Output Signal Of Sensor Research Articles

Simulation Research on Variable Frequency Flash Based on Blind Source Separation

This dissertation proposes a method of constructing a delay matrix using the output signal sequence of single voltage transformer instead of the multiple sensor output signal arrays. The matrix satisfies the basic requirement of BSS so that each frequency component is separated from flicker,harmonics and inter-harmonics which contain a number of frequencies.

NEURAL-BASED RECOGNITION OF MULTI-PARAMETER SENSOR SIGNAL DESCRIBED BY MATHEMATICAL MODEL

The possibility of artificial neural network usage for recognition of a signal of a multi-parameter sensor is described in this paper. The general structure of data acquisition channel with usage of neural networks as well as mathematical model of output signal of a multi-parameter sensor is studied in this article. The model of neural network, training algorithm and achieved results of simulation modeling of a multi-parameter sensor signal recognition using MATLAB software are presented at the end of this paper.

Design of Monitoring System of Automatic Track Human Body in Residential Quarters

With the improvement of living standards, people's requirements on their living environment are higher, Especially, safety has become the primary considerationBut now the surveillance cameras which often be installed in residential quarters can only monitor the area setted, can not take initiative to track the target, so the monitoring effect is often not be satisfied. In order to change the fact, writer designed a new monitoring system.In this system, piezoelectric infrared sensors sense humans body, MCU detects sensors output signal, then controls motor to make the camera can automatic tack human body in residential quarters.

Signal analysis of a polarimetric fiber optic sensor for dynamic strain monitoring

Polarimetric fiber optic sensors have many advantages over other fiber optic sensors and strain gauges. As opposed to Fiber Bragg Grating sensors, polarimetric fiber sensors can be constructed with very simple, portable and robust experimental setup. In the paper we propose two methods of the polarimetric sensor output signal analyzing. First method is based on depolarization phenomena, and calculates degree of polarization (DOP), second one uses Fast Fourier Transform to analyze dynamic sensor response. Usefulness of both methods has been shown and experimentally proven. Full Text: PDF References K. Schroeder, W. Ecke, J. Apitz, E. Lembke, G. Lenschow, "A fibre Bragg grating sensor system monitors operational load in a wind turbine rotor blade," Meas. Sci. Technol. 17, 1167–1172 (2006). CrossRef G. Hegde, A. Asundi, "Performance analysis of all-fiber polarimetric strain sensor for composites structural health monitoring," NDT&E International 39, 320–327 (2006). CrossRef G. Wehrle, P. Nohama, H. J. Kalinowski, P. I. Torres, L. C. G.Valente, "A fibre optic Bragg grating strain sensor for monitoring ventilatory movements" Meas. Sci. Technol. 12, 805–809 (2001). CrossRef W. J. Bock, A. W. Domanski, T. R. Wolinski, "Influence of High Hydrostatic Pressure on Beat Length in Highly Birefringent Single-Mode Bow-Tie Fibers," Appl. Optics 29, 3484-3488 (1990). CrossRef A. W. Domański, M. Bieda, P. Lesiak, P. Makowski, M. Szeląg, T. Poczęsny, K. Prokopczuk, P. Sobotka, M. Chychłowski, M. Sierakowski, T. R. Woliński, "Polarimetric optical fiber sensors for dynamic strain measurement in composite materials," Acta Physica Polonica A. 124, 399-401 (2013). CrossRef P. Lesiak, G. Rajan, Y. Semenova, G. Farrell, A. Boczkowska, A. W. Domański, T. R. Woliński, "A hybrid highly birefringent fiber optic sensing system for simultaneous strain and temperature measurement," PLP 3, 140-142 (2010). CrossRef R. A. Chipman, "Depolarization in the Mueller Calculus," Proc. SPIE 5158, 184–192 (2003). CrossRef N. Furstenau, M. Schmidt, W. J. Bock, W. Urbanczyk, "Dynamic pressure sensing with a fiber-optic polarimetric pressure transducer with two-wavelength passive quadrature readout," App. Opt. 37, 663-671 (1998). CrossRef

Piezoresistive Chemical Sensors Based on Functionalized Hydrogels

Thin films of analyte-specific hydrogels were combined with microfabricated piezoresistive pressure transducers to obtain chemomechanical sensors that can serve as selective biochemical sensors for a continuous monitoring of metabolites. The gel swelling pressure has been monitored in simulated physiological solutions by means of the output signal of piezoresistive sensors. The interference by fructose, human serum albumin, pH, and ionic concentration on glucose sensing was studied. With the help of a database containing the calibration curves of the hydrogel-based sensors at different values of pH and ionic strength, the corrected values of pH and glucose concentration were determined using a novel calibration algorithm.

Multi-rate sensor fusion for underwater heading estimation

Purpose – This paper presents the results of a heading estimation method for a remotely operated vehicle (ROV). The output rate of commercially available underwater compasses is typically in the order of a few Hz. Heading frequencies of at least 1 KHz are desirable for navigation and control purposes. Design/methodology/approach – The estimation was performed by fusioning the signals of three inertial sensors: the ROV’s own underwater compass (which operates roughly at 10 Hz or less), the ROV’s embedded gyro and an additional angular rate sensor that provides readings from 1 to 3 KHz. The output signal of the additional angular rate sensor is not part of the proposed Kalman filter. Nonetheless a five-point Newton-Cotes closed integration of such signal is fed into the Kalman filter implementation that performs the required heading estimation at 1 KHz or more. Findings – The proposed Kalman filter implementation is a suitable approach to estimate heading position even though the original compass signal rate is significantly slower than the signal required for both assisted and autonomous control. Research limitations/implications – The estimated heading yield good results in both simulation and experimental environments. Originality/value – The method was embedded in a dedicated 16-bit DSP that handles both the acquisition of the three signals and the heading estimation, hence resulting in a very low-cost solution. The embedded solution was tested in the developed submarine and the obtained high-rate heading parameter is now used by the control system of the ROV.

Frequency-Variance Based Antistrong Vibration Interference Method for Vortex Flow Sensor

Vortex flowmeter is apt to be disturbed by pipe vibration in industrial applications. It is a very difficult problem to be solved, and affects the applications of vortex flowmeter. To solve this key problem, the frequency features of the flow signal and vibration noise are analyzed. A frequency-variance algorithm is proposed to deal with the vortex flow sensor output signal. A variance threshold is set to distinguish the vortex flow signal from the vibration noise interference. A signal processing system based on an ultralow-power microcontroller is developed to implement the algorithm and to extract the flow rate information from the signal containing strong vibration noise. At the same time, this system meets the requirements of low-power and two-wire mode, and can be used in process control. The strong vibration experiments are conducted to validate the effectiveness of both antistrong vibration algorithm and the system. Only one vortex flow sensor is required in the vortex flowmeter, which avoids the design and installation of the vibration sensor and saves the costs of meter.

SU‐E‐J‐126: Respiratory Gating Quality Assurance: A Simple Method to Achieve Millisecond Temporal Resolution

Purpose:Low temporal latency between a gating on/off signal and a linac beam on/off during respiratory gating is critical for patient safety. Although, a measurement of temporal lag is recommended by AAPM Task Group 142 for commissioning and annual quality assurance, there currently exists no published method. Here we describe a simple, inexpensive, and reliable method to precisely measure gating lag at millisecond resolutions.Methods:A Varian Real‐time Position Management™ (RPM) gating simulator with rotating disk was modified with a resistive flex sensor (Spectra Symbol) attached to the gating box platform. A photon diode was placed at machine isocenter. Output signals of the flex sensor and diode were monitored with a multichannel oscilloscope (Tektronix™ DPO3014). Qualitative inspection of the gating window/beam on synchronicity were made by setting the linac to beam on/off at end‐expiration, and the oscilloscope's temporal window to 100 ms to visually examine if the on/off timing was within the recommended 100‐ms tolerance. Quantitative measurements were made by saving the signal traces and analyzing in MatLab™. The on and off of the beam signal were located and compared to the expected gating window (e.g. 40% to 60%). Four gating cycles were measured and compared.Results:On a Varian TrueBeam™ STx linac with RPM gating software, the average difference in synchronicity at beam on and off for four cycles was 14 ms (3 to 30 ms) and 11 ms (2 to 32 ms), respectively. For a Varian Clinac™ 21EX the average difference at beam on and off was 127 ms (122 to 133 ms) and 46 ms (42 to 49 ms), respectively. The uncertainty in the synchrony difference was estimated at ±6 ms.Conclusion:This new gating QA method is easy to implement and allows for fast qualitative inspection and quantitative measurements for commissioning and TG‐142 annual QA measurements.

DEVELOPMENT OF ECONOMICAL ASIC FOR PCS FOR WATER QUALITY MONITORING

In this paper, the design of an ASIC is presented that implement a low-cost system for the supervision of water quality in urban areas or rivers. Photo catalytic sensor (PCS) estimates the parameter biological oxygen demand (BOD) which is generally used to estimate quality of water. The system proposed in this paper involves a simple potentiometric approach that provides a correlation in the input–output signals of low-cost sensors. This approach which is more users friendly and fast in operation is obtained by modeling and optimization of sensor for water quality monitoring. This is to overcome several drawbacks generally found in the previous flow injection analysis method of determining chemical oxygen demand (COD)-like complex designing, nonlinearity and long computation time. The system constitutes a significant cost reduction in the supervision of water quality monitoring. The main reason of employing a readout circuit to PCS circuitry, is the fact that the fluctuation of O 2 influences the threshold voltage, which is internal parameter of the FET and can manifest itself as a voltage signal at output but as a function of the trans-conductance gain. The trans-conductance is a passive parameter and in order to derive voltage or current signal from its fluctuations the sensor has to be attached to readout circuit. This circuit provides high sensitivity to the changes in percentage of O 2 in the solution. In this design simple potentiometric approach with few passive components are used to build a readout circuit. The paper focuses on the electronic implementation of the readout system for the PCS which optimize the circuit performance and increases reliability.

Statistical modeling and signal reconstruction processing method of EMF for slurry flow measurement

According to the experimental data, an amplitude probability density function (PDF) model of the slurry flow signal is built up for electromagnetic flowmeter (EMF) by the method combining statistical analysis with numerical fitting, in order to reveal the effect of slurry noise on the flow signal and describe the features of slurry flow signal. Based on this model, a signal reconstruction processing algorithm is proposed to deal with the output signal of EMF sensor for realizing the slurry flow measurement. At the same time, the high-low voltage switching mode based square-wave excitation method is presented for EMF so as to reduce the slurry noise interferences. A slurry-type EMF transmitter is developed with a DSP chip – TMS320F28335, to implement the signal processing algorithm and control function. Finally water flow calibrations and slurry flow experiments are conducted to verify the reliability and stability of the method and system. Experimental results show that its measurement accuracy of water flow is better than 0.5%, and its steady-state volatility of paper slurry is less than 3%, and its dynamic response time is less than 4s.

Thermal-wave balancing flow sensor with low-drift power feedback

A control system using a low-drift power-feedback signal was implemented applying thermal waves, giving a sensor output independent of resistance drift and thermo-electric offset voltages on interface wires. Kelvin-contact sensing and power control is used on heater resistors, thereby inhibiting the influence of heater resistance drift. The thermal waves are detected with a sensing resistor using a lock-in amplifier and are mutually cancel­led by a thermal-wave balancing controller. Offset due to thermal gradient across the chip and resistor drift are eliminated by the lock-in amplifier and power controller, and therefore do not influence the sensor output signal. A microchannel thermal-wave balancing flow sensor with integrated Al resistors has successfully been fabricated. The thermal flow sensor is capable of measuring water flow rates with nl ⋅ min−1 precision, up to about 500 nl ⋅ min−1 full scale. Measurement results are in good agreement with a dynamic model of the flow sensor. Drift measurements show the sensor output signal to be compensated for resistance drift and thermal gradient across the chip.

Wide bandwidth room-temperature THz imaging array based on antenna-coupled MOSFET bolometer

We report on the design, fabrication and measurements of a new THz sensor concept based on an antenna-coupled MOSFET bolometer for room-temperature passive THz imaging for security and medical-diagnostic applications. The device is fabricated in a 180-nm CMOS SOI technology followed by a post-CMOS MEMS process which guaranties a very high thermal insulation of the sensor. In this sensor, the wide bandwidth THz antenna absorbing the electromagnetic field is directly coupled to the bolometer for maximum energy collection, whereas its design aims at minimizing its thermal mass as is necessary for fast frame rates. DC measurements before and after the MEMS process as well as sensor output signal time constant and THz antenna pattern measurements are presented. The final sensor is part of a large pixel array of 117 elements. Simulated array characteristic is presented proving that the mutual interaction between the pixels is small enough for imaging applications.

3D 프린팅 방법으로 제작된 유연 촉각센서의 출력 특성 분석

Flexible tactile sensors can provide valuable feedback to intelligent robots about the environment. This is especially important when the robots, e.g., service robots, are sharing the workspace with human. This paper presents a flexible tactile sensor that was manufactured by direct writing technique, which is one of 3D printing method with multi-walled carbon nano-tubes. The signal processing system consists of two parts: analog circuits to amplify and filter the sensor output and digital signal processing algorithms to reduce undesired noise. Finally, experimental setup is implemented and evaluated to identify the characteristics of the flexible tactile sensor system. This paper showed that this type of sensors can detect the initiation and termination of contacts with appropriate signal processing.

Detection of random vapour concentrations using an integrating diamond gas sensor

Hydrogenated diamond (HD) gas sensors feature an integrator-like response which occurs at room temperature and which is mediated by a thin layer of adsorbed water on the HD surface. In the present work a HD gas sensor had been exposed to randomly varying acid vapour concentrations to assess its potential in a practical gas monitoring situation. Our results demonstrate that the time-differentiated sensor output signal yields a detailed temporal image of the random vapour pulses with a time resolution in the order of 1s. In contrast, the sensor signal itself provides a measure of the total vapour concentration that had been interacting with the HD sensor surface up to the point of sensor interrogation. Large accumulated vapour concentrations lead to sensor saturation. It is further demonstrated that saturated HD sensors can be repeatedly reset into a reproducible initial condition, simply by replacing the contaminated water adsorbate layer by a fresh one.

Thick-film Load-sensing bridges – Effect of Temperature and Mechanical Boundary Conditions

Although inorganic thick-film materials are usually very stable, load sensors (i.e. force, torque and pressure) based on the piezoresistive effect of thick-film resistors often exhibit some drift, with major contributions stemming from a) temperature changes or gradients, coupled with the temperature coefficient of resistance (TCR) of the sensing bridge resistors, and b) ill- defined mechanical boundary conditions, due to insufficient decoupling, plastic deformation used materials, friction or loading errors. These problems also potentially affect test samples for measuring piezoresistive response, a.k.a. the gauge factors. Here, we examine and discuss effects on the output signal of simple cantilever force sensors of two disturbances: parasitic loads and temperature gradients, and discuss / demonstrate mitigation options, and a system to reliably measure gauge factor.

Mechanical Stress Analyses of Packaged Pressure Sensors for Very High Temperatures

Methods for investigations of stresses specialized for devices operating up to 500°C are presented in this study. Resistive pressure sensors and test chips with microstrain (μ-strain) gauges are processed in thin film technology. The sensor structure was a Wheatstone bridge on a silicon membrane with platinum resistors. The μ-strain gauges were characterized with tensile tests in combination with optical strain measurements. A gauge factor of 3.6 was measured at room temperature. After characterization as bare dice, the chips were mounted with a borosilicate glass solder on two ceramic substrates, AlN and Si3N4. We generated a FE model of the sensor assemblies including temperature-dependent material properties. The distribution of mechanical strains and stresses in the sensor was analyzed. The chip warpage dependent on temperature up to 500°C was obtained from FE simulations and compared with high-precision 3D deformation measurements. Deformation results from digital image correlation (DIC) verified the utilized FE model. The correlation of experimental results for the chip warpage exhibited good agreement with the numerical results obtained from FEM. The chip deflection from the center to the edges in the out-of-plane direction on AlN was 4.5 μm; on Si3N4 a concave warpage of 3 μm at 25°C was found. Temperature-induced deformations of the sensor chip in the range of micrometers were recorded up to 500°C. The output signal of the pressure sensors is strongly affected by superimposed strains based on the sensor assembly. The bridge voltage increased by 40% after the glass solder process on AlN and by 34% for devices on Si3N4. The analysis of the μ-strain gauges showed compressive strains in the sensor membrane of −1.39% on average for assemblies on AlN and of −0.168% for glass soldered chips on Si3N4. The FEM simulations revealed an average in-plane stress in the sensor membrane of −45 MPa for chips on AlN and −20 MPa for Si3N4 substrates. The compressive strains in the membrane obtained by FEM were verified by the μ-strain gauge measurements. A higher strain and stress gradient in the membrane of devices on AlN was found with FEM, which is consistent with the higher signal offset of assembled pressure sensors that was measured in this study.

The Random Sampling Method for Gas Sensing Signal Based on Compressed Sensing

This paper presents a random sampling method for gas signal,which is based on the principle called compressed sensing. This method is suitable for gas sensor network, and it is conducive to the realization of low power, low cost of the gas sensor network. According to the characteristics of the output signal of gas sensor, we design the random sampling method which acquire the useful information in signal. Using compressed sensing recovery algorithm to reconstruct signal,we finally fulfill complete signal collection. The simulation results show that the method we proposed can achieve signal acquisition with a sampling frequency less than 1/5 of standard sampling frequency.

A Novel Coupling of Three-contact Parallel-field Hall Devices for Offset Compensation

A novel coupling of two three-contact parallel-field Hall devices, ensuring almost full offset compensation and doubled output voltage at an increased signal-to-offset ratio is presented. The two silicon Hall elements are coupled as follows - the two pairs of outer contacts are connected via two load resistors of equal value converting simultaneously the current changes in a magnetic field into Hall voltage. Since the currents in both structures are opposite, the Hall voltages are equal in value but of opposite sign. At fabrication of the devices on the same silicon chip, the two offsets are almost equal and their temperature drifts are perfectly matched. The sensor output signal results from subtraction of two device output voltages using circuitry with three op-amps. The residual offset is about 150 times smaller than the internal ones. The obtained output voltage-to-residual offset ratio at channel magnetosensitivity of 76 V/AT is very promising, reaching 7x103.

Performance evaluation of piezoelectric and differential pressure sensor for vortex flowmeters

Piezoelectric and transient differential pressure sensors are two among the most widely employed sensors for vortex flowmeter application. The present study evaluates the performance of these two techniques under fully developed and disturbed flow conditions. Firstly, the location of the transient differential pressure sensor is optimized to obtain high amplitude signals and good linearity in Strouhal number. Empirical mode decomposition method in combination with autocorrelation decay is successfully employed at high Reynolds numbers to identify the vortex shedding frequency in presence of hydrodynamic noise. The performance of the differential pressure sensor deteriorates significantly under disturbed flow conditions at low Reynolds number due to the presence of low frequency components. This deterioration in the signal quality limits the lower operating range of the flowmeter with differential pressure sensor. The output signals of the piezoelectric sensor and differential pressure sensor under no flow condition are compared to obtain the background noise due to piping vibrations and electrical interferences. These results will help a designer to suggest robust signal processing algorithms for vortex frequency detection.

Piezoelectric Force Response of Novel 2D Textile Based PVDF Sensors

This paper describes the development of 2D flexible sensors designed by integration of conductive fibrous electrodes and piezoelectric polyvinylidene fluoride (PVDF) fibers into a conventional plain woven polyester fabric. The piezoelectric properties and electrical response to the mechanical deformation of the sensors were tested using an electromechanical device built in-house. Both the amplitude of movement and the frequency of the sensors were controlled using this device and the signal efficiency of these sensors was tested for maximum signal response to the sine frequencies between 80 and 1000 Hz. The electrical signal generated by the sensors was correlated to the fineness of the PVDF fibers used, the distance between the electrodes and the nature of the electrodes. Relationships between sensor output signal under load and the type of structure were thus established.