US-12618673-B2 - Vibratory gyroscope sensor

US12618673B2US 12618673 B2US12618673 B2US 12618673B2US-12618673-B2

Abstract

A vibratory gyroscope sensor is provided. The vibratory gyroscope sensor consists of a base, and a resonator that includes a central foot attached to the base and a sidewall that rises from the foot up to a free end edge delimiting an opening. The sidewall has a proximal portion that extends from and around the foot and a cylindrical distal portion that extends in line with the proximal portion up to the free edge with the proximal portion progressively widening from the foot towards the distal portion.

Inventors

José Louis BEITIA

Assignees

HALLIBURTON ENERGY SERVICES, INC.

Dates

Publication Date: 20260505
Application Date: 20230922
Priority Date: 20220923

Claims (13)

1 . A vibratory gyroscope sensor comprising: a base, a resonator that includes a central foot by which the resonator is attached to said base and a sidewall that extends from said foot up to a free end edge delimiting an opening, wherein said sidewall has a proximal portion and a cylindrically shaped distal portion, said proximal portion extending from and around said foot, said cylindrically shaped distal portion extending from said proximal portion up to said free end edge, said proximal portion flaring out from the foot towards the distal portion, wherein said proximal portion includes a plurality of arms separated from each other by clear spaces and arranged equiangularly around said foot, each of said arms extending longitudinally between a central end arranged on the side of the foot and a peripheral end arranged on the side of the distal portion, wherein the vibratory gyroscope sensor comprises a plurality of excitation devices attached to said proximal portion to excite said resonator into vibration, as well as a plurality of detection devices attached to said proximal portion to detect vibrations of said resonator, and wherein said excitation devices and/or said detection devices are attached to said arms.
2 . The vibratory gyroscope sensor according to claim 1 , wherein said proximal portion extends between a first circular edge connected to said foot, and a second circular edge connected to said distal portion and from which the distal portion extends up to said free end edge, said first and second circular edges having such a first and a second diameter, respectively, that said first diameter represents at most 60% of the second diameter, said proximal portion having an external face that extends on the side of the base and an opposite, internal face, said foot comprising an external portion protruding on the side of the external face.
3 . The vibratory gyroscope sensor according to claim 2 , wherein said external portion has a local cross-sectional restriction forming a concave surface to which said external face is connected.
4 . The vibratory gyroscope sensor according to claim 2 , wherein said foot comprises an internal portion protruding on the side of said internal face, said resonator comprising a connection fillet that extends around said internal portion to connect the internal portion to said internal face.
5 . The vibratory gyroscope sensor according to claim 1 , wherein said foot is monolithic.
6 . The vibratory gyroscope sensor according to claim 5 , wherein the central foot and the base are assembled by welding or brazing.
7 . The vibratory gyroscope sensor according to claim 1 , wherein each of said arms includes at least: a main section, which extends from said central end, and an end section of reduced cross-section with respect to that of the main section and that extends between the main section and said peripheral end.
8 . The vibratory gyroscope sensor according to claim 1 , wherein said proximal portion comprises a first flange that extends from and around said foot, each first end of each of said arms being integral with said first flange.
9 . The vibratory gyroscope sensor according to claim 8 , wherein said proximal portion comprises a second flange that extends from the distal portion towards the inside of the resonator, each second end of each of said arms being integral with said second flange.
10 . The vibratory gyroscope sensor according to claim 1 , wherein it comprises piezoelectric elements that form said excitation devices and said detection devices.
11 . The vibratory gyroscope sensor according to claim 10 , wherein it comprises conductive rods electrically connected to said piezoelectric elements by micro-cables.
12 . The vibratory gyroscope sensor according to claim 1 , wherein said proximal portion has a straight circular frustoconical profile.
13 . The vibratory gyroscope sensor according to claim 12 , wherein said straight circular frustoconical profile is defined from a cone that has a symmetry axis and is inclined with respect to a plane (P) perpendicular to said symmetry axis by an angle (a) between 10 and 45°.

Description

The present invention relates to the general technical field of rotation sensors, and more particularly that of gyroscope sensors based on Coriolis forces to measure rates of rotation and/or angular positions, such as Coriolis vibratory gyrometers or gyroscopes. The present invention more particularly relates to a vibratory gyroscope sensor comprising a base, as well as a resonator that itself includes a central foot by which the resonator is attached to said base and a sidewall that rises from said foot up to a free end edge delimiting an opening. Vibrating structure gyrometers for measuring angular velocities are well known. These vibratory gyrometers are based on Coriolis effect, which causes a vibrating object, having a 2nd-order resonance mode divided into a primary mode and a secondary mode that are modally orthogonal to each other, to undergo a force, when it rotates, to continue vibrating in a single and same plane in the mode space defined by the primary and secondary modes. Applying an opposite force makes it possible to rotate the vibration plane with the object. The vibration is then motionless relative to a rotating reference system linked to the object. Measuring this force makes it possible to determine the angular velocity. When no force opposite to the Coriolis forces is applied, measuring the position of the reference system linked to the rotating object with respect to the vibration, which is itself fixed, gives directly the object angular position information. This operating mode is called gyroscope mode, by opposition to the previous operating mode, called gyrometer mode. In particular, vibratory cylinder gyrometers are known, which use a base to which is fastened, by means of a central rod, a metal resonator having the shape of a pot with a cylindrical sidewall and a flat bottom provided with a sleeve for receiving the central rod. Piezoelectric elements are arranged on and against said cylindrical sidewall to excite the resonator into vibration and detect the vibrations of the latter. These vibratory cylinder gyrometers have undergone various changes over the last few decades. In particular, a mushroom-shaped resonator has been proposed, which has a central foot fastened to the base and supporting a cylindrical cap with a flat top on which are arranged eight piezoelectric elements. This mushroom-shaped design was aimed in particular at reducing the dimensions and reducing the manufacturing costs. However, it induces, just like the above-mentioned flat-bottomed pot design, the presence of parasitic structural modes that affect the good operation of the control electronic system of the resonator, in particular in the presence of external vibrations as it is usually the case in an operational environment. More precisely, with the vibratory cylinder designs of the prior art mentioned hereinabove, the occurrence of three parasitic modes is observed, i.e. a drum mode in which the flat bottom is deformed parallel to the main axis of symmetry of the resonator, a flexural mode on the central foot and a rotational mode in which the entire cylinder rolls around the foot, whose frequencies are close to those of the symmetrical primary and secondary modes used to detect the angular rotations or the angular velocities. Rejection of these parasitic modes is one of the main technical challenges as regards the Coriolis vibratory gyrometers implementing, in particular, a cylindrical resonator. Indeed, the parasitic modes prevent the implementation of high-bandwidth control electronics (for example, from several hundreds of Hz to about 1 kHz), required for example for high-end stabilization applications, insofar as singularities appear in the Nyquist phase diagram causing unstable control loops for the useful, primary and secondary, modes. Moreover, these parasitic modes are most often strongly coupled to external mechanical vibrations, including external mechanical impacts. Therefore, in the presence of such external vibrations, strong signals are likely to be detected and to disturb, or even saturate, the control electronics. In order to overcome this problem, it has been proposed to use a greater number of piezoelectric elements, suitably connected to each other by means of an internal electronic module to obtain a natural rejection of the signals generated by the parasitic modes of the resonator, after suitable combination of the signals. However, this solution is not fully satisfying, because it generates increased complexity and cost, and does not prevent the parasitic modes to exist and to be stimulated when the resonator is subjected to external vibrations. To solve this problem of occurrence of parasitic modes, an alternative design has been proposed, which is based on the implementation of elastomeric vibration isolators integrated to the base to mechanically isolate the resonator from the external system. Such a design makes it possible to reduce amplitude of the signals generated at the piez