Increasing the Sensitivity of Vibrating Wire Pressure Sensor
TL;DR: The design of a sensitivity improved dual diaphragm based vibrating wire transducer for sensing pneumatic pressure and an experimental setup for efficiently assessing the dynamic performances of the pressure transducers are presented.
Abstract: Design of a sensitivity improved dual diaphragm based vibrating wire transducer for sensing pneumatic pressure is proposed. The improvement achieved in sensitivity of dual diaphragm structure over single diaphragm category has been verified by conducting experiments. Experimental setup for assessing efficiently the dynamic performances of the pressure transducers is presented. Eventually, the improved sensitivity concedes improvement in precision and resolution of the instrument. While the vibrating wire transducer based pressure sensors are always showing better dynamic performances over others the present dual diaphragm structure offering improved sensitivity adds on to their dynamic performances and overall performance characteristics.
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TL;DR: In this paper, an artificial neural network (ANN)-based improved inductive signal conditioning circuit for pressure transducers with a bellow as a sensor is presented, where the ANN modeling estimates and compensates the nonlinearity of OISCC.
Abstract: This paper presents the development of an artificial neural network (ANN)-based improved inductive signal conditioning circuit for pressure transducer with bellow as sensor. A bellow is an elastic-type mechanical pressure sensor. The deflection of the bellow due to applied pressure must be translated into an efficient electrical signal for continuous monitoring, wireless transmission, and digital readout. A ferromagnetic wire attached to the bellow as a part of an inductive coil arrangement, gets deflected due to applied pressure, thereby changing the self inductance of the coil. An op-amp inductive signal conditioning circuit (OISCC) is designed to produce voltage proportional to changes in self-inductance, but the OISCC voltage versus applied pressure exhibits a considerable nonlinearity error due to stray inductances and component drifts. The ANN modeling estimates and compensates the nonlinearity of OISCC. An embedded unit is used for implementation of ANN learning process. The pressure transducer with significant stability has exhibited high linearity and sensitivity of ±0.35% and 10 mH/psig, respectively, in the measuring range of 0–70 psig. The design and experimental aspects of the technique are reported.
16 citations
Cites methods from "Increasing the Sensitivity of Vibra..."
...A dual diaphragm based vibrating wire transducer for pneumatic pressure measurement is developed in [8]....
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TL;DR: This paper proposes a new method of dynamic frequency excitation and measurement based on vibrating wire sensors which adopts intermittent self-adaptive excitation which allows the internal steel in the sensor to vibrate continuously, without attenuation.
Abstract: Vibrating wire sensors are widely used in long-term static strain monitoring. However, when dynamic measurements are needed, conventional measuring methods are unsuitable. On the basis of the static measuring method, in this paper we propose a new method of dynamic frequency excitation and measurement based on vibrating wire sensors. In the dynamic frequency excitation method, we adopt intermittent self-adaptive excitation which allows the internal steel in the sensor to vibrate continuously, without attenuation. In turn, this allows us to continuously collect and analyze the sensor signal. We use a dynamic frequency measurement algorithm to subsequently process the data, which interpolates three spectral lines based on a windowed fast Fourier transform. The resonance frequency of the sensor is obtained, which then allows us to dynamically acquire the strain. Through data analysis, the theoretical calculation error of the resonance frequency can be obtained to within 0.015 Hz, and the theoretical sampling rate of dynamic strain measurement can reach to 325 Hz. In addition, through our experiments, the efficiency and the feasibility of our methods are verified.
4 citations
Dissertation•
03 Jun 2014
TL;DR: In this paper, an attempt is made to digitise the output of load cells using electronic circuitry and microcontrollers and its loading profile has been made, the circuit used to excite internal coils of load cell is Wien Bridge Oscillator.
Abstract: In this study an attempt is made to digitise the output of load cells using electronic circuitry and microcontrollers and its loading profile has been made. The circuit used to excite internal coils of load cell is Wien Bridge Oscillator. The frequency range of each coil was determined for which optimum output is produced from the load cell. The overall frequency range observed during experiment is 60 to 160 kHz. Wien Bridge Oscillator circuit was developed which gives a frequency range of 78 to 143 kHz. Wien Bridge oscillator was interfaced with the instrument and it was loaded from 0 to 25 T using Compression Testing Machine (CTM) and changing the input frequency for a certain load within its range i.e. 78 to 143 kHz. The output rms voltage changed from 1.15 to 0.195 V for red coil, 1.17 to 0.18 V for yellow coil and 1.18 to 0.172 V for green coil. Finally the microcontroller was introduced at the output end for display of digitised load reading from the VW type load cell. The load display in microcontroller display was showing fluctuations. The experimental setup can be further improved by introducing a rectifier along with a suitable filter which would convert the AC output signal to DC. This will minimise the fluctuations of the microcontroller display. It can also be proposed to further extend the work for continuous monitoring using a wireless sensor network.
Cites background from "Increasing the Sensitivity of Vibra..."
...20 the pressure and offer reasonable durability[13]....
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...The improved performance of the dual diaphragm based vibrating wire pressure cell in its sensitivity encourages us to replace the single diaphragm vibrating wire pressure transducers used in practice[13]....
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References
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TL;DR: In this article, a new analytical solution for the load-deflection of thin polysilicon nitride membranes is presented. But the results of this solution are not as accurate as those obtained from FEM analysis.
Abstract: Accurate models are essential for the determination of the elastic properties of thin films from load-deflection experiments. Although finite element method (FEM) models have the potential to be very accurate, analytical models are desirable because of their simplicity. In this paper we present a new analytical solution for the load-deflection of membranes. Our solution yields the same relationship between the load and the deflection as the known analytical solution. However, the values of two constants are up to 35% higher and correspond well with the results from FEM analysis. In addition, the new solution yields analytical forms of the bending lines, which agree well with experimental measurements carried out with silicon nitride membranes.
216 citations
"Increasing the Sensitivity of Vibra..." refers background in this paper
...INTRODUCTION Pressure sensors and acoustic transducers working on the elastic properties of metallic diaphragms were reported in the past [1]–[2]....
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TL;DR: In this article, a quasi-analytical technique for representing the relationship between stress, diaphragm deflection, and resistance change with pressure in closed-form expressions for square, thin silicon diophragms with built-in edges is presented.
Abstract: A quasi-analytical technique which is capable of representing the relationships between stress, diaphragm deflection, and resistance change with pressure in closed-form expressions for square, thin silicon diaphragms with built-in edges is presented. As a result of this study, a simulation technique for silicon piezoresistive pressure sensors has been obtained based upon a thermoelastic plane-stress formulation of the deflection and stress equations and on a solid-state process-oriented model of the piezoresistive pressure sensors. This technique also gives a clear understanding of the basic response mechanisms in such devices.
40 citations
"Increasing the Sensitivity of Vibra..." refers background in this paper
...INTRODUCTION Pressure sensors and acoustic transducers working on the elastic properties of metallic diaphragms were reported in the past [1]–[2]....
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TL;DR: In this paper, it was shown that for maximum sensitivity the electrode should be located at the center of the diaphragm, with a radius depending on the value of the amplifier input capacitance.
Abstract: In many designs of capacitive microphones or pressure sensors the electrode size is chosen to be equal to the diaphragm size In this paper it will be discussed whether an electrode size or shape that differs from that of the diaphragm is attractive for obtaining a maximum value for the sensor sensitivity and the signal-to-noise ratio A theoretical analysis will be given for circular diaphragms and electrodes, from which it can be shown that for maximum sensitivity the electrode should be located at the centre of the diaphragm, with a radius depending on the value of the amplifier input capacitance
25 citations
TL;DR: In this paper, a clamped circular metallic diaphragm, with shallow spherical shell deformation, elongates spherically proportional to the pressure acting on it, is proposed.
Abstract: A clamped circular metallic diaphragm, with shallow spherical shell deformation, elongates spherically proportional to the pressure acting on it. By making use of the inflation characteristics and mechanical properties of the diaphragm, three types of pneumatic pressure sensor are proposed in this article. In the first type, an optical mirror is engraved on its outer surface in an optimal position falling midway between its vertex and circumference. A laser beam is made to incident on the mirror and it gets deflected to fall over a matrix of photocells; the excitation of a particular cell in the coordinates of the matrix determines the pressure acting on the diaphragm. In the second proposal, a weightless secondary coil of a transformer is fixed around the vertex of the diaphragm which would move around a stationary magnetic core. The excitation of the primary coil wound over the magnetic core causes a voltage to be picked up in the secondary coil which would depend upon the displacement of the vertex bec...
10 citations
10 May 1994
TL;DR: In this paper, a new and sensitive pneumatic pressure measuring device is proposed, which consists of a diaphragm and a string fixed inside a hollow cylinder attached to a pnumatic medium.
Abstract: A new and sensitive pneumatic pressure measuring device is proposed The sensor consists of a diaphragm and a string fixed inside a hollow cylinder attached to a pneumatic medium While one side of the diaphragm is exposed to pneumatic pressure, the string is stretched on the other side With the use of a microprocessor, the string is periodically excited through an electromagnet and the vibrating frequency is measured from the signal obtained at an optocoupler The frequency is calibrated to indicate the pressure >
9 citations
"Increasing the Sensitivity of Vibra..." refers background in this paper
...DUAL DIAPHRAGM ACTUATED VIBRATING WIRE PRESSURE SENSOR The single diaphragm based vibrating wire pressure sensor reported earlier [10]–[11] is presently extended to dual diaphragm structure....
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