Office National D'etudes Et De Recherches Aerospatiales

Office National D'etudes Et De Recherches Aerospatiales (onera)

Onera

Claude Chartier

Denis Janiaud

Olivier Le Traon

Jean Guerard

Raphaël Levy

Vincent Gaudineau

Marc Pernice

Steve Masson

Oliver Le Traon

Rachid Taibi

Stève Masson

The invention is a device for measuring the temperature of the vibrating beam of a vibrating-beam sensor. It comprises a resonator () vibrating in torsion in resonant mode and exhibiting a torsional vibration node (N), said node being its zone of fixing in the vicinity of the middle of the length (L) of the vibrating beam, said fixing allowing thermal transfers between the resonator and the beam. The frequency of the resonator and the variations of this frequency are representative respectively of the mean temperature T of the beam and of the variations of this temperature T, the effects of which may be compensated by a model.

Device for measuring the temperature of a vibrating beam and application to the improvement of the precision of measurement of a vibrating-beam sensor

Mechanical resonators for making timepieces have the drawback of not being simultaneously efficient, compact, and inexpensive. The invention is a planar structure of a mechanical resonator () that is suitable for reducing bulkiness and manufacturing cost and comprises a bar (R) vibrating in longitudinal expansion/compression resonance and two beams, () each vibrating simultaneously in longitudinal expansion/compression and it bending oscillation in the plane of the structure and connected to the bar by a connection element () on the median plane (&#x3c0;) of the bar, thereby enabling the effects of the transverse deformations of the bar, due to the Poisson ratio of the material, to not be transmitted to the attachment pads (PF) of the resonator. Thus, the quality factor of the resonator can be very high.

Planar structure of a mechanical resonator decoupled by bending oscillation and expansion/compression vibrations

The Coriolis-effect gyrometer has a tuning fork having two tines, which tuning fork is formed in a plate of piezoelectric crystal and provided with electrodes composed of ribbon conductors supported solely by the faces of the tines parallel to the plate. The drive excitation and drive detection electrodes are connected to an oscillator circuit, and the Coriolis detection electrodes are connected to a detection circuit. For each of the faces parallel to the plate of each of the tines the drive detection ribbon is disposed between the drive excitation ribbon and the Coriolis detection ribbon and is connected to the inverting input of an operational amplifier, the non-inverting input of which is connected to the electric ground, said operational amplifier forming part of the oscillator circuit.

Electrodes and associated electronic circuits for a piezoelectric vibrating gyrometer

The present disclosure relates to a vibrating element which is planar parallelly to an electrical crystallographic axis of a piezoelectric material such as quartz. The element comprises a beam holding electrodes, a stationary portion rigidly connected to one end of the beam, and a solid portion rigidly connected to the other end of the beam. The structure with facets from the chemical machining of the element has an axis of symmetry parallel to the electrical axis, and the solid portion has a center of gravity on the axis of symmetry. The useful vibration modes of the vibrating element, according to which the solid portion is reciprocatingly rotated about the axis of symmetry and reciprocatingly moved parallel to the plane of the element, are uncoupled. The measurement of an angular speed by a rate gyroscope including said vibrating elements is more precise.

Element vibrating in two uncoupled modes, and use in vibrating rate gyroscope

Growing community of inventors

Massy, France

Claude Chartier