Vibrating gyrometer with planar structure

An inertial angular position sensor, comprising at least three identical resonators arranged symmetrically about an axis, referred to as a sensitive axis, so as to be invariant under a rotation of 2π/n about the sensitive axis, where n is the number of resonators of the sensor,

• the n resonators being coupled together so that the sensor has at least two degenerate modes of vibration, allowing to characterize a rotation of the sensor about the sensitive axis,
• each of the resonators comprising a respective portion of a wafer having two opposite faces which are flat and parallel, the wafer portion dedicated to each resonator being intended to vibrate flexurally during use of the sensor, and referred to as a vibrating portion of said resonator, the wafer being common to the n resonators of the sensor, and
• the sensor further comprising a coupling element which connects the vibrating portion of each resonator to the vibrating portions of all the others among the n resonators of the sensor, the coupling element also being invariant under the rotation of 2π/n about the sensitive axis, and the vibrating portions of the n resonators being angularly distributed about the coupling element, wherein the vibrating portion of each resonator is connected to a support part of the sensor which is external to the vibrating portions and to the coupling element, by an intermediate segment of the wafer, referred to as a foot, which is dedicated to the resonator, said foot being integral with the vibrating portion and forming a connection between the support part and said vibrating portion, and wherein, for each resonator:
• the vibrating portion of said resonator has a first plane of symmetry, referred to as a midplane, which is parallel to both faces of the wafer and equidistant from said both faces, and a second plane of symmetry, referred to as a plane of symmetry orthogonal to the wafer, which is perpendicular to the midplane and passes longitudinally through the connection formed by the foot between the support part and the vibrating portion,
• an intersection between the midplane and the plane of symmetry orthogonal to the wafer forms a center axis of the vibrating portion,
• the vibrating portion comprises two extensions which are each intended to vibrate flexurally, said two extensions extending symmetrically from the foot on each side of the plane of symmetry orthogonal to the wafer,
• each extension is provided with a longitudinal slot which passes through the vibrating portion perpendicularly to the midplane, from the plane of symmetry orthogonal to the wafer towards a distal end of said extension but without reaching said distal end, such that each extension is meander shaped,
• the respective slots of both of the two extensions being symmetrical relative to the plane of symmetry orthogonal to the wafer, and meeting at said plane of symmetry orthogonal to the wafer, so that the vibrating portion comprises two primary segments which each connect the foot to the distal end of one of the extensions, and two secondary segments which are interconnected at the plane of symmetry orthogonal to the wafer by respective proximal ends of said secondary segments, and which each extend to the distal end of one of the extensions so as to connect to one of the primary segments at said distal end,
• so that, for both of the at least two degenerate modes of vibration of the sensor allowing to characterize the rotation about the sensitive axis, the vibrating portion of each resonator only has movements which are parallel to the midplane and which are symmetrical relative to the plane of symmetry orthogonal to the wafer, both of the two primary segments having instantaneous velocity components, parallel to the center axis, which at each instant during vibration, are in the opposite direction to that of instantaneous velocity components of the secondary segments, also parallel to the center axis.