Micromachined inertial angular sensor

Abstract

The invention relates to an angular sensor which further comprises at least one vibrating mass (8), which is movable relative to the support member (6), and at least one electrostatic adjustment transducer (Q+), which is configured to apply an adjustable electrostatic strength to the vibrating mass (8), the or each electrostatic adjustment transducer (Q+) comprising at least two rows of teeth (20A, 20B) forming a pair of combs. The angular sensor further comprises at least one intermediate structure (18) which is elongate in at least one extension direction (26), the intermediate structure (18) projecting from an attachment edge (28, 30) of the vibrating mass (8) or the support member (6) and supporting one of the rows of teeth.

Description

[0001] TITLE: Micromachined Inertial Angular Sensor

[0002] The present invention relates to a micro-machined inertial angular sensor.

[0003] The invention relates to the field of inertial angular sensors intended to be embedded. Such sensors are used, for example, for navigation, piloting, guidance or heading search.

[0004] Inertial angular sensors are configured to measure angular position, and are usually called gyroscopes in this case. In another case, angular sensors are configured to measure angular velocity, in which case they are called gyrometers.

[0005] Inertial angle sensors, which are micromachined, also called MEMS inertial sensors, are known per se, for example from EP 2 960 625 A1.

[0006] Such a sensor generally comprises one or more masses that are excited into vibration in a plane formed by X and Y axes perpendicular to each other. This plane is perpendicular to a Z axis that forms a so-called sensitive axis of the sensor. When the sensor rotates around its sensitive axis, a combination of the vibration of the moving mass(es) with an angular rotation vector generates, by Coriolis effect, forces that put the moving masses into natural vibration perpendicular to the excitation vibration and to the sensitive axis. The amplitude of this natural vibration is proportional to the speed of rotation of the sensor, and then makes it possible to deduce a value of the angular speed around the sensitive axis.

[0007] Inertial angle sensors, for example, have mechanical deviations due to manufacturing tolerances. To improve the measurement accuracy of such sensors, adjustment actuators can be provided to compensate for or balance these mechanical deviations, for example, deviations in the mass or shape of the sensor or individual parts of the sensor.

[0008] In one example, mechanical deviations or defects of the micromachined sensor introduce a quadrature bias. The quadrature bias corresponds to a coupling of stiffnesses acting on a vibrating mass of the micromachined sensor along two perpendicular axes. To compensate for this quadrature bias, one or more electrostatic transducers should be provided, which apply a force compensating for the quadrature bias. However, such adjustment transducers often take up a lot of space on the surface of the micromachined sensor. Also, an increase in the force applicable by these electrostatic transducers often implies an increase in the size of these transducers. Given a limited surface area of ​​the micromachined inertial angular sensor, it is then difficult to provide electrostatic transducers, in particular to compensate for the quadrature bias, with a high applicable force for compensation.

[0009] An aim of the present invention is to overcome the aforementioned drawbacks.

[0010] Thus, an object of the present invention is to obtain a micro-machined inertial angular sensor which makes it possible to obtain compensation for mechanical deviations, even in the presence of a strong bias, while having a reduced size.

[0011] To this end, the subject of the invention is a micro-machined inertial angular sensor comprising a support having a first axis in a support plane and a second axis perpendicular to the first axis and included in said support plane, the angular sensor further comprising at least one vibrating mass movable relative to the support, at least one excitation transducer configured to generate a vibration movement of the vibrating mass, and at least one transducer for detecting a vibration of the vibrating mass.

[0012] The angular sensor comprises at least one electrostatic adjustment transducer configured to apply an adjustable electrostatic stiffness to the vibrating mass, the or each electrostatic adjustment transducer comprising at least two rows of teeth forming a pair of combs.

[0013] The angular sensor further comprises at least one intermediate structure elongated in at least one direction of extension, the intermediate structure projecting from a fixing edge of the vibrating mass or the support, and carrying one of the rows of teeth. The or each intermediate structure comprises a plurality of sections extending in respective directions of extension in a plane parallel to the support plane or merged with the support plane, the directions of extension of two consecutive sections preferably having an angle perpendicular to each other.

[0014] The angular sensor comprising at least one elongated intermediate structure makes it possible to increase the surface area, or the edge length available for arranging rows of teeth within the sensor, without increasing the total surface area required by the electrostatic adjustment transducer(s). Indeed, instead of arranging the rows of teeth of the transducer(s), for example directly on a fixing edge of the vibrating mass or the support, the rows of teeth are carried by the elongated intermediate structure, which has an increased surface area for fixing these rows of teeth.

[0015] Thus, thanks to the angular sensor according to the invention, rows of teeth having in particular a high number of teeth are arranged on the elongated intermediate structure. Consequently, the force applicable by the adjustment transducer is increased, without increasing the surface occupied by this transducer.

[0016] According to other advantageous aspects of the invention, the angular sensor comprises one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0017] - each row of teeth comprises a plurality of teeth extending parallel to one another, each tooth of the row of teeth carried by the intermediate structure projecting from said intermediate structure, preferably projecting from said intermediate structure in a direction perpendicular to the direction of extension of the intermediate structure;

[0018] - the or each adjustment transducer is an electrostatic transducer for compensating a quadrature bias, configured to modify the distribution of stiffnesses acting on the vibrating mass, the quadrature bias corresponding to a coupling of the stiffnesses acting on the vibrating mass along the first axis and the second axis;

[0019] - the direction of extension of the or each intermediate structure forms an angle with the fixing edge of between 45 and 90 degrees;

[0020] - the angle is approximately equal to 90 degrees;

[0021] - the angular sensor comprises several intermediate structures parallel to each other;

[0022] - the two rows of teeth comprise a first row of teeth secured to the vibrating mass and a second row of teeth secured to the support, the intermediate structure projecting from the fixing edge of the vibrating mass, called the moving edge, when it carries the first row of teeth, the intermediate structure projecting from the fixing edge of the support, called the fixed edge, when it carries the second row of teeth;

[0023] - the angular sensor comprises both at least one intermediate structure projecting from the movable edge and carrying the first row of teeth, and at least one intermediate structure projecting from the fixed edge and carrying the second row of teeth;

[0024] - the or each intermediate structure comprises a plurality of sections extending in respective extension directions in a plane parallel to the support plane or coincident with the support plane;

[0025] - the extension directions of two consecutive sections have a perpendicular angle to each other;

[0026] - the or each intermediate structure and at least one of said rows of teeth form a fractal structure, in which said row of teeth is provided with a row of secondary teeth, projecting from said row of teeth; - at least the or each intermediate structure and the row of teeth carried by said intermediate structure are formed in a single piece;

[0027] - the angular sensor comprises at least two vibrating masses movable relative to the support, and movable relative to each other, suspended by suspension springs at fixed anchor points of the support and coupled together by coupling springs to vibrate in phase opposition.

[0028] These characteristics and advantages of the invention will appear on reading the description which follows, given solely as a non-limiting example, and made with reference to the appended drawings, in which:

[0029] [Fig 1] Figure 1 is a schematic view of an example of an inertial angular sensor according to the invention;

[0030] [Fig 2] Figure 2 is a schematic view of an example of a part of the angular sensor of Figure 1 comprising intermediate structures and adjustment transducers according to the invention;

[0031] - [Fig 3] Figure 3 is a schematic view similar to Figure 2 according to another example of the invention;

[0032] - [Fig 4] Figure 4 is a schematic view similar to figures 2 and 3 according to another example of the invention;

[0033] - [Fig 5] Figure 5 is a schematic view similar to Figures 2 to 4 according to another example of the invention.

[0034] With reference to Figure 1, an angular sensor 2 comprises a support 6 extending in a support plane, along a first axis X and a second axis Y perpendicular to the first axis.

[0035] Subsequently, the micromachined inertial angular sensor 2 is referred to as angular sensor 2.

[0036] The angular sensor 2 is, for example, a gyrometer that is configured to measure an angular velocity. Alternatively or additionally, the angular sensor 2 is a gyroscope for measuring an angular position.

[0037] The angular sensor 2 is a micro-machined sensor, and thus forms a micro-electromechanical system, also defined by its acronym MEMS (from the English “Micro-Electro-Mechanical Systems”).

[0038] The angular sensor 2 is in particular a sensor intended to be embedded in a vehicle, not shown, for example in an aircraft, a drone or a ship.

[0039] The angular sensor 2 is for example intended to be embedded in a vehicle navigation, control or guidance unit.

[0040] The angular sensor comprises at least one vibrating mass. With reference to FIG. 1, the angular sensor 2 comprises for example two vibrating masses 8, 10, arranged in particular around each other, to form a mass called internal mass 8 and a mass called external mass 10.

[0041] In particular, the angular sensor is a tuning fork type gyrometer, in particular a tuning fork type gyrometer with two vibrating masses.

[0042] By “vibrating mass”, it is understood that the or each mass 8, 10 is capable of performing oscillations, for example driven by means described later, and by the Coriolis effect during rotation of the angular sensor 2.

[0043] Each vibrating mass 8, 10 is movable relative to the support 6.

[0044] In the case of two vibrating masses 8, 10, the vibrating masses 8, 10 are preferably also movable relative to each other. The centers of gravity 0 of the vibrating masses 8, 10 are in particular coincident at rest.

[0045] The angular sensor 2 further comprises, for example, suspension springs 12, for example four for each vibrating mass 8, 10, suspending each vibrating mass 8, 10 from a respective anchoring point 14 which is fixed relative to the support 6.

[0046] The angular sensor 2 further comprises, for example, coupling springs 16, for example four when the angular sensor comprises two masses 8, 10, coupling the vibrating masses 8, 10 together to allow vibration of the masses 8, 10 in phase opposition.

[0047] With reference to figures 2 to 5, the angular sensor 2 comprises at least one intermediate structure 18 projecting from the vibrating mass s, 10 or from the support 6. The examples of figures 2 to 5 show intermediate structures 18 projecting from the vibrating mass 8 and intermediate structures 18 projecting from the support 6. In addition, not shown, the angular sensor 2 further comprises intermediate structures 18 projecting from the vibrating mass 10.

[0048] With reference to figure 1, the angular sensor 2 further comprises at least one detection transducer Dx, Dy configured to detect a vibration of the vibrating mass 8, 10. Each detection transducer Dx, Dy comprises for example at least one comb secured to the vibrating mass 8, 10 and at least one comb secured to the support 6. In this case, each detection transducer Dx, Dy is thus configured to detect the vibration by measuring load variations between the combs.

[0049] The angular sensor 2 further comprises at least one excitation transducer Ex, Ey configured to generate a vibration movement of the vibrating mass 8, 10.

[0050] The angular sensor 2 further comprises at least one electrostatic adjustment transducer Tx, Ty, Q+, Q-. In the example of FIG. 1, only the detection transducers Dx, Dy, the excitation transducers Ex, Ey and the electrostatic adjustment transducers Tx, Ty, Q+, Q- arranged on the internal mass 8 are shown. Preferably, the angular sensor 2 also comprises detection transducers Dx, Dy, excitation transducers Ex, Ey and / or electrostatic adjustment transducers Tx, Ty, Q+, Q- arranged on the external mass 10.

[0051] For example, each electrostatic tuning transducer Tx, Ty, Q+, Q- is configured to apply an adjustable electrostatic stiffness to the vibrating mass 8, 10.

[0052] By "adjustable electrostatic stiffness" it is understood that the corresponding electrostatic adjustment transducer is configured to apply a force to the vibrating mass 8, 10, for example as a function of a received voltage.

[0053] According to one example, the angular sensor 2 comprises a first type of electrostatic transducer Tx, Ty and a second type of electrostatic transducer Q+, Q-.

[0054] The first type of electrostatic adjustment transducer Tx, Ty is for example configured to apply an electrostatic stiffness to compensate for a frequency bias of a tuning fork vibration mode along the first X axis and / or along the second Y axis. In particular, the first type of electrostatic adjustment transducer Tx, Ty is configured to compensate for a difference in vibration frequency between vibrations along the first X axis and the second Y axis.

[0055] An example of the first type of electrostatic tuning transducer Tx, Ty is seen in Figure 1.

[0056] The first type of electrostatic adjustment transducer Tx, Ty comprises, for example, interdigitated teeth, which are in particular either elongated along the first X axis or elongated along the second Y axis.

[0057] The second type of electrostatic tuning transducer Q+, Q- is particularly configured to compensate for quadrature bias.

[0058] The quadrature bias corresponds to a coupling of one or more stiffnesses acting on the vibrating mass 8, 10, and corresponds in particular to a coupling of the stiffnesses of the suspension springs 12 along the first axis X and the second axis Y. For example, the quadrature bias is due to manufacturing deviations of the suspension springs 12. An example of operation of the second type of electrostatic adjustment transducer Q+, Q- is described in the document EP 2 960 625 A1.

[0059] In particular, the second type of electrostatic adjustment transducer Q+, Q- is configured to modify the distribution of the stiffness(ies) acting on the vibrating mass 8, 10, in particular so as to align main axes of dynamic stiffness on the first axis X and the second axis Y. In particular, by adjusting electrostatic stiffnesses applied to the vibrating mass 8, 10, the second type of electrostatic adjustment transducer Q+, Q- is configured to compensate for the quadrature bias, for example caused by manufacturing tolerances of the angular sensor 2.

[0060] The electrostatic transducer Tx, Ty, Q+, Q- and an example of its arrangement in the angle sensor 2 are described in the following for the electrostatic transducer of the second type Q+, Q-, referred to as electrostatic transducer Q+, Q- in the following. However, the person skilled in the art understands that the arrangement of the electrostatic transducer Q+, Q- is also applicable to the transducer of the first type Tx, Ty as a variant.

[0061] Examples of the electrostatic adjustment transducer Q+, Q- are shown in Figures 2 to 5 showing parts of the angle sensor 2 comprising the electrostatic transducers Q+, Q-.

[0062] Each electrostatic transducer Q+, Q- comprises at least two rows of teeth 20A, 20B forming a pair of combs, in particular a pair of interdigital combs. Each row of teeth 20A, 20B comprises, and is preferably formed by, a plurality of teeth 22A, 22B extending parallel to each other.

[0063] By “interdigitated combs”, it is understood in particular that the teeth 22A, 22B are parallel to each other, so as to apply or receive respectively an electrostatic force.

[0064] At least one of the rows of teeth 20A, 20B is carried by the corresponding intermediate structure 18 of the angular sensor 2.

[0065] Each tooth 22A of the row of teeth 20A forms in particular a pair of teeth with a corresponding tooth 22B of the row of teeth 20B. The teeth 22A, 22B of each pair of teeth are arranged substantially parallel to each other, and in particular at a distance less than a minimum distance to other teeth 22A, 22B. In particular, the teeth 22A, 22B of each pair of teeth are configured to apply an electrostatic force to each other.

[0066] For example, the two rows of teeth 20A, 20B comprise a first row of teeth 20A secured to the vibrating mass 8, 10, and a second row of teeth 20B secured to the support 6.

[0067] For example, with reference to figures 2 and 3, the teeth 22A are integral with the vibrating mass 8, 10, and the teeth 22B are integral with the support 6, and are carried by the corresponding intermediate structures 18.

[0068] Figure 2 shows an example of a part of the angular sensor 2 comprising the intermediate structures 18 carrying the rows of teeth 20A, 20B of an electrostatic transducer Q+ forming an electrostatic transducer for compensating a positive quadrature bias. By "positive quadrature bias", it is in particular understood that the coupling of the stiffnesses acting on the vibrating mass 8, 10 is a positive value.

[0069] Preferably, by "positive quadrature bias", it is understood that a movement of the vibrating mass 8, 10 along the second axis Y generates a force, along the first axis X, proportional and of the same sign as the movement along the second axis Y.

[0070] Figure 3 shows an example of a part of the angular sensor 2 comprising the intermediate structures 18 carrying the rows of teeth 20A, 20B of an electrostatic transducer Q- forming an electrostatic transducer for compensating a negative quadrature bias.

[0071] By "negative quadrature bias" it is in particular understood that the coupling of the stiffnesses acting on the vibrating mass 8, 10 is a negative value.

[0072] Preferably, by "negative quadrature bias", it is understood that a movement of the vibrating mass 8, 10 along the second axis Y generates a force, along the first axis X, proportional and of opposite sign to the movement along the second axis Y.

[0073] In the following, the intermediate structure 18 is described in more detail, with reference to Figures 2 to 5.

[0074] Preferably, the angular sensor 2 comprises several intermediate structures 18 arranged parallel to each other. Alternatively, the angular sensor 2 comprises a single intermediate structure 18.

[0075] Each intermediate structure 18 is elongated in at least one respective extension direction 26.

[0076] By "elongated in at least one respective direction of extension 26", it is understood in particular that the intermediate structure 18 has a geometric shape having a width perpendicular to the direction of extension 26 strictly less than a length of the intermediate structure 18 in the direction of extension 26.

[0077] For example, the width is strictly less than half the length, preferably strictly less than one-third of the length.

[0078] In particular, each intermediate structure 18 has a rectangular shape extending in the direction of extension 26, of which in particular edges parallel to the direction of extension 26 have a length strictly greater than edges perpendicular to the direction of extension 26.

[0079] Each intermediate structure 18 projects from a fixing edge 28 of the vibrating mass 8, 10 or from a fixing edge 30 of the support 6.

[0080] In particular, each intermediate structure 18 projects from the corresponding fixing edge 28, 30 in an extension plane. The extension plane is parallel to the support plane or coincides with the support plane.

[0081] Each fixing edge 28, 30 extends in particular in the extension plane.

[0082] For example, the extension direction 26 of the intermediate structure 18 forms an angle with the fixing edge 28, 30 of between 45° and 90°. Preferably, the angle is substantially equal to 90°, i.e. the intermediate structure 18 projects from the respective fixing edge 28, 30 in a direction perpendicular to said edge 28, 30, in the extension plane.

[0083] Each intermediate structure 18 carries one of the rows of teeth 20A, 20B.

[0084] With reference to Figures 2 and 3, each tooth 22A of the row of teeth 20A forms in particular a respective pair of teeth with a corresponding tooth 22B of the row of teeth 20B. In the example of Figure 2, following the direction of extension 26 of each intermediate structure 18 projecting from the support 6, each pair of teeth first comprises the tooth 22B carried by this intermediate structure 18, then the tooth 22A carried by the corresponding intermediate structure 18 projecting from the vibrating mass 8. In the example of Figure 3, the arrangement of the teeth 22A, 22B of each pair of teeth is reversed. This order of arrangement of the teeth 22A, 22B of each pair of teeth makes it possible in particular to compensate for the corresponding quadrature bias, namely the positive quadrature bias with regard to the example of figure 2, and the negative quadrature bias with regard to the example of figure 3.

[0085] For example, each tooth 22A, 22B projects from the corresponding intermediate structure 18 in a direction perpendicular to the direction of extension 26 of this intermediate structure 18. For example, each tooth 22A, 22B extends in a direction parallel to the fixing edge 28, 30, from which the intermediate structure 18 projects. In particular, each tooth 22A, 22B projects from one of the edges of the corresponding intermediate structure 18, which are parallel to the direction of extension 26 of this intermediate structure 18.

[0086] Preferably, the intermediate structure 18 projects from the fixing edge 28 of the vibrating mass 8, 10, called the moving edge, when it carries the first row of teeth 20A. In particular, this intermediate structure 18 thus connects the first row of teeth 20A to the vibrating mass 8, 10.

[0087] More preferably, the intermediate structure 18 projects from the fixing edge 30 of the support 6, called the fixed edge, when it carries the second row of teeth 20B. In particular, this intermediate structure 18 thus connects the second row of teeth 20B to the support 6.

[0088] According to one example, the angular sensor 2 comprises one or more intermediate structures 18 projecting from the movable edge and carrying the first row of teeth 20A, and further comprises one or more intermediate structures 18 projecting from the fixed edge and carrying the second row of teeth 20B.

[0089] With reference to figures 2 and 3, the angular sensor 2 comprises for example several intermediate structures 2 projecting with different sections, in particular perpendicular and / or parallel to each other, from the fixing edge 30 of the support 6 and / or several intermediate structures 2 projecting with different sections, for example perpendicular and / or parallel to each other, from the fixing edge 28 of the corresponding vibrating mass 8, 10.

[0090] With reference to Figures 4 and 5, the or each intermediate structure 18 comprises for example a plurality of sections S1, S2, S3, S4, S5, and optionally S6, S7. In this case, each section S1 to S7 extends in a respective extension direction 26, in the extension plane. In particular, the extension directions 26 of two consecutive sections S1 to S7, following the corresponding extension directions 26, have a perpendicular angle to each other.

[0091] For example, with reference to Figure 4, the extension directions 26 of the sections S1 to S7 of the or each intermediate structure 18 have the following angles between them, following the extension directions 26 of the intermediate structure 18 projecting from the fixing edge 30 of the support 6: an angle equal to 90° in the counterclockwise direction between the sections S1 and S2, two angles of 90° in the clockwise direction between the sections S2 and S3 as well as S3 and S4, two angles of 90° in the counterclockwise direction between the sections S4 and S5 as well as S5 and S6, and an angle of 90° in the clockwise direction between the sections S6 and S7.

[0092] The teeth 22A are carried by at least two sections S1 to S7, here by the sections S1 to S3, and likewise the teeth 22B are carried by at least two sections S1 to S7, here the sections S1 to S3. Thus, the teeth 22A, 22B carried by the same intermediate structure 18 are not all parallel to each other. Advantageously and not shown, the teeth 22A, 22B extend over each section of the intermediate structure 18 which carries them.

[0093] According to one example, with reference to FIG. 5, the extension directions 26 of two consecutive sections S1 to S5 have an angle of 90° between them in the counterclockwise direction. In particular, the or each intermediate structure 18 has a substantially snail-shaped shape.

[0094] According to an example not shown, the or each intermediate structure 18 and one of the rows of teeth 20A, 20B form a fractal structure.

[0095] For example, one of the rows of teeth 20A, 20B is provided with a secondary row of teeth, not visible in the figures. The secondary row of teeth projects from the teeth 22A, 22B of the row of teeth 20A, 20B provided with this secondary row of teeth. Thus, the teeth 22A, 22B form the intermediate structure for the secondary row of teeth. The secondary teeth carried by the teeth 22A are then configured to apply an electrostatic force to the secondary teeth carried by the teeth 22B, and conversely the secondary teeth carried by the teeth 22B are configured to apply an electrostatic force to the secondary teeth carried by the teeth 22A, in a similar manner to what has been described for the rows of teeth 20A and 20B.

[0096] The secondary teeth, being closer to each other than the primary teeth, are then responsible for the resulting electrostatic forces, with the forces exerted by the primary teeth contributing only marginally to the resultant force.

[0097] Advantageously, the arrangement of the secondary teeth is provided such that the teeth 22A and 22B as well as the secondary teeth are all arranged such as to compensate for the positive quadrature bias, or, conversely, such that the teeth 22A and 22B as well as the secondary teeth are all arranged such as to compensate for the negative quadrature bias.

[0098] Preferably, the secondary row of teeth comprises secondary teeth projecting from the teeth 22A, 22B in a secondary direction perpendicular to a direction of extension of the teeth 22A, 22B. The secondary direction is in particular parallel to the direction of extension 26 of the intermediate structure 18 carrying the teeth 22A, 22B. The presence of secondary teeth thus makes it possible to further increase the number of teeth on the adjustment transducers Q+, Q- without increasing a surface area occupied by the transducer Q+ or Q-.

[0099] Preferably, the intermediate structure 18 and the row of teeth 20A, 20B, which is carried by the intermediate structure 18 are formed in a single piece.

[0100] Similarly, in the example where the or each intermediate structure 18 and one of the rows of teeth 20A, 20B form a fractal structure, the intermediate structure 18, the row of teeth 20A, 20B, which is carried by the intermediate structure 18 and the secondary teeth carried by the row of teeth 20A, 20B are formed in a single piece.

[0101] For example, when the intermediate structure 18 projects from the fixing edge 28 of the vibrating mass 8, 10, the vibrating mass 8, 10, the intermediate structure 18, and the teeth 22A carried by this intermediate structure 18 are formed in a single piece. In an example according to which the intermediate structure 18 is fixed on the fixing edge 30 of the support 6, the support 6, the intermediate structure 18, and the teeth 22B are formed in a single piece.

[0102] For example, elements formed in a single piece are elements obtained by etching or by machining. According to one example, at least one element among the following elements, preferably all of the following elements, comprises silicon or consists of silicon: the support 6, the intermediate structure 18, the vibrating mass 8, 10, the teeth 22A, 22B of each row of teeth 20A, 20B. It is understood that the sensor 2 according to the invention has a large number of advantages.

[0103] In particular, the sensor 2 according to the invention comprising the intermediate structure(s) 18 makes it possible to increase the space available for the arrangement of a high number of teeth 22A, 22B of each row of teeth 20A, 20B carried by the corresponding intermediate structure 18. Indeed, among a large number of variables and modifications that can be envisaged for the sensor 2 to increase the electrostatic stiffness applicable by the electrostatic adjustment transducer Tx, Ty, Q+, Q- concerned, increasing the number of teeth by arranging them on the intermediate structure(s) 18 makes it possible to compensate for mechanical deviations in a reliable and efficient manner. For example, this makes it possible to compensate for mechanical deviations without increasing an electrical voltage of the transducer.

Claims

CLAIMS 1 . Micromachined inertial angular sensor (2) comprising a support (6) having a first axis (X) in a support plane and a second axis (Y) perpendicular to the first axis (X) and included in said support plane, the angular sensor (2) further comprising at least one vibrating mass (8, 10) movable relative to the support (6), at least one excitation transducer (Ex, Ey) configured to generate a vibration movement of the vibrating mass (8, 10), and at least one detection transducer (Dx, Dy) of a vibration of the vibrating mass (8, 10), the angular sensor (2) comprising at least one electrostatic adjustment transducer (Tx, Ty, Q+, Q-) configured to apply an adjustable electrostatic stiffness to the vibrating mass (8, 10), the or each electrostatic adjustment transducer (Tx, Ty, Q+, Q-) comprising at least two rows of teeth (20A, 20B) forming a pair of combs,wherein the angular sensor (2) further comprises at least one intermediate structure (18) elongated in at least one direction of extension (26), the intermediate structure (18) projecting from a fixing edge (28, 30) of the vibrating mass (8, 10) or of the support (6), and carrying one of the rows of teeth (20A, 20B), wherein the or each intermediate structure (18) comprises a plurality of sections (S1, S2, S3, S4, S5, S6, S7) extending in respective directions of extension (26) in a plane parallel to the support plane or coinciding with the support plane, the directions of extension (26) of two consecutive sections (S1, S2, S3, S4, S5, S6, S7) preferably having an angle perpendicular to each other., 2. Angular sensor (2) according to claim 1, wherein each row of teeth (20A, 20B) comprises a plurality of teeth (22A, 22B) extending parallel to each other, each tooth (22A, 22B) of the row of teeth (20A, 20B) carried by the intermediate structure (18) projecting from said intermediate structure (18), preferably projecting from said intermediate structure (18) in a direction perpendicular to the direction of extension (26) of the intermediate structure (18).

3. Angular sensor (2) according to claim 1 or claim 2, in which the or each adjustment transducer (Q+, Q-) is an electrostatic compensation transducer (Q+, Q-) of a quadrature bias, configured to modify the distribution of stiffnesses acting on the vibrating mass (8, 10), the quadrature bias corresponding to a coupling of the stiffnesses acting on the vibrating mass (8, 10) along the first axis (X) and the second axis (Y).

4. Angular sensor (2) according to any one of the preceding claims, in which the direction of extension (26) of the or each intermediate structure (18) forms an angle with the fixing edge of between 45 and 90 degrees, the angle preferably being substantially equal to 90 degrees.

5. Angular sensor (2) according to any one of the preceding claims, comprising several intermediate structures (18) parallel to each other.

6. Angular sensor (2) according to any one of the preceding claims, wherein the two rows of teeth (20A, 20B) comprise a first row of teeth (20A) secured to the vibrating mass (8, 10) and a second row of teeth (20B) secured to the support (6); wherein the intermediate structure (18) projects from the fixing edge (28) of the vibrating mass (8, 10), called the movable edge, when it carries the first row of teeth (20A); wherein the intermediate structure (18) projects from the fixing edge (30) of the support (6), called the fixed edge, when it carries the second row of teeth (20B).

7. Angular sensor (2) according to claim 6 taken in combination with claim 5, comprising both at least one intermediate structure (18) projecting from the movable edge and carrying the first row of teeth (20A), and at least one intermediate structure (18) projecting from the fixed edge and carrying the second row of teeth (20B).

8. Angular sensor (2) according to any one of the preceding claims, wherein the or each intermediate structure (18) and at least one of said rows of teeth (20A, 20B) form a fractal structure, wherein said row of teeth (20A, 20B) is provided with a row of secondary teeth, projecting teeth (22A, 22B) from said row of teeth (20A, 20B).

9. Angular sensor (2) according to any one of the preceding claims, wherein at least the or each intermediate structure (18) and the row of teeth (20A, 20B) carried by said intermediate structure (18) are formed in a single piece.

10. Angular sensor (2) according to any one of the preceding claims, comprising at least two vibrating masses (8, 10) movable relative to the support (6), and movable relative to each other, suspended by suspension springs (12) at fixed anchoring points (14) of the support (6) and coupled together by coupling springs (16) to vibrate in phase opposition.

Images