Office National D'etudes Et De Recherches Aerospatiales

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

Onera

Raphaël Levy

Jean Guerard

Olivier Le Traon

Denis Janiaud

Vincent Gaudineau

Claude Chartier

Béatrice Verlhac

Pierre Lavenus

Guillaume Aoust

Marc Pernice

Steve Masson

Béatrice Bourgeteau

Oliver Le Traon

Stève Masson

Thomas Perrier

A resonator is suitable for reducing or suppressing a force transmitted by a vibrating portion of the resonator to a support part. To this end, the vibrating portion includes two extensions which are each meander shaped such that two segments of each extension have respective speed components that are oriented in opposite directions. Such a resonator, which is balanced, can advantageously be used within a rate gyro or a force sensor.

High-quality-factor flexural-vibration resonator for producing time references force sensors or gyrometers

An electrical field detector includes an electromechanical oscillator, part of which is included of a piezoelectric element, a frequency measuring device which is coupled to the oscillator so as to measure the oscillation frequency, and an electrical masking assembly. The electrical masking assembly is arranged close to the piezoelectric element so that, during an use of the detector, the piezoelectric element moves by vibrating relative to the electrical masking assembly. A variable part of the piezoelectric element is thus exposed to the electrical field to be measured. A change in the oscillating frequency then forms an electrical field measurement result.

Electric field detector

Disclosed is a system and method that provide an amplitude value and a phase delay value which relate to a sinusoidal signal to be measured. For this purpose, phase values of a reference signal, at which the signal to be measured exceeds or falls below the reference signal, are collected and transmitted to a computation unit. The computation unit determines the amplitude and delay values from the collected phase values. The system can be implemented in a cost-effective manner, in particular using an ASIC circuit or an FPGA circuit.

System and method for providing the amplitude and phase delay of a sinusoidal signal

An electric measurement circuit possesses an electrical reaction leg for forming an oscillator from a resonator, and furthermore possesses a measurement leg the input of which is supplied by the electrical reaction leg. The measurement leg contains an adjustable phase shifter so that an additional excitation force that is applied to the resonator in the measurement leg can be adjusted in phase quadrature with respect to an excitation force that is applied to the resonator in the electrical reaction leg. Such an electrical measurement circuit is particularly suitable for forming a photoacoustic gas detector.

Electrical measurement circuit, gas detector and method for measuring a gas concentration

A resonator includes a prong of which the width between edges is close to &#x3bb;/2. The pressure variation at one edge is then in phase opposition with that at the other edge. Acoustic coupling with an incident wave having the wavelength is thus improved. The ratio between the width between edges and the height of the prong is chosen so that only the fundamental mode with bending oscillation of the prong is present. It to prongs of a tuning fork embedded in a solid shared base optimized to contain the energy in the tuning fork while avoiding energy losses in the support. Finally, the tuning fork is advantageously combined with a unit for containing acoustic energy including a rigid reflecting screen.

Mechanical resonator optimised to operate in a fluid

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

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.

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Paris, France

Raphaël Levy