Output Signal Of Sensor Research Articles

Directional Sound Detection by Sensing Acoustic Flow

The ability to determine the direction of propagation of an acoustic wave is crucial to sound source detection, localization, and identification. Current techniques based on sensing acoustic pressure using membranes at multiple spatial locations tend to have directionality and output sensitivity that depend strongly on the sound frequency, which compromises performance, especially in miniaturized applications. Unlike pressure, which is a scalar, the fluctuating flow of the acoustic medium (i.e., the acoustic particle velocity) is a vector, which inherently contains the direction information of sound propagation. Here, we experimentally demonstrate an alternative, and more direct, method of directional sound detection by sensing acoustic flow using nanofibers, which are driven by viscous forces applied by the fluctuating medium. The measured output signal of this prototype sensor exhibits bidirectional response and flat frequency response across a wide range of frequencies from 100 ${\rm Hz}$ to 10000 ${\rm Hz}$ . While pressure-sensing microphones now enjoy an annual market in the billions of units sold, a broadband sound flow sensor with almost full fidelity will provide considerable benefits.

A new smart nanoforce sensor based on suspended gate SOIMOSFET using carbon nanotube

This paper presents a new nanoforce sensor based on a suspended carbon nanotube gate field-effect transistor. To do so, a numerical investigation of Suspended Gate Silicon-on-Insulator MOSFET (SG-SOIMOSFET) is carried out using ATLAS 2D simulator. Based on the relationship between the nanotube’s deflection and the applied force, a comprehensive study of the proposed nanoforce sensor behavior is performed. Moreover, we describe the evolution of the drain current characteristics as a function of the applied force while examining the influence of capacity variation of the insulating gate on the drain current in the saturation region. It is found that the sensor has a good sensitivity of 230.68 ln(A)/pN. Our second contribution in this paper is to develop a model based on artificial neural networks (ANNs). We successfully integrate our neural model of nanoforce sensor as a new component in the ORCAD-PSPICE electric simulator library; this component must accurately express the behavior of the sensor. A second model based on neural networks, which deals with correction and linearization of the sensor output signal, is designed and implemented into the same simulator. The proposed device can be considered as a potential alternative for CMOS-based nanoforce sensing.

Polarimetric Polarization-Maintaining Photonic Crystal Fiber Vibration Sensor With Shortest Sensor Head

Here we experimentally demonstrate a polarimetric polarization-maintaining photonic crystal fiber (PM-PCF) vibration sensor with the shortest sensor head, which shows an enhanced frequency response. The fabricated vibration sensor consists of a polarization beam splitter for forming a polarization-diversified loop (i.e., a kind of Sagnac loop), PM-PCF, and two polarization controllers. For high-speed vibration sensing, intensity-based measurement was carried out using a laser diode and a photodetector. Three PM-PCF segments with lengths of 3.0, 6.5, and 11.6 cm were utilized to investigate the effect of the PM-PCF length on the frequency response of the sensor. In this investigation, single-frequency vibration from 1 – 3000 Hz was applied to the sensor head using a piezoelectric transducer. For three measured frequency responses, the same resonance frequency was observed at ~400 Hz, and cut-off frequencies were measured as ~2750, ~2100, and ~1630 Hz for 3.0-, 6.5-, and 11.6-cm-long PM-PCF, respectively. That is, the cut-off frequency increases with decreasing sensor head length, allowing the frequency response to be broadened. It is concluded that a short sensor head can provide an improved frequency response and offer a smaller variation of the frequency-dependent amplitude in the sensor output signal within a 3-dB bandwidth, in addition to the convenience of installation and the reduced sensitivity to external perturbations.

Ice detection by ultrasonic guided waves

This paper describes a method for inflight ice detection using ultrasonic guided waves that is little studied until now. Unlike existing systems, the proposed method can immediately detect icing at the place of formation. The detection area can also include whole structural segments and the proposed sensor can be integrated into a wing structure without any effect on the flow around the aerofoil or increase in drag. The proposed detection method is based on excitation with a burst signal and a sine sweep. The system was tested on a plate made from carbon fibre-reinforced plastic (CFRP) and two leading edges of a NACA 0012 profile. Ice was applied to the CFRP-plate in a cooling chamber using regular water and built up onto the leading edges in an ice wind tunnel using super cooled water droplets. Piezo ceramic patches and discs were affixed to the testing model structures for use as transceivers and receivers, respectively, to initiate the guided waves and convert them back into electric signals. The influence of variation in ice layer thickness and temperature on the sensor output signal was then investigated using the average and maximum absolute sensor output and runtime to calculate the group velocity, which was then compared to calculated group velocity values. Based on the test results, the proposed method was determined to be sensitive to the build-up of ice and, thus, effective in principle.

A fast estimation of shock wave pressure based on trend identification

In this paper, a fast method based on trend identification is proposed to accurately estimate the shock wave pressure in a dynamic measurement. Firstly, the collected output signal of the pressure sensor is reconstructed by discrete cosine transform (DCT) to reduce the computational complexity for the subsequent steps. Secondly, the empirical mode decomposition (EMD) is applied to decompose the reconstructed signal into several components with different frequency-bands, and the last few low-frequency components are chosen to recover the trend of the reconstructed signal. In the meantime, the optimal component number is determined based on the correlation coefficient and the normalized Euclidean distance between the trend and the reconstructed signal. Thirdly, with the areas under the gradient curve of the trend signal, the stable interval that produces the minimum can be easily identified. As a result, the stable value of the output signal is achieved in this interval. Finally, the shock wave pressure can be estimated according to the stable value of the output signal and the sensitivity of the sensor in the dynamic measurement. A series of shock wave pressure measurements are carried out with a shock tube system to validate the performance of this method. The experimental results show that the proposed method works well in shock wave pressure estimation. Furthermore, comparative experiments also demonstrate the superiority of the proposed method over the existing approaches in both estimation accuracy and computational efficiency.

A novel ionic liquid/polyoxomolybdate based sensor for ultra-high sensitive monitoring of Al(III): Optimization by Taguchi statistical design

A novel ionic liquid electrostatically supported Nano-Cs-polyoxomolybdate modified carbon paste electrode (Nano-IL-PMo12-CPE) has been developed by using 1-n-butyl-3-methylimidazolium tetrafluoroborate (Bmim.BF4) as a superconductive hydrophobic binder. The supramolecular gel (IL-PMo12) exhibits an ordered structure, various physicochemical properties, and specifically as a result of its substantial reversible self-assembly, it can be used as an intelligent ion-exchange smart platform in the carbon paste bulk of the electrode. The provided materials were characterized by XRD, FT-IR, UV–vis, and elemental analyses. As expected, a significant linear correspondence was found between the sensor output signal (emf/mV) and logarithm of Al(III) ion activity with a Nernstian slope of 19.9 (±0.2) mV decade−1 over a wide concentration range of 1.0 × 10−9 to 2.2 × 10−1 mol L−1 (R2 = 0.9997). The sensor considered, exploits an astounding lower limit of detection and short response time of 7.94 × 10−10 mol L−1 and 8 s respectively within the working pH range of 2.0 to 5.0. A statistical design of experimental (Taguchi method with Qualitek-4 software and L16 orthogonal array robust design) was implemented in this work to optimize the process to achieve the least number of experimental runs as much as possible. Ultimately, practical capability of the sensor was investigated successfully by assessment of Al(III) ion quantity in some aqueous samples namely mineral water, Al-Mg syrup, black tea extract, and ore samples (Basalt and Andesite), in perfect agreement with flame atomic absorption spectroscopy (FAAS).

An angle displacement sensor using a simple gear

This paper presents an angle displacement sensor that consisting of a specified gear, permanent magnets, pairs of tunnel magnetoresistance (TMR) magnetic sensors, and a shaft. The shaft and the gear fixed on it move together with the object under measurement. TMR magnetic sensors with the permanent magnet behind it are placed beside the gear. The gear is made up with high magnetic permeability, which constitutes the magnetic circuit with the permanent magnet. With the rotation of the gear, an alternating magnetic field with displacement information is generated. Pairs of TMR sensors separated by 90° electrically angle and applied with sine and cosine voltages respectively are used to perceive the changing magnetic field. So, the angle displacement detection can be realized by analyzing the output signals of TMR sensors. That is, the phase shift of the signals is proportional to the displacement and the phase detection can be realized by serve high frequency time pulses as standard. Thus, the displacement is measured by counting the time pulses. Finite element stimulation and experiment are performed using a prototype of the angular sensor. The proposed scheme is proven to be feasible. The proposed angle displacement sensor can reach up to ±5″ stability with 0.1° resolution.

Improvement of the Accuracy of the Orientation of an Object by Using a Pair of Rotating IMS

Abstract Inertial measurement systems (IMS) belong among navigation systems which permit the monitoring of the position and orientation of an object in three-dimensional space. The functional principle of IMS is based on the integration of the output signal (acceleration and angular rate) of inertial sensors to the actual position and orientation of IMS. This integration causes the rapid accumulation of systematic IMS’s errors, which leads to a rapid increase in position and orientation errors over time. The paper deals with the design of a prototype for a pair of lowcost IMSs, which are regularly rotated around their vertical axis by stepper motors. To eliminate the systematic errors of gyroscopes in the direction of the rotation axis, two counter-rotating IMSs are used. An optimal model of the data processing was developed and presented.

Triboelectric nanogenerators as self-powered acceleration sensor under high-g impact

In the field of automobiles and many other industries, there is an urgent demand for the sensing of high-g acceleration. In this paper, a self-powered high-g acceleration sensor based on a triboelectric nanogenerator is proposed for the first time. It is micro-fabricated with a total volume of 14×14×8mm3, and its sensing ability is confirmed via a Machete hammer experiment, with a measurement range of up to 1.8×104g, a sensitivity of 1.8mV/g, and a Pearson correlation coefficient of 0.99959. In addition, the output signal of this novel acceleration sensor has few clutters, which is beneficial for recognition and subsequent signal processing. The effects of the aluminum-electrode thickness on the sensitivity and linearity of the sensor are investigated via modeling, theoretical analysis, and experiment, providing a reliable basis for the parameter optimization of the structural design. Experiment results indicate that this novel acceleration sensor covers a wide measurement range and meets the urgent needs of monitoring various high-g impacts for military equipment and automobiles.

Experimental assessment and validation of an oil ferrous wear debris sensors family for wind turbine gearboxes

PurposeThe purpose of this study was to perform a complete experimental assessment of a family of oil ferrous wear debris sensor is performed. The family comprised the original sensor and its re-engineered evolution, which is capable of detecting both amount and size of wear debris particles trapped by the sensor and some predefined oil condition properties.Design/methodology/approachIn this work, the first step was to perform a design of experiments for the sensor validation. A specially defined test rig was implemented, and different ferrous wear debris was collected. For each sensor, two different tests were performed. The first test was called a “void test”, where quantified amounts of debris were collided with the sensor without oil. The second one was a dynamic test, where the sensor was installed in the test rig and different amounts of wear debris were added at a constant rate. In addition, specific tests related with oil properties detection were studied.FindingsThe results show excellent correlation of the sensor output signal with the amount of wear debris and a satisfactory detection of debris size in all ranges. Also, the dynamic test presented adequate representativeness, and sensors performed well in this scenario.Practical implicationsThis paper shows the practical implementation of this type of sensor and the usual detection range and rate of detection for different debris size and quantities.Originality/valueThis work has a great utility for maintenance managers and equipment designers to fully understand the potential of this type of sensor and its suitability for the application required.

Electrochemical impedance analysis on solid electrolyte oxygen sensor with gas and liquid reference electrodes for liquid LBE

The ionic conductivity of solid electrolyte may insufficient, and the sensor output signal will deviate from the theoretical one in low temperature. The performance of oxygen sensor with Ag/air reference electrode (RE) and liquid Bi/Bi2O3 RE was tested in low-temperature LBE at 300°– 450°C and the charge transfer reactions impedance at the electrode-electrolyte interface was analyzed by electrochemical impedance analysis (EIS). After steady state condition, both of the sensors performed well and can be used at 300°– 450°C. Bi/Bi2O3 RE has lower impedance than Ag/air RE. Therefore, the response time of the oxygen sensor with Bi/Bi2O3 RE is faster than the oxygen sensor with Ag/air RE in the low-temperature region.

<italic>In Situ</italic> Observation of Metal Properties in a Piezoresistive Pressure Sensor

Relaxation phenomena in metal interconnects are a potential source of drift in piezoresistive pressure sensors. Since the properties of a metal film are influenced by its fabrication process, it is of interest to study such phenomena in an environment that resembles a production device. For this purpose, a piezoresistive pressure sensor has been modified for characterization of thin film metallization. Extra metal has been placed on the passivation layer over the piezoresistors such that the strain in the metal can be controlled isothermally by applying a test pressure as well as by temperature. We show that the sensor output signal contains information on the stress development in the metal film. By limiting the design modification to one metal mask only, we have achieved a cost effective approach for characterization of metal properties with test structures that can be processed together with functional devices.

EVALUATION METHODS AND WAYS OF IMPROVING THE OPERATIONAL DEPENDABILITY OF MASS AIRFLOW SENSORS IN ENGINES

The design of today’s car engine electronic control system practically always includes an engine load sensor. Normally, its role is played by the intake manifold absolute pressure sensor or the mass airflow sensor. Film mass airflow sensors are the most common ones. The sensor is installed in the intake between the air filter and the throttle plate of the engine intake manifold. In the process of operation the sensor is exposed to pollution and ageing of the gauging element due to interaction with dust particles and motor oil fumes in the airflow. That causes the output signal to deviate from the reference values and consequently inaccurate calculation of the fuel blend composition by the electronic engine control system. Given the design of the sensors, they cannot be repaired and are replaced with new ones. A new sensor is quite costly. Given the above, it is obvious that the subject is of relevance. The aim of the paper is to find methods of evaluation and ways of improving the operational dependability of film mass airflow sensors installed in modern automobiles. The evaluation of sensor operability is based on the voltage of the sensor output signal. Using a diagnostic scanner plugged into the automobile’s diagnostics port in the analog-to-digital converter channel viewing mode the voltage of the sensor output signal is recorded, the fuel blend long-lasting correction factor is evaluated, and the presence of error codes associated with the malfunction of mass airflow sensor in the memory of electronic control unit is verified. A digital oscilloscope is used for measuring the voltage at the moment of ignition lock activation and the resting voltage at zero airflow, as well as the transient time. Based on the obtained findings it becomes obvious that the operational dependability of such sensors can only be improved by correcting the calibration tables of the mass airflow sensor stored in the memory of the engine control unit. Using a mass airflow sensor test stand, input data is prepared for the correction procedure. The reference and tested sensors are installed on the same vacuum pump nozzle, and the airflow rate is changed gradually. Under a fixed airflow rate the sensors’ output voltage is measured. The resulting data is summarized in a table and processed with the Chip Tuning PRO calibration software. As can be seen, one of the causes of the loss of the sensors’ operational dependability is the pollution of the sensing element. The layer of pollution on the sensing element reduces the coefficient of heat transmission between the airflow and the sensor’s gauging element. Based on the conducted research, the paper presents the results of changing sensor output signal in operation as compared to the reference values, suggests a method of correction of the calibration table of mass airflow sensor parameters in the engine control program stored in the memory of the electronic control unit, provides recommendations regarding the methods of evaluation and ways of improving the sensors’ operational dependability.

Simulasi Alat Photoplethysmograph (PPG)

Heart is a vital organ in the human body. The heart functions circulated the blood throughout the body. The volume of blood in a body organ will vary due to blood pumping by the heart. Photoplethysmograph (PPG) is a device that can detect changes in blood volume using optical sensors. The purpose of this research is to make Photoplethysmograph monitoring system online. That is a device to monitor blood volume changes and display the change graph. Fluctuations in blood volume changes are influenced by the rhythm of blood pumping by the heart. Each peak on the PPG signal is correlated with one heartbeat. Photoplethysmograph charts can be used to determine the condition and abnormalities of a person's heart.
 Photoplethysmograph system online is realized in the form of sensors, amplifiers, LPF, ADC, and microcontroller as a serial interface, wiz610wi module, and web applications as online PPG graph viewer. Sensors composed of red LED and photoresistor (LDR) are placed on the fingers. The rays emitted by the LEDs are received by the LDR. The signals received by the LDR vary according to the volume of blood changes. The sensor output signal is then amplified and filtered. Incoming filter output signal ADC, serial interface by AT89C2051 then by wiz610wi module transmitted for display and monitored. Obtained Devices and apps created have worked well. The signal shown is pretty good, clean of noise. Transmission distance measured up to 70 m with delay less than 200 ms. The average heart rate calculation was in error 3%

Evaluation of Output Signal Nonlinearity for Semiconductor Strain Gage with ANSYS Software

The paper is devoted to the study of the nonlinearity of the output signal of the pressure sensor on the silicon on sapphire structure (SOS). The authors constructed a mathematical model of the strain-gauge and carried out numerical simulation by using the ANSYS 12.1 software. For comparative analysis, the problem was solved both in a geometrically nonlinear and in a geometrically linear formulation. To account for the elastic-plastic properties of the silver solder PSR72, the Prandtl diagram was used. As a result, the maximum stresses and deformations in the sapphire crystal, solder, and titanium membrane under which the design successfully works were determined, and also the nonlinearity of the output signal was estimated in depending of the applied pressure. According to calculations, the nonlinearity of the output signal is 11.3%. The received value is unacceptable for this type of sensor, and requires further tuning, which negatively affects the accuracy of the product and its cost.

Magnetic Field Distortion From Conductive Layers for High-Frequency Speed Sensor Applications

In previous works, the known scalar approach for the vector potential was extended to determine the influences of eddy currents in metallic layers in a closed form, based on a connection between infinite integrals of Bessel functions and the complete elliptic integrals. While the original idea treats only thin layers with respect to the penetration depth, in this paper, the formalism is extended to the opposite limit of thick layers. It was shown that the developed formalism can be used as a framework to analyze and classify the development of eddy currents in speed sensor systems and even to advocate on chip layout. This extension to thick layers is of great interest in this context as it describes the regime where eddy currents strongly influence the sensor output signal.

Improved Color Mapping Methods for Multiband Nighttime Image Fusion

Previously, we presented two color mapping methods for the application of daytime colors to fused nighttime (e.g., intensified and longwave infrared or thermal (LWIR)) imagery. These mappings not only impart a natural daylight color appearance to multiband nighttime images but also enhance their contrast and the visibility of otherwise obscured details. As a result, it has been shown that these colorizing methods lead to an increased ease of interpretation, better discrimination and identification of materials, faster reaction times and ultimately improved situational awareness. A crucial step in the proposed coloring process is the choice of a suitable color mapping scheme. When both daytime color images and multiband sensor images of the same scene are available, the color mapping can be derived from matching image samples (i.e., by relating color values to sensor output signal intensities in a sample-based approach). When no exact matching reference images are available, the color transformation can be derived from the first-order statistical properties of the reference image and the multiband sensor image. In the current study, we investigated new color fusion schemes that combine the advantages of both methods (i.e., the efficiency and color constancy of the sample-based method with the ability of the statistical method to use the image of a different but somewhat similar scene as a reference image), using the correspondence between multiband sensor values and daytime colors (sample-based method) in a smooth transformation (statistical method). We designed and evaluated three new fusion schemes that focus on (i) a closer match with the daytime luminances; (ii) an improved saliency of hot targets; and (iii) an improved discriminability of materials. We performed both qualitative and quantitative analyses to assess the weak and strong points of all methods.

Digital photography for tracking the phenology of an evergreen conifer stand

Gap fraction measurements with digital a hemispherical camera were carried out in 2007–2016 in a Scots pine (Pinus sylvestris L.) stand growing on transitional Sphagnum bog in Järvselja, Estonia. The measurements were done at the time when (1) the pines had maximum foliage, or (2) after autumn needle fall or before bud burst. Data for gap fraction calculation were extracted from camera raw files. For data recording, the sensor output signal maximum was kept according to the image brightness histogram within the interquartile range of the sensor dynamic range. A linear conversion method (LinearRatio) was used for image processing. The relative needle loss in autumn (20–30%) increased gap fraction by 0.02–0.05 at view zenith angles from 10° to 60° and decreased the mean plant area index from 1.86 to 1.68 after autumn litter fall. The measurement results were in good agreement with a theoretical gap fraction model simulation and with gap fraction estimates made from cover photos. The measurement and data processing protocol is appropriate for long-term monitoring in permanent sample plots.

Optimization of the parameters of the current transducer of block protection of electric motors

We determined the parameters of a current and voltage inductive transducer with a magnetic core made of a ferromagnetic material. The inductive transducer is used as a part of the block multifunctional protection of three-phase asynchronous electric motors. An equivalent circuit of a passive inductive current transducer is given. We determined the main relationships connecting the output voltage of the transducer with the measured current. Modeling of parameters was performed to expand the ranges of measured currents at a fixed frequency and in a wide frequency range. We examined the operating modes of the transducer at an idle speed, with a short circuit. The mathematical model takes into account the characteristics of the magnetic circuit, the possibility of its saturation, the higher harmonic components of the sensor output signal.

Control strategy research of a selective catalytic reduction system for heavy-duty application

An AdBlue dosing control strategy of the selective catalytic reduction (SCR) system is developed for a heavy-duty diesel (HDD) engine. The strategy includes a raw emission prediction model, an ammonia (NH3) coverage prediction model, a transient heat hysteresis correction algorithm, an NH3 leakage control model for transient operation conditions, and a feedback controller (FBC). FBC has been developed by using mathematical manipulation to change output signal of sensor based on cross-sensitivity of nitrogen oxide (NO x ) sensor to NH3. The quantification of control parameters is based on experiments and Nyquist stability criterion. FBC is enabled in most test conditions to satisfy the stability requirements. NO x conversion (DeNO x ) efficiency of SCR system is 82.4% in European steady-state cycle (ESC) test and 80.3% in European transient cycle (ETC) test, while the leakage of NH3 is under 10−5 volume fraction in average.