Coriolis effect gyrometric or gyroscopic sensor of the electromechanical microsystem type

Abstract

The invention relates to a Coriolis effect gyrometric or gyroscopic sensor (10) which comprises a support (12), a vibrating element (14) comprising an internal mass (16) and a peripheral mass (18) which are coupled by a mechanical coupling device (20), and a movement transformation device (22) comprising longitudinal (24) and transverse (26) transformation elements which are configured to transform input movements of the internal mass (16) and peripheral mass (18), in phase opposition relative to one another in translation, into an output movement chosen from a rotational movement about an axis parallel to the sensing axis (OZ) and a translational movement in an orthogonal direction, and to limit relative movements in phase of these masses in translation in the longitudinal direction (Y) and in the transverse direction (X) by transferring the kinetic energy associated with these movements to the support (12) without transformation into an output movement.

Description

[0001] DESCRIPTION

[0002] TITLE: Coriolis effect gyrometric or gyroscopic sensor of the microelectromechanical system type

[0003] The present invention relates to a Coriolis effect gyrometric or gyroscopic sensor of the microelectromechanical system type, enabling the measurement of an angular velocity or an angular position.

[0004] In the field of gyroscopic and gyrometric inertial sensors, Coriolis effect sensors (in English, "Coriolis Vibratory Gyroscope"; abbreviated CVG) exploit the Coriolis force exerted on a vibrating element in a reference frame attached to the sensor, when this sensor is rotating as seen from an inertial reference frame.

[0005] Such sensors therefore include a support and a vibrating element.

[0006] The vibrating element can comprise a plurality of vibrating masses suspended relative to the support and coupled together by means of elastic elements.

[0007] Vibrating masses are capable of vibrating relative to the support at least in a longitudinal direction and a transverse direction of a vibration plane parallel to an extension plane of the support.

[0008] When vibrating masses are in motion in a reference frame attached to the support, the work of the Coriolis force allows a transfer of mechanical energy between these two directions, and indirectly, the measurement of an angular velocity of rotation or an angular position of the sensor around a sensitive axis of the sensor which is orthogonal to the plane of vibration.

[0009] The sensor includes excitation means configured to excite vibrating masses into vibration relative to the support, as well as means for detecting the movements of the vibrating masses.

[0010] The angular position or angular velocity to be measured is deduced from the movements of vibrating masses detected by the detection means.

[0011] Micro-Electro-Mechanical-Systems (CVG MEMS) offer the advantage of being compact, lightweight, and providing good measurement performance, with low production cost and low power consumption. CVG MEMS are, for example, fabricated on and / or in a substrate wafer, such as a silicon or quartz wafer, with the various components being micro-machined on / in the wafer.

[0012] Many CVG MEMS architectures are known, including axisymmetric architectures, in which the vibrating element is globally symmetric with respect to two orthogonal axes of the vibration plane.

[0013] Axisymmetric CVG MEMS sensors have the advantage of being able to be excited along any direction of the vibration plane, so that the performance of the sensor and in particular its sensitivity is particularly high.

[0014] The useful vibration modes of axisymmetric CVGs are the so-called "out of phase" or "tuning fork" modes, in which the vibrating masses have a translational movement in opposite phase to each other in a particular direction.

[0015] The so-called "in-phase" modes, in which the vibrating masses have an oscillatory motion in translation in phase with respect to each other in this particular direction, can then be disturbing modes of the measurement performed by the sensor.

[0016] In particular, in-phase modes can disturb tuning fork modes via parasitic couplings due to a possible imbalance of the vibrating element of the CVG, i.e. a possible difference between the stiffnesses of the suspensions of the different vibrating masses to the support and / or between the values ​​of the masses of these vibrating masses.

[0017] Thus, the excitation of the in-phase mode in the presence of vibrations or acoustic disturbances applied to the sensor causes a degradation of the CVG's performance in the form of a random walk error or drift on its output.

[0018] It is therefore necessary to reduce the influence of in-phase modes by configuring the CVG MEMS so that the frequencies of the disturbing in-phase modes are as far away as possible from the frequencies of the useful tuning fork modes.

[0019] Furthermore, a static acceleration applied to the sensor can cause a combined movement of the two masses, which can disrupt the measurement by altering the gains of the excitation and / or detection devices, thus introducing error terms into the sensor output. It is therefore necessary to prevent such combined movements of the two masses.

[0020] Document FR1401451 describes an axisymmetric MEMS CVG that achieves high measurement accuracy, but in which the in-phase motion of the masses is not restricted. It is necessary to limit the in-phase motion of the masses, particularly for applications where high measurement accuracy must also be achieved in the presence of vibrations or static accelerations.

[0021] One aim of the invention is therefore to propose a Coriolis effect gyrometric or gyroscopic sensor of the microelectromechanical system type for which the in-phase modes are further attenuated compared to prior art sensors.

[0022] To this end, the invention relates to a Coriolis effect gyrometric or gyroscopic sensor of the microelectromechanical system type comprising:

[0023] a) a support;

[0024] b) a vibrating element comprising an internal mass and a peripheral mass arranged around the internal mass,

[0025] the internal mass and the peripheral mass being able to vibrate relative to the support in a vibration plane orthogonal to a sensitive axis of the sensor and of structures generally symmetrical with respect to a longitudinal plane comprising a longitudinal axis of the vibration plane and the sensitive axis and with respect to a transverse plane comprising a transverse axis of the vibration plane and the sensitive axis when the sensor is in a rest position in an inertial reference frame;

[0026] (c) a mechanical coupling device between the peripheral mass and the internal mass, generally symmetrical in structure with respect to the longitudinal and transverse planes in said rest position,

[0027] characterized in that the mechanical coupling device comprises a motion transformation device comprising at least one longitudinal transformation element and at least one transverse transformation element, each connected to the support at at least one respective anchor point and to each of the internal and peripheral masses at at least one respective coupling point, the longitudinal transformation element, respectively transverse transformation element, being configured for:

[0028] - to transform input movements of the internal mass and the peripheral mass, in opposite phase to each other, in translation along the longitudinal direction of the longitudinal axis, respectively the transverse direction of the transverse axis, into an output movement chosen from a rotational movement around an axis parallel to the sensitive axis and a translational movement along the transverse direction, respectively the longitudinal direction, and

[0029] - to limit relative movements of the internal mass and the peripheral mass in translation along the longitudinal, respectively transverse, direction, in phase with respect to each other, by directly transferring to the support at least a part of the kinetic energy associated with these movements in phase without transformation into an output movement; the movement transformation device comprising at least in the case where the output movement of the longitudinal, respectively transverse, transformation element is said rotational movement:

[0030] at least one transverse, respectively longitudinal, decoupling element, through which the longitudinal, respectively transverse, transformation element is linked to the respective coupling points of the internal mass and the peripheral mass, the transverse, respectively longitudinal, decoupling element being elastically deformable and exhibiting greater stiffness along the longitudinal, respectively transverse, direction than along the transverse, respectively longitudinal direction.

[0031] The motion transformation device is configured to allow translational movements of the internal and peripheral masses in opposite phase along the two directions of vibration, longitudinal and transverse, of the internal and peripheral masses by transforming this movement into a respective output movement of the first or second transformation element, while hindering translational movements of the internal and peripheral masses in phase along these two directions, by transferring the associated kinetic energy directly to the support via the anchor points.

[0032] The first transformation element, possibly in combination with the transverse decoupling element, allows the internal and peripheral masses to move in translation along the transverse direction both in phase and in opposite phase, so that the control of the vibration modes along the transverse direction is ensured essentially by the second transformation element, and possibly by the transverse decoupling element.

[0033] Similarly, the second transformation element, possibly in combination with the longitudinal decoupling element, allows the internal and peripheral masses to move in translation along the longitudinal direction both in phase and in opposite phase, so that the control of the vibration modes along the longitudinal direction is ensured essentially by the first transformation element, and possibly by the longitudinal decoupling element.

[0034] In the end, the motion transformation device increases the stiffness of the vibrating element for the disturbing in-phase modes both along the longitudinal axis and along the transverse axis, without changing its stiffness for the useful tuning fork modes.

[0035] The gap between the frequency of a tuning fork mode of interest, for example the fundamental tuning fork mode, and the frequency of the closest in-phase mode, for example the fundamental in-phase mode, is therefore increased compared to the CVG MEMS of the prior art.

[0036] According to other advantageous aspects of the invention, the Coriolis effect gyrometric or gyroscopic sensor comprises one or more of the following features, taken individually or in any technically possible combination:

[0037] - the mechanical coupling device further includes at least one additional element for suspending the internal mass of the support and / or at least one additional element for suspending the peripheral mass of the support;

[0038] - the mechanical coupling device further includes at least one additional coupling spring for the internal mass with the peripheral mass;

[0039] - at least one transverse decoupling element, respectively longitudinal, is a folded beam spring;

[0040] - the sensor includes at least one electrode for detecting movement of the internal mass or peripheral mass and / or at least one excitation electrode for the internal mass or peripheral mass attached to at least one transverse decoupling element, respectively longitudinal;

[0041] - if the output movement is said translational movement along the transverse, or longitudinal, direction, respectively, the longitudinal, or transverse, transformation element comprises a plurality of deformable parallelogram structures, each exhibiting:

[0042] * two principal vertices opposite in the longitudinal and transverse directions, respectively linked to a coupling point of the internal mass and the peripheral mass, and

[0043] *two secondary vertices opposite in the transverse direction, respectively longitudinal, each linked to a first end of a respective spring of said transformation element, a second end of the respective spring being linked to a respective anchor point;

[0044] - the principal vertices of said deformable parallelogram structure of the longitudinal, respectively transverse, transformation element are linked to the respective coupling point via said transverse, respectively longitudinal, decoupling device;

[0045] - at least one electrode, included in the sensor, for detecting movement of the internal mass or the peripheral mass and / or at least one electrode, included in the sensor, for exciting the internal mass or the peripheral mass is integral with at least one non-deformable element of the longitudinal transformation element or the transverse transformation element; - if the output movement of the longitudinal, or respectively transverse, transformation element is said rotational movement, the longitudinal, or respectively transverse, transformation element comprises a plurality of beams movable relative to the support rotating around a respective axis of rotation parallel to the sensing axis, each beam extending between:

[0046] * an internal end connected to the internal mass via a transverse, or respectively longitudinal, decoupling element, and

[0047] * a peripheral end connected to the peripheral mass via a transverse, or respectively longitudinal, decoupling element,

[0048] said respective axis of rotation being linked to the support at the level of at least one respective anchor point.

[0049] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0050] Figure 1 represents a CVG MEMS according to a first embodiment of the invention, in a top view relative to the direction of the sensitive axis of this CVG in the rest position;

[0051] Figure 2 represents a cross-sectional view of the CVG MEMS of Figure 1 along a transverse plane including the sensitive axis of this CVG and the transverse direction, in which the mechanical coupling device is omitted;

[0052] Figure 3 represents a variant of the CVG MEMS of Figure 1, as well as the predicted movements of the different elements of this CVG when the internal and peripheral masses vibrate in opposite phase along the longitudinal direction from the rest position;

[0053] Figure 4 represents the CVG MEMS of Figure 3, as well as the predicted movements of the different elements of this CVG when the internal and peripheral masses vibrate in phase along the longitudinal direction from the rest position;

[0054] Figure 5 represents a CVG MEMS according to a second embodiment of the invention, in top view relative to the direction of the sensitive axis of this CVG, as well as the expected movements of the different elements of this CVG when the internal and peripheral masses vibrate in opposite phase along the longitudinal direction from the rest position;

[0055] Figure 6 represents the MEMS CVG of Figure 5, as well as the predicted movements of the various elements of this CVG when the internal and peripheral masses vibrate in phase along the longitudinal direction from the rest position. Figure 7 represents an enlarged and detailed view of Figure 4 around the second deformable parallelogram structure located on the right of this figure, in the case where this structure is subjected at its two opposite ends along the longitudinal direction by forces in the same direction along the longitudinal direction; and

[0056] Figure 8 represents an enlarged view of Figure 5 around the transverse decoupling element located at the top left of this figure, in the case where the internal and peripheral masses vibrate in opposite phase along the longitudinal direction from the rest position.

[0057] The invention relates to a 10 gyrometric or gyroscopic sensor.

[0058] Sensor 10 is a Coriolis effect sensor of the microelectromechanical system (MEMS) type. Sensor 10 will be referred to hereafter as CVG 10.

[0059] The CVG 10 according to the invention comprises a support 12, a vibrating element 14 comprising an internal mass 16 and a peripheral mass 18 disposed around the internal mass 16, as well as a mechanical coupling device 20 between the peripheral mass 18 and the internal mass 16.

[0060] The support 12 is in the form of a plate extending along a longitudinal direction Y and a transverse direction X perpendicular to the longitudinal direction Y, and of thickness e along an elevation direction Z orthogonal to the longitudinal direction Y and transverse direction X.

[0061] In MEMS-based devices, the dimensions in the longitudinal Y and transverse X directions are typically on the order of one to a few millimeters.

[0062] Support 12 is for example formed from a material such as silicon, glass or ceramic.

[0063] The elements which make up an active part of the CVG 10, in particular the internal mass 16 and peripheral mass 18, the mechanical coupling device 20, as well as excitation means (not shown) and detection means (not shown) known to the person skilled in the art, are formed in and / or above the support 12 in the elevation direction Z, as can be partially seen in the cross-sectional view of Figure 2. The active part of the CVG 10 is for example formed in a material such as silicon, a metal or quartz.

[0064] As an example, the active part of the CVG 10 can be obtained by one or more micromachining processes chosen from photolithography, dry or wet etching, sealing, layer deposition, sealing. The internal mass 16 and the peripheral mass 18 are able to vibrate relative to the support 12 in a vibration plane OXY orthogonal to a sensitive axis OZ of the CVG 10, in the direction of the elevation Z.

[0065] The OZ sensitive axis is the axis around which the CVG 10 is configured to perform an angle or velocity measurement.

[0066] When the CVG 10 is in a rest position in an inertial frame of reference, the internal mass 16 and the peripheral mass 18 each have a generally symmetrical structure:

[0067] - with respect to a longitudinal plane OYZ, comprising a longitudinal axis OY of the vibration plane OXY and the sensitive axis OZ, and

[0068] - with respect to a transverse plane OXZ, comprising the sensitive axis OZ and a transverse axis OY of the vibration plane OXY, intersecting with the longitudinal axis OY at a reference point O and perpendicular to the longitudinal axis OY.

[0069] "Generally symmetric" means in this description that the element thus qualified is symmetric except for manufacturing defects, for example within machining tolerance, or without taking into account minor asymmetries introduced into the structure to compensate for a mass imbalance observed before the introduction of such asymmetries.

[0070] Perfect symmetry in the rest position is not required for the invention. Those skilled in the art will observe that the symmetry obtained in the rest position is maintained for certain movements of the vibrating element relative to the support 12.

[0071] The inertial reference frame is chosen according to the use of the CVG 10. In many use cases of the CVG 10, a local terrestrial reference frame can be considered inertial.

[0072] The internal mass 16 therefore exhibits symmetry with respect to the longitudinal plane OYZ and with respect to the transverse plane OXZ in the rest position of the CVG 10.

[0073] The internal mass 16 is for example polygonal with geometric center Oi, in particular of geometry invariant under symmetry of order 4 in rotation around an axis OiZ coincident with the sensitive axis OZ in the rest position, in particular of overall geometry square as seen in figure 1, or even discoidal.

[0074] The geometric center Oi of the internal mass 16 coincides with its center of gravity.

[0075] The center of gravity Oi of the internal mass 16 coincides with the reference point O in the rest position of the CVG 10.

[0076] The peripheral mass 18 has a symmetry with respect to the longitudinal plane OYZ and with respect to the transverse plane OXZ in the rest position of the CVG 10. The peripheral mass 18 is for example polygonal with geometric center O2, in particular of geometry invariant under rotation of order 4 around an axis O2Z coincident with the sensitive axis OZ in the rest position, in particular of overall geometry square as seen in figure 1, or even discoidal.

[0077] The geometric center O2 of the peripheral mass 18 coincides with its center of gravity.

[0078] The center of gravity O2 of the peripheral mass 18 coincides with the reference point O in the rest position of the CVG 10.

[0079] The peripheral mass 18 is arranged around the internal mass 16 so that when the CVG 10 is in the rest position, the center of gravity O1 of the internal mass 16 and the center of gravity O2 of the peripheral mass 18 are located at the reference point O.

[0080] The internal mass 16 and peripheral mass 18 are configured to be excited into vibration in the OXY vibration plane by the excitation means of the CVG 10.

[0081] The excitation means include, for example, electrostatic transducers such as interdigitated electrostatic combs. In a particular embodiment, the excitation means include movable electrodes attached to the internal mass 16 and peripheral mass 18. The positions and / or velocities and / or acceleration of the internal mass 16 and peripheral mass 18 along two detection directions, preferably the transverse X and longitudinal Y directions, are measured by the detection means of the CVG 10.

[0082] The detection means include, for example, electrostatic transducers such as interdigitated electrostatic combs. In a particular embodiment, the detection means include movable electrodes attached to the internal mass 16 and peripheral mass 18.

[0083] Other embodiments of the detection elements could be considered, such as strain gauges.

[0084] The internal mass 16 and peripheral mass 18 are mechanically coupled by the mechanical coupling device 20.

[0085] The mechanical coupling device 20 has a structure that is generally symmetrical with respect to the longitudinal OYZ and transverse OXZ planes in the rest position.

[0086] The mechanical coupling device 20 includes a motion transformation device 22 comprising at least one longitudinal transformation element 24 and one transverse transformation element 26. The longitudinal transformation element 24 is linked to the support 12 at at least one first anchorage point 28, as well as to each of the internal mass 16 and peripheral mass 18 at at least one first coupling point 30, 31 respectively.

[0087] The longitudinal transformation element 24 is configured to transform input movements of the internal mass 16 and peripheral mass 18 in translation along the longitudinal direction Y of the longitudinal axis OY and in opposite phase to each other into a first output movement chosen from a first translational movement along the transverse direction X of the transverse axis OX and a rotational movement around an axis parallel to the sensitive axis OZ.

[0088] The longitudinal transformation element 24 is further configured to limit movements of the internal mass 16 and peripheral mass 18 in translation along the longitudinal direction Y in phase with respect to each other by directly transferring to the support 12 at least a part of the kinetic energy associated with these movements in phase without transformation into an output movement.

[0089] The energy transfer takes place at the level of at least one first anchor point 28, as will be explained later.

[0090] The transverse transformation element 26 is linked to the support 12 at at least one second anchor point 32, as well as to each of the internal mass 16 and peripheral mass 18 at at least one second coupling point 34, 35 respectively.

[0091] The transverse transformation element 26 is configured to transform input movements of the internal mass 16 and peripheral mass 18 in translation along the transverse direction X of the transverse axis OX in opposite phase to each other into a second output movement chosen from a second translational movement along the longitudinal direction Y of the longitudinal axis OY and a second rotational movement around an axis parallel to the sensitive axis OZ.

[0092] The transverse transformation element 26 is further configured to limit movements of the internal mass 16 and peripheral mass 18 in translation along the transverse direction Y of the transverse axis OY in phase with respect to each other, by directly transferring to the support 12 at least a part of the kinetic energy associated with these movements without transformation into an output movement.

[0093] The energy transfer takes place at the level of at least one second anchor point 32, as will be explained later.

[0094] Thanks to the symmetry of the architecture according to the invention, by design, the various mass-spring systems of the CVG 10 have very similar natural frequencies. However, manufacturing defects actually lead to a structure that is not perfectly symmetrical. In a particular embodiment, the CVG 10 further includes adjustment means, configured to compensate for these asymmetry defects, such as electrodes for applying adjustable electrostatic stiffness. Such electrodes compensate for the anisotropy defects of dynamic stiffness by canceling the stiffness coupling between the X and Y axes and equalizing the resonance frequencies of the two tuning fork resonance modes. The operation of adjusting the resonance frequencies is known as "frequency trimming."

[0095] In a particular embodiment, the adjustment means include movable electrodes attached to the internal mass 16 and peripheral mass 18.

[0096] FIRST METHOD OF IMPLEMENTING THE MECHANICAL COUPLING DEVICE

[0097] 20

[0098] The motion transformation device 22 of the mechanical coupling device 20 according to a first embodiment is described with reference to figures 1 to 4.

[0099] In this first embodiment, the output movement of the longitudinal transformation element 24 is a translational movement along the transverse direction X.

[0100] The longitudinal transformation element 24 can then comprise a plurality of first deformable parallelogram structures 36.

[0101] Each first deformable parallelogram structure 36 exhibits:

[0102] - two first principal vertices A, B opposite along the longitudinal direction Y, linked respectively to a coupling point 30 of the internal mass 16 and to a coupling point 31 of the peripheral mass 18, and

[0103] - two first secondary vertices C, D opposite along the transverse direction X, each linked to a first end of a first respective spring 38 of the longitudinal transformation element 24, a second end of the first respective spring 38 being linked to a first respective anchor point 28 of the support 12.

[0104] The longitudinal transformation element 24 is generally symmetrical in structure with respect to the longitudinal OYZ and transverse OXZ planes in the rest position of the CVG 10.

[0105] In the example of figures 1 to 4, the longitudinal transformation element 24 comprises two first deformable parallelogram structures 36, each centered on the longitudinal axis OY, and symmetrical to each other with respect to the transverse plane OXZ in the rest position.

[0106] The number and positions of the first deformable parallelogram structures 36 can be modified as long as this generally symmetrical structure of the longitudinal transformation element 24 with respect to the longitudinal OYZ and transverse OXZ planes in the rest position is preserved.

[0107] Each first spring 38 is, for example, micro-machined.

[0108] Each first spring 38 is configured to deform elastically along the transverse direction X.

[0109] Each first spring 38 is for example capable of deforming in bending along the transverse direction X.

[0110] In a particular embodiment, as represented, each first spring 38 is therefore more flexible, advantageously much more flexible, along the transverse direction X than along the longitudinal direction Y. For example, each first spring 38 has a stiffness at least 10 times lower along the transverse direction X than along the longitudinal direction Y.

[0111] As an example, each first spring 38 includes a straight beam, an L-shaped beam, or a folded beam, for example in the shape of a U (in English, "folded beam flexure spring").

[0112] In the example shown in the figures, each first spring 38 comprises U-shaped folded beams, similar to the example in Figure 7 detailed later.

[0113] In the example of figures 1 to 4, each first spring 38 is linked to the respective main vertex A, B via an intermediate rigid element 39.

[0114] The transverse transformation element 26 can include in the first embodiment a plurality of second deformable parallelogram structures 40.

[0115] Each second deformable parallelogram structure 40 presents:

[0116] - two second principal vertices A', B' opposite along the transverse direction X, linked respectively to a second coupling point 34 of the internal mass 16 and to a second coupling point 35 of the peripheral mass 18, and

[0117] - two second secondary vertices C', D' opposite along the longitudinal direction Y, each linked to a first end of a second respective spring 42 of the transverse transformation element 26, a second end of the second respective spring 42 being linked to a second respective anchor point 32 of the support 12.

[0118] The transverse transformation element 26 is generally symmetrical in structure with respect to the longitudinal OYZ and transverse OXZ planes in the rest position of the CVG 10.

[0119] In the example of figures 1 to 4, the transverse transformation element 26 comprises two second deformable parallelogram structures 40, each centered on the transverse axis OX, and symmetrical to each other with respect to the longitudinal plane OYZ in the rest position.

[0120] The number and positions of the second deformable parallelogram structures 40 can be modified as long as the generally symmetrical structure of the transverse transformation element 26 with respect to the longitudinal OYZ and transverse OXZ planes in the rest position is preserved.

[0121] Each second spring 42 is, for example, micro-machined

[0122] Each second spring 42 is configured to deform elastically along the longitudinal direction Y.

[0123] Each second spring 42 is for example capable of deforming in bending along the longitudinal direction Y.

[0124] Each second spring 42 is therefore more flexible, advantageously much more flexible, along the longitudinal direction Y than along the longitudinal direction X. For example, each second spring 42 has a stiffness at least 10 times lower along the longitudinal direction Y than along the transverse direction X.

[0125] For example, each second spring 42 comprises a straight beam, an L-shaped beam, or a bent beam. In the example shown in the figures, each second spring 42 comprises U-shaped bent beams.

[0126] In particular, in the embodiment visible in Figure 7, each second spring 42 comprises two U-shaped springs positioned face-to-face.

[0127] In a particular embodiment, as shown in the example of Figures 1 to 4, each second spring 42 is linked to the respective main vertex A', B' via an intermediate rigid element 43.

[0128] The operation of the motion transformation device 22 according to the first embodiment with respect to the translational movements of the internal mass 16 and peripheral mass 18 along the longitudinal direction Y can be understood in light of Figure 3 for the case of out-of-phase movements, and Figure 4 for the case of in-phase movements. This operation is described in the following paragraphs.

[0129] If the internal mass 16 and the peripheral mass 18 have translational movements in opposite phase along the longitudinal direction Y, as represented by arrows without a reference sign in Figure 3:

[0130] - the first deformable parallelogram structures 36 will deform reversibly due to the opposing actions to which they are subjected at the level of their first principal vertices A, B, this deformation being made possible by the simultaneous elastic deformation of the first springs 38 linked to the first secondary vertices C,D along the transverse direction X; and- the second deformable parallelogram structures 40 will deform reversibly due to the flexibility of the second springs 42 along the longitudinal direction Y.

[0131] If the internal mass 16 and the peripheral mass 18 have translational movements in phase along the longitudinal direction Y, as represented by arrows without a reference sign in Figure 4:

[0132] - the first springs 38, in particular due to their connection to the first respective anchor points 28 and their rigidity along the longitudinal direction Y, do not allow significant deformation of the first deformable parallelogram structures 36 under the effect of the actions in the same direction to which they are subjected at the level of their first principal vertices A, B. The kinetic energy of the translational movements of the internal mass 16 and the peripheral mass 18 in phase along the longitudinal direction Y is therefore dissipated, at least partially, through the first respective anchor points 28, without associated outward movement;

[0133] - the second deformable parallelogram structures 40 do not prevent these movements, due to the flexibility of the second springs 42 along the longitudinal direction Y.

[0134] In the end, the longitudinal transformation element 24 therefore allows the movements of the internal mass 16 and the peripheral mass 18 in opposite phase in translation along the longitudinal direction Y and converts these movements into a translational movement along the transverse direction X. It also limits the movements of these masses in phase in translation along the longitudinal direction Y, the transverse transformation element 26 not significantly hindering these movements.

[0135] Due to the symmetry of the roles played by the longitudinal transformation element 24 and by the transverse transformation element 26, it is understood that the transverse transformation element 26 allows the movements of the internal mass 16 and the peripheral mass 18 in opposite phase in translation along the transverse direction X and limits the movements of these masses in phase in translation along the transverse direction X, the longitudinal transformation element 24 not significantly hindering these movements.

[0136] The kinetic energy of the translational movements of the internal mass 16 and the peripheral mass 18 in phase along the transverse direction X is dissipated, at least partially, through the respective second anchor points 32, without any associated output movement. In the end, it is understood that the motion transformation device 22 therefore makes it possible to adjust the frequencies of the useful modes (i.e. the tuning fork modes) and the parasitic modes in order to reduce the disturbances induced by these parasitic modes.

[0137] In general, the dimensioning, number and positioning of the longitudinal transformation elements 24 and transverse transformation elements 26 according to the first embodiment make it possible to adjust the frequencies of the vibration modes in phase and out of phase of the internal mass 16 and peripheral mass 18 along the longitudinal Y and transverse X directions to desired values, in particular:

[0138] - by adjusting the values ​​of the angles at the respective principal vertices A, B, A', B' of the first and second deformable parallelogram structures 36, 40 in the rest position; and / or

[0139] - by modulating the rigidity of the respective sides of the first and second deformable parallelogram structures 36, 40, for example by varying the thickness of one or more of these sides along their respective elongation direction, as shown in Figure 1; and / or

[0140] - by adjusting the dimensions and geometry of the first and / or second springs 38, 42, for example the thickness, length or number of branches in the case where said springs include folded beams.

[0141] In a particular embodiment, in the case where the motion transformation device 22 includes an intermediate rigid element 39, 43, at least one mobile electrode included in the excitation means of the CVG 10 and / or in the detection means of the CVG 10 and / or at least part of the means for adjusting a vibration frequency of at least one of the internal 16 and peripheral 18 masses implemented in the CVG 10 is integral with said intermediate rigid element 39, 43.

[0142] This arrangement is particularly advantageous since it also allows for a reduction in the stiffness coupling between the transverse X and longitudinal Y directions, which is responsible for the quadrature bias of the CVG10.

[0143] Furthermore, when the electrode is included in the excitation means, the intermediate rigid element 39, 43, to which the electrode is attached, allows a force to be applied in the desired direction without simultaneously generating an orthogonal force. This arrangement thus reduces mean and harmonic drift errors, as well as scale factor harmonic errors. Harmonic errors are defined here as errors that depend on the angular position of the vibration direction of the internal mass 16 and peripheral mass 18 in the OXY vibration plane. Moreover, by judiciously selecting the values ​​of the angles at the principal vertices A, B, A', B' of the first and second deformable parallelogram structures 36, 40, it is possible to obtain a force amplification effect between the intermediate rigid elements 39, 43 and the internal mass 16 and peripheral mass 18.This effect makes it possible in particular to amplify the forces applied by the excitation means and the frequency adjustment means of the CVG 10 when these are attached to the intermediate rigid elements 39, 43.

[0144] This effect is further accompanied by an amplification effect of the movement between the internal mass 16 and peripheral mass 18 and the intermediate rigid elements 39, 43. This makes it possible in particular to increase the detection gain when the detection means are attached to the intermediate rigid elements 39, 43.

[0145] Optionally, the motion transformation device 22 according to the first embodiment includes at least one transverse decoupling element 44 and / or at least one longitudinal decoupling element 46.

[0146] This case is represented in Figures 3 and 4, in which the motion transformation device 22 comprises two transverse decoupling elements 44, each linked to a respective longitudinal transformation element 24, and two longitudinal decoupling elements 46, each linked to a respective transverse transformation element 26.

[0147] In a particular embodiment, each longitudinal transformation element 24 is linked to at least one respective transverse decoupling element 44 and / or each transverse transformation element 26 is linked to at least one respective longitudinal decoupling element 46.

[0148] In a particular embodiment, at least one longitudinal transformation element 24 is linked by each of its first principal vertices A, B to a respective transverse decoupling element 44 and / or at least one transverse transformation element 26 is linked by each of its second principal vertices A', B' to a respective longitudinal decoupling element 46.

[0149] Each longitudinal transformation element 24 is in the case of figures 3 and 4 linked at the level of its first principal vertices A, B to the first coupling points 30, 31 respectively of the internal mass 16 and the peripheral mass 18 via the respective transverse decoupling element 44.

[0150] Each transverse transformation element 26 is, in the case of Figures 3 and 4, linked at the level of its second principal vertices A', B' to the respective second coupling points 34, 35 of the internal mass 16 and the peripheral mass 18 via the respective longitudinal decoupling element 46. In general, the number and positions of the transverse decoupling elements 44 and longitudinal 46 can vary as long as the generally symmetrical nature of the mechanical coupling device 20 with respect to the longitudinal plane OYZ and transverse plane OXZ in the rest position is maintained.

[0151] The transverse decoupling element 44 is generally configured to transfer actions along the longitudinal direction Y to the longitudinal transformation element 24, and to absorb by its deformation along the transverse direction X part of the actions along this direction, so that the longitudinal transformation element 24 hinders as little as possible the translational movements in phase or in opposite phase of the internal mass 16 and peripheral mass 18 along the transverse direction X.

[0152] Each transverse decoupling element 44 is elastically deformable and has a greater stiffness, advantageously much greater, for example at least 10 times greater, along the longitudinal direction Y than along the transverse direction X.

[0153] Each transverse decoupling element 44 is therefore significantly elastically deformable along the transverse direction X, while being only slightly deformable, or even rigid, along the longitudinal direction Y.

[0154] As an example, each transverse decoupling element 44 comprises at least one straight beam, and / or at least one L-shaped beam, and / or at least one folded beam such as a U-shaped beam.

[0155] In a particular embodiment, the transverse decoupling element 44 comprises two parallel U-springs, formed for example by micromachining, in a manner analogous to the example shown in Figure 7. It is understood from this example that the relatively elongated arms along the longitudinal Y direction of the U-springs shown allow deformation along the transverse X direction, while limiting deformation along the longitudinal Y direction.

[0156] Each longitudinal decoupling element 46 is elastically deformable and has a greater stiffness, advantageously much greater, for example 10 times greater, along the transverse direction X than along the longitudinal direction Y.

[0157] Each longitudinal decoupling element 46 is therefore significantly elastically deformable along the longitudinal direction Y, while being only slightly deformable, or even rigid, along the transverse direction X.

[0158] As an example, each longitudinal decoupling element 46 comprises at least one straight beam, and / or at least one L-shaped beam, and / or at least one folded beam, for example two U-shaped folded beams on the principle of the example shown in Figure 7.

[0159] It is therefore understood that the transverse decoupling element 44 and the longitudinal decoupling element 46 are configured to partially decouple the effects of the motion transformation device 22 along the longitudinal Y and transverse X directions, so that the control of the movements of the internal mass 16 and peripheral mass 18:

[0160] - in phase or opposite phase along the longitudinal direction Y is essentially ensured by the longitudinal transformation element 24, and

[0161] - in phase or opposite phase along the transverse direction X is essentially ensured by the transverse transformation element 26.

[0162] This arrangement is particularly advantageous since it allows the quadrature bias of CVG 10 to be reduced by limiting the couplings between the X and Y axes.

[0163] By limiting the translational movement of points A and B along the transverse direction X, the transverse decoupling elements 44 also prevent the longitudinal transformation element 24 from working in torsion, which allows its dimensioning to be optimized for its function of converting a translational movement along the longitudinal direction Y.

[0164] On the same principle, by limiting the translational movement of points A' and B' along the longitudinal direction Y, the longitudinal decoupling elements 46 also prevent the transverse transformation element 26 from working in torsion, which allows its dimensioning to be optimized only for its function of converting a translational movement along the transverse direction X.

[0165] The transverse decoupling elements 44 and longitudinal 46 therefore act synergistically with the longitudinal transformation elements 24 and transverse 26 and allow to simplify and optimize the dimensioning of these elements.

[0166] In general, the dimensioning, number and positioning of the transverse decoupling elements 44 and longitudinal 46 in combination with those of the longitudinal transformation elements 24 and transverse 26 according to the first embodiment allow the frequencies of the vibration modes in phase and in opposite phase of the internal mass 16 and peripheral mass 18 in the longitudinal Y and transverse X directions to be adjusted in a particularly flexible and precise manner to the desired values.

[0167] In summary, the restoring stiffness opposing the out-of-phase translational motion along the longitudinal Y direction of the internal mass 16 and peripheral mass 18, due to the presence of the motion transformation device 22 according to the first embodiment, can be generally low, as at least one longitudinal decoupling element 46 contributes to reducing this stiffness, so that the resonance frequency of the fundamental mode in out-of-phase along the longitudinal Y direction can be relatively low. Conversely, the restoring stiffness opposing the in-phase translational motion along the longitudinal Y direction of the internal mass 16 and peripheral mass 18, due to the presence of the motion transformation device 22 according to the first embodiment, can be generally high, so that the resonance frequency of the fundamental mode in phase along the longitudinal Y direction can be relatively high.

[0168] Conversely, the restoring stiffness opposing the out-of-phase translational motion along the transverse X direction of the internal mass 16 and peripheral mass 18, due to the presence of the motion transformation device 22 according to the first embodiment, can be generally low, as at least one transverse decoupling element 44 contributes to reducing this stiffness, so that the resonance frequency of the fundamental mode in out-of-phase along the transverse X direction can be relatively low. On the other hand, the restoring stiffness opposing the in-phase translational motion along the transverse X direction of the internal mass 16 and peripheral mass 18, due to the presence of the motion transformation device 22 according to the first embodiment, can be generally high, so that the resonance frequency of the fundamental mode in phase along the transverse X direction can be relatively high.

[0169] In the case where the motion transformation device 22 includes at least one transverse decoupling element 44 or longitudinal decoupling element 46, at least one mobile electrode included in the excitation means of the CVG 10 and / or in the detection means of the CVG 10 and / or in the vibration frequency adjustment means of at least one of the internal 16 and peripheral 18 masses implemented in the CVG 10 is integral with said decoupling element 44, 46.

[0170] This arrangement is particularly advantageous since it also allows for a reduction in stiffness coupling along the transverse X and longitudinal Y directions, which is responsible for the quadrature bias of the CVG10.

[0171] Furthermore, when the electrode is included in the excitation means, the decoupling element to which it is attached allows a force to be applied in the desired direction without simultaneously generating an orthogonal force. This arrangement thus reduces mean and harmonic drift errors, as well as scale factor harmonic errors. Harmonic errors here refer to errors that depend on the angular position of the vibration direction of the internal mass 16 and peripheral mass 18 in the OXY vibration plane.

[0172] Due to the presence of the first, respectively second, anchor points 28, respectively 32, the motion transformation device 22 ensures in itself the suspension of the internal mass 16 and the peripheral mass 18 in addition to their mechanical coupling with each other.

[0173] Consequently, in a particular embodiment, the CVG 10, and in particular the mechanical coupling device 20, does not include any other means of suspending the internal mass 16 and peripheral mass 18 from the support 12 and / or of coupling the internal mass 16 with the peripheral mass 18 than the longitudinal transformation elements 24 and transverse transformation elements 26.

[0174] This arrangement is particularly favorable for reducing stiffness coupling along the transverse X and longitudinal Y directions which is responsible for the quadrature bias of the CVG10, while allowing the frequencies of the vibration modes in phase and in opposite phase of the internal mass 16 and peripheral mass 18 to be obtained along the longitudinal Y and transverse X directions equal to the desired values.

[0175] Optionally, the mechanical coupling device 20 includes at least one additional suspension element 48 of the internal mass 16 to the support 12 and / or at least one additional suspension element 50 of the peripheral mass 18 to the support 12.

[0176] Each additional suspension element 48 is linked to the internal mass 16 at at least one respective suspension point 52 and to the support 12 at at least one respective additional anchorage point 54.

[0177] Each additional suspension element 48 is elastically deformable along the longitudinal direction Y and / or along the transverse direction X.

[0178] In one particular embodiment, the additional suspension element 48 comprises a plurality of deformable parallelogram structures.

[0179] The number and positions of the additional suspension elements 48 may vary, as long as the generally symmetrical character with respect to the longitudinal OYZ and transverse OXZ planes of the mechanical coupling device 20 in the rest position is maintained.

[0180] Each additional suspension element 50 is linked to the peripheral mass 18 at at least one respective suspension point 56 and to the support 12 at at least one respective additional anchorage point 58.

[0181] Each additional suspension element 50 is elastically deformable along the longitudinal direction Y and / or along the transverse direction X. In a particular embodiment, the additional suspension element 50 comprises a plurality of deformable parallelogram structures.

[0182] The number and positions of the additional suspension elements 50 may vary, as long as the generally symmetrical character with respect to the longitudinal OYZ and transverse OXZ planes of the mechanical coupling device 20 in the rest position is maintained.

[0183] In general, the dimensioning, number and positioning of the additional suspension elements 48, 50, in combination with those of the motion transformation device 22 according to the first embodiment, makes it possible to increase the latitude of adjustment of the frequencies of the vibration modes in phase and in opposite phase of the internal mass 16 and peripheral mass 18 in the longitudinal Y and transverse X directions to the desired values.

[0184] Optionally, the mechanical coupling device 20 includes at least one additional spring 60 for coupling the internal mass 16 with the peripheral mass 18.

[0185] Each additional spring 60 is linked to the internal mass 16 at at least one respective additional coupling point 60-1 and to the peripheral mass 18 at at least one respective additional coupling point 60-2.

[0186] Each additional spring 60 is elastically deformable along the longitudinal direction Y and / or along the transverse direction X.

[0187] The number and positions of the additional springs 60 may vary, as long as the generally symmetrical character with respect to the longitudinal OYZ and transverse OXZ planes of the mechanical coupling device 20 in the rest position is preserved.

[0188] In general, the dimensioning, number and positioning of the additional springs 60, in combination with those of the motion transformation device 22 according to the first embodiment, and where applicable of the additional suspension elements 48, 50, makes it possible to increase the latitude of adjustment of the frequencies of the vibration modes in phase and in opposite phase of the internal mass 16 and peripheral mass 18 in the longitudinal Y and transverse X directions to the desired values.

[0189] The adjustment of the frequencies of the useful modes (i.e., the tuning fork modes) and the parasitic modes is done in particular as follows:

[0190] - by adjusting the dimensions (e.g., thickness, length or number) of the additional suspension elements 48, 50 and / or the additional coupling springs 60; and / or

[0191] - by adjusting the dimensions of the springs of the decoupling elements 44 and 46. In a particular embodiment, the active elements of the CVG 10 are distributed in a plurality of successive layers along the Z elevation direction.

[0192] SECOND METHOD OF IMPLEMENTING THE MECHANICAL COUPLING DEVICE 20

[0193] The motion transformation device 22 of the mechanical coupling device 20 according to a second embodiment is described with reference to figures 5 and 6.

[0194] This second embodiment differs from the first embodiment in that the output movement of the longitudinal transformation element 24 is a rotational movement around an axis parallel to the sensitive axis OZ.

[0195] In the second embodiment, the longitudinal transformation element 24 can comprise a plurality of first beams 62 movable relative to the support 12 rotating about a respective axis of rotation parallel to the sensitive axis OZ.

[0196] In the example of figures 5 and 6, the longitudinal transformation element 24 comprises four first beams 62, with respective axes of rotation Z1, Z2, Z3 and Z4, forming a symmetrical assembly with respect to the longitudinal plane OYZ and the transverse plane OXZ in the rest position of the CVG 10.

[0197] The number and positions of the first 62 beams can be modified as long as the generally symmetrical structure of the longitudinal transformation element 24 with respect to the longitudinal plane OYZ and the transverse plane OXZ in the rest position is preserved.

[0198] Each first beam 62 extends between an internal end 64 linked to the internal mass 16 via a respective transverse decoupling element 44, and a peripheral end 66 linked to the peripheral mass 18 via a respective transverse decoupling element 44.

[0199] Each first beam 62 is, for example, micro-machined.

[0200] The respective axis of rotation Z1, Z2, Z3, Z4 of each first beam 62 is linked to the support 12 at the level of at least one respective first anchorage point 28 of the support 12.

[0201] The longitudinal transformation element 24 is then configured to be relatively flexible in torsion around an axis of direction parallel to the sensitive axis OZ and relatively rigid in translation along the longitudinal direction Y.

[0202] Each first beam 62 is relatively rigid. Torsional flexibility is achieved by one or more springs arranged between the beam 62 and the anchorages 28.

[0203] The realization of such springs based on beams deforming in bending is known to those skilled in the art and notably described in the publication Trusov AA, Schofield AR, Shkel AM, “Micromachined rate gyroscope architecture with ultra-high quality factor and improved mode ordering.”, Sensors and Actuators A. Physical, 2011;165:26-34.

[0204] In the second embodiment, the transverse transformation element 26 can comprise a plurality of second beams 68 movable relative to the support 12 rotating about a respective axis of rotation parallel to the sensitive axis OZ.

[0205] In the example of figures 5 and 6, the transverse transformation element 26 comprises four second beams 68, with respective axes of rotation Z5, Z6, Z7 and Z8, forming a symmetrical assembly with respect to the longitudinal plane OYZ and the transverse plane OXZ in the rest position of the CVG 10.

[0206] The number and positions of the second beams 68 can be modified as long as the generally symmetrical structure of the transverse transformation element 26 with respect to the longitudinal plane OYZ and the transverse plane OXZ in the rest position is preserved.

[0207] Each second beam 68 extends between an internal end 70 connected to the internal mass 16 via a respective longitudinal decoupling element 46, and a peripheral end 72 connected to the peripheral mass 18 via a respective longitudinal decoupling element 46.

[0208] The operation of the motion transformation device 22 according to the second embodiment with respect to the translational movements of the internal mass 16 and peripheral mass 18 along the longitudinal direction Y can be understood in light of Figure 5 for the case of out-of-phase movements, and Figure 6 for the case of in-phase movements. This operation is described in the following paragraphs.

[0209] If the internal mass 16 and the peripheral mass 18 have translational movements in opposite phase along the longitudinal direction Y, as represented by arrows without a reference sign in Figure 5:

[0210] - each first beam 62 undergoes a rotation around its respective axis of rotation Z1, Z2, Z3, Z4 due to the torque of forces to which it is subjected, a torque due to the transmission of mechanical actions by each respective transverse decoupling element 44 due to its rigidity along the longitudinal direction Y; and

[0211] - the second beams 68 do not impede these movements due to the flexibility of the respective longitudinal decoupling elements 46 along the longitudinal direction Y, as shown in figure 8.

[0212] If the internal mass 16 and the peripheral mass 18 have translational movements in phase along the longitudinal direction Y, as represented by arrows without reference signs in Figure 6: - each first beam 62 is subjected to moments of forces in opposite directions, due to the transmission of mechanical actions by each respective transverse decoupling element 44 because of its rigidity along the longitudinal direction Y.Since each first beam 62 can neither rotate under the effect of these opposing moments, nor deform, the kinetic energy of the translational movements of the internal mass 16 and the peripheral mass 18 in phase along the longitudinal direction Y is therefore dissipated, at least partially, through the respective first anchorage points 28, without associated outward movement; and - the second beams 68 do not hinder these movements due to the flexibility of the respective longitudinal decoupling elements 46 along the longitudinal direction Y.

[0213] In the end, the longitudinal transformation element 24 according to the second embodiment therefore allows, as in the first embodiment, the movements of the internal mass 16 and the peripheral mass 18 in opposite phase in translation along the longitudinal direction Y and limits the movements of these masses in phase in translation along the longitudinal direction Y, the transverse transformation element 26 not significantly hindering these movements.

[0214] Due to the symmetry of the roles played by the longitudinal transformation element 24 and by the transverse transformation element 26, it is understood that the transverse transformation element 26 according to the second embodiment allows, as in the first embodiment, the movements of the internal mass 16 and the peripheral mass 18 in opposite phase in translation along the transverse direction X and limits the movements of these masses in phase in translation along the transverse direction X, the longitudinal transformation element 24 not significantly hindering these movements.

[0215] The kinetic energy of the translational movements of the internal mass 16 and the peripheral mass 18 in phase along the transverse direction X is notably dissipated, at least partially, through the respective second anchor points 32, without associated outward movement.

[0216] As in the first embodiment, in a particular embodiment, the transverse decoupling element 44 and / or the longitudinal decoupling element 46 is in the form of a U-shaped spring, formed for example by micromachining, as shown in Figures 5 and 6.

[0217] As in the first embodiment, due to the presence of the first, and respectively second, anchor points 28 and 32, the motion transformation device 22 itself provides a suspension function for the internal mass 16 and the peripheral mass 18 relative to the support 12 in the second embodiment. Consequently, the CVG 10, and in particular the mechanical coupling device 20 according to the second embodiment, may not include any means other than the longitudinal 24 and transverse 26 transformation elements for suspending the internal mass 16 and peripheral mass 18 from the support 12 and / or coupling the internal mass 16 with the peripheral mass 18.

[0218] Alternatively, the mechanical coupling device 20 according to the second embodiment includes at least one additional suspension element 48 of the internal mass 16 to the support 12 and / or at least one additional suspension element 50 of the peripheral mass 18 to the support 12 as described for the first embodiment, as seen in Figures 5 and 6.

[0219] Alternatively or in addition, the mechanical coupling device 20 according to the second embodiment includes at least one additional coupling spring 60 of the internal mass 16 with the peripheral mass 18 as described for the first embodiment, as seen in Figures 5 and 6.

[0220] It is therefore understood that, regardless of the embodiment, the numerous degrees of freedom for adjusting the stiffness of the mechanical coupling device 20 along the longitudinal Y and transverse X directions, particularly at the level of the longitudinal 24 and transverse 26 transformation elements,

[0221] and where applicable:

[0222] - transverse decoupling elements 44 and longitudinal decoupling elements 46, and / or

[0223] - additional suspension elements 48, 50 of the internal mass 16 and of the peripheral mass 18 to the support 12, and / or

[0224] - 60 additional coupling springs,

[0225] allow the frequency of the two useful vibration modes in translation to be placed in opposite phase to the target frequency fMopet to place the frequency of at least one parasitic vibration mode in translation in phase along this direction at a frequency far from the frequencies of the two useful vibration modes, in particular significantly higher, and optionally the placement of possible other parasitic modes, for example torsional modes around the transverse X, longitudinal Y and / or sensitive axis Z directions of the internal 16 and peripheral 18 masses both in phase and in opposite phase at frequencies far from the frequencies of the two useful vibration modes, whether higher or lower.

Claims

26 DEMANDS 1. Gyrometric or gyroscopic sensor (10) with Coriolis effect of the microelectromechanical system type comprising: a) a support (12); b) a vibrating element (14) comprising an internal mass (16) and a peripheral mass (18) arranged around the internal mass (16), the internal mass (16) and the peripheral mass (18) being capable of vibrating relative to the support (12) in a vibration plane (OXY) orthogonal to a sensitive axis (OZ) of the sensor (10) and of structures generally symmetrical with respect to a longitudinal plane (OYZ) comprising a longitudinal axis (OY) of the vibration plane (OXY) and the sensitive axis (OZ) and with respect to a transverse plane (OXZ) comprising a transverse axis (OX) of the vibration plane (OXY) and the sensitive axis (OZ) when the sensor (10) is in a rest position in an inertial frame of reference, c) a mechanical coupling device (20) between the peripheral mass (18) and the internal mass (16), generally of symmetrical structure with respect to the longitudinal (OYZ) and transverse (OXZ) planes in said rest position, characterized in that the mechanical coupling device (20) comprises a motion transformation device (22) comprising at least one longitudinal transformation element (24) and at least one transverse transformation element (26), each connected to the support (12) at at least one respective anchor point (28, 32) and to each of the internal (16) and peripheral (18) masses at at least one respective coupling point (30, 31, 34, 35), the longitudinal transformation element (24), respectively transverse (26), being configured for: - to transform input movements of the internal mass (16) and the peripheral mass (18) in opposite phase to each other in translation along the longitudinal direction (Y) of the longitudinal axis (OY), respectively the transverse direction (X) of the transverse axis (OX), into an output movement chosen from a rotational movement around an axis parallel to the sensitive axis (OZ) and a translational movement along the transverse direction (X), respectively the longitudinal direction (Y), and - to limit relative movements of the internal mass (16) and the peripheral mass (18) in translation along the longitudinal (Y) and transverse (X) directions, respectively, in phase with respect to each other, by directly transferring to the support (12) at least a part of the kinetic energy associated with these movements in phase without transformation into an output movement; the movement transformation device (22) comprising at least in the case where the output movement of the longitudinal (24) and transverse (26) transformation element is said rotational movement: at least one transverse decoupling element (44), respectively longitudinal (46), through which the longitudinal transformation element (24), respectively transverse (26), is linked to the coupling points (30, 31, 34, 35) respectively of the internal mass (16) and the peripheral mass (18), the transverse decoupling element (44), respectively longitudinal (46), being elastically deformable and having a greater stiffness along the longitudinal (Y), respectively transverse (X), direction than along the transverse (X), respectively longitudinal (Y) direction.

2. Sensor (10) according to claim 1, wherein the mechanical coupling device (20) further comprises at least one additional suspension element (48) of the internal mass (16) to the support (12) and / or at least one additional suspension element (50) of the peripheral mass (18) to the support (12).

3. Sensor (10) according to any one of the preceding claims, wherein the mechanical coupling device (20) further comprises at least one additional coupling spring (60) of the internal mass (16) with the peripheral mass (18).

4. Sensor (10) according to any one of the preceding claims, wherein at least one transverse decoupling element (44), respectively longitudinal (46), is a folded beam spring.

5. Sensor (10) according to any one of the preceding claims, comprising at least one electrode for detecting movement of the internal mass (16) or of the peripheral mass (18) and / or at least one excitation electrode of the internal mass (16) or of the peripheral mass (18) attached to at least one transverse decoupling element (44), respectively longitudinal (46).

6. Sensor (10) according to any one of the preceding claims, wherein if the output motion is said translational motion along the transverse (X) or longitudinal (Y) direction, respectively, the longitudinal (24) or transverse (26) transformation element comprises a plurality of deformable parallelogram structures (36, 40), each having: - two main vertices (A, A', B, B') opposite along the longitudinal (Y) direction, respectively transverse (X), linked respectively to a coupling point (30, 34, 31, 35) of the internal mass (16) and the peripheral mass (18), and - two secondary vertices (C, C', D, D') opposite along the transverse (X) direction, respectively longitudinal (Y), each linked to a first end of a spring (38, 42) of said transformation element (24, 26), a second end of the respective spring (38, 42) being linked to a respective anchor point (28, 32).

7. Sensor (10) according to the preceding claim, wherein the principal vertices (A, A', B, B') of said deformable parallelogram structure (36, 40) of the longitudinal transformation element (24), respectively transverse (26), are linked to the respective coupling point (30, 34, 31, 35) by means of said transverse decoupling device (44), respectively longitudinal (46).

8. Sensor (10) according to any one of claims 6 and 7, wherein at least one sensing electrode, included in the sensor (10), of a movement of the internal mass (16) or of the peripheral mass (18) and / or at least one excitation electrode, included in the sensor (10), of the internal mass (16) or of the peripheral mass (18) is integral with at least one non-deformable element (39,42) of the longitudinal transformation element (24) or of the transverse transformation element (26).

9. A sensor (10) according to any one of claims 1 to 5, wherein if the output motion of the longitudinal (24) or transverse (26) transformation element is said rotational motion, the longitudinal (24) or transverse (26) transformation element comprises a plurality of beams (62, 68) movable relative to the support (12) rotating about a respective axis of rotation (Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8) parallel to the sensing axis (OZ), each beam (62, 68) extending between: - an inner end connected to the internal mass (16) via a respective transverse (44) or longitudinal (46) decoupling element, and - a peripheral end connected to the peripheral mass (18) via a respective transverse (44) or longitudinal (46) decoupling element, said axis of rotation respective being linked to the support (12) at the level of at least one respective anchor point (28, 32).

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