MEMS gyroscope with real-time calibration scale factor and calibration method thereof

Abstract

The present disclosure relates to a MEMS gyroscope with a real-time calibration scale factor and a calibration method thereof. The MEMS gyroscope has a moving mass supported by a support structure to move in a driving direction and a first sensing direction perpendicular to each other. The driving structure controls the movement of the moving mass in the driving direction at a driving frequency. A moving sensing structure is coupled to the moving mass and detects the movement of the moving mass in the sensing direction. An orthogonal injection structure is coupled to the moving mass and causes the moving mass to perform a first movement and a second movement in the sensing direction in a first and a second calibration half-cycle, respectively. The moving sensing structure supplies a sensing signal having an amplitude switching between a first value and a second value, the first value and the second value depending on the movement of the moving mass due to an external angular velocity and the first and second orthogonal movements. The first value and the second value of the sensing signal are subtracted from each other and compared with a stored difference value to provide information on a change in the scale factor.

Description

Technical Field

[0001] The present disclosure relates to a MEMS gyroscope with a real-time calibration scale factor and a calibration method thereof. Background Art

[0002] As is well known, microelectromechanical systems (MEMS) are being used in an increasingly wide range of applications due to their small size, cost compatibility with consumer applications, and increasing reliability. In particular, inertial sensors such as micro-integrated gyroscopes and electromechanical oscillators are manufactured using this technology.

[0003] This type of MEMS sensor generally includes a support body and at least one mobile mass that is suspended from and coupled to the support body via springs or "flexures." The flexures are configured to allow the mobile mass to oscillate relative to the support body according to one or more degrees of freedom. The mobile mass is generally capacitively coupled to the support body and forms a capacitor with a variable capacitance with the support body. In particular, due to the action of forces acting on the mobile mass, the movement of the mobile mass relative to a fixed electrode on the support body modifies the capacitance of the capacitor. The displacement of the mobile mass relative to the support body is detected based on the capacitance change, and the external force causing the displacement is calculated based on the detected displacement.

[0004] Among MEMS sensors, gyroscopes have a complex electromechanical structure that typically includes at least two masses that move relative to a supporting body and are coupled to each other to have several degrees of freedom, depending on the system architecture. In most cases, each moving mass has one or at most two degrees of freedom, but MEMS gyroscopes with a single moving mass having three degrees of freedom are becoming increasingly popular. In all cases, capacitive coupling is achieved via a fixed drive electrode or actuation electrode and a mobile drive electrode or actuation electrode, and via a fixed sense electrode and a mobile sense electrode.

[0005] In an implementation with two moving masses, the first moving mass is dedicated to driving and is kept oscillating in or about a first direction at a resonant frequency and with a controlled oscillation amplitude. The second moving mass is driven by the first moving mass and, when the gyroscope rotates about its axis perpendicular to the first direction and at an angular velocity, is subjected to a Coriolis force proportional to the angular velocity and perpendicular to the driving direction and the axis of rotation.

[0006] In an implementation with a single moving mass, the mass is coupled to a support body using two independent degrees of freedom (i.e., a degree of freedom for driving and a degree of freedom for sensing) to move relative to the support body. The support body can include movement of the moving mass in the plane of the support body (in-plane movement) or in a direction perpendicular to the support body (out-of-plane movement). A drive device maintains the moving mass in controlled oscillation according to one of the two degrees of freedom. Due to the Coriolis force, the moving mass moves according to the other degree of freedom in response to rotation of the support body.

[0007] exist Figure 1 A basic diagram of a single proof-mass gyroscope is shown in FIG, which broadly represents the mechanical sensing structure of the gyroscope 1. Here, the gyroscope 1 comprises a mobile proof-mass 2 supported by a support structure 3 (shown schematically) via a first flexure system 4 and a second flexure system 5, and the first and second flexure systems 4, 5 (also shown only schematically) are each composed of a respective elastic element 4.1, 5.1 (with a respective elastic constant k x and k y ) and corresponding damping elements 4.2 and 5.2 (with corresponding elastic constants r x and r y )express.

[0008] exist Figure 1 , the first flexure system 4 enables the mobile mass 2 to move in a first direction, which is parallel to the first axis of the Cartesian reference system (here axis X) and is therefore called the driving direction X; and the second flexure system 5 enables the mobile mass 2 to move in a second direction, which is parallel to the second axis of the Cartesian reference system (here axis Y) and is therefore called the sensing direction Y.

[0009] exist Figure 1 In the embodiment of the present invention, a drive electrode (not shown) causes the mass 2 to oscillate in the drive direction X. In the presence of a rotational movement Ω of the gyroscope 1 about an axis parallel to the axis Z (which therefore forms the rotational direction Z), the Coriolis force, in a known manner, causes an oscillatory movement of the mobile mass 2 in the sensing direction Y. This movement brings about a change in the distance or gap between the mobile mass 2 (or the mobile electrode fixed thereto in the movement direction Y) and the fixed electrode 7, and can be detected based on the resulting capacitive change ΔC.

[0010] As mentioned, real MEMS gyroscopes have a complex structure and often have non-ideal electromechanical interactions between the moving mass and the supporting body due to, for example, manufacturing defects, process expansion, environmental conditions and aging that modify the gyroscope's scale factor (i.e., the ratio between the gyroscope's output signal (change in capacitance ΔC) and the angular velocity to be detected Ω).

[0011] In fact, the above conditions can cause interference acting in the sensing direction Y, thereby increasing or decreasing the elongation of the mobile mass 2 in the sensing direction Y caused by the Coriolis force and / or changing the distance between the mobile mass 2 and the fixed electrode 7, and thus causing different capacitance changes between the mobile mass and the fixed electrode, thereby causing a change in the proportional factor.

[0012] The above facts can also be based on Figure 1 The definition of the scale factor s for a gyroscope of the type illustrated in is shown mathematically.

[0013] In detail, we have:

[0014]

[0015] where y is the sensed displacement, ε0 is the dielectric constant of vacuum, A is the facing area between the fixed electrode 7 and the moving mass 2, is the amplitude of the external disturbance, is the gap based on external disturbance, is the gyroscope's transfer function, (i.e., the unit displacement due to an external disturbance), and F C is the Coriolis force due to the angular velocity Ω.

[0016] According to equation (1), it is confirmed that the proportionality factor depends on the external disturbance to a non-negligible extent.

[0017] On the other hand, since the scale factor has a direct impact on detection reliability, the stability of the scale factor over the entire service life is an important parameter for the gyroscope.

[0018] Solutions that attempt to compensate for known disturbances through fine-tuning techniques are known. For example, when the proportionality factor changes due to variations in the external temperature (which, for example, results in a change in the stiffness of the elastic suspension structure), the external temperature can be measured and the measurement corrected to eliminate the error using a known and / or measured performance model during final testing. However, when the disturbance cannot be measured (for example, because it is caused by the handling of soldering on the mounting plate), and especially when the disturbance is temporally variable (for example, as in the case of modifications of elastic parameters due to aging or other degradation phenomena of the material), the problem is more difficult to solve.

[0019] Therefore, it is desirable that the gyroscope be resilient to external disturbances, especially temporally variable disturbances, such as disturbances caused by changes in temperature, stress, humidity etc., which in turn lead to changes in electrical and / or mechanical parameters in the gyroscope.

[0020] To this end, other known solutions consist in interrupting the operation of the gyroscope in order to measure the scale factor changes that have occurred during its service life. However, this solution is disadvantageous since the gyroscope is not operational during these periods, a fact that may be unacceptable in certain applications. Summary of the Invention

[0021] It is therefore an object of the present disclosure to provide a gyroscope that overcomes one or more of the shortcomings of the prior art.

[0022] According to the present disclosure, a MEMS gyroscope, an electronic processing unit, a gyroscope system and a calibration method thereof are provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] For a better understanding of the present disclosure, embodiments of the present disclosure will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

[0024] Figure 1 shows a schematic diagram of a known MEMS gyroscope;

[0025] Figure 2A and Figure 2B Shown respectively Figure 1 The movement of the gyroscope in the absence of normal forces and in the presence of normal forces and without angular velocity;

[0026] Figure 3 shows the basic diagram of the present gyroscope;

[0027] Figure 4A and Figure 4B Shown Figure 3 Movement of the gyroscope in the first operating step and in the second operating step, respectively, in the absence of an angular velocity;

[0028] Figure 5A and Figure 5B Shown Figure 3 A graph showing the charge in the gyroscope;

[0029] Figure 6 A flow chart of the present calibration method is shown;

[0030] Figure 7 Shown Figure 3 The principle electrical diagram of the gyroscope control circuit;

[0031] Figure 8 Shown Figure 3 Possible embodiments of a gyroscope;

[0032] Figure 8A Shown Figure 8 Zoomed-in detail of the gyroscope; and

[0033] Figure 9A and Figure 9B Shown Figure 8 Zoomed-in detail of the gyroscope. DETAILED DESCRIPTION

[0034] The present gyroscope comprises an “in-flight” measurement circuit, that is, one that operates during normal operation of the gyroscope based on the application of an orthogonal stress of known value at a preset instant (which therefore acts perpendicularly to the driving stress and parallel to the sensing direction), and based on the measurement and comparison of the signal thus obtained with the signal measured in the absence of the orthogonal stress.

[0035] As reference Figure 1 The gyroscope 1 in Figure 2A and Figure 2B As shown in the figure, due to the undesirable influence of manufacturing defects, quadrature signals often exist in gyroscopes and cause forces acting perpendicular to the driving direction (called normal forces). In particular, Figure 2A The driven movement of the mobile mass 2 in the driving direction X is shown (exaggerated for clarity). As indicated by the dashed position of the mobile mass 2 and the arrow 10, in the absence of angular velocity and normal forces, the mobile mass 2 moves only in an oscillatory and translational motion in the driving direction X. Figure 2B As represented by the dashed lines in FIG, possible normal forces acting perpendicularly to the drive direction X (even in the absence of angular velocity) bring about a movement of the mobile mass 2 in the sensing direction Y. Thus, in the presence of an angular velocity about the second Cartesian axis Y, the orthogonal movement due to one or more normal forces is added to the movement due to the Coriolis force. As used herein, "orthogonal movement" refers to movement of the mobile mass in a direction perpendicular to the drive direction.

[0036] In this case, the capacitance change between the mobile mass 2 and the fixed sensing electrode 7 is determined by two contributions: one due to the Coriolis force (ΔC, see equation (1)), and another due to the normal force (ΔC Γ ), can be expressed as follows:

[0037]

[0038] The parameters common to equation (1) have the same meanings as mentioned above, y Γ is the displacement due to the normal force, and FΓ is the normal force.

[0039] Based on equation (2), it can be seen that the signal generated by the orthogonal force is subject to the same transfer function of the useful signal It is also referred to below as the Coriolis signal (see equation (1) above).

[0040] This behavior (which is usually undesirable because it is difficult to distinguish the contribution of the desired angular velocity Ω from the contribution of disturbances) is exploited in the present gyroscope to track changes or drifts in the transfer function due to disturbances, and thus to track changes in the gyroscope's scale factor.

[0041] Figure 3 A gyroscope 30 is shown which utilizes the principles set out above.

[0042] In detail, the gyroscope 30 has a well-known structure and is represented in a greatly simplified manner, omitting the elastic support system, the biasing structure of the mobile mass, and the drive structure (fixed drive electrodes operating according to the drive principle and corresponding electrical connections). In addition, the gyroscope 30 is described with reference to the three Cartesian axes XYZ.

[0043] exist Figure 3 The gyroscope 30 illustrated in FIG. 1 comprises a mobile mass 31 which is schematically represented as having a rectangular shape, but the mobile mass 31 may also be made according to any known geometric shape of a triangular type, a trapezoidal type or a circular type. Figure 3 In the schematic representation shown in FIG, the mobile mass block 31 (such as Figure 1 The mobile mass 2 is driven in a direction parallel to the first Cartesian axis X (driving direction X), and the gyroscope 30 is configured to rotate about the third Cartesian axis Z in the presence of an angular velocity Ω to be detected, and to detect along the second Cartesian axis Y (sensing direction Y). However, it will be apparent to those skilled in the art that the discussion below also applies to driving and sensing along different axes.

[0044] Here, the mobile mass 31 faces the sensing electrode 32 (and is capacitively coupled to the sensing electrode 32) and a pair of orthogonal injection electrodes (a first orthogonal injection electrode 33A and a second orthogonal injection electrode 33B) via its own facing surface 31A. However, this arrangement is not essential, and the mobile mass 31 can have different surfaces facing the sensing electrode 32 and the orthogonal injection electrodes 33A, 33B, as long as they are configured and arranged so as to be able to detect capacitive changes in the sensing direction Y. In particular, the sensing electrode 32 supplies a sensing signal S to its own sensing terminal 35 (which can be accessed from the outside); the orthogonal injection electrodes 33A, 33B are respectively connected to a first calibration terminal 36A and a second calibration terminal 36B, which receive, for example, Figure 5A The orthogonal injection signals V1 and V2 are shown in the figure.

[0045] Typically, the sensing electrode 32 has a much larger area than the orthogonal injection electrodes 33A, 33B, for example ten times larger.

[0046] exist Figure 3 In FIG, the sensing electrode 32 is arranged in front of the central portion of the mobile mass 31, and therefore, the facing area between the sensing electrode 32 and the facing surface 31A remains unchanged during the movement of the mobile mass 31 in both the driving direction X and the sensing direction Y. In contrast, the first and second orthogonal injection electrodes 33A and 33B are arranged here only partially facing the facing surface 31A of the mobile mass 31; in particular, here, the first and second orthogonal injection electrodes 33A and 33B are arranged on opposite circumferential sides of the facing surface 31A of the mobile mass 31 and protrude laterally to the right and left, respectively, from the facing surface 31A. In this manner, as discussed below, during the driven movement of the moving mass 31, the first orthogonal injection electrode 33A and the second orthogonal injection electrode 33B have a variable surface area facing the moving mass 31; that is, due to the driven movement in the driving direction X, the useful facing surface between each orthogonal injection electrode 33A, 33B and the moving mass 31 (that is, for detecting capacitance changes) has a variable area.

[0047] In the embodiment discussed, the quadrature injection signals V1, V2 are AC voltages, where the quadrature injection frequency f C The frequency f0 of the driving signal is different and the waveform is opposite (see Figure 5A ). In particular, the orthogonal injection frequency f C Lower than the driving frequency f0. For example, the driving frequency f0 can be 20kHz, and the orthogonal injection frequency f C It can be 1kHz. In addition, the first orthogonal injection electrode V1 and the second orthogonal injection electrode V2 are Figure 5A and 5BDuring the first half-cycle, the voltage step ΔV0 switches between a first value V0 (identical for both) specified by T1 and a second value (different for V1 and V2) specified by T2. For the first orthogonal injection signal V1, the second value is V0+ΔV0, while for the second orthogonal injection signal V2, the second value is V0-ΔV0, where V0 is typically lower than (e.g., half) the bias voltage of the moving mass 31, and the voltage step ΔV0 is a fraction of the first value, e.g., one-tenth of V0 (ΔV0=0.1V0). Therefore, during the first half-cycle T1, the potential difference between the orthogonal injection electrodes 33A, 33B and the moving mass 31 is the same, and no orthogonal force is generated (the first orthogonal force is zero). Conversely, during the second half-period T2, the potential difference of the orthogonal injection electrodes 33A, 33B increases or decreases by ΔV0 relative to the mobile mass 31 and generates an additional force acting on the mass (with a sign depending on the instantaneous position occupied by the mobile mass 31), as will be described below with reference to Figure 5A and Figure 5B Explained (second normal force).

[0048] Figure 4A and Figure 4B The behavior of the mobile mass 31 in two half-periods T1 , T2 in the presence of quadrature injection signals V1 , V2 is shown.

[0049] In detail, Figure 4A The movement of the moving mass 31 during the first half period T1 is shown in the presence of a drive signal and natural quadrature (and / or angular velocity Ω) and with the calibration terminals 36A, 36B biased to a first value V0. In particular, Figure 4A The solid line P0 shows the intermediate position (also corresponding to the rest position of the mobile mass 31), and the dashed lines show the two possible maximum oscillation positions of the mobile mass 31 (corresponding to a first extended position P1 with maximum proximity to the electrodes 32, 33A, 33B and a second extended position P2 corresponding to the maximum distance from the electrodes 32, 33A, 33B). Therefore, in the first half-period T1, no quadrature signal (calibration quadrature signal) is applied or injected. Figure 5B , the corresponding diagram of the sensing signal S in the first half period T1 is illustrated in ; in particular, in the first half period T1 the sensing signal S has, in a manner known per se, a sinusoidal diagram at the drive frequency f0 and a first amplitude related to the natural quadrature (and possibly also to the angular velocity Ω).

[0050] Figure 4B The movement of the moving mass 31 in the second half period T2 is shown in the presence of a drive signal and natural quadrature (and / or angular velocity Ω) and with the calibration terminals 36A, 36B set to V0+ΔV0 and V0-ΔV0, respectively. In particular, Figure 4B The middle position P0 of the mobile mass 31 is again shown by a solid line, and the Figure 4A The maximum oscillation positions P1, P2 of FIG. 3 are shown, and two possible maximum oscillation positions P3, P4 of the mobile mass 31 in the presence of a voltage step ±ΔV0 are shown by dash-dotted lines.

[0051] It should be noted that during the second half-cycle T2, when mobile mass 31 is in first extended position P1 (the position of maximum extension on the right side and minimum distance from electrodes 32, 33A, 33B), it is now fully facing first orthogonal injection electrode 33A (set to voltage V0+ΔV0) but no longer facing second orthogonal injection electrode 33B (set to voltage V0-ΔV0). Therefore, it is subjected to an additional force (positive calibrated orthogonal force) that amplifies its movement toward electrodes 32, 33A. Consequently, mobile mass 31 moves from first extended position P1 to the position indicated by the dotted line (also referred to as third extended position P3).

[0052] Similarly, during the same second half-cycle T2, when mobile mass 31 is in second extended position P2 (the position of maximum extension on the left and greatest distance from electrodes 32, 33A, 33B), it fully faces second orthogonal injection electrode 33B (set to voltage V0-ΔV0) but no longer faces first orthogonal injection electrode 33A (set to voltage V0+ΔV0); therefore, it experiences a smaller force (negative calibrated orthogonal force) that amplifies the movement of mobile mass 31 away from electrodes 32, 33A, 33B. Consequently, mobile mass 31 moves from second extended position P2 to the position indicated by the dotted line (also referred to as fourth extended position P4).

[0053] It should be emphasized that, as discussed below, when the changes in the facing surface between the mobile mass 31 and the orthogonal injection electrodes 33A, 33B are similar to those described above, Figure 3 、 Figure 4A and Figure 4B The same effect of applying normal forces in the two maximum extension positions of the mobile mass 31 can also be obtained, except for the variations shown in FIG.

[0054] It can be seen that in the second half period T2, the increase in the positive and negative extensions of the mobile mass 31 leads to a modification of the minimum and maximum distances of the mobile mass 31 from the sensing electrode 32, and therefore (correspondingly), as Figure 5B As shown, during the detection movement, the capacitance between them changes greatly, so the amplitude of the sensing signal S increases; it should be noted that in the second half cycle T2, the sensing signal S still has a sinusoidal waveform with the same frequency as that in the first half cycle T1, but the second amplitude of the sensing signal S is greater than the first amplitude.

[0055] In fact, in the second half-period T2, a quadrature signal of known value is injected and generates a measurable step ΔS in the amplitude of the sensed signal S. In the presence of variable interference and drift, the step ΔS may vary with time and is related to the transfer function H(d) of equations (1) and (2).

[0056] By monitoring the change in the value of the step ΔS in time, any change in the proportionality factor can be detected; moreover, a correction factor for the proportionality factor can be obtained, which can be used to compensate the processing system.

[0057] exist Figure 6 A flow chart of a method for detecting and correcting for changes in the scale factor is illustrated in FIG.

[0058] In detail, Figure 6 The method comprises an initial sensing step, typically performed in the factory during the gyroscope's final verification and testing operations, and a detection and correction step, performed in a continuous manner or at pre-set intervals during the gyroscope's operation, however without interrupting the gyroscope's operation, in particular without interrupting the flow of angular velocity output signals to the electronic devices that use them.

[0059] In detail, the initial sensing step includes: step (100), driving the mobile mass block 31 at a preset driving frequency f0; step 102, as in Figure 5A During the first half cycle T1 shown in FIG, the orthogonal injection electrodes 33A, 33B are initially biased at the first value V0 of the orthogonal injection signals V1, V2; step 104, a first reference value S of the sensing signal S is measured. 01 ; Step 106, as in Figure 5A During the second half cycle T2 shown in FIG, a calibration voltage step ±ΔV0 is applied; Step 108, a second reference value S of the sensing signal S is measured. 02 ; Step 110, subtract the first reference value S from the second reference value 02 -S 01 To obtain a reference deviation value ΔS0; and step 112, storing the reference calibration scale factor ΔS0.

[0060] In detail, the detection and correction steps include: step 200, driving the mobile mass block 31 at a preset driving frequency f0; step 202, as in Figure 5A During the first half cycle T1 shown in FIG, the orthogonal injection electrodes 33A, 33B are biased at the first value V0 of the orthogonal injection signals V1, V2; Step 204, the first half cycle value S of the sensing signal is measured. IR1 ; Step 206, as in Figure 5ADuring the second half cycle T2 shown in FIG, a calibration voltage step ±ΔV0 is applied; Step 208, the second half cycle value S of the sensing signal S is measured. IR2 ; Step 210, subtract the first half cycle value S from the second half cycle value IR2 -S IR1 To obtain the running deviation value ΔS IR ; Step 212, according to the following equation:

[0061] GCF=ΔS IR / ΔS0 (3)

[0062] Calculated as the deviation value ΔS in operation IR The gain correction factor GCF of the ratio between the calibration deviation value ΔS0 and the reference calibration deviation value ΔS0; Step 214, store the correction factor GCF; and Step 216, according to the equation:

[0063] Ω C =Ω M / GCF (4)

[0064] The angular velocity value Ω will be measured and calculated in a standard way M Divide by the correction factor GCF to correct the angular velocity value Ω M .

[0065] Therefore, as indicated, it is possible to Figure 5A The frequency f of the orthogonal injection signals V1 and V2 C At a predetermined time interval, or at predetermined time intervals, steps 202 to 214 for detecting the correction factor GCF are repeated.

[0066] Figure 7 A block diagram of an angular velocity sensing system, generally designated 250 , is shown.

[0067] The angular velocity sensing system 250 includes Figure 3 The gyroscope 30 and the electronic processing unit 251 (eg, an ASIC (Application Specific Integrated Circuit)) are merely provided for understanding the detection and correction of the above referenced Figure 6 The described method of scaling factor variation is useful for both components. Therefore, the control unit for driving the movement of the mobile mass 31 is not shown.

[0068] In the illustrated embodiment, the gyroscope 30 and the electronic processing unit 251 are here formed on two separate chips 280 , 290 , for example side by side or on top of each other on a printed circuit board or encapsulated in a single package.

[0069] exist Figure 7In the embodiment of the present invention, the sensing terminal 35 of the gyroscope 30 is electrically coupled to a capacitance / voltage converter (C / V) 258, which generates a sensing signal S. The output of the capacitance / voltage converter 258 is connected to the signal input terminal 252 of the processing unit 251. The calibration terminals 36A and 36B are electrically coupled to the quadrature injection control unit 255 of the processing unit 251 through the respective bias terminals 253A and 253B. The quadrature injection control unit 255 receives the voltages V0, V0-ΔV, and V0+ΔV from a voltage source or charge pump (not shown), and supplies quadrature injection signals V1 and V2 at the frequency of the low-frequency clock signal LF_CLK having a period T1+T2 based on the low-frequency clock signal LF_CLK generated by the clock generator 257.

[0070] The signal input terminal 252 of the processing unit 251 is coupled to an angular velocity calculation channel 260 for processing a Coriolis signal, and is coupled to a proportional correction factor calculation channel 261 .

[0071] Angular velocity calculation channel 260 and scale correction factor calculation channel 261 are similar to each other. In particular, angular velocity calculation channel 260 has a standard structure and includes a signal demodulator 262 and an analog-to-digital signal converter (ADC) 263. In particular, signal demodulator 262 multiplies sense signal S (voltage signal) by a first clock signal CLK1 having a frequency equal to the frequency f0 of the drive signal of gyroscope 30. The demodulated sense signal S_d thus obtained (possibly filtered in a manner known per se for eliminating higher harmonics) is digitized in analog-to-digital signal converter 263 and supplied to angular velocity calculation block 264.

[0072] As explained below, the angular velocity calculation block 264 includes a calculation section 264A of a known type that supplies the measured angular velocity value Ω M ; and a correction portion 264B basically formed by a multiplier.

[0073] For example, in a typical embodiment, the computing portion 264A may be a digital signal processor (DSP) that includes the following main standard blocks: a SINC filter for sampling data from an analog-to-digital converter; a digital compensation unit (DCU) for adjusting sensitivity (in addition to other possible parameters); and an additional digital filter (FIR-finite impulse response type or IIR-infinite impulse response type) for reducing output noise. In the present application, the sensitivity compensation within the DCU also depends on the output of the GCF block, thereby enabling real-time gain adjustment.

[0074] The scale correction factor calculation channel 261 includes a quadrature demodulator 266, a quadrature analog-to-digital converter 267, a scale correction factor calculation block 268, and a memory (MEM.) 269. In detail, the quadrature demodulator 266 multiplies the sense signal S by a clock signal CLK2 = CLK1 + 90°, which has a frequency f0 equal to the frequency of the first clock signal CLK1 but shifted by 90°, in order to take into account the phase shift of the quadrature injection signals V1 and V2 relative to the Coriolis signal. The demodulated quadrature signal S_r thus obtained (possibly filtered in a manner known per se for eliminating higher harmonics) is digitized in the quadrature analog-to-digital converter 267 and supplied to the scale correction factor calculation block 268, which determines the correction factor GCF according to equation (3) based on the ratio between the scale factor stored in the memory 269 during fine tuning and the scale factor just calculated.

[0075] Then, the correction factor GCF is supplied to the angular velocity calculation block 264 based on the activation signal supplied from the control unit 270 .

[0076] The computation portion 264A of the angular velocity computation block 264 then processes the demodulated and digitized sense signal S_d in a known manner to obtain the measured angular velocity Ω M , and the angular velocity calculation block 264 converts the measured angular velocity Ω into M The correction factor GCF in the correction section 264B is multiplied to output a corrected angular velocity value Ω. C .

[0077] If the gyroscope 50 is a three-axis gyroscope or the processing unit 251 is coupled to three single-axis gyroscopes 50, the angular velocity calculation channel 260 and the scale correction factor calculation channel 261 are repeated for each roll movement, pitch movement, and yaw movement.

[0078] Figure 8 A possible implementation of calibration electrodes for a gyroscope 50 of the three-axis type for detecting angular velocities about a first Cartesian axis X, a second Cartesian axis Y and a third Cartesian axis Z (yaw, roll and pitch movements respectively) is shown.

[0079] In detail, the gyroscope 50 comprises a first mobile mass 51A, a second mobile mass 51B, a third mobile mass 51C, and a fourth mobile mass 51D, which are carried by a system of flexures 53A to 53D (represented only schematically) via a fixed structure 52, which couple each respective mobile mass 51A, 51B, 51C, and 51D to a central anchoring element 54, which is rigid relative to the fixed structure 52 and is shown only schematically. Contact pads 90 are formed on the fixed structure 52 for electrically connecting the structures of the gyroscope 50 in a manner known to those skilled in the art and not shown in detail herein.

[0080] Figure 8 Gyroscope 50 has an approximately symmetrical structure with respect to two central axes, A and B, which pass through the gyroscope's center O and are parallel to the Cartesian axis system XYZ, respectively. In particular, first and second masses 51A and 51B are symmetrically arranged with respect to second central axis B, and third and fourth masses 51C and 51D are symmetrically arranged with respect to first central axis A. Furthermore, first and second masses 51A and 51B have a symmetrical configuration with respect to first central axis A, which intersects them at their center, and third and fourth masses 51C and 51D have a first, approximately symmetrical configuration with respect to second central axis B, which intersects them at their center. As discussed below, third and fourth masses 51C and 51D differ only in the shape and position of their yaw sensing electrodes and associated orthogonal injection electrodes.

[0081] Each mobile mass 51A to 51D is coupled to a respective drive structure 55A to 55D of known type, shown only schematically, which sets the respective mobile mass 51A to 51D to oscillate in a drive direction. Specifically, in the illustrated gyroscope 50, the first mobile mass 51A and the second mobile mass 51B are driven in a direction parallel to the first Cartesian axis X, as indicated by a first arrow D1, and the third mobile mass 51C and the fourth mobile mass 51D are driven in a direction parallel to the second Cartesian axis Y, as indicated by a second arrow D2. For example, the drive structures 55A to 55D can be formed by so-called capacitive comb actuation.

[0082] exist Figure 8In the gyroscope 50 of FIG. 5 , the first mobile mass 51A and the second mobile mass 51B respectively include a first roll sensing structure 60A and a second roll sensing structure 60B, which are intended to detect the roll movement of the gyroscope 50 around the second Cartesian axis Y. In practice, the first sensing structure 60A and the second sensing structure 60B detect the movement of the respective mobile masses 51A, 51B in the roll sensing direction Roll parallel to the third Cartesian axis Z, which is caused by the presence of an angular velocity Ω. Y The Coriolis forces acting on the respective mobile masses 51A, 51B in the case of φ and φ are caused by driving the suspended masses 51A, 51B in the first direction D1.

[0083] To this end, the first roll sensing structure 60A and the second roll sensing structure 60B respectively include a first roll sensing electrode 63A and a second roll sensing electrode 63B made of a conductive material. Figure 8 The roll sensing electrodes 63A, 63B extend on a substrate not visible in the drawing (parallel to the suspended masses 51A to 51D arranged in a plane behind the drawing plane) and face the respective mobile masses 51A, 51B. Each roll sensing electrode 63A, 63B is formed here by a transverse portion 64A, 64B, respectively, extending perpendicularly to the first drive direction D1 and parallel to the second Cartesian axis Y, and a plurality of arms 65A, 65B extending parallel to each other and to the first drive direction D1 and connected to the respective transverse portion 64A, 64B.

[0084] The third and fourth mobile masses 51C, 51D include first and second pitch sensing structures 61C, 61D and first and second yaw sensing structures 62C, 62D.

[0085] In particular, the first pitch sensing structure 61C and the second pitch sensing structure 61D are capable of detecting the pitch movement of the gyroscope 50 about the first Cartesian axis X. In practice, the first pitch sensing structure 61C and the second pitch sensing structure 61D detect the movement of the respective mobile masses 51C, 51D in a pitch sensing direction Pitch parallel to the third Cartesian axis Z, the movement being caused by the angular velocity Ω X In the case of , the Coriolis forces acting on the respective mobile masses 51C, 51D are caused by driving the suspended masses 51A, 51B in the second direction D2.

[0086] The first and second pitch sensing structures 61C and 61D have similar structures to the first and second roll sensing structures 60A and 60B, but are rotated 90° relative to the first and second roll sensing structures 60A and 60B. Thus, they include first and second roll sensing electrodes 63C and 63D made of a conductive material, extending on a substrate (not visible) and facing the respective mobile masses 51C and 51D. Thus, each roll sensing electrode 63C and 63D is formed by a transverse portion 64C and 64D, respectively, extending perpendicular to the second drive direction D2 and parallel to the first Cartesian axis X, and a plurality of arms 65C and 65D, respectively, extending parallel to each other and parallel to the second drive direction D2, and connected to the respective transverse portion 64C and 64D.

[0087] The first yaw sensing structure 62C and the second yaw sensing structure 62D are designed to detect the movement (in-plane movement) of the gyroscope 50 about the third Cartesian axis Z. In practice, the first yaw sensing structure 62C and the second yaw sensing structure 62D detect the movement of the respective mobile masses 51C, 51D in the yaw sensing direction Yaw parallel to the first Cartesian axis X, which movement is in the presence of an angular velocity Ω Z In the case of , the Coriolis force acting on the respective moving masses 51C, 51D is caused by the driving of the suspended masses 51A, 51B in the second direction D2.

[0088] At a magnified scale Figure 8A The first and second yaw sensing structures 62C, 62D, which are more clearly visible in the details of the drawings, comprise first and second yaw sensing openings 66C, 66D, respectively, which are formed in the mobile masses 51C, 51D, and second yaw sensing electrodes 67C, 67D made of a conductive material, which are rigid relative to the fixed structure 51 and extend from the substrate (not visible) in a vertical direction (parallel to the third Cartesian axis Z) within the first and second yaw sensing openings 66C, 66D.

[0089] In the illustrated embodiment, the first yaw sensing opening 66C and the second yaw sensing opening 66D have a generally elongated rectangular shape (in a top plan view) with its long sides parallel to the second Cartesian axis Y (parallel to the second drive direction D2). Similarly, the first yaw sensing electrode 67C and the second yaw sensing electrode 67D have an elongated rectangular shape (in a top plan view) with its long sides parallel to the second Cartesian axis Y. When stationary, the first yaw sensing electrode 67C is arranged in an eccentric position of the corresponding first yaw sensing opening 66C and is precisely arranged closer to a first longer side of the first yaw sensing opening 66C (in a top plan view) than to an opposite longer side. Figure 8 In contrast, the second yaw sensing electrode 67D is arranged in an eccentric position in the corresponding second yaw sensing opening 66D, and is precisely arranged closer to the opposite longer side of the second yaw sensing electrode 67D relative to the first yaw sensing electrode 67C (in the left). Figure 8 center, further to the left).

[0090] Moreover, the gyroscope 50 includes: a first roll orthogonal injection structure 70A and a second roll orthogonal injection structure 70B, which are associated with the first moving mass block 51A and the second moving mass block 51B, respectively; a first pitch orthogonal injection structure 70C and a second pitch orthogonal injection structure 70D, which are associated with the third moving mass block 51C and the fourth moving mass block 51D, respectively; and a first yaw orthogonal injection structure 80C and a second yaw orthogonal injection structure 80D, which are associated with the third moving mass block 51C and the fourth moving mass block 51D, respectively.

[0091] The roll and pitch orthogonal injection structures 70A to 70D are similar to each other but rotated 90 degrees relative to each other. In particular, the first roll orthogonal injection structures 70A, 70B include a first roll orthogonal injection opening 71A and a first roll orthogonal injection electrode 73A; the second roll orthogonal injection structure 70A includes a second roll orthogonal injection opening 71B and a second roll orthogonal injection electrode 73B; the first pitch orthogonal injection structure 70C includes a first pitch orthogonal injection opening 71C and a first pitch orthogonal injection electrode 73C; and the second pitch orthogonal injection structure 70D includes a second pitch orthogonal injection opening 71D and a second pitch orthogonal injection electrode 73D.

[0092] In detail, the roll and pitch orthogonal injection electrodes 73A-73D have a similar shape to the roll and pitch sensing electrodes 63A, 63B, 63C, and 63D. In particular, in the illustrated embodiment, the roll and pitch orthogonal injection electrodes 73A-73D are arranged adjacent to the cognate sensing electrodes 63A-63D in a flipped position. Thus, each roll and pitch orthogonal injection electrode 73A, 73B, 73C, and 73D has a corresponding transverse portion 74A, 74B, 74C, and 74D and a corresponding plurality of arms 75A, 75B, 75C, and 75D. The transverse portions 74A, 74B, 74C, and 74D of the roll and pitch orthogonal injection electrodes 73A, 73B, 73C, and 73D extend perpendicular to the drive directions D1 and D2 of the corresponding mobile masses 51A-51D. The arms 75A to 75D of each roll and pitch quadrature injection electrode 73A to 73D extend parallel to one another and perpendicular to the corresponding lateral portions 74A to 74D, and the arms 75A to 75D interdigitate with the arms 65A to 65D of the corresponding roll and pitch sense electrodes 63A to 63D. In this manner, the center of mass of the roll and pitch quadrature injection electrodes 73A to 73D is close to the center of mass of the corresponding roll and pitch sense electrodes 63A, 63B, 63C, and 63D.

[0093] Furthermore, each of the orthogonal injection openings 71A, 71B, 71C and 71D has an elongated rectangular shape that is perpendicular to the driving direction of the corresponding moving mass 51A to 51D.

[0094] In the gyroscope 50, in the static position, the orthogonal injection openings 71A to 71D extend over the ends of the arms 75A to 75D of the corresponding orthogonal injection electrodes 73A to 73D and the middle portions of the arms 65A to 65D of the corresponding sensing electrodes 63A to 63D. In particular, the orthogonal injection openings 71A to 71D, the sensing electrodes 63A to 63D, and the orthogonal injection electrodes 73A to 73D are arranged relative to each other and are sized so that, depending on the oscillation position of the corresponding moving mass 51A to 51D, each orthogonal injection opening 71A to 71D always covers the arms 65A to 65D of the corresponding sensing electrode 63A to 63D and completely covers, partially covers, or does not cover at all the arms 75A to 75D of the corresponding orthogonal injection electrodes 73A to 73D. Therefore, as for the second roll orthogonal injection structure 63B, Figure 9A and Figure 9B As shown in detail in FIG, the facing area between each sensing electrode 63A to 63D and the corresponding moving mass 51A to 51D does not change with the position of the moving mass 51A to 51D, while the facing area between each moving mass 51A to 51D and the arm 51A to 75D of the corresponding orthogonal injection electrode 73A to 73D does change.

[0095] In particular, Figure 9A shows half of a second tilted normal injection structure 70B; more particularly, Figure 9A The roll-orthogonal injection opening 71B in the rest position of the second mobile mass 51B is indicated by a dashed line, and the roll-orthogonal injection opening 71B in the right-hand maximum extension position of the second mobile mass 51B is indicated by a solid line. Figure 9B The roll-orthogonal injection opening 71B in the rest position of the second mobile mass 51B is shown with dashed lines, and in the left, maximum extended position of the second mobile mass 51B is shown with solid lines.

[0096] As can be noted, in Figure 9A and Figure 9B In the dotted rest position of FIG, the roll orthogonal injection opening 71B covers the arm 75B of the second roll orthogonal injection electrode 73B for only a portion of its width (in a direction parallel to the first Cartesian axis X). In the right maximum extension position of the second mobile mass 51B, the roll orthogonal injection opening 71B (in the Figure 9A Finally, in the left most extended position of the second mobile mass 51B, the roll orthogonal injection opening 71B (in the left most extended position) does not cover the arm 75B of the second roll orthogonal injection electrode 73B. Figure 9B The arm 75B (shown as a solid line and highlighted in gray) covers the second roll orthogonal injection electrode 73B over its entire width. Therefore, in the static position of the second mobile mass 51B, the mutual facing area between the second mobile mass 51B and the second roll orthogonal injection electrode 73B has an intermediate value. In the rightmost extended position ( Figure 9A ), the mutual facing area between the second mobile mass 51B and the second tilt orthogonal injection electrode 73B has a maximum value. Finally, at the left maximum extension position ( Figure 9B ), the mutual facing area between the second mobile mass 51B and the second roll orthogonal injection electrode 73B has a minimum value.

[0097] In this manner, for example, by applying the first orthogonal injection signal V1 to the second roll orthogonal injection electrode 73B and the first pitch orthogonal injection electrode 73C, and applying the second orthogonal injection signal V2 to the first roll orthogonal injection electrode 73A and the second pitch orthogonal injection electrode 73D, the reference Figure 4A 、 Figure 4B 、 Figure 5A 、 Figure 5B and Figure 6 Similar to what has been described, injection of corresponding roll normal forces and pitch normal forces is achieved.

[0098] The yaw orthogonal injection structures 80C and 80D respectively include a plurality of first yaw orthogonal injection electrodes 81C and a plurality of second yaw injection electrodes 81D, and a plurality of first yaw orthogonal injection openings 82C and a plurality of second yaw orthogonal injection openings 82D. Figure 8A In particular, with respect to the first yaw orthogonal injection structure 80C and the first yaw sensing structure 62C, it can be noted that the yaw orthogonal injection structures 80C and 80D are interleaved with the first yaw sensing structure 62C and the second yaw sensing structure 62D, respectively.

[0099] Specifically, first and second yaw-orthogonal injection openings 82C, 82D extend side by side with first and second yaw sensing openings 66C, 66D. For example, in the illustrated embodiment, in third mobile mass 51C, first and second yaw-orthogonal injection openings 82C, 82D each extend between two first pitch sensing openings 66C. Alternatively, in fourth mobile mass 51D, first and second yaw-orthogonal injection openings 82C, 82D each extend between two second pitch sensing openings 66D. First and second yaw-orthogonal injection openings 82C, 82D each have an elongated shape parallel to second drive direction D2, but have steps 85C and 85D, respectively, on opposite longer sides. In particular, each first yaw-orthogonal injection opening 82C has a step 85C on its first longer side (here, the left side), and each second yaw-orthogonal injection opening 82D has a step 85D on its second longer side (here, the right side). For example, the first yaw-orthogonal injection openings 82C and the second yaw-orthogonal injection openings 82D may alternate with each other.

[0100] The first and second yaw orthogonal injection electrodes 81C and 81D are made of a conductive material, are rigid relative to the fixed structure 52, and extend from the substrate (not visible) in a vertical direction (parallel to the third Cartesian axis Z) within the first and second yaw orthogonal injection openings 82C and 82D.

[0101] Furthermore, the first yaw orthogonal injection electrode 81C and the second yaw orthogonal injection electrode 81D have an elongated rectangular shape (in a top plan view) with the long sides thereof parallel to the second drive direction D2. The first yaw orthogonal injection electrode 81C is arranged in the corresponding first yaw orthogonal injection opening 82C near the longer side having the step 85C. The second yaw orthogonal injection electrode 81D is arranged in the corresponding second yaw orthogonal injection opening 82D near the longer side having the step 85D.

[0102] In use, the first yaw quadrature injection electrode 81C and the second yaw quadrature injection electrode 81D receive the second quadrature injection signal V2 and the first quadrature injection signal V1 respectively, and in the presence of a yaw angular velocity Ω Z Due to the movement of the third 51C and fourth 51D mobile masses (about the third Cartesian axis Z) in the second drive direction D2, the distances from the respective longer sides (in the direction X) are variable.

[0103] In addition, as described above, due to the steps 85C, 85D, during the driving movement of the third mobile mass 51C and the fourth mobile mass 51D in the second driving direction D2, the first yaw orthogonal injection electrode 81C and the second yaw orthogonal injection electrode 81D have a facing area variable between a minimum value and a maximum value with respect to the value of the projected portion of the corresponding adjacent longer side, and therefore, as described above with reference to Figure 5A 、 Figure 4B 、 Figure 5A 、 Figure 5B and Figure 6 As depicted, a variable normal force is injected during the second half-cycle T2.

[0104] In this manner, the drift of the gyroscope 50 with respect to the scale factor can be monitored in all angular velocity sensing directions.

[0105] Thus, with the described gyroscope it is possible to adjust the scale factor at runtime without interrupting its operation.

[0106] The adjustment does not require measurement of disturbances inside or outside the MEMS gyroscope chip 280 , nor does it require knowledge of the nature of such disturbances; moreover, the adjustment can follow the drift of the scale factor.

[0107] Finally, it is apparent that modifications and variations may be made to the gyroscope and scale factor correction method described and illustrated herein without departing from the scope of the present disclosure as defined in the appended claims. For example, the various embodiments described may be combined to provide additional solutions.

[0108] Moreover, in Figure 8In the three-axis gyroscope, regarding the first orthogonal injection electrode 33A and the second orthogonal injection electrode 33B of FIG4 , the roll and pitch orthogonal injection structures 70A to 70D can be replicated so that each of the moving masses 51A to 51B faces both the first orthogonal injection electrode 73A and the second orthogonal injection electrode 73D. In this case, the first orthogonal injection electrode 73A and the second orthogonal injection electrode 73B (or 73C and 73D) can be arranged side by side, and the roll orthogonal injection openings or the pitch orthogonal injection openings 71A and 71B (or 71C and 71D) of the first orthogonal injection electrode 73A and the second orthogonal injection electrode 73B (or 73C and 73D) can be different orthogonal injection openings or the same orthogonal injection opening. Vice versa, the yaw orthogonal injection structures 80C, 80D can be arranged on different moving masses 51C, 51D, so that the moving mass (e.g., moving mass 51C) only faces the first orthogonal injection electrode 81C (receiving the second orthogonal injection signal V2), while the other moving mass (e.g., moving mass 51D) only faces the second orthogonal injection electrode 81D (receiving the first orthogonal injection signal V1).

[0109] The mutual facing position between the suspended masses 51A to 51D and the roll and pitch orthogonal injection electrodes 73A to 73D can be varied relative to the position shown, and can be associated with two different conditions (in the maximum extension position), namely: the condition in which each orthogonal injection opening 71A to 71D covers the corresponding orthogonal injection electrode 73A to 73D over its entire width (or length); the condition in which each orthogonal injection opening 71A to 71D only partially covers the corresponding orthogonal injection electrode 73A to 73D; and the condition in which each orthogonal injection opening 71A to 71D does not cover the corresponding orthogonal injection electrode 73A to 73D.

[0110] Finally, even if Figures 4 and Figure 8 The MEMS gyroscopes 30, 50 have been described as being integrated with the integrated Figure 7 The chip 290 of the electronic processing unit 251 is separated from the chip 280, the MEMS gyroscope 30, 50 and the electronic processing unit 251 can also be formed in only one chip, or some components of the electronic sensor unit 251 can also be directly formed in the chip 280 integrating the MEMS gyroscope 30, 50.

[0111] The step-like structure 85 of the main side of the first yaw orthogonal injection opening 82C and the second yaw orthogonal injection opening 82D may be formed on the roll and pitch orthogonal injection electrodes 73A to 73D.

[0112] The various embodiments described above can be combined to provide additional embodiments. These and other changes can be made to the embodiments in light of the above detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments and equivalents to the full scope of protection sought by the claims. Therefore, the claims are not limited by this disclosure.

Claims

1. A MEMS gyroscope comprising: Support structure; a first mobile mass carried by the support structure and configured to move in a first driving direction and a first sensing direction that are perpendicular to each other; a first drive structure coupled to the first moving mass and configured to drive the first moving mass to move in the first drive direction at a drive frequency; an orthogonal injection structure coupled to the first moving mass and configured to selectively generate a first orthogonal movement of the first moving mass in the first sensing direction during a first calibration half of a cycle and to selectively generate a second orthogonal movement of the first moving mass in the first sensing direction during a second calibration half of the cycle; a first motion sensing structure coupled to the first moving mass and configured to detect movement of the first moving mass in a first sensing direction, the motion sensing structure configured to supply a sensing signal having an amplitude that switches between a first value and a second value, the first value and the second value being dependent on movement of the first moving mass due to an external angular velocity and the first and second orthogonal movements; as well as a processing unit coupled to the first motion sensing structure and configured to determine a difference between the first value and the second value of the sense signal, determine a gain correction factor based on the difference between the first value and the second value and a stored reference calibration scale factor, and adjust the measurement of the external angular velocity with the gain correction factor.

2. The MEMS gyroscope according to claim 1, wherein: A bias structure configured to bias the quadrature injection structure, the bias structure being coupled to the quadrature injection structure and configured to bias the quadrature injection structure with a voltage that switches between a quiescent value in the first calibration half cycle and a quadrature injection value in the second calibration half cycle.

3. The MEMS gyroscope according to claim 2, wherein: The orthogonal injection structure includes a first orthogonal injection electrode and a second orthogonal injection electrode, wherein the first orthogonal injection electrode and the second orthogonal injection electrode are coupled to the first moving mass; The bias structure is configured to supply a first orthogonal injection signal to the first orthogonal injection electrode and a second orthogonal injection signal to the second orthogonal injection electrode; as well as The first and second orthogonal injection signals have a first value and a second value, respectively. The first values ​​of the first and second orthogonal injection signals are the same, the second value of the first orthogonal injection signal is equal to a value by which the first values ​​of the first and second orthogonal injection signals are increased by a voltage step, and the second value of the second orthogonal injection signal is equal to a value by which the first values ​​of the first and second orthogonal injection signals are decreased by the voltage step. 4 . The MEMS gyroscope according to claim 3 , wherein during movement of the first moving mass in the first driving direction, a facing area of ​​the first and second orthogonal injection electrodes is variable along with the first moving mass.

5. The MEMS gyroscope according to claim 4, wherein: The first mobile mass is a first mobile mass selected between a roll sensing mass and a pitch sensing mass; The first orthogonal injection electrode extends below the first mobile mass; as well as The first moving mass has a first orthogonal injection opening configured to move between two different facing positions relative to the first orthogonal injection electrode during movement in the first drive direction.

6. The MEMS gyroscope according to claim 5, further comprising: a second mobile mass carried by the support structure and configured to move in the first driving direction and the first sensing direction; a second drive structure coupled to the second moving mass and configured to drive movement of the second moving mass in the first drive direction at the drive frequency; as well as a second motion sensing structure coupled to the second moving mass and configured to detect movement of the second moving mass in the first sensing direction, wherein: The second orthogonal injection electrode extends below the second mobile mass; as well as The second moving mass has a second orthogonal injection opening configured to move between two different facing positions relative to the second orthogonal injection electrode during movement in the first drive direction.

7. The MEMS gyroscope according to claim 4, wherein: The first mobile mass is a mobile yaw sensing mass; The first mobile mass has a first orthogonal injection opening and a second orthogonal injection opening; The first orthogonal injection electrode extends from a fixed structure within the first orthogonal injection opening and has a surface facing the first orthogonal injection opening, one of the first orthogonal injection opening and the first orthogonal injection electrode forming a first orthogonal injection element, and the other of the first orthogonal injection opening and the first orthogonal injection electrode forming a second orthogonal injection element; The first orthogonal injection element has a first wall with a protruding portion and a concave portion, the protruding portion and the concave portion of the first orthogonal injection element being arranged at different distances from the second orthogonal injection element; the second orthogonal inject electrode extending from the fixed structure within the second orthogonal inject opening, one of the second orthogonal inject opening and the second orthogonal inject electrode forming a third orthogonal inject element, and the other of the second orthogonal inject opening and the second orthogonal inject electrode forming a fourth orthogonal inject element; the third orthogonal injection element having a third wall with a protruding portion and a concave portion, the protruding portion and the concave portion of the third orthogonal injection element being arranged at different distances from the fourth orthogonal injection element; as well as During movement in the first drive direction, the first mobile mass is configured to move between two different facing conditions utilizing the first and second orthogonal injection elements, and between two different facing conditions utilizing the third and fourth orthogonal injection elements.

8. The MEMS gyroscope according to claim 4, further comprising: a second mobile mass carried by the support structure and configured to move in the first driving direction and the first sensing direction; a second drive structure coupled to the second moving mass and configured to drive movement of the second moving mass in the first drive direction at the drive frequency; as well as a second motion sensing structure coupled to the second moving mass and configured to detect movement of the first moving mass in the first sensing direction, wherein: The first mobile mass and the second mobile mass are yaw sensing mobile masses; The first mobile mass has a first orthogonal injection opening; The second mobile mass has a second orthogonal injection opening; The first orthogonal injection electrode extends from a fixed structure within the first orthogonal injection opening and has a surface facing the first orthogonal injection opening, one of the first orthogonal injection opening and the first orthogonal injection electrode forming a first orthogonal injection element, and the other of the first orthogonal injection opening and the first orthogonal injection electrode forming a second orthogonal injection element; the second orthogonal inject electrode extending from the fixed structure within the second orthogonal inject opening, one of the second orthogonal inject opening and the second orthogonal inject electrode forming a third orthogonal inject element, and the other of the second orthogonal inject opening and the second orthogonal inject electrode forming a fourth orthogonal inject element; The first orthogonal injection element has a first wall with a protruding portion and a concave portion, the protruding portion and the concave portion of the first orthogonal injection element being arranged at different distances from the second orthogonal injection element; the third orthogonal injection element having a third wall with a protruding portion and a concave portion, the protruding portion and the concave portion of the third orthogonal injection element being arranged at different distances from the fourth orthogonal injection element; and During movement in the first drive direction, the first moving mass is configured to move between two different facing conditions utilizing the first and second orthogonal injection elements, and the second moving mass is configured to move between two different facing positions utilizing the third and fourth orthogonal injection elements.

9. The MEMS gyroscope of claim 1, wherein the first orthogonal movement of the first moving proof mass is a zero movement.

10. An electronic processing unit, comprising an angular velocity correction circuit, the angular velocity correction circuit comprising: a subtractor configured to perform a subtraction operation between a first value and a second value of a sensing signal received from a MEMS gyroscope in an initial sensing step and obtain a reference calibration scale factor, and configured to perform a subtraction operation between the first value and the second value of the sensing signal received from the MEMS gyroscope in an operating step from the MEMS gyroscope and obtain a current calibration scale factor; a memory element configured to store the reference calibration scale factor; a divider for dividing the current calibration scale factor by the reference calibration scale factor to obtain a gain correction factor; an angular velocity calculation element configured to generate a measured angular velocity value; as well as The measurement correction element is configured to multiply the measured angular velocity value by the gain correction factor.

11. The electronic processing unit according to claim 10, further comprising: a signal demodulator configured to demodulate the sensing signal using a first clock signal having a clock frequency and obtain a demodulated sensing signal; an analog-to-digital signal converter coupled to the signal demodulator and configured to supply the demodulated and digitized sensing signal to the angular velocity calculation element; a calibration demodulator configured to demodulate the sensing signal using a second clock signal, the second clock signal having the clock frequency and being phase-shifted by 90° relative to the first clock signal; as well as An analog-to-digital calibration converter is coupled to the calibration demodulator and is configured to supply the first value and the second value of the sense signal to the subtractor.

12. An angular velocity sensing system comprising: MEMS gyroscopes, including: Support structure; a first mobile mass carried by the support structure and configured to move in a first driving direction and a first sensing direction that are perpendicular to each other; a first drive structure coupled to the first moving mass and configured to drive the first moving mass to move in the first drive direction at a drive frequency; an orthogonal injection structure coupled to the first moving mass and configured to selectively generate a first orthogonal movement of the first moving mass in the first sensing direction in a first calibration half-cycle and to selectively generate a second orthogonal movement of the first moving mass in the first sensing direction in a second calibration half-cycle; a first motion sensing structure coupled to the first moving mass and configured to detect movement of the first moving mass in the first sensing direction, the motion sensing structure configured to supply a sensing signal having an amplitude switched between a first value and a second value, the first value and the second value being dependent on the movement of the first moving mass due to an external angular velocity and the first and second orthogonal movements; and An electronic processing unit having an angular velocity correction circuit, the electronic processing unit comprising: a subtractor configured to, in an initial sensing step, perform a subtraction operation between a first value and a second value of a sensing signal received from a MEMS gyroscope and obtain a reference calibration scale factor, and, in an operating step of the MEMS gyroscope, perform a subtraction operation between the first value and the second value of the sensing signal received from the MEMS gyroscope and obtain a current calibration scale factor; a memory element configured to store the reference calibration scale factor; a divider for dividing the current calibration scale factor by the reference calibration scale factor to obtain a gain correction factor; an angular velocity calculation element configured to generate a measured angular velocity value; and The measurement correction element is configured to multiply the measured angular velocity value by the gain correction factor.

13. The angular velocity sensing system of claim 12 , wherein the MEMS gyroscope includes a bias structure configured to bias the quadrature injection structure, the bias structure being coupled to the quadrature injection structure and configured to bias the quadrature injection structure with a voltage that switches between a quiescent value in the first calibration half cycle and a quadrature injection value in the second calibration half cycle.

14. The angular velocity sensing system according to claim 13, wherein: The orthogonal injection structure includes a first orthogonal injection electrode and a second orthogonal injection electrode, wherein the first orthogonal injection electrode and the second orthogonal injection electrode are coupled to the first moving mass; The bias structure is configured to supply a first orthogonal injection signal to the first orthogonal injection electrode and a second orthogonal injection signal to the second orthogonal injection electrode; as well as The first and second orthogonal injection signals have a first value and a second value, respectively. The first values ​​of the first and second orthogonal injection signals are the same, the second value of the first orthogonal injection signal is equal to a value by which the first values ​​of the first and second orthogonal injection signals are increased by a voltage step, and the second value of the second orthogonal injection signal is equal to a value by which the first values ​​of the first and second orthogonal injection signals are decreased by the voltage step.

15. The angular velocity sensing system of claim 12, wherein the first orthogonal movement of the first moving mass is a zero movement.

16. A method comprising: driving a moving mass of the MEMS gyroscope in a driving direction at a driving frequency; applying a first orthogonal force during a first half-cycle, the first orthogonal force generating a first orthogonal movement in an orthogonal direction perpendicular to the drive direction; applying a second orthogonal force during a second half-cycle, the second orthogonal force generating a second orthogonal movement in the orthogonal direction; acquiring a sense signal having an amplitude that switches between a first value and a second value, the first value and the second value being dependent on the movement of the first moving mass due to an external angular velocity and the first and second orthogonal movements; obtaining a current calibration scale factor based on a difference between the first value and the second value of the sensed signal; generating a gain correction factor based on the calibration scale factor; obtaining a measurement of said external angular velocity; as well as The measurement of the external angular velocity is adjusted by the gain correction factor.

17. The method according to claim 16, wherein: Generating the gain correction factor includes: dividing the calibration scale factor by a previous calibration scale factor; and Adjusting the measure of the external angular velocity includes dividing the measure of the external angular velocity by the gain correction factor.

18. The method of claim 16, wherein: Applying the first orthogonal force includes: generating a bias voltage having a quiescent value during the first half cycle; and Applying the second orthogonal force includes generating the bias voltage having an orthogonal injection value different from the rest value during the second half-cycle.

19. The method of claim 18, wherein generating the bias voltage comprises: A first orthogonal injection signal and a second orthogonal injection signal are generated, each having a first value and a second value, wherein the first value of the first orthogonal injection signal and the second orthogonal injection signal are the same as each other, and the second value of the first orthogonal injection signal is equal to a value by which the first value of the first orthogonal injection signal and the second orthogonal injection signal are increased by a voltage step, and the second value of the second orthogonal injection signal is equal to a value by which the first value of the first orthogonal injection signal and the second orthogonal injection signal are decreased by a voltage step.

20. The method of claim 16, comprising: demodulating the sensing signal using a first clock signal having a clock frequency, and obtaining a demodulated sensing signal; calculating the measurement of the external angular velocity based on the demodulated sensing signal; demodulating the sensed signal using a second clock signal to obtain a demodulated quadrature signal, the second clock signal having the clock frequency and being phase-shifted by 90° relative to the first clock signal; and The demodulated quadrature signal is used to determine the current calibration scale factor between the first and second values ​​of the sense signal.

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