed accordingly.

Claims

[1] Method for the precise measurement operation of a micromechanical angular rate sensor, comprising at least one deflectable seismic mass (1, 15, 20), at least one drive device for driving the seismic mass (1, 15, 20) and at least one first (2, 11, 18) and one second (3, 12, 19) trim electrode element, which are directly or indirectly jointly assigned to the seismic mass (1, 15, 20), wherein a first electrical trim voltage (U) is applied between the first trim electrode element (2, 11, 18) and the seismic mass (1, 15, 20). TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) and a second electrical trim voltage (U) between the second trim electrode element (3, 12, 19) and the seismic mass (1, 15, 20) TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V) are set, whereby the first and second electrical trim voltages depend at least on a quadrature parameter (U). T ) and a resonance parameter (U f ) will be set up, characterized by , that the first (U TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) and the second (U TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V ) electrical trim voltage is set so that the sum of the square of the first electrical trim voltage (U) TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) multiplied by a first constant factor (α) and from the square of the second electrical trim voltage (U) TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V) multiplied by a second constant factor (β), is kept constant and / or is based on a first reference value of the resonance parameter (U) f ) is set to the square. [2] Method for the precise measurement operation of a micromechanical angular rate sensor, comprising at least one deflectable seismic mass (1, 15, 20), at least one drive device for driving the seismic mass (1, 15, 20) and at least one first (2, 11, 18) and one second (3, 12, 19) trim electrode element, which are directly or indirectly jointly assigned to the seismic mass (1, 15, 20), wherein a first electrical trim voltage (U) is applied between the first trim electrode element (2, 11, 18) and the seismic mass (1, 15, 20). TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) and a second electrical trim voltage (U) between the second trim electrode element (3, 12, 19) and the seismic mass (1, 15, 20)TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V ) are set, whereby the first and second electrical trim voltages depend at least on a quadrature parameter (U). T ) and a resonance parameter (U f ) will be set up, characterized by , that the first (U TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) and the second (U TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V ) electrical trim voltage is set so that the sum of the first electrical trim voltage (U TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) multiplied by a first constant factor (α) and from the second electrical trim voltage (U TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V) multiplied by a second constant factor (β), is kept constant and / or is based on a first reference value of the resonance parameter (U) f ) is set and in particular that the difference from the first electrical trim voltage (U) is also added TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) multiplied by a third constant factor (γ) and the second electrical trim voltage (U) TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V ) multiplied by a fourth constant factor (δ), is kept constant and / or is based on a first reference value of the quadrature parameter (U). T ) is set up. [3] Method according to claim 1, characterized by , that the first (U TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) and the second (U TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , UT1V ) electrical trim voltage can also be adjusted in mutual dependence on each other. [4] Method according to claim 1 or 2, characterized by that the setting of the first and second trim voltage is carried out by means of a control system. [5] Method according to any one of the preceding claims, characterized by , that additionally the difference, from the square of the first electrical trim voltage (U) TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) multiplied by a third constant factor (γ) and from the square of the second electrical trim voltage (U) TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V ) multiplied by a fourth constant factor (δ), is kept constant and / or is based on a first reference value of the quadrature parameter (U). T ) is set to the square. [6] Method according to at least one of claims 1 to 5, characterized by , that the first (α), the second (β), the third (γ) and the fourth (δ) constant factor have a positive value, each of which depends at least on a first (C TO1 , C TLO1 , C TRO1 ) and a second trimming capacity (C TO2 , C TL02 , C TR02 ) where the first trim capacitance (C TO1 , C TLO1 , C TRO1 ) is at least dependent on the respective configuration of the first trim electrode element (2, 11, 18) and the seismic mass (1, 15, 20) as well as their arrangement and relative motion behavior to each other, and wherein the second trim capacitance (C TO2 , C TL02 , G TRO2 ) is at least dependent on the respective design of the second trim electrode element (3, 12, 19) and the seismic mass (1, 15, 20) as well as their arrangement and relative motion behavior to each other. [7] Method according to at least one of claims 1 to 6, characterized bythat this includes a control procedure by which the resonance parameter (U) f ) or the first reference value of the resonance parameter is specified as a function of time based on at least one additional parameter of the gyroscope and / or an additional parameter that influences the operation of the gyroscope, or is replaced by at least one second reference value of the resonance parameter. [8] Method according to claim 7, characterized by , that this additional parameter is the temperature prevailing in the gyroscope and / or in its immediate vicinity. [9] Method according to at least one of claims 1 to 8, characterized by , that at least the first trim electrode element (2, 11, 18) is connected to a first electrical voltage source and the second trim electrode element (3, 12, 19) and / or the seismic mass (1, 15, 20) is / are connected in particular to a second electrical voltage source. [10] Method according to at least one of claims 1 to 7, characterized by , that the first (2) and the second (3) trim electrode element each have at least one electrode surface (6, 7) which are arranged substantially parallel to a trim surface (8) of the seismic mass (1) and wherein the electrode surfaces of the first (6) and second (7) trim electrode element are always assigned to an opposite region (4, 5) of the trim surface of the seismic mass and / or overlap it, in particular regardless of the deflection state of the seismic mass (1), at least up to a defined amplitude / deflection. [11] Micromechanical angular rate sensor comprising at least one deflectable seismic mass (1, 15, 20), at least one drive device for driving the seismic mass, and at least one first (2, 11, 18) and one second (3, 12, 19) trim electrode element, which are directly or indirectly associated with the seismic mass (1, 15, 20), wherein in particular at least the first trim electrode element (2, 11, 18) is connected to a first electrical voltage source, and wherein a first electrical trim voltage (U) is applied between the first trim electrode element (2, 11, 18) and the seismic mass (1, 15, 20). TO1 , U TLO1 , U TRO1 , U TU2 , U T1H , U T2V ) and a second electrical trim voltage (U) between the second trim electrode element (3, 12, 19) and the seismic mass (1, 15, 20) TO2 , U TLO2 , U TRO2 , U TU1 , U T2H , U T1V ) is set up, characterized by , that the gyroscope is designed such that it is suitable for carrying out the method according to at least one of claims 1 to 10. [12] Use of the yaw rate sensor according to claim 11 in motor vehicles, in particular in a motor vehicle control system.

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