CN117330042A

CN117330042A - MEMS gyroscope with enhanced anti-vibration robustness and reduced size

Info

Publication number: CN117330042A
Application number: CN202310794367.4A
Authority: CN
Inventors: L·G·法罗尼; P·费德利; G·加特瑞; C·瓦尔扎西纳; P·卡鲁里
Original assignee: STMicroelectronics SRL
Current assignee: STMicroelectronics SRL
Priority date: 2022-07-01
Filing date: 2023-06-30
Publication date: 2024-01-02

Abstract

Embodiments of the present disclosure relate to MEMS gyroscopes with enhanced anti-vibration robustness and reduced size. A MEMS gyroscope, having: a first movable mass configured to move relative to the fixed structure; a first drive assembly coupled to the first movable mass and configured to generate a first alternating drive movement; a first drive spring structure coupled to the first movable mass and to the first drive assembly, rigid in a first drive direction, and compliant in a first sense direction; a second movable mass configured to move relative to the fixed structure; a second drive assembly coupled to the second movable mass and configured to generate a second alternating drive movement in a second drive direction; a second driven elastic structure is coupled to the second movable mass and to the second drive assembly, is rigid in a second driving direction, and is compliant in a second sensing direction.

Description

MEMS gyroscope with enhanced anti-vibration robustness and reduced size

Technical Field

The present disclosure relates to a MEMS gyroscope with enhanced anti-vibration robustness and reduced size.

Background

Gyroscopes fabricated using MEMS ("microelectromechanical systems") technology are formed in a die of semiconductor material (e.g., silicon) and include at least one movable mass suspended from a substrate and free to oscillate relative to the substrate in one or more degrees of freedom.

The movable mass is typically coupled to a drive structure that oscillates the movable mass along a drive direction and to the substrate through detection electrodes that are capable of detecting displacement of the movable mass along a sense direction.

When the MEMS gyroscope rotates at an angular velocity about an axis of rotation perpendicular to the drive direction, the movable mass is subjected to a coriolis force along a sense direction perpendicular to the axis of rotation and the drive direction. Thus, the measurement of the movable mass displacement allows sensing of the external angular velocity.

Current MEMS gyroscopes are of the single, dual or tri-axis type configured to sense movement along one, two or three axes.

In all cases, they are generally sensitive to vibrations parallel to one or more sensing and/or driving axes, and may result in spurious (also known as "spurious") displacements and thus parasitic signals. Such spurious signals are undesirable because they can produce noise and can affect the stability of the gyroscope.

In fact, in general, a sensor (in particular a gyroscope) is considered to be stable when the output signal depends only on the quantity to be sensed (here the external rate).

In particular, for gyroscopes that can be used in the automotive field, it is desirable that they are resistant to vibrations up to several tens of kHz ("robustness to vibrations").

To increase sensing robustness, multiple redundant structures are typically used in order to make the device less sensitive to external vibrations.

However, doubling or even fully doubling the gyroscope structure requires very large dimensions and does not always solve the problem.

Disclosure of Invention

Various embodiments of the present disclosure provide a gyroscope that has high anti-vibration robustness and has a reduced size.

In accordance with the present disclosure, a MEMS gyroscope is provided. The MEMS gyroscope includes: a first movable mass configured to move relative to the fixed structure along a first drive direction and along a first sense direction transverse to the first drive direction; a first drive assembly coupled to the first movable mass and configured to generate a first alternating drive movement; a first drive spring structure coupled to the first movable mass and to the first drive assembly, rigid in a first drive direction, and compliant in a first sense direction; a second movable mass configured to move relative to the fixed structure in a second drive direction parallel to the first drive direction and in a second sense direction parallel to the first sense direction; a second drive assembly coupled to the second movable mass and configured to generate a second alternating drive movement in a second drive direction; and a second driven elastic structure coupled to the second movable mass and to the second drive assembly, rigid in a second driving direction, and compliant in a second sensing direction.

Drawings

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

FIG. 1 is a schematic top view of the basic structure of a MEMS gyroscope in a stationary condition;

FIG. 2 is a schematic top view of the basic structure of FIG. 1 in a drive mode;

FIG. 3 is a schematic top view of the basic structure of FIG. 1 in a sensing mode;

FIG. 4 is a schematic top view of the basic structure of FIG. 1 in the presence of vibrations along the drive direction;

FIG. 5 is a schematic top view of a MEMS gyroscope formed from the two basic structures of FIG. 1;

FIG. 6 shows a possible implementation of the gyroscope of FIG. 5 for sensing yaw (yaw) movements;

FIG. 7 is a schematic top view of a MEMS gyroscope for sensing roll/pitch/roll movements;

FIG. 8 shows a possible implementation of the gyroscope of FIG. 7;

FIG. 9 shows a possible implementation of the gyroscope of FIG. 5 for sensing yaw and roll (also known as pitch)/pitch movements (dual-axis gyroscope);

FIG. 10 shows a block diagram of a system for controlling gyroscope parameters;

FIG. 11 shows a block diagram of another system for controlling gyroscope parameters;

Fig. 12 shows a block diagram of a signaling system using the system for controlling parameters of fig. 11;

fig. 13 shows a block diagram of another signaling system using the control system of fig. 11;

FIGS. 14A-14G show greatly simplified diagrams of different gyroscope configurations and accelerations acting thereon due to the Coriolis effect and linear and/or rotational vibrations;

FIG. 15 is a schematic top view of a gyroscope using the principles illustrated in FIGS. 14D-14F;

FIG. 16 shows an enlarged view of the basic structure of the gyroscope of FIG. 15, in which movement in the drive mode is presented;

FIG. 17 illustrates the basic structure of FIG. 16, wherein movement in a deflection sensing mode is presented;

FIG. 18 illustrates the basic structure of FIG. 16, wherein movement in a roll sensing mode is presented;

FIG. 19 is a schematic top view of a yaw and roll dual-axis gyroscope incorporating the basic structure shown in FIGS. 17 and 18, in which movement in a drive mode is presented;

FIG. 20 is a schematic top view of the gyroscope of FIG. 19, in which movement in a sense mode is presented;

FIG. 21 shows a possible implementation of the gyroscope of FIGS. 19-20;

FIG. 22 is a schematic top view of another dual-axis gyroscope in which movement in a drive mode is presented;

FIG. 23A shows an enlarged view of the basic structure of the gyroscope of FIG. 22, in which the elastic coupling and driving movement is presented;

FIG. 23B is a schematic top view of the gyroscope of FIG. 22, in which movement in a sense mode is presented;

FIG. 24 is a schematic top view of a gyroscope based on the scheme of FIG. 22, in which drive movement is presented;

FIG. 25 is a schematic top view of the gyroscope of FIG. 24, in which yaw/pitch sense movements are presented; and

fig. 26 shows a possible implementation of the gyroscopes of fig. 24 and 25.

Detailed Description

The following description refers to the arrangement as shown; accordingly, expressions such as "above", "below", "top", "bottom", "right", "left", "high", "low", "clockwise", "counterclockwise", etc., relate to the drawings and are not intended to be limiting.

Fig. 1 shows a gyroscope 1, which is made using MEMS technology and has a substantially planar structure, extending mainly in the horizontal plane XY of the inertial reference system XYZ.

The gyroscope 1 is uniaxial for sensing deflections, i.e. the gyroscope 1 rotates about an axis perpendicular to the horizontal plane XY (the vertical axis Z of the inertial reference system XYZ).

The gyroscope 1 of fig. 1 comprises a gyroscope unit 40 having a first axis of gravity B1 parallel to a vertical axis Z, a second axis of gravity B2 parallel to a first horizontal axis X, and a third axis of gravity B3 parallel to a second horizontal axis Y of the inertial reference system XYZ.

The gyroscope 1 has a substantially three-level architecture, which is symmetrical about the second and third triple axes B2, B3, and includes a drive structure 2, a coriolis structure 3, and a sense mass 4.

The drive structure 2, coriolis structure 3 and sense mass 4 extend mainly in a plane XY (along first and second horizontal axes X, Y) and have a negligible thickness relative to the other dimensions (measured parallel to the vertical axis Z).

The driving structure 2 comprises two frames 10, 11 (hereinafter also referred to as first frame 10 and second frame 11, in order to distinguish them), here approximately C-shaped, arranged with the respective concave surfaces facing each other, symmetrically with respect to the second concentric axis B2.

The frames 10, 11 are coupled to a support 13 (e.g., a substrate of a semiconductor die forming part of a fixed structure) by a first spring 14A; the first and second frames 10, 11 are also elastically coupled to each other by a frame coupling spring 14B. The first springs 14A and the frame coupling springs 14B allow the frames 10, 11 to hang on the support 13 (via the respective anchor points 15) and allow the frames 10, 11 to move in one driving direction (driving movement), here parallel to the second horizontal axis Y.

As indicated by arrows 30, 31 in fig. 2, and as described in more detail below, an actuation assembly, for example of the capacitive electrostatic type (schematically shown at 17 in fig. 1 to 4, and for example in fig. 6) is coupled to the frames 10, 11 to control the driving movements of the frames 10, 11 in driving directions, in opposition to each other. For example, an actuation assembly 17 is coupled between each frame 10, 11 and the support 13.

The coriolis structure 3 comprises two coriolis masses 18, 19, which are also approximately C-shaped here, which are arranged symmetrically with respect to the second and third center axes B2, B3 in the concave surfaces of the frames 10, 11, wherein the respective concave surfaces face one another. In other words, here, each coriolis mass 18, 19 is surrounded on three sides by the respective frame 10, 11.

Furthermore, in fig. 1, each coriolis mass 18, 19 is formed by three sides, which are arranged at right angles to the adjacent sides, parallel to the corresponding sides of the respective frame 10, 11.

Each coriolis mass 18, 19 is coupled to the respective frame 10, 11 by a second spring 20, the second spring 20 allowing a mutual movement (sensing movement) between the frame 10, 11 and the respective coriolis mass 18, 19 in a direction parallel to the second horizontal axis Y.

Here, the sensing mass 4 extends into both concave surfaces of the coriolis masses 18, 19. In fig. 1, the sensing masses are generally quadrilateral in shape with each side parallel to the sides of the coriolis masses 18, 19 and the sides of the frames 10, 11.

Here, the sensing mass 4 is anchored to the support 13 by a sensing elastic anchoring system 25 (shown schematically), the sensing elastic anchoring system 25 allowing the sensing mass 4 to rotate about a rotation axis (here the first concentric axis B1).

Furthermore, the sensing masses 4 are elastically coupled to the coriolis masses 18, 19 by respective third springs 26, the third springs 26 allowing a relative movement between the coriolis masses 18, 19 and the sensing mass 4 in the second horizontal axis Y direction (decoupling the driving movement of the coriolis masses 18, 19 from the sensing mass 4 as shown in fig. 2) and coupling the coriolis masses 18, 19 to the sensing mass 4 during the sensing movement (to cause rotation of the sensing mass 4 in the sensing mode as shown in fig. 3 and discussed below).

The gyroscope 1 also has a schematically shown quadrature compensation structure 21; for example, each coriolis mass 18, 19 may be capacitively coupled to a compensation electrode integral with the support 13.

The gyroscope also has a sensing structure 22, as schematically represented in fig. 3 and as shown in fig. 6, the sensing structure 22 is capable of sensing the angular position of the sensing mass 4. For example, the sensing mass 4 may be capacitively coupled to a fixed electrode carried by the support 13.

The gyroscope 1 of fig. 1 operates as follows (hereinafter, the movement caused by actuation and coriolis forces are described as a drive mode and a sense mode, respectively; it will be apparent to those skilled in the art and as discussed below, the sense movement occurs when the gyroscope 1 is driven in a drive direction).

Referring to fig. 2 and as indicated above, in the drive mode, the frames 10, 11 are operated by applying a drive signal to an actuation assembly 17 associated with each frame 10, 11. In particular, the drive signals are alternating periodic signals (e.g., sine waves, square waves or waves of other shapes) that are equal and opposite in phase, applied to the equivalent elements (e.g., by comb structures) so as to generate a net harmonic force at each instant and cause a drive movement that is both parallel to the second horizontal axis Y but opposite in direction. In fact, the frames 10, 11 move linearly in opposite ways, as indicated by the arrows 30, 31, away from and towards each other in opposite directions each half-cycle of the drive signal.

The coriolis masses 18, 19 are thus pulled by the frames 10, 11 by the second springs 20, but the sensing mass 4 is stationary, constrained to the support 13 by the sensing elastic anchoring system 25 and decoupled from the coriolis masses 18, 19 (in the drive mode) by the deformed third springs 26.

As shown in fig. 3, in the presence of an angular velocity Ω about a vertical axis Z, an acceleration parallel to the first horizontal axis X acts on the gyroscope 1 due to the coriolis effect. Since the coriolis masses 18, 19 are actuated in opposite directions, they are affected by accelerations (forces) in opposite directions and correspondingly move in opposite phases, as indicated by arrow 32 in fig. 3.

Since the coriolis masses 18, 19 are coupled to the sense mass 4 by the third spring 26 (rigid in the sense direction, here parallel to the first horizontal axis X), and since the sense elastic anchoring system 25 (which allows the sense mass 4 to rotate), the sense mass 4 rotates about the first gravitational axis B1 (in fig. 3, the sense movement is performed in a counterclockwise direction).

The rotation of the sensing mass 4 may be sensed as a change in distance relative to the fixed electrode (sensing structure 22) by an angular position sensing structure. However, other schemes (sensing as modification of the facing area) are also possible.

Thus, the gyroscope 1 can reliably sense yaw movement (rotation relative to the vertical axis Z) and is, in fact, insensitive to linear vibrations.

In fact, vibrations along the first horizontal axis X, which may cause the coriolis masses 18, 19 to move along the axis X, cannot be transferred to the sensing mass 4, since the coriolis masses 18, 19 will be accelerated in the same direction.

As regards vibrations along the second horizontal axis Y (which may cause the coriolis masses 18, 19 to move along this axis, as shown in fig. 4 and represented by the unidirectional arrow 34), they do not substantially cause rotation of the sense mass 4 and are therefore undetectable in the case of an ideal structure. However, in case of small dimensional errors and asymmetries (e.g. the presence of orthogonal effects) due to manufacturing tolerances, undesired rotation of the sensing mass 4 may occur, even without the angular velocity Ω along the vertical axis Z being interpreted as due to coriolis forces.

In order to improve the stability of the gyroscope 1, a gyroscope was developed which is also resistant to secondary influences, having a double structure, as shown in fig. 5.

Fig. 5 shows a gyroscope 50 comprising two gyroscope units which are identical to the gyroscope unit 40 of fig. 1 and are therefore denoted by the same reference numerals (but referred to as a first gyroscope unit 40A and a second gyroscope unit 40B where understanding is facilitated).

The gyro units 40A, 40B are coupled to each other by two bridge elements (top bridge element 51A, bottom bridge element 51B).

In detail, in fig. 5, a top bridge element 51A is coupled to the first frame 10 of each gyro unit 40, and a bottom bridge element 51B is coupled to the second frame 11 of each gyro unit 40. In particular, the bridging elements 51A, 51B are connected at a substantially central point of the respective frame 10, 11. In fig. 5, the bridging elements 51A, 51B are connected at their respective ends to the respective frames 10, 11.

The bridging elements 51A, 51B (shown schematically as being substantially rigid in the direction of the second horizontal axis Y and allowing a small relative rotation) are coupled to the frames 10, 11 by fourth springs 55 such that the bridging elements 51A, 51B follow the movement of the frames 10, 11 as explained below.

Furthermore, the bridging elements 51A, 51B are anchored to the support 13 by means of bridging anchors 56, the bridging anchors 56 being arranged centrally with respect to the same bridging elements 51A, 51B and allowing them to rotate about respective axes passing through the bridging anchors 56 and parallel to the vertical axis Z.

In the gyroscope 50 of fig. 5, the gyroscope unit 40 is driven in antiphase, i.e., when the frames 10, 11 of the first gyroscope unit 40A are moved toward the second axis of gravity B2, the frames 10, 11 of the second gyroscope unit 40B are moved away from the second axis of gravity B2 (as indicated by arrow 60 in fig. 5), and vice versa.

Thus, the portion of the bridging elements 51A, 51B coupled to the frames 10, 11 (here the ends of the bridging elements 51A, 51B) is moved up or down in fig. 5 in an alternating manner (as a first approximation, in a direction parallel to the second horizontal axis Y), i.e. movement of the first frame 10 of the gyroscope structure 40 (e.g. the first gyroscope structure 40A) in one direction (e.g. downward) and upward movement of the first frame 10 of the other gyroscope structure 40 (in this example the second gyroscope structure 40B) rotates the top bridging element 51A around its own bridging anchor 56 in the first direction (in this example counterclockwise); and vice versa for the second frame 11 and the bottom bridge member 51B, as indicated by arrow 61.

Thus, any angular velocity Ω acting on gyroscope 50 will cause displacement of coriolis mass 18 of gyroscope unit 40A, 40B and coriolis mass 19 of gyroscope unit 40A, 40B in opposite directions and rotation of sense mass 4 of first and second gyroscope units 40A, 40B in opposite directions. Thus, the angular position sensing structures 22 of the first and second gyroscope units 40A, 40B provide equal and opposite signals.

In this configuration, any vibrations parallel to the second vertical axis Y do not cause any movement of the frames 10, 11, since any acceleration acting thereon is blocked by the bridging elements 51A, 51B, the bridging elements 51A, 51B being unable to translate due to the bridging anchors 56. In any case, as explained above with reference to fig. 4, any residual vibrations may be eliminated.

A possible implementation of a gyroscope 50 for sensing deflection movements is shown in fig. 6, in which the gyroscope unit 40 is visible, as well as the actuation assembly 17, the quadrature compensation structure 21 and the sensing structure 22.

Fig. 7 shows a gyroscope 100 for sensing roll/pitch movement (i.e., rotation of the gyroscope 100 about one of the horizontal axes X, Y of the inertial system XYZ). In particular, the following description relates to roll movements; pitch sensing may be sensed by rotating the entire structure 90 ° (or by structures modified by those skilled in the art).

The gyroscope 100 of fig. 7 has a basic structure similar to the gyroscope 1 of fig. 1 and operates according to similar principles, even if based on different movements of the coriolis mass; therefore, elements similar to those of the gyroscope 1 are denoted by reference numerals increased by 100 and will be described as usefully as possible.

Specifically, in the gyroscope 100 of fig. 7, to allow sensing of roll/pitch movements, the coriolis mass (indicated here at 118, 119) and the sensing mass (indicated here at 104) have degrees of freedom along a vertical axis Z.

Here, in particular, in the sensing mode, the coriolis masses 118, 119 may rotate in anti-phase about respective hinge axes parallel to the first horizontal axis X, and the sensing masses (indicated by 104) may be pulled away from these hinge axes with respective portions.

Furthermore, the sensing mass 104 may rotate about a second axis of gravity B2 (the axis of gravity of the gyroscope 1, here also forming the sensing mass 104 and the axis of gravity of the basic structure, here denoted by 140), the second axis of gravity B2 being parallel to the first horizontal axis X and passing through the first axis of gravity B1 of the sensing mass 104.

In detail, in fig. 7, the frames 110, 111 are driven to move in alternating and anti-phase motion parallel to the second horizontal axis Y (as described above with reference to fig. 2), and are coupled to the coriolis masses 118, 119 such that they also move parallel to the second horizontal axis Y and in anti-phase in the drive mode.

Furthermore, the coriolis masses 118, 119 are coupled to the frames 110, 111 such that in the sense mode, they can also rotate about the hinge axis (as described above) and cause rotation of the sense mass 104 in the event of any roll movement of the gyroscope 100 (i.e., rotation about the second axis of gravity B2). In fact, in the case of an indication drive, the rolling movement generates coriolis forces parallel to the vertical axis Z in opposite directions on both sides of the second gravitational axis B2; the rotating sensing mass 104 has a displacement component parallel to the vertical axis Z, which can be sensed by an electrode arranged on a fixed structure (support 113), which electrode is placed for example under or sideways of the sensing mass 104.

In particular, in the gyroscope 100 of fig. 7, the sensing mass 104 has an elongated shape in a direction parallel to the second horizontal axis Y, wherein the sensing components 104A, 104B are arranged on opposite sides of the second gravitational axis B2 and rotate in opposite directions relative to the horizontal plane XY (as explained below). However, while the elongated shape of the sensing mass 104 is advantageous, this is not necessary as it allows for area optimization.

In fig. 7, each coriolis mass 118, 119 is still generally C-shaped, having a base side 135 and a projecting arm 136.

The base side 135 of each coriolis mass 118, 119 is coupled to the respective frame 110, 111 by a second spring (here indicated by 120) and thus forms a hinge portion hinged to the respective frame 110, 111; the protruding arm 136 extends toward the second spindle B2.

The second springs 120 are here configured to allow the aforementioned rotation of the coriolis masses 118, 119 about an axis parallel to the first horizontal axis X in the sensing mode. Thus, the second spring 120 is rigid in the driving direction (parallel to the second horizontal axis Y), but compliant in the sensing direction (parallel to the vertical axis Z).

The coriolis forces determine the opposite rotations of the coriolis masses 118, 119 due to the opposite driving movements (communicated by the frames 110, 111 to the respective coriolis masses 118, 119). Thus, for example, when the first coriolis mass 118 rotates causing the free ends of its own projecting arms 136 to move toward the support 113 (away from the viewer, cross mark 145 in fig. 7), the second mass 119 rotates in the opposite direction, and the free ends of its own projecting arms 136 move away from the support 113 (toward the viewer, point mark 146), and vice versa.

Furthermore, a third spring (here indicated by 126) coupling the coriolis mass 118, 119 (more precisely, the protruding arm 136) to the sensing mass 104 is configured to allow rotation of the sensing mass 104.

The sensing mass 104 then moves with its own sensing components 104A, 104B following parallel to the vertical axis Z of the protruding arm 136 with respect to the plane XY and rotates about the second gravitational axis B2.

To allow rotation of the sensing mass 104, it is coupled to the support 113 by a sensing elastic anchoring system (indicated schematically by 125, see fig. 8).

As mentioned above, rotation of the sensing components 104A, 104B may be sensed by a sensing structure 122 (e.g., electrode 122, schematically shown in dashed lines), the sensing structure 122 being integrated with the support 113 and capacitively coupled to the sensing components 104A, 104B to sense a capacitance difference due to a change in distance between the same sensing components 104A, 104B and the support 113.

Fig. 7 also shows quadrature compensation structure 121.

One possible implementation of a gyroscope 100 for sensing yaw movement is shown in fig. 8, which doubles the structure to make it more resistant to linear vibrations in the direction of the second horizontal axis Y (similar to that described with reference to fig. 5), where the actuation assembly 117 is also indicated.

Here, the frames 110, 111 are driven to move in an anti-phase motion (parallel to the second horizontal axis Y) in each gyro unit (here denoted by 140A, 140B), similar to that described above with reference to fig. 5.

In particular, in the gyroscope 100, the sensing components 104A, 104B (arranged on opposite sides of the second gravitational axis B2) in the two gyroscope units 140A, 140B move in opposite directions relative to the vertical axis Z, as explained below.

In fact, here, the coriolis forces parallel to the vertical axis Z determine the opposite rotations of the coriolis masses 118, 119 in the two gyroscope units 140A, 140B. Thus, for example, when the first coriolis mass 118 of the first gyroscope unit 140A and the second coriolis mass 119 of the second gyroscope unit 140B are rotated such that the free ends of their own protruding arms 136 are moved toward the support 113, the second coriolis mass 119 of the first gyroscope unit 140A and the first coriolis mass 118 of the second gyroscope unit 140B are counter-rotated such that the free ends of their own protruding arms 136 are moved away from the support 113, and vice versa.

Thus, the two sensing masses 104 counter-rotate about the second gravitational axis B2; that is, when the first sensing component 104A of one of the gyro units 140 (e.g., the first gyro unit 140A) moves upward (toward the observer, away from the support 113), the first sensing component 104A of the other gyro unit 140 (in this example, the second gyro unit 140B) moves downward (away from the observer, toward the support 113), and vice versa.

Fig. 8 shows a sensing elastic anchoring system 125 that allows the sensing mass 104 to rotate about a second gravitational axis B2.

The gyroscope 100 of fig. 8 is also highly resistant to vibrations parallel to the second horizontal axis Y (and to the first horizontal axis X) for reasons similar to those described with reference to fig. 5.

Fig. 9 shows a gyroscope 150 that couples the structures 40 and 140 of fig. 6 and 8 to allow in-plane sensing (yaw movement) and out-of-plane sensing (roll/pitch movement).

The gyroscope 150 is particularly advantageous because the presence of a single drive chain (actuation assembly 117, frames 110, 111, bridging elements 151A, 151B) for both sensing directions simplifies the associated control circuitry (typically contained in a separate device such as an ASIC-application specific integrated circuit).

Gyroscope 150 also allows for damping of linear vibrations (accelerations) while maintaining good performance and reduced size (e.g., 1.5x 2.5 mm).

Fig. 10 shows a circuit 160 for sensing angular velocity, which may be used in combination with a MEMS gyroscope, for example suitable for use in the gyroscopes 1, 50, 100, 150 of fig. 1 to 9.

In particular, the circuit 160 has the function of processing the signal provided by the gyroscope to obtain angular velocity data to be provided to the user.

The circuit 160 also has the function of regulating the correct operation of the same gyroscope, in particular with reference to the drive amplitude and frequency and the quadrature compensation (by generating the quadrature compensation voltage).

The circuit 160 includes a drive stage 161 and a sense stage 162.

Specifically, the drive stage 161 is exemplified here by a resonant drive block 165 and a regulation block (pll+agc) 166.

The resonant drive block 165 comprises the mechanical drive structure (frames 10, 11, 110, 111 and associated drive structures/electrodes) and associated circuitry and movement detection circuitry for generating the drive voltage.

The adjustment block 166 includes circuitry intended to control the drive parameters, including circuitry for adjusting the drive voltage and controlling the gain, and is connected in feedback with the resonant drive block 165 to adjust the amplitude and frequency of the drive signal of the resonant drive block 165 in a closed loop. The adjustment block 166 thus generates the output signal PLL OUT.

The driver stage 161 operates in any manner, for example as described in Ajit Shalma et al, article "A104-dB Dynamic Range Transimpedance-Based CMOS ASIC for Tuning Fork Microgyroscopes," IEEE Journal of Solid-State Circuits, vol 42.No.8,August 2007 (see, inter alia, FIG. 2 and Part II B, related description in "Drive Oscillator").

The sensing stage 162 is illustrated herein as: a resonant sense block 170; a C/V amplifier 171; a first demodulator 172, a second demodulator 173; a PID block 174 and an a/D conversion block 175.

The resonant sense mass 170 includes mechanical sense structures (coriolis masses 18, 19, 118, 119; sense masses 4, 104 and sense structures/electrodes) and quadrature compensation structures (21, 121) and motion detection circuitry.

The capacitive voltage conversion amplifier 171 illustrated herein comprises a signal amplifier connected to a sensing structure/electrode.

The first demodulator 172 and the second demodulator 173 demodulate the output signal of the C/V amplifier 171 with the drive signal PLL OUT generated by the adjustment block 166 and the signal phase shifted by 90 ° (PLL out+90°) respectively, so as to separate the signal component caused by the coriolis force (coriolis signal dem_i, proportional to the angular velocity of the sensing mass 4, 104) from the quadrature component dem_q (proportional to the position of the sensing mass 4, 104), as explained by the "Sense channel" in Part II B in the document mentioned before.

The PID block 174 performs closed-loop control of the compensation voltage applied to the quadrature compensation structure 21 based on the quadrature signal dem_q generated by the second demodulator 173.

An a/D conversion block 175 connected to the output of the first demodulator 172 converts the coriolis signal dem_i into digital form and outputs an angular velocity signal s1 uniquely related to the angular velocity Ω.

The operation of the Sense control stage 162 operates generally as explained above in "Sense Change" in Part II B in the aforementioned documents or in the article "Quadrature-Error Compensation and Corresponding Effects on the Performance of Fully Decoupled MEMS Gyroscopes" by Erdinc Tatar et al, IEEE Journal of Microelectromechanical Systems, vol.21.No.3, june 2012, (see in particular FIG. 4, including Quadrature compensation loops).

While the graph of fig. 10 allows for reliable adjustment of gyroscope operation in most applications, in some applications a more rigorous inspection is required to ensure high safety conditions. This is the case, for example, in the automotive sector for gyroscopes for controlling parameters of vehicle components and for checking driving conditions, for satisfying the vehicle and/or personnel safety conditions required today.

In these cases, it is often necessary to actively confirm that the controlled parameters, amounts and conditions match the design characteristics or expected values, and to generate signaling, for example, by a flag or alarm signal instead.

Fig. 11 illustrates an angular velocity sensing circuit 180 that may be used for the purpose of monitoring the deflection and sensitivity stability of a MEMS gyroscope (e.g., gyroscopes 50, 100 of fig. 5, 6 and 8).

For this purpose, the angular velocity sensing circuit 180 includes: the drive control stage, like the drive control stage 161 of fig. 10, is therefore designated with the same reference numeral; and two sense control stages, each similar to sense control stage 162 of fig. 10, and therefore indicated as first and second sense control stages 162.1, 162.2.

In the angular velocity sensing circuit 180, each sensing control stage 162.1, 162.2 is an independent processing channel and includes one own resonant sensing block 170; for example, a first sensing control stage 162.1 may be associated with the sensing masses 4, 104 (and with the corresponding coriolis masses 18, 19, 118, 119) of the first gyroscope unit 40A, 140A of fig. 5, 6, or 8, and a second sensing control stage 162.2 may be associated with the corresponding portion of the second gyroscope unit 40B, 140B of fig. 5, 6, or 8.

Similar to fig. 10, each sense control stage 162.1, 162.2 includes a C/V amplifier 171 in addition to a corresponding resonant sense block 170; a first demodulator 172 (generating a demodulation rate signal dem_i.1, and correspondingly dem_i.2), and a second demodulator 173 (generating a demodulation quadrature signal dem_ Q.1, and correspondingly dem_ Q.2); the PID block 174 and the a/D conversion block 175 (generating the angular velocity signal s1.1 and correspondingly also s1.2, uniquely related to the angular velocity Ω, sensed by their own processing channels).

Obtaining two angular velocity signals s1.1, s1.2 from two nearly identical but distinct channels allows a more extensive monitoring of the operation of the system and an evaluation of the safety conditions.

For example, the angular velocity signals s1.1, s1.2 may be used as shown in the graph of fig. 12, involving a gyroscope system 185 configured to generate security condition signaling.

In fig. 12, a gyroscope system 185 includes a dual sense channel gyroscope and security monitoring circuitry, represented in a very schematic manner.

In detail, the gyro system 185 includes a resonance driving block 186, a first sensing channel 187.1, a second sensing channel 187.2, and a threshold comparator 189.

The resonance driving block 186 may correspond to the resonance driving block 165 of fig. 10 and 11; specifically, it may be coupled to a conditioning block pll+agc similar to the conditioning block 166 of fig. 10 and 11.

The first and second sensing channels 187.1, 187.2 are identical to each other and each comprise a respective moving resonator 190.1, 190.2 and a respective detection structure 191.1, 191.2.

The moving resonators 190.1, 190.2 of fig. 12 are identical to each other and may correspond to the resonant sensing block 170 of fig. 11; in particular, they may be formed by the gyro units 40A, 40B of fig. 5, 6 and 8; the sense masses 4, 104 of 140A, 140B are formed. The moving resonators 190.1, 190.2 may be coupled to respective quadrature compensation loops (e.g., to blocks 173, 174 or other quadrature control circuits of fig. 11).

The detection structures 191.1, 191.2 are identical to each other and comprise a detection electrode and a processing circuit for the signals sensed by said electrode; for example, they may correspond to blocks 171, 172 and 175 or similar blocks of the first and second sensing control stages 162.1, 162.2 of fig. 11.

The detection structures 191.1, 191.2 generate respective channel angular velocity signals o1, o2 which are provided to a summing block 193, which summing block 193 sums them and generates an output angular velocity signal o3 at an output. The output angular velocity signal o3 has complete dynamic characteristics with respect to the mechanical/electrical structure and can be used by the processing system or device to obtain parameters useful for operation, for example for controlling driving conditions and/or mechanisms and equipment installed on the motor vehicle.

If the sense channels 187.1, 187.2 are identical, the channel angular velocity signals o1, o2 will be identical. In practice, since the two sensing channels 187.1, 187.2 are different, typically under correct operating conditions, the channel angular velocity signals o1, o2 are slightly different due to manufacturing tolerances, small dimensional or shape variations or small differences in the processing circuitry.

However, in some cases, the channel angular velocity signals o1, o2 may differ in a significant, perceptible manner, for example due to different drift of the respective characteristics over time, failure of one of the sensing channels 187.1, 187.2, fatigue or initial failure of one of the moving resonators 190.1, 190.2.

The gyroscope system 185 thus includes: a difference block 194 that subtracts the channel angular velocity signals o1, o2 from each other to output a difference signal S _D The method comprises the steps of carrying out a first treatment on the surface of the And a threshold comparator 189 which compares the difference signal S _D And comparing with a set threshold. If the difference signal S _D Below the set threshold, the threshold comparator 189 outputs the correct operation signal (ok in fig. 12); if the difference signal S _D Below the set threshold, the threshold comparator 189 outputs an alarm signal (e.g., flag F) for a suitable processing circuit or a suitable control system provided in the device.

If the detection structures 191.1, 191.2 comprise a/D converters as shown in fig. 11, they may also comprise corresponding high pass filters; in this case, the threshold comparator 189 may compare the difference between the digital angular velocity signals with an appropriate threshold.

For example, the channel angular velocity signals o1, o2 may differ in a non-negligible way, having an asymmetric effect on the semiconductor substrate (e.g. on the supports 13, 113 of fig. 1 to 9), due to packaging reasons, and in particular due to the presence of soldering areas or to the bending of the board on which the gyroscope integrated die is mounted ("PCB bending" phenomenon).

This may result in a gain change of the sense channels 187.1, 187.2. In this case it may also be useful to filter the channel angular velocity signals o1, o2 with a low-pass filter.

For example, fig. 13 shows a gyroscope system 195 comprising first and second sense channels 187.1, 187.2 similar to the channel of fig. 12, wherein the detection structures 191.1, 191.2 each comprise a high pass filter 196 (generating respective first digital angular velocity signals o1_h, o2_h) and a low pass filter 197 (generating respective second digital angular velocity signals o1_l, o2_l).

The first digital angular velocity signals o1_h, o2_h are each provided to a summing block 193 and to a first differencing block 194 (similar to the differencing block 194 of fig. 12 and therefore indicated with the same reference numerals) for generating an output angular velocity signal o3 and a difference signal, here indicated as first difference signal S _D1 Similar to that described above with respect to fig. 12.

First difference signal S _D1 Is provided to a first threshold comparator 189 which is similar to the threshold comparator 189 of fig. 12 and is therefore indicated with the same reference numerals.

In addition, the second digital angular velocity signals o1_l, o2_l are provided to a second differencing block 198, the second differencing block 198 generating a second difference signal S _D2 Second difference signal S _D2 Is provided to a second threshold comparator 199.

In this way, the drift phenomenon can be highlighted.

In fact, by naming the gains of the sense channels 187.1, 187.2 as g.1 and g.2, respectively, and their offsets as zrl.1, zrl.2, respectively (output null input condition, i.e. gyro stationary), it is:

o1＝G.1Ω+ZRL.1

o2＝G.2Ω+ZRL.2

thus, the output angular velocity signal o3 is given by:

conversely, the first difference signal S after high-pass filtering _D1 Equal to

S _D1 ＝(G.1-G.2)Ω

This can be directly compared with the first threshold Th 1.

Conversely, the low-pass filtered second difference signal S _D2 Equal to

S _D2 ＝(G.1–G.2)+(ZRL.1-ZRL.2)

Which is different from the first difference signal S _D1 Together with the information given, provides information about the possible offset differencesInformation of the partial drift (ZRL.1-ZRL.2).

The presence of two distinct but equal channels allows to obtain a large amount of information about the operation of the gyroscope.

For example, in the case of wide displacements of a mass such as the sensing mass 4, 104 of fig. 5, 6 or 8, harmonic distortion may be generated. The response of the system to this distortion is the generation of odd harmonics which, if the frequency is tuned with a parasitic sense mode, can lead to offset variations and gains in the gyroscope.

In addition, spurious mode frequency adaptation may also be triggered due to stresses during customer packaging or assembly.

The presence of two sensing channels 187.1, 187.2 allows to highlight these problems and to introduce compensation measures or in any case to replace defective components, thus improving the safety of the system in which they are used.

Fig. 14A to 14G show in an extremely simplified manner the different basic structures of the gyroscope and its behaviour in the presence of vibrations of the coriolis force and of the linear type (parasitic movements of the gyroscope parallel to the main extension direction) and of the rotation type (parasitic movements of the gyroscope about one of the axes of inertia).

In particular, in fig. 14A to 14G, the gyroscope comprises one or more movable masses (M1-M4) driven in alternating rectilinear motion along a drive shaft Dr (described below and represented by arrows D1-D4) at a drive frequency fd and rotated about a rotation axis R due to an external rotation field (angular velocity Ω).

In particular, in fig. 14A-14E, the movable masses M1-M4 are constrained to a bearing structure so as to be translatable in the presence of coriolis forces (indicated by arrows Co1-Co 4) along a sense direction S perpendicular to the drive direction Dr and perpendicular to the rotation axis R (translating coriolis motion).

In fig. 14F-14G, the movable masses M1-M4 are constrained to a bearing structure so as to be capable of rotating (indicated by arrows Co1-Co4, rotating coriolis motions) about an axis parallel to the rotational axis R in the presence of coriolis forces.

In all the figures, the dashed lines indicate the rest positions of the movable masses M1-M4, while the solid lines indicate the end positions of displacement possible due to the coriolis forces.

For example, in fig. 14A to 14E, the driving shaft Dr and the sensing shaft S may be a horizontal shaft X, Y of the gyroscope; in fig. 14F to 14G, the driving axis Dr and the sensing axis S may be the second horizontal axis Y and the vertical axis Z of the gyroscope.

Further, fig. 14A to 14G show forces (accelerations) acting on the movable masses M1 to M4 in the presence of linear vibrations, acting along the sense direction S (arrow Lin vitr), and acting around the rotation axis R (arrow Rot vitr) in the presence of rotational vibrations.

Fig. 14A to 14G also show by arrows parasitic forces SF, SF1-SF4 due to parasitic vibrations of the respective gyroscopes G1-G3, which may act on the movable masses M1-M4 in the same direction as the coriolis force. It is therefore desirable to exclude the parasitic forces SF, SF1-SF4 in order to be able to calculate correctly the angular velocities that cause the displacements of the masses M1-M4.

In these figures, sensing structures E1-E4 are also shown, e.g., electrodes capacitively coupled to the movable masses M1-M4 to sense their movement (e.g., as a change in distance).

Specifically, fig. 14A shows a gyroscope G1 having a movable mass M1, the gyroscope G1 being driven by alternating linear motion (driving movement D1) along a driving shaft Dr.

The coriolis force acting on the movable mass M1 in the sense direction S is indicated by arrow Co 1. Any parasitic vibrations parallel to the sensing axis (arrow SF 1) may act on the movable mass M1 in the same direction as the coriolis force Co1 and may cause parasitic movements that cannot be distinguished from the sensed movements.

Therefore, the gyroscope G1 cannot resist the linear vibration.

Fig. 14B shows a gyroscope G2 having two movable masses (first and second movable masses M1, M2) equal to each other (same shape, same inertial mass M, same support structure, driven in antiphase along the drive axis Dr as indicated by the arrows D1, D2).

The first sensing structure E1 is coupled to the first movable mass M1, and the second sensing structure E2 is coupled to the second movable mass M2.

Due to the back drive, the coriolis forces acting on the movable masses M1, M2 are directed in opposite directions (arrows Co1, co 2). In contrast, parasitic vibrations (arrow Lin Vibr) parallel to the sensing axis S generate parasitic forces SF1, SF2 (on the first movable mass M1 and the second movable mass M2, respectively) that all point in the same direction. Thus, in each drive cycle, in one of the two movable masses M1, M2, the parasitic force is directed in the same direction as the coriolis force (in fig. 14B, on the first movable mass M1), while in the other of the movable masses M2, M1, the parasitic force is directed in the opposite direction to the coriolis force (in the case shown in fig. 14B, on the second movable mass M2).

In fact, in fig. 14B, the movement due to the parasitic vibration Lin Vibr acts on one movable mass in the same direction as the (coriolis) sensing movement, and on the other movable mass in the opposite direction. Thus, parasitic vibrations Lin Vibr can be sensed and eliminated, for example, by subtracting the sense signals measured on the movable masses M1, M2.

Thus, the gyroscope G2 resists linear vibration.

Fig. 14C shows the behavior of the same gyroscope G2 in the presence of rotational vibration.

Here too, the coriolis forces acting on the movable masses M1, M2 are directed in opposite directions (arrows Co1, co 2). However, even parasitic rotational vibrations (arrow Rot Vibr) that cause the gyroscope G2 to rotate about the gravitational axis O generate parasitic forces SF1, SF2 that are along the sensing axis S and in opposite directions. Thus, the parasitic forces SF1, SF2 point in the same direction as the coriolis forces Co1, co2 in the two movable masses M1, M2 and cause movement in the same direction as the sense movement. Since the rotational vibration induced movements coincide with the sensed movements of the two movable masses M1, M2, they cannot be distinguished from coriolis force induced movements.

The same applies to the drive half cycle, wherein the parasitic forces SF1, SF2 are directed in opposite directions to the coriolis forces Co1, co 2; however, they are indistinguishable.

Therefore, the gyroscope G2 cannot resist the rotational vibration.

Fig. 14D shows that the gyroscope G3 comprises four movable masses M1, M2, M3, M4, which are equal to each other (same shape, same inertial mass M, same support structure) and are arranged side by side along one direction (here the drive axis Dr), wherein the movable masses M1-M4 can translate parallel to the sense axis S perpendicular to the drive axis Dr when the gyroscope G3 is rotated about the rotation axis R.

In the gyroscope G3, the two farthest movable masses (first and fourth movable masses M1, M4, hereinafter also referred to as outer movable masses) are driven in phase (arrow D1), and the two adjacent movable masses (second and third movable masses M2, M3, hereinafter also referred to as center movable masses) are driven in phase but in opposite phase to the two outer movable masses M1, M4 (arrow D2 is opposite to arrow D1).

Since the second and third movable masses M2, M3 are driven in phase, they can combine and form a single central movable mass M2-3.

The sensing structures E1-E4 are each coupled to a respective movable mass M1-M4.

Due to the back drive, the coriolis forces (arrows Co1, co 4) acting on the outer movable masses M1 and M4 are opposite to the coriolis forces (arrows Co2, co 3) acting on the center movable masses M2 and M3. In contrast, parasitic vibrations (arrow Lin Vibr) parallel to the sense axis S produce all parasitic forces SF1-SF4 having the same direction. Thus, in two movable masses (in fig. 14D, in the outer movable masses M1, M4), the parasitic forces (SF 1, SF 4) are directed in opposite directions to the coriolis forces Co1, co4, and in the other two movable masses (in fig. 14D, in the center movable masses M2, M3), the parasitic forces (SF 2, SF 3) are directed in directions consistent with the coriolis forces.

In fact, in each driving half-cycle, the parasitic vibrations coincide with the sensed movements in two movable masses and not with the sensed movements in the other two movable masses. Thus, the parasitic vibration Lin Vibr can be sensed and eliminated.

Thus, the gyroscope G3 resists linear vibration.

Fig. 14E shows the same gyroscope G3 as fig. 14D in the presence of rotational vibration Rot Vibr.

Here, the coriolis forces (arrows Co1, co 4) acting on the outer movable masses M1, M4 are also directed in mutually identical directions, as opposed to the coriolis forces (arrows Co2, co 3) acting on the center movable masses M2, M3. Here, parasitic rotational vibrations (arrows Rot Vibr) create parasitic forces SF1-SF4, which tend to rotate gyroscope G3 about its own center of gravity O, and thus have opposite directions on both sides of center of gravity O. In fact, the parasitic forces SF1, SF2 acting on the first and second movable masses M1, M2 are opposite to the parasitic forces SF3, SF4 acting on the third and fourth movable masses M3, M4.

Thus, the movable masses M1-M4 have Coriolis forces and parasitic forces that act differently on the different movable masses M1-M4. For example, in FIG. 14E, the forces (Co 1, SF1; co3, SF 3) acting on the first and third movable masses M1, M3 have opposite directions; the forces (Co 2, SF2; co4, SF 4) acting on the second and fourth moving masses M2, M4 have a uniform direction.

Due to the different behavior of the movable masses M1-M4, the movement caused by the coriolis force can be distinguished from the movement caused by the rotational vibration Rot Vibr.

Therefore, the gyroscope G3 also resists rotational vibration.

Fig. 14F shows a gyroscope G4 comprising four movable masses M1, M2, M3, M4 (same shape, same inertial mass M, same support structure) equal to each other, arranged side by side along one direction (here the drive shaft Dr).

Here, the movable masses M1-M4 are coupled in pairs, i.e. they form pairs of masses (first pair M1-M2, second pair M3-M4), for each pair of masses they can rotate about the centre of gravity of the rotation axes O1, O2.

Furthermore, in the gyroscope G4, the two outer movable masses (first and fourth movable masses M1, M4) are driven in the same phase (arrow D1), and the two center movable masses (second and third movable masses M2, M3) are driven in phase but in opposite phase to the outer movable masses M1, M4 (arrow D2 is opposite to arrow D1).

Similar to what is described with respect to fig. 14D, the coriolis forces (arrows Co1, co 4) acting on the outer movable masses M1 and M4 are identical to each other and are opposite to the coriolis forces (arrows Co2, co 3) acting on the center movable masses M2 and M3 due to the back drive. In contrast, parasitic vibrations (arrow Lin Vibr) parallel to the sense axis S may generate all parasitic forces SF1-SF4 having the same direction. Thus, in two movable masses (in fig. 14F, in the outer movable masses M1, M4), the direction of the parasitic forces (SF 1, SF 4) is opposite to the direction of the coriolis forces Co1, co4, and in the other two movable masses (in fig. 14D, in the center movable masses M2, M3), the direction of the parasitic forces (SF 2, SF 3) coincides with the direction of the coriolis forces.

In fact, in each driving half-cycle, the parasitic vibrations coincide with the sensed movements in the two movable masses and are not in agreement in the other two movable masses. The parasitic vibration Lin Vibr can thus be sensed and eliminated.

Thus, the gyroscope G3 resists linear vibration.

Fig. 14G shows the same gyroscope G4 as fig. 14F in the presence of rotational vibration Rot Vibr.

Here, the coriolis forces (arrows Co1, co 4) acting on the outer movable masses M1, M4 are also directed in mutually identical directions, as opposed to the coriolis forces (arrows Co2, co 3) acting on the center movable masses M2, M3. Here, the parasitic rotational vibration (arrow Rot Vibr) generates parasitic forces SF1 to SF4, which tend to rotate the gyroscope G3 around its own center of gravity O, and thus the parasitic forces SF1 to SF4 have opposite directions on both sides of the center of gravity O. In fact, the parasitic forces SF1, SF2 acting on the first and second movable masses M1, M2 (first pair) are opposite to the parasitic forces SF3, SF4 acting on the third and fourth movable masses M3, M4 (second pair).

Thus, the movable masses M1-M4 have Coriolis forces and parasitic forces that act differently on the different movable masses M1-M4. For example, in FIG. 14G, on the first and third moving masses M1, M3, the forces (Co 1, SF1; co3, SF 3) have opposite directions; the forces (Co 2, SF2; co4, SF 4) on the second and fourth moving masses M2, M4 have a uniform direction.

Therefore, the gyroscope G4 can also resist rotational vibration.

Fig. 15 shows a gyroscope 200 operating in accordance with the principles shown in fig. 14D, 14E.

The gyroscope 200 is of the MEMS type and has a substantially planar structure with a greater dimension parallel to a first horizontal axis X and a second horizontal axis Y of an inertial reference system XYZ having a vertical axis Z.

The gyroscope 200 has a symmetrical structure about second and third triple axes B2, B3 parallel to the first and second horizontal axes X, Y, respectively, but is configured to be driven as described with reference to fig. 14D, 14E.

Specifically, gyroscope 200 includes four basic structures 201. To distinguish them, the four basic structures 201 are also referred to as first, second, third, and fourth basic structures 201A, 201B, 201C, and 201D (clockwise in fig. 15, the first basic structure 201A is in the upper right corner of fig. 15).

Referring also to fig. 16, which shows, for example, a first basic structure 201A, each basic structure 201 includes a drive structure 202; a coriolis structure 203 and a sense mass 204.

The driving structure 202 comprises two frames 210, 211 configured to generate driving forces in opposite directions, here parallel to the second horizontal axis Y.

In each driving structure 202, two frames 210, 211 are arranged adjacent in a direction parallel to the second horizontal axis Y, the first frame 210 being arranged farther, and the second frame 211 being arranged closer to the second gravitational axis B2 of the gyroscope 200.

The coriolis structure 203 of each base structure 201 includes two coriolis masses 218, 219 that are adjacently arranged in a direction parallel to the second horizontal axis Y.

Hereinafter, coriolis mass 218 of each of the basic structures 201 disposed farther from second axis B2 of gyroscope 200 is also referred to as first coriolis mass 218, and coriolis mass 219 of each of the basic structures 201 disposed closer to second axis B2 of gyroscope 200 is also referred to as second coriolis mass 219.

First coriolis mass 218 is coupled to first frame 210; the second coriolis mass 219 is coupled to a second frame 211. The coriolis masses 218, 219 are coupled to the respective frames 210, 211 by second springs 220.

The second springs 220 are stiff in the drive direction (parallel to the second drive shaft Y) to pull the respective coriolis masses 218, 219 to move in the drive mode. However, the second spring 220 is compliant in the sensing direction, as discussed below with reference to fig. 17 and 18.

In fig. 15, coriolis masses 218, 219 of base structure 201 are approximately L-shaped, and coriolis masses 218, 219 of two base structures 201 (pairs of base structures 201A/201C and 201B/201C) adjacent in a direction parallel to first horizontal axis X are joined so as to have an overall C shape (common coriolis mass, indicated usefully by 218A, 218B, 219A, 219B) similar to gyroscope 1 of fig. 1-4.

In fact, in the gyroscope 200 of fig. 15, 16, each pair 201A/201C and 201B/201C of the basic structure has a structure substantially symmetrical with respect to the symmetry axis S1 parallel to the first horizontal axis X, which also represents the gravitational axis of each sensing mass 204, and is therefore also referred to hereinafter as the barycentric sensing axis S1. First coriolis mass 218 and first frame 210 are disposed on one side of symmetry axis S1; the second coriolis mass 218 and the second frame 211 are arranged on opposite sides of the symmetry axis S1. In practice, the symmetry axis S1 here also forms the axis of gravity of each pair 201A/201C and 201B/201C of the basic structure.

Thus, the first coriolis masses 218 of the pairs of primary structures 201A/201C and 201B/201C have the same drive movement (i.e., they all move in the same direction and the same phase displacement); similarly, the second coriolis mass 219 of the fundamental structure pair 201A/201C and 201B/201C both move in the same manner (i.e., in the same direction and same phase) but in antiphase with the first coriolis mass 218.

Since the second coriolis masses 219 (which are closer to the second center of gravity B2 of the gyroscope 200) move in a uniform manner, they are integral herein.

The second drive frames 211 (which generate a uniform drive movement as described previously) may also be coupled to each other if the geometry allows, i.e., gyroscope 200 may have a second common drive frame 211 coupled to a second common coriolis mass 219.

In this way, high symmetry of movement is obtained.

Further, here, the sense masses 204 are shared between the two basic structures of each pair 201A/201C, 201B/201C, such that the gyroscope 200 of fig. 15 includes two sense masses, referred to (where helpful for understanding) as a first sense mass 204A (common to the first and fourth basic structures 2021A, 201D) and a second sense mass 204B (common to the second and third basic structures 2021B, 201C).

In practice, each sensing mass 204A, 204B is disposed between a first common coriolis mass 218A and a corresponding second common coriolis mass 219A, and between a first common coriolis mass 218B and a corresponding second common coriolis mass 219B.

Sense masses 204A, 204B are coupled to coriolis masses 218, 219 by third springs 226.

The third springs 226 are compliant in the drive direction (parallel to the second drive axis Y) to decouple the coriolis masses 218, 219 from the respective sense masses 204 in the drive mode and rigid in the sense direction to transfer the sense movement of the coriolis masses 218, 219 to the respective sense masses 204 as explained below with reference to fig. 17 and 18.

The sensing masses 204 are anchored to the support 213 in a central position by respective sensing elastic anchoring systems 225 (schematically shown in fig. 16) and each sensing mass 204 is allowed to rotate about a respective concentric axis (central axis C, parallel to the vertical axis Z).

Fig. 16 also shows a resilient structure 284 that couples the frames 210, 211 of the first base structure 201A to each other and to the support 213. A similar elastic structure 284 is also provided for the base structures 201B-201D, as schematically shown in fig. 15.

In detail, the resilient structure 284 includes a first rocker element 276 and a second rocker element 277. The rocker elements 276, 277 are hinged to the support 213 at a hinge point 278 and are rotatable about an axis oriented parallel to the vertical axis Z and passing through the same hinge point 278.

The rocker elements 276, 277 are L-shaped with a first portion 276A, a corresponding 277A and a second portion 276B, a corresponding 277B.

The first portions 276A, 277A are coupled to the first frame 210 and correspondingly to the second frame 211, respectively, by fifth springs 281. The second portions 276B, 277B are coupled to each other by a sixth spring 282.

The fifth spring 281 is relatively rigid so as to transfer the driving movement of the frame 210, 211 to the first portion 276A (277A, respectively) of the rocker element 277, 278, while the sixth spring 282 is compliant in the plane, as indicated below.

The gyroscope 200 of fig. 15 is operable to sense yaw or roll movements, as described below with reference to fig. 16-18, wherein a single basic structure 201 is shown. Specifically, fig. 16 shows forces (accelerations) acting on the basic structure 201 in the driving mode; fig. 17 shows forces acting on the basic structure 201 in a deflection sensing mode; and fig. 18 shows forces acting on the basic structure 201 in a roll sensing mode.

Referring to fig. 16 and as indicated above, in the drive mode, the frames 210, 211 of the basic structure 201 operate in opposite directions parallel to the second horizontal axis Y. The frames 210, 211 move in opposite phases in alternating linear motion and are moved away from and towards each other each half period of the drive signal, as indicated by the arrows D1, D2 pointing in opposite directions.

During the driving movement, the elastic structure 284 rotates and deforms, thereby coupling the movements of the frames 210, 211 of each basic structure 201.

In detail, when the frames 210, 211 are moved in the driving directions D1, D2, they act on the first portions 276A (respectively 277A) of the rocker elements 277, 278, respectively, causing them to rotate in opposite directions about the respective hinge points 278, as indicated by the arrows 283.

Thus, according to arrow 284, second portions 276B, 277B also rotate, causing deformation and displacement of sixth spring 282.

In the drive mode shown in fig. 16, coriolis masses 218, 219 are pulled in opposite directions by frames 210, 211, coriolis masses 218, 219 are coupled to frames 210, 211 by second springs 220, but sense mass 204 is stationary, constrained to support 213 (in translation) and decoupled from coriolis masses 218, 219 by deformed third springs 226.

Fig. 17 shows gyroscope 200 in a deflection sensing mode. In this case it responds to accelerations caused by the angular velocity Ω about the vertical axis Z.

In detail, in this case, the second spring 220 is configured to yield (yield) in a direction parallel to the first horizontal axis X (sensing axis) and the third spring 226 is configured to be substantially rigid in that direction.

Here, rotation of gyroscope 200 about vertical axis Z (due to the coriolis effect in the presence of the drive movement shown in fig. 16) generates an acceleration on coriolis masses 218, 219 that is parallel to the first horizontal direction X-axis, but in the opposite direction (arrows 232, 233). Thus, coriolis masses 218, 219 move parallel to first horizontal axis X in opposite directions (in a first approximation).

The opposite movement of coriolis masses 218, 219 causes rotation of sense mass 204 about its own central axis C as indicated by arrow 221.

The rotation of the sensing mass 204 may be sensed by a position sensing structure (indicated by 222 in fig. 17) which generates a corresponding measurement signal based on a change in distance between the sensing mass 204 and the stationary electrode facing it (a change in distance in a direction parallel to the first horizontal axis X indicated by arrow 223). Processing circuitry (e.g., as described with reference to fig. 10-13) allows for calculation of the rotation angle of the sensing mass 204.

Fig. 18 shows the gyroscope 200 in the roll sensing mode. In this condition, it is responsive to acceleration caused by angular velocity Ω (as represented by arrow 224) about the first horizontal axis X and can sense its value.

In detail, in this case, the second spring 220 is configured to yield in a direction parallel to the vertical axis Z, and the third spring 226 is configured to be substantially rigid in this direction.

Thus, in the presence of angular velocity Ω about first horizontal axis X, the coriolis force causes rotation of coriolis masses 218, 219 about symmetry axis S1 (as indicated above, the center of gravity axis of each pair 201A/201C and 201B/201C of the base structure as well).

Specifically, in each base structure 201, one of the coriolis masses (first coriolis mass 218 in fig. 18) rotates away from the viewer (labeled X, 245), while the other coriolis mass (second coriolis mass 219 in fig. 18) rotates toward the viewer (labeled·, 246).

Because of the coupling with coriolis masses 218, 219 by third spring 226, sense mass 204 rotates in the same direction.

For example, arranged below the sensing mass 204, position sensing structures (indicated schematically by 230 in fig. 18) arranged on two opposite sides with respect to the center of gravity sensing axis S1 allow to measure the rotation of the sensing mass 204 based on a change in distance between the sensing mass 204 and the fixed electrode facing it (a change in distance in a direction parallel to the first horizontal axis X, indicated by arrow 223).

In fact, the basic structure 201 of fig. 18 behaves as described above with reference to fig. 14B, 14C, and thus can resist linear vibrations, but cannot resist rotational vibrations.

In contrast, the gyroscope 200 of fig. 15 behaves in each vertical half (basic structures 201A/201B and 201C/201D) as described with reference to fig. 14D to 14G, so it resists both linear and rotational vibrations.

Fig. 19 and 20 illustrate a dual-axis type gyroscope 250 configured to sense yaw and roll movements.

Specifically, the gyroscope 250 has a central axis B4 parallel to the second horizontal axis Y that divides the gyroscope 250 into a left half 250A (intended to sense yaw movement) and a right half 250B (intended to sense roll movement).

As described above, the left half 250A and the right half 250B have similar overall structures and are driven in the same manner.

Specifically, as discussed above with reference to fig. 15-18 and as represented by arrows D1, D2 in fig. 19 (display drive mode), the frames 218, 219 move completely symmetrically in the left and right halves 250A, 250B.

In contrast, coriolis masses 218, 219 and sense mass 204 move in different ways in two halves 250A, 250B due to the different configurations of second and third springs 220, 226 (as explained above with reference to fig. 16-18) and as shown in fig. 20 (which illustrates the sense mode).

Specifically, left half 250A rotates as indicated by arrow 221 (as described with reference to fig. 17), while right half 250B rotates as indicated by labels 245, 246 (as described with reference to fig. 18).

Since the gyroscope 250 of fig. 19 and 20 is based on the structure shown and described in fig. 14D to 14G, it resists both linear vibration and rotational vibration.

A possible implementation of the gyroscope 250 of fig. 20 is shown in fig. 21, where the quadrature compensation structure 221 and the sensing structure 222 in the left half 250A are visible.

Fig. 22 shows a schematic diagram of a dual-axis gyroscope 300 capable of sensing deflection and pitch movement by a basic structure having a driving section, a deflection sensing member, and a pitch sensing member.

Since each basic structure has sensing components for two different movements, these components act in an alternating manner depending on the instantaneous rotating field applied to gyroscope 300.

In detail, gyroscope 300 is of the MEMS type and has a substantially planar structure, with a greater dimension parallel to a first horizontal axis X and a second horizontal axis Y of inertial reference system XYZ.

The gyroscope 300 has a first axis of gravity B1 parallel to the vertical axis Z of the inertial reference system XYZ and comprises four basic structures 301 symmetrically arranged about second and third axes of gravity B2, B3 (parallel to the first and second horizontal axes X, Y, respectively). To distinguish them, the four basic structures 301 are also referred to as first, second, third and fourth basic structures 301A, 301B, 301C and 301D, respectively (clockwise in fig. 22, with the first basic structure 301A at the upper right corner of fig. 22).

Referring also to fig. 23A, which shows, for example, a first basic structure 301A, each basic structure 301 includes a driving member 302; a pitch sense mass 303, a coriolis mass 403, and a yaw sense mass 404.

The pitch sensing mass 303 is a pitch sensing component; coriolis mass 403 and deflection sensing mass 404 are deflection sensing components; and the drive structure 302 is common to the pitch sensing component (303) and the yaw sensing components (403, 404).

The drive structure 302 of each basic structure 301 comprises two drive assemblies 310, 311 configured to translate along a drive axis (here parallel to the first horizontal axis X) in opposite drive directions, alternately and in phase with each other; the drive assemblies 310, 311 are here arranged alongside one another parallel to the second horizontal axis Y.

Further, here the driving assemblies 310, 311 of adjacent basic structures 301A and 301D or 301B and 301C operate in opposite phases, as indicated by arrows D1, D2 of fig. 22 and explained below.

The pitch sensing mass 303 is centrally anchored here by a first sensing anchoring system 325, which first sensing anchoring system 325 allows its rotation about its own central axis C. The pitch sensing mass 303 is also directly coupled to the driving structure 302 by a coupling spring system 323, which coupling spring system 323 couples the driving structure 302 to the pitch sensing mass 303 and rotates the latter alternately about its central axis C in a driving mode.

In the illustrated embodiment, the pitch sensing mass 303 has a rectangular shape with an axis of symmetry S1 parallel to the first horizontal axis X and a drive side 390 perpendicular to the axis of symmetry S1 and facing the drive structure 302.

In particular, the pitch sensing mass 303 is coupled to the first and second drive assemblies 310, 311 (in fig. 23A, above and below the symmetry axis S1, respectively) at two portions thereof disposed on opposite sides with respect to the symmetry axis S1, such that opposite movements of the drive assemblies 310, 311 determine their alternating drive rotations.

Thus, the coupling spring system 323 is substantially rigid in the driving direction (parallel to the first horizontal axis X), but compliant in the direction parallel to the vertical axis Z to allow pitch movement, as explained below with reference to fig. 25.

Here, the coriolis mass 403 extends laterally to the drive structure 302 on the opposite side of the coriolis mass 403 from the pitch sense mass 303.

The coriolis mass 403 here has a substantially rectangular shape elongated parallel to the second horizontal axis Y and is coupled to one of the two drive assemblies 310, 311 (in fig. 22, 23A, 23B, to the first drive assembly 310) by a drive spring 320, which drive spring 320 is rigid in the drive direction (parallel to the first horizontal axis X) but compliant in a planar direction perpendicular to the drive direction (here parallel to the second horizontal axis Y).

In this way, coriolis mass 403 is actuated to move (in drive mode) parallel to first horizontal axis X with one of the two drive assemblies 310, 311, but it can move (in sense mode) in a vertical direction parallel to second horizontal axis Y, as explained below with reference to fig. 25.

The deflection sensing mass 404 is coupled to the coriolis mass 403 by a sensing spring system 326, the sensing spring system 326 decoupling the deflection sensing mass 404 from the coriolis mass 403 in a drive mode (in a drive direction, here parallel to the first horizontal axis X), but coupling the masses 403, 404 in a deflection sensing mode (rotation of the gyroscope 300 about the axis of gravity B1 300, as explained below with reference to fig. 25).

The sensing spring system 326 also couples the deflection sensing mass 404 to a second sensing anchor system 327, the second sensing anchor system 327 being integral with the support 313 (e.g., semiconductor substrate) and compliant in the sensing direction (here parallel to the second horizontal axis Y).

In gyroscope 300 of fig. 22, coriolis masses 403 of first base structure 301A are coupled with coriolis masses 403 of second base structure 301B to form a first common coriolis mass 403A; similarly, the coriolis mass 403 of the third primary structure 301C is coupled to the coriolis mass 403 of the fourth primary structure 301D to form a second common coriolis mass 403B.

Furthermore, the deflection sensing masses 404 are here coupled in pairs by first bridge elements 351A, 351B, which first bridge elements 351A, 351B extend between the first basic structure 301A and the fourth basic structure 301D, respectively, between the second basic structure 301B and the third basic structure 301B.

The first bridging elements 351A, 351B here extend parallel to the first horizontal axis X and are anchored to the support 313 in respective first bridging anchors 356.

Furthermore, the pitch sense masses 303 are here coupled in pairs by second bridge elements 352A, 352B, the second bridge elements 352A, 352B extending between the first basic structure 301A and the fourth basic structure 301D, between the second basic structure 301B and the third basic structure 301B, respectively, on the outside of the basic structures 301A-301D remote from the second gravitational axis B2 of the gyroscope 300.

The second bridging elements 352A, 352B here extend parallel to the first horizontal axis X and parallel to the first bridging elements 351A, 351B and are anchored to the support 313 at respective second bridging anchors 357 arranged in a central position.

Furthermore, the pitch sensing masses 303 are all coupled by a central bridging element 352C, the central bridging element 352C extending parallel to the first horizontal axis X along the second gravitational axis B2 of the gyroscope 300.

At the first concentric axis B1, the central bridging element 352C is also anchored to the support 313 in a third bridging anchor 358.

In practice, the first basic structure 301A and the fourth basic structure 301D form a pair of basic structures 301A/301D; the same is true for the second and third basic structures 301D (301B/301C pairs).

In this way, as mentioned above, here the drive assemblies 310, 311 of the pairs 301A/301D and 301/301C of the basic structure 301 operate in antiphase and drive the respective pitch sense masses 303 in opposite directions (thus, for example, the first basic structure 301A has a pitch sense mass 303 with a counter-drive rotation (antiphase) with respect to the fourth basic structure 301D, in addition to the second basic structure 301B; conversely, it has a drive movement in unison (in phase) with the third drive structure 301C).

The gyroscope 300 of fig. 22 may be operable to sense yaw and roll movements. Specifically, fig. 22 and 23A show forces (accelerations) acting on the basic structure 301A in the driving mode; fig. 23B shows the forces acting on the base structure 301 in yaw and roll sensing mode.

Referring to fig. 22, 23A and as indicated above, in the drive mode, the frames 310, 311 of each base structure 301 operate in opposite directions (parallel to the second horizontal axis Y). Further, the first frames 310 of each elementary structure pair 301A/301D, 301B/301D of each elementary structure operate in opposite directions. As indicated by the arrows parallel to the first horizontal axis X in fig. 22, 23A, the frames 310, 311 move in opposite phases in alternating linear motion.

The corresponding sensing movement is indicated in fig. 23B. Specifically, with respect to the deflection movement, the first common coriolis mass 403A translates parallel to the second horizontal axis Y in an opposite direction (anti-phase) relative to the second common coriolis mass 403A.

Further, with respect to pitch movements, the pitch sensing masses 303 of the pairs 301A/301D, 301B/301C are rotated in opposite directions (cross marks and dot marks) about the respective symmetry axes S1 (parallel to the first horizontal axis X), respectively, such as the pitch sensing masses 303 are rotated on both sides of the second gravitational axis B2, as described in detail below with reference to fig. 24 and 25.

In the sensing mode, the first bridging elements 351A, 351b rotate in the same direction (clockwise or counterclockwise) about respective axes of rotation parallel to the vertical axis Z and passing through the first bridging anchor 356.

Furthermore, the second bridging elements 352A, 352B and the central bridging element 352C rotate about the same rotational axis parallel to the second horizontal axis Y and passing through the bridging anchors 357, 358. In effect, the second bridging elements 352A, 352B rotate in the same direction as each other and in the opposite direction to the central bridging element 352C as the portion of the sense mass 303 is coupled thereto.

Fig. 24 and 25 show a biaxial MEMS gyroscope 350 configured to sense deflection and pitch movement and obtained by doubling the gyroscope 300 of fig. 22.

In detail, the gyroscope 350 has a central axis B4, the central axis B4 being parallel to the second horizontal axis Y and dividing the gyroscope 350 into a first portion 350A and a second portion 350B.

Here, the first and second portions 350A, 350B have the same structure as the gyroscope 300 of fig. 22. Thus, like numbers are used to indicate like elements. However, with ease of understanding, the pitch sense masses 303 are also identified as pitch sense masses 303A-303H, wherein the sense masses 303A-303D are part of the respective base structures 301A-301D of the first portion 350A and the sense masses 303E-303H form part of the respective base structures 301A-301D of the second portion 350B. Furthermore, for better understanding, the common coriolis masses 403A, 403B are also identified as a first common coriolis mass 403A1 (respectively, 403A 2) and a second common coriolis mass 403B1 (respectively, 403B 2), respectively, when applicable, depending on whether they belong to the first portion 350A (respectively, the second portion 350B), respectively.

The two parts 350A, 350B of the gyroscope 350 are arranged side by side along a first horizontal axis X and form a right half (here forming the first part 350A) and a left half (here forming the second part 350B), the first and second basic structures 301A, 301B of the second part 350B (left half) being adjacent and continuous with the fourth and third basic structures 301D, 301C of the first part 350A (right half), respectively.

Thus, gyroscope 350 is asymmetric in drive (but symmetric in sense, as discussed below) with respect to central axis B4.

As indicated above and shown in fig. 24, the two parts 350A, 350B of the gyroscope 350 are driven in an opposite manner, i.e. the drive components 310, 311 of the first, second, third and fourth basic structures 301A-301D in the two parts 350A, 350B have opposite movements (inversions), as indicated by arrows D1, D2 in fig. 24. In this way, the drive assemblies 310, 311 of adjacent base structures 301 (near the central axis B4) are driven in phase.

Since the first common coriolis mass 403A2 of the second portion 350B is continuous and driven (same driving movement) in the same manner as the second common coriolis mass 403B1 of the first portion 350A, they also move in the same manner in the sensing mode; they are joined here to form a central sense mass 403C.

Similarly, adjacent deflection sensing masses 404 of first and second portions 350A, 350B of gyroscope 350 may be joined to form central deflection sensing masses 404A, 404B, coupled to opposite ends of central coriolis mass 403C. Alternatively, they may remain distinct, as in the implementation shown in fig. 26.

Thus, in the drive mode, the center sense mass 403C oscillates in anti-phase (opposite phase) with the first common coriolis mass 403A1 of the first portion 350A and the second common coriolis mass 403B2 of the second portion 350B, with translational motion parallel to the first horizontal axis X mass, as indicated by arrows D1, D2.

On the other hand, the deflection sensing mass 404 is decoupled from the driving movement.

Further, in the drive mode, the pitch sensing mass 303 rotates about its own gravitational axis, as explained above with reference to fig. 23A; also here, the pitch sensing mass 303 of the two parts 350A, 350B of the gyroscope 350 does not rotate symmetrically due to the existing drive. For example, the pitch sensing mass 303E (the first basic structure 301A belonging to the second portion 350B) rotates in the same direction as the pitch sensing mass 303D (the fourth basic structure 301D belonging to the first portion 350A and adjacent to the pitch sensing mass 303E just mentioned along the first transverse axis X); similarly, the pitch sensing mass 303F (the second basic structure 301B belonging to the second portion 350B) rotates in the same direction as the pitch sensing mass 303C (the third basic structure 301C belonging to the first portion 350A), and so on.

Fig. 25 shows the movement of gyroscope 350 in the sense mode and just in the presence of yaw and pitch movements, so the movements shown for pitch sense mass 303, for coriolis mass 403, and for yaw sense mass 404 do not typically occur simultaneously.

In detail, in the presence of a deflection movement, coriolis mass 403 moves as indicated in fig. 25; then, the center coriolis mass 403C translates parallel to the second horizontal axis Y (downward in fig. 25), pulling the center deflection sense masses 404A, 404B in this direction; the first common coriolis mass 403A1 of the first portion 350A and the second common coriolis mass 403B2 of the second portion 350B translate in opposite directions (upward in fig. 25) relative to the center coriolis mass 403C, pulling the deflection sense mass 404 coupled thereto in the same direction.

In this movement, the first bridging elements 351A, 351B rotate about an axis passing through the respective first bridging anchors 356 and parallel to the vertical axis Z, as shown in fig. 25, due to the opposite translational directions of the coriolis masses 403A1, 403B2 (and thus the respective deflection sensing masses 404) relative to the central coriolis mass 403C.

In particular, the first bridging elements 351A, 351B of the first portion 350A (right side) each rotate in one direction (counterclockwise in fig. 25), and the first bridging elements 351A, 351B of the second portion 350B (left side) each rotate in the opposite direction (clockwise in fig. 25).

The movement of the deflection sensing mass 404 may be sensed by a position sensing structure 322 associated therewith, as schematically represented in fig. 25 (see also fig. 26).

In the presence of pitch movement, each pitch sensing mass 303 rotates about a respective center of gravity sensing axis S1 (shown in fig. 25 as pitch sensing mass 303A).

Due to the opposite driving direction of the pitch sensing masses 303 caused by the driving assemblies 310, 311, they rotate in opposite directions, e.g. as represented by the cross marks (moving towards the support 113 and away from the viewer) and by the dot marks (moving from the support 113 to the viewer).

In this sensing mode, the second bridging elements 352A, 352B and the central bridging element 352C rotate about axes parallel to the second horizontal axis Y and passing through the respective second and third bridging anchors 357, 358 following the opposite movement of the couplings of the pair of pitch sensing masses 303 (adjacent along the first horizontal axis X) and the consistent movement of the couplings of the pitch sensing masses 303 adjacent along the second horizontal axis Y, similar to that described above with reference to fig. 23B.

The gyroscope 350 of fig. 25 is based on the structure shown and described in fig. 14D to 14G. In fact, with respect to the deflection sensing structure, coriolis masses 403A1, 403C, and 403B2 correspond to movable masses M1, M2-3, and M4 of fig. 14D and 14E, respectively, and are driven by drive assemblies 310, 311 such that coriolis masses 403A1, 403B2, which are away from central axis B4, move in the same direction as each other along first horizontal axis X, and coriolis masses (central coriolis mass 403C), which are relatively close to central axis B4, move in opposite directions, as indicated by the arrows in fig. 25. The same applies to the sensing mode, wherein the movements of the coriolis masses 403A1, 403B2 (along the second horizontal axis Y) are directed in mutually coincident directions and in opposite directions relative to the center movable mass 403C, as indicated by the arrows in fig. 26.

In contrast, linear vibrations acting on gyroscope 350 tend to vibrate all of coriolis masses 403A-403C (and deflection sense masses 404 integrated therewith in the sense mode) in the same direction (either positive or negative along second horizontal axis Y). Here, the first bridging elements 351A, 351B prevent such parasitic movements; furthermore, since possible residual movements have different directions relative to the sensed movements in some deflection sensing masses 404, any residual vibrations may be counteracted by the sensed signals.

In addition, the coriolis mass pair 403A-403C (and the deflection sensing mass 404 integrated therewith in the sensing mode) are also resistant to rotational vibrations, as these would cause the coriolis masses 403A1, 403B2 (and each half of the center coriolis mass 403C) to move in opposite directions about the center of gravity C1 of the gyroscope 350 away from the center axis B4, and the geometrically blocked rotation would in any case produce a signal different from the deflection sensing signal and could therefore be eliminated.

The same applies to the pitch sensing component.

Here, the configuration and connection of the drive assemblies 310, 311 and the pitch sensing masses 303 (four half masses, also indicated as 303A1, 303A2, 303B1, 303B2 in fig. 24) coupled along the second horizontal axis Y, coupled together two by two, for example to form pitch sensing masses 303A and 303B, corresponds to that described above with reference to fig. 14F and 14G, so that the pitch sensing components also resist linear and rotational vibrations.

According to another possible identification, the movable masses M1-M4 of FIGS. 14F and 14G correspond to the pairs of pitch sensing masses 303A-303B, 303C-303D, 303E-303F, and 303G-303H.

A possible implementation of the gyroscope 350 of fig. 22-25 is shown in fig. 26.

The gyroscopes described herein are therefore particularly robust, have balanced drive and are insensitive to linear and/or rotational acceleration.

Specifically, in the minimum structure (basic structure of fig. 1 to 4, 14B to 14C, 16 to 18 and 23A, 23B), it is insensitive to parasitic linear vibration, whereas in the configuration described with reference to fig. 14D to 14G, 15, 19 to 21, 22, 24 to 26, it can resist linear and rotational parasitic vibration.

The coriolis force applied to the drive mass cannot generate a torque that can cause parasitic movement; therefore, the driving motion is not affected by the external acceleration.

As discussed above, the sensed movement (yaw and/or roll and/or pitch movement) is insensitive to external linear or angular acceleration and therefore cannot be imposed.

These structures can be provided in a compact manner and thereby reduce costs; in particular, the biaxial approach allows sensing external rotating fields acting around different axes of rotation with a compact structure, even capable of providing redundant signals (e.g. as can be used as described with reference to fig. 10 to 13), and also simplifies signal processing by the associated ASIC.

Finally, it is apparent that modifications and variations can be made to the gyroscopes described and illustrated herein without departing from the scope of the present disclosure. For example, the different embodiments described may be combined to provide further solutions.

The MEMS gyroscope (1; 50;100;150;200;250;300; 350) may be summarized as comprising: a fixed structure (13; 113;213; 313); a first movable mass (18; 118;218; M1;303, 403A;303A1;403A 1) configured to move relative to the fixed structure along a first driving direction and along a first sensing direction transverse to the first driving direction; a first drive assembly (10; 110;210; 310) coupled to the first movable mass and configured to generate a first alternating drive movement in a first drive direction; a first drive spring structure (20; 120;220, 323, 320) coupled to the first movable mass and to the first drive assembly, the first drive spring structure being rigid in a first drive direction, configured to transfer a first alternating drive movement to the first movable mass and compliant in a first sense direction; a second movable mass (19; 119;219; M2;303, 403B;303A2, 403B 1) configured to move relative to the fixed structure in a second driving direction parallel to the first driving direction and in a second sensing direction parallel to the first sensing direction; a second drive assembly (11; 111;211; 311) coupled to the second movable mass and configured to generate a second alternating drive movement in a second drive direction, the second alternating drive movement being inverted relative to the first alternating drive movement; and a second driving spring structure (20; 120;220;320, 323) coupled to the second movable mass and coupled to the second driving assembly, the second driving spring structure being rigid in a second driving direction, configured to transfer a second alternating driving movement to the second movable mass and compliant in a second sensing direction.

The MEMS gyroscope may further include: a first sensing spring system (4, 25;104, 125;204, 225;404, 325, 326;352A, 352B, 357, 327) coupling the first movable mass (18; 118;218; M1;303, 403A;303A1;403A 1) to the fixed structure (13; 113;213; 313) and configured to allow movement of the first movable mass relative to the fixed structure in a first driving direction and in a first sensing direction; a second sensing spring system (4, 25;104, 125;204, 225;404, 325, 326;352a, 352B, 357, 327) couples the second movable mass (19; 119;219; m2;303, 403;303a2, 403B 1) to the fixed structure and is configured to allow movement of the second movable mass relative to the fixed structure in a second driving direction and in a second sensing direction.

The first sensing spring system may comprise a first sensing mass (4; 104;204, 204A; 404), a first sensing spring structure (26; 126;226; 326) and a first anchoring spring structure (25; 125;225; 327), the first sensing spring structure (26; 126;226; 326) being coupled between the first movable mass (18; 118;218, 218A; M1;303, 403;303A1;403A 1) and the first sensing mass (4; 104;204, 204A; 404), being compliant in a first driving direction and being rigid in a first sensing direction, the first anchoring spring structure (25; 125;225; 325) being coupled between the first sensing mass and the fixed structure (13; 113;213; 313) and being compliant in the first sensing direction; the second sensing spring system may comprise a second sensing mass (4; 104;204, 204A; 404), a second sensing spring structure (26; 126;226; 326) and a second anchoring spring structure (25; 125;225; 327), the second sensing spring structure (26; 126;226; 326) being coupled between the second movable mass (19; 119;219, 219B; M2;303, 403;303B1;403B 1) and the second sensing mass (4; 104;204; 404), being compliant in the second driving direction and being rigid in the second sensing direction, the second anchoring spring structure (25; 125;225; 325) being coupled between the second sensing mass and the fixed structure, and being compliant in the second driving direction and being rigid in the second sensing direction; and the first and second sensing masses may be coupled to respective position sensing structures (22; 122;222;230; 322).

The MEMS gyroscope may further include: a third movable mass (M3; 219, 219A;303, 403;303B1, 403A 2) configured to move relative to the fixed structure (13; 113;213; 313) in a third driving direction parallel to the first driving direction and in a third sensing direction parallel to the first sensing direction; a third drive assembly (211; 311) coupled to the third movable mass and configured to generate a third alternating drive movement in a third drive direction, the third alternating drive movement being in phase with the second alternating drive movement; a third drive spring structure (220, 323, 320) coupled to the third movable mass and to the third drive assembly, the third drive spring structure being rigid in a third drive direction, configured to transfer a third alternating drive movement to the third movable mass, and compliant in a third sense direction; a fourth movable mass (M4; 218, 218B;303, 403;303B2, 403B 2) configured to move relative to the fixed structure in a fourth driving direction parallel to the first driving direction and in a fourth sensing direction parallel to the first sensing direction; a fourth drive assembly (210; 310) coupled to the fourth movable mass and configured to generate a fourth alternating drive movement in a fourth drive direction, the fourth alternating drive movement being in phase with the first alternating drive movement; and a fourth drive spring structure (220, 323, 320) coupled to the fourth movable mass and the fourth drive assembly, the fourth drive spring structure being rigid in a fourth drive direction, configured to transfer a fourth alternating drive movement to the fourth movable mass, and compliant in a fourth sense direction.

The MEMS gyroscope may further include: a third sensing spring system (204, 225;303;404, 325, 326, 327, 352C) coupling the third movable mass (M3; 219, 219A;303, 403;303B1, 403A 2) to the fixed structure (213; 313) and configured to allow movement of the third movable mass relative to the fixed structure in a third driving direction and in a third sensing direction; and a fourth sensing spring system (204, 225;303, 325, 326, 327, 352C) coupling the fourth movable mass (M4; 218, 218B;303, 403;303B2, 403B 2) to the fixed structure and configured to allow movement of the fourth movable mass relative to the fixed structure in a fourth driving direction and in a fourth sensing direction.

The third sensing spring system may include a third sensing mass (204, 204B; 404), a third sensing spring structure (226; 326) and a third anchoring spring structure (225; 327), the third sensing spring structure (226; 326) being coupled between the third movable mass (M3; 219B; 403A 2) and the third sensing mass, being compliant in a third driving direction and rigid in the third sensing direction, the third anchoring spring structure (225; 327) being coupled between the third sensing mass and the fixed structure and being compliant in the third sensing direction; the fourth sensing spring system may include a fourth sensing mass (204, 204B; 404), a fourth sensing spring structure (226; 326), and a fourth anchoring spring structure (225; 327), the fourth sensing spring structure (226; 326) being coupled between the fourth movable mass (M4; 218, 218B; 403B 2) and the fourth sensing mass, being compliant in a fourth driving direction and rigid in the fourth sensing direction, the fourth anchoring spring structure (225; 327) being coupled between the fourth sensing mass and the fixed structure, and being compliant in the fourth sensing direction; and the third and fourth sensing masses may be coupled to respective position sensing structures (222; 230; 322).

The second movable mass (219A; 403B 1) and the third movable mass (219B; 403A 1) may be coupled to and integral with each other, or the first and second movable masses (303; 303A1, 303A 2) may be coupled to and integral with each other, and the third and fourth movable masses (303; 303B1, 303B 2) may be coupled to and integral with each other.

The MEMS gyroscope may further include a first bridge element (351A, 351B) coupling the first and second sense masses (404, 404A, 404B), the first bridge element (351A, 351B) being coupled to the fixed structure (313) and being rotatable about a first vertical axis transverse to the first driving direction and transverse to the first sensing direction.

The first and second movable masses (18, 19;218, 218A, 219A;403A, 403B;403A1, 403B 1) may be deflection sensing components.

The first and second movable masses (118, 119;218, 218A, 219A;303A1, 303A 2) may be roll/pitch sensing members.

The MEMS gyroscope may further include a roll/pitch sensing component comprising: a fifth movable mass (303A 1) configured to move relative to the fixed structure (13; 113;213; 313) in a fifth driving direction parallel to the first driving direction and in a fifth sensing direction transverse to the fifth driving direction and transverse to the first sensing direction; a fifth drive spring structure (323) coupled to the fifth movable mass and to the first drive assembly (310), the fifth drive spring structure being rigid in a fifth drive direction, configured to transfer the first alternating drive movement to the fifth movable mass, and compliant in a fifth sense direction; a sixth movable mass (303 A2) configured to move relative to the fixed structure in a sixth driving direction parallel to the first driving direction and in a sixth sensing direction parallel to the fifth sensing direction; a fifth drive assembly (311) coupled to the sixth movable mass and configured to generate a fifth alternating drive movement in the sixth drive direction, the fifth alternating drive movement being in antiphase with the first alternating drive movement; and a sixth driving spring structure (323) coupled to the sixth movable mass and the fifth driving assembly (311), the sixth driving spring structure being rigid in a sixth driving direction, configured to transfer a fifth alternating driving movement to the sixth movable mass, and compliant in a sixth sensing direction.

The roll/pitch sensing component may further include: a seventh movable mass (303B 1) configured to move relative to the fixed structure (13; 113;213; 313) in a seventh driving direction parallel to the first driving direction and in a seventh sensing direction parallel to the fifth sensing direction; a sixth drive assembly (311) coupled to the seventh movable mass and configured to generate a sixth alternating drive movement in a seventh drive direction, the sixth alternating drive movement being in phase with the first alternating drive movement; a seventh drive spring structure (323) coupled to the seventh movable mass and to the sixth drive assembly (310), the seventh drive spring structure being rigid in a seventh drive direction, configured to transfer a sixth alternating drive movement to the seventh movable mass, and compliant in a seventh sense direction; an eighth movable mass (303B 2) configured to move relative to the fixed structure in an eighth driving direction parallel to the first driving direction and in an eighth sensing direction parallel to the fifth sensing direction; a seventh drive assembly (310) coupled to the eighth movable mass and configured to generate a seventh alternating drive movement in the eighth drive direction, the seventh alternating drive movement being in phase with the first alternating drive movement; an eighth drive spring structure (323) coupled to the eighth movable mass and the seventh drive assembly, the eighth drive spring structure being rigid in an eighth drive direction, configured to transfer the seventh alternating drive movement to the eighth movable mass, and compliant in an eighth sense direction.

The fifth and sixth movable masses (303 A1, 303 A2) may be coupled to and integrated with each other, and the seventh and eighth movable masses (303B 1, 303B 2) may be coupled to and integrated with each other.

The MEMS gyroscope may further include a fifth anchored spring structure (352C) resiliently coupled with the fifth, sixth, seventh, and eighth movable masses.

The MEMS gyroscope may further include: a ninth movable mass (303D) configured to move relative to the fixed structure (13; 113;213; 313) in a ninth driving direction parallel to the first driving direction and in a ninth sensing direction parallel to the fifth moving direction; a ninth driven elastic structure (323) coupled to the ninth movable mass and to the second drive assembly (311), the ninth driven elastic structure being rigid in the second drive direction, configured to transfer the second alternating drive movement to the ninth movable mass, and compliant in the ninth sense direction; a second bridge element (352A) extending between the fifth (303 A1), sixth (303B 1) and ninth (303D) movable masses, the second bridge element being coupled to the fixed structure (313) and being rotatable about a second vertical axis transverse to the first driving direction and parallel to the fifth sensing direction.

A method for driving a MEMS gyroscope, which may be summarized as including: a fixed structure (13; 113;213; 313); a first movable mass (18; 118;218; M1;303, 403A;303A1;403A 1) configured to move relative to the fixed structure along a first driving direction and along a first sensing direction transverse to the first driving direction; a first drive assembly (10; 110;210; 310) coupled to the first movable mass; a first drive spring structure (20; 120;220, 323, 320) coupled to the first movable mass and to the first drive assembly, the first drive spring structure being rigid in a first drive direction and compliant in a first sense direction; a second movable mass (19; 119;219;303, 403B;303A2, 403B 1) configured to move relative to the fixed structure in a second driving direction parallel to the first driving direction and in a second sensing direction parallel to the first sensing direction; a second drive assembly (11; 111;211; 311) coupled to the second movable mass; and a second driven elastic structure (20) coupled to the second movable mass and to the second drive assembly, the second driven elastic structure being rigid in a second drive direction and compliant in a second sense direction, the method may be summarized as including: generating a first alternating drive movement of the first drive assembly in a first drive direction; transmitting a first alternating drive motion from the first drive assembly to the first movable mass; generating a second alternating drive movement of the second drive assembly in a second drive direction, the second alternating drive movement being in antiphase with the first alternating drive movement; and transmitting a second alternating drive movement from the second drive assembly to the second movable mass.

The various embodiments described above may be combined to provide further 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 the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the present disclosure.

Claims

1. A microelectromechanical system, MEMS, gyroscope, comprising:

a fixed structure;

a first movable mass configured to move relative to the fixed structure along a first drive direction and along a first sense direction transverse to the first drive direction;

a first drive assembly coupled to the first movable mass and configured to generate a first alternating drive movement in the first drive direction;

a first drive spring structure coupled to the first movable mass and to the first drive assembly, the first drive spring structure being rigid in the first drive direction, configured to transfer the first alternating drive movement to the first movable mass, and compliant in the first sense direction;

A second movable mass configured to move relative to the fixed structure in a second drive direction parallel to the first drive direction and in a second sense direction parallel to the first sense direction;

a second drive assembly coupled to the second movable mass and configured to generate a second alternating drive motion in the second drive direction, the second alternating drive motion being inverted relative to the first alternating drive motion; and

a second drive spring structure coupled to the second movable mass and to the second drive assembly, the second drive spring structure being rigid in the second drive direction, configured to transfer the second alternating drive movement to the second movable mass, and compliant in the second sense direction.

2. The MEMS gyroscope of claim 1, further comprising:

a first sensing spring system coupling the first movable mass to the fixed structure and configured to permit movement of the first movable mass relative to the fixed structure in the first drive direction and in the first sensing direction;

A second sensing spring system couples the second movable mass to the fixed structure and is configured to permit movement of the second movable mass relative to the fixed structure in the second driving direction and in the second sensing direction.

3. The MEMS gyroscope of claim 2, wherein:

the first sensing spring system includes a first sensing mass, a first sensing spring structure coupled between the first movable mass and the first sensing mass, compliant in the first drive direction, and rigid in the first sense direction, and a first anchoring spring structure coupled between the first sensing mass and the fixed structure, and compliant in the first sense direction;

the second sensing spring system includes a second sensing mass, a second sensing spring structure coupled between the second movable mass and the second sensing mass, compliant in the second drive direction, and rigid in the second sense direction, and a second anchoring spring structure coupled between the second sensing mass and the fixed structure, and compliant in the second sense direction; and

The first and second sense masses are coupled to respective position sensing structures.

4. The MEMS gyroscope of claim 1, further comprising:

a third movable mass configured to move relative to the fixed structure in a third drive direction parallel to the first drive direction and in a third sense direction parallel to the first sense direction;

a third drive assembly coupled to the third movable mass and configured to generate a third alternating drive movement in the third drive direction, the third alternating drive movement being in phase with the second alternating drive movement;

a third drive spring structure coupled to the third movable mass and to the third drive assembly, the third drive spring structure being rigid in the third drive direction, configured to transfer the third alternating drive movement to the third movable mass, and compliant in a third sense direction;

a fourth movable mass configured to move relative to the fixed structure in a fourth drive direction parallel to the first drive direction and in a fourth sense direction parallel to the first sense direction;

A fourth drive assembly coupled to the fourth movable mass and configured to generate a fourth alternating drive movement in the fourth drive direction, the fourth alternating drive movement being in phase with the first alternating drive movement; and

a fourth drive spring structure coupled to the fourth movable mass and the fourth drive assembly, the fourth drive spring structure being rigid in the fourth drive direction, configured to transfer the fourth alternating drive movement to the fourth movable mass, and compliant in a fourth sense direction.

5. The MEMS gyroscope of claim 4, further comprising:

a first sensing spring system coupling the third movable mass to the fixed structure and configured to permit movement of the third movable mass relative to the fixed structure in the third drive direction and in the third sense direction; and

a second sensing spring system couples the fourth movable mass to the fixed structure and is configured to permit movement of the fourth movable mass relative to the fixed structure in the fourth drive direction and in the fourth sense direction.

6. The MEMS gyroscope of claim 5, wherein:

the first sensing spring system includes a third sensing mass, a third sensing spring structure coupled between the third movable mass and the third sensing mass, compliant in the third drive direction, and rigid in the third sense direction, and a third anchoring spring structure coupled between the third sensing mass and the fixed structure, and compliant in the third sense direction;

the second sensing spring system includes a fourth sensing mass, a fourth sensing spring structure coupled between the fourth movable mass and the fourth sensing mass, compliant in the fourth drive direction, and rigid in the fourth sense direction, and a fourth anchoring spring structure coupled between the fourth sensing mass and the fixed structure, and compliant in the fourth sense direction; and

the third and fourth sense masses are coupled to respective position sensing structures.

7. The MEMS gyroscope of claim 4, wherein

The second movable mass and the third movable mass are coupled to each other and integrated, or

The first movable mass and the second movable mass are coupled to each other and integrated, and the third movable mass and the fourth movable mass are coupled to each other and integrated.

8. The MEMS gyroscope of claim 3, further comprising:

a first bridge element coupling the first and second sense masses, the first bridge element being coupled to the fixed structure and rotatable about a first vertical axis transverse to the first drive direction and transverse to the first sense direction.

9. The MEMS gyroscope of claim 1, wherein the first movable mass and the second movable mass are deflection sensing components.

10. The MEMS gyroscope of claim 1, wherein the first movable mass and the second movable mass are roll/pitch sensing components.

11. The MEMS gyroscope of claim 9, wherein the MEMS gyroscope further comprises a roll/pitch sensing component comprising:

A third movable mass configured to move relative to the fixed structure in a third driving direction parallel to the first driving direction and in a third sensing direction transverse to the third driving direction and transverse to the first sensing direction;

a third drive spring structure coupled to the third movable mass and to the first drive assembly, the third drive spring structure being rigid in the third drive direction, configured to transfer the first alternating drive movement to the third movable mass, and compliant in the third sense direction;

a fourth movable mass configured to move relative to the fixed structure in a fourth drive direction parallel to the first drive direction and in a fourth sense direction parallel to the third sense direction;

a third drive assembly coupled to the fourth movable mass and configured to generate a fifth alternating drive movement in the fourth drive direction, the fifth alternating drive movement being in antiphase with the first alternating drive movement; and

A fourth drive spring structure coupled to the fourth movable mass and the third drive assembly, the fourth drive spring structure being rigid in the fourth drive direction, configured to transfer the fifth alternating drive movement to the fourth movable mass, and compliant in the fourth sense direction.

12. The MEMS gyroscope of claim 11, wherein the roll/pitch sensing component further comprises:

a fifth movable mass configured to move relative to the fixed structure in a fifth drive direction parallel to the first drive direction and in a fifth sense direction parallel to the third sense direction;

a fourth drive assembly coupled to the fifth movable mass and configured to generate a sixth alternating drive movement in the fifth drive direction, the sixth alternating drive movement being in phase with the first alternating drive movement;

a fifth drive spring structure coupled to the fifth movable mass and to the fourth drive assembly, the fifth drive spring structure being rigid in the fifth drive direction, configured to transfer the sixth alternating drive movement to the fifth movable mass, and compliant in the fifth sense direction;

A sixth movable mass configured to move relative to the fixed structure in a sixth drive direction parallel to the first drive direction and in a sixth sense direction parallel to the third sense direction;

a fifth drive assembly coupled to the sixth movable mass and configured to generate a seventh alternating drive movement in the sixth drive direction, the seventh alternating drive movement being in phase with the first alternating drive movement; and

a sixth driven elastic structure coupled to the sixth movable mass and the fourth drive assembly, the sixth driven elastic structure being rigid in the sixth drive direction, configured to transfer the seventh alternating drive movement to the sixth movable mass, and compliant in the sixth sense direction.

13. The MEMS gyroscope of claim 12, wherein the third movable mass and the fourth movable mass are coupled and integral with each other, and wherein the fifth movable mass and the sixth movable mass are coupled and integral with each other.

14. The MEMS gyroscope of claim 12, further comprising an anchoring elastic structure that elastically couples the third movable mass, the fourth movable mass, the fifth movable mass, and the sixth movable mass.

15. The MEMS gyroscope of claim 12, further comprising:

a seventh movable mass configured to move relative to the fixed structure in a seventh drive direction parallel to the first drive direction and in a seventh sense direction parallel to the third sense direction;

a seventh driven elastic structure coupled to the seventh movable mass and the second drive assembly, the seventh driven elastic structure being rigid in the second drive direction, configured to transfer the second alternating drive movement to the seventh movable mass, and compliant in the seventh sense direction; and

a bridge element extending between the third, fourth and seventh movable masses, the bridge element being coupled to the fixed structure and rotatable about a second vertical axis that is axial transverse to the first drive direction and parallel to the third sense direction.

16. A method for driving a microelectromechanical system, MEMS, gyroscope, the method comprising:

generating a first alternating drive motion for the MEMS gyroscope, the MEMS gyroscope comprising:

A fixed structure;

a first drive assembly coupled to the first movable mass;

a first drive spring structure coupled to the first movable mass and to the first drive assembly, the first drive spring structure being rigid in the first drive direction and compliant in the first sense direction;

a second drive assembly coupled to the second movable mass; and

a second driven elastic structure coupled to the second movable mass and to the second drive assembly, the second driven elastic structure being rigid in the second drive direction and compliant in the second sense direction, the first alternating drive movement being a drive movement of the first drive assembly in the first drive direction;

Transmitting the first alternating drive movement from the first drive assembly to the first movable mass;

generating a second alternating drive movement of the second drive assembly in the second drive direction, the second alternating drive movement being in anti-phase with the first alternating drive movement; and

the second alternating drive movement is transferred from the second drive assembly to the second movable mass.

17. The method of claim 16, wherein

18. A gyroscope, comprising:

a support;

a first frame elastically coupled to the support;

a first mass elastically coupled to the first frame;

A second frame elastically coupled to the support and the first frame;

a second mass elastically coupled to the second frame; and

a sensing mass is elastically coupled to the support, the first mass, and the second mass.

19. The gyroscope of claim 18, further comprising:

a first actuation assembly on the support, the first actuation assembly configured to control movement of the first frame in a first direction; and

a second actuation assembly on the support configured to control movement of the second frame in a second direction opposite the first direction.

20. The gyroscope of claim 18, wherein the sense mass is configured to rotate about a rotational axis.