Output Signal Of Sensor Research Articles

Capacitive throughput sensor for plant materials – Effects of frequency and moisture content

The empirically determined material moisture content and frequency are among the main parameters that affect the dielectric properties of plant material. When using a capacitive sensor to measure the throughput of plant materials, an unexpected change in the measured material moisture content can result in significant error. This problem can be minimised by using a suitable electric field frequency. Thus, we studied the effect of various frequencies on capacitive throughput sensor behaviour.A novel laboratory capacitor was developed, and two sets of experiments using balsa blocks as plant material were performed. We confirmed that the dependence of sensor output voltage on the measured material moisture content could be described by S-shaped curves with two breakpoints between three sections. The first and third sections were characterised by a low influence of material moisture content on the capacitive throughput sensor output signal, whereas the moisture content had a larger influence in the second section. The shapes of the calculated curves were influenced by both the frequency of the electric field and the level of sensor filling. The sensor was less sensitive to moisture content changes when lower frequencies were employed and when the fill level was lower.

Automatic control of positioning along the joint during EBW in conditions of action of magnetic fields

Positioning along the joint during the electron beam welding is a difficult scientific and technical problem to achieve the high quality of welds. The final solution of this problem is not found. This is caused by weak interference protection of sensors of the joint position directly in the welding process. Frequently during the electron beam welding magnetic fields deflect the electron beam from the optical axis of the electron beam gun. The collimated X-ray sensor is used to monitor the beam deflection caused by the action of magnetic fields. Signal of X-ray sensor is processed by the method of synchronous detection. Analysis of spectral characteristics of the X-ray sensor showed that the displacement of the joint from the optical axis of the gun affects on the output signal of sensor. The authors propose dual-circuit system for automatic positioning of the electron beam on the joint during the electron beam welding in conditions of action of magnetic interference. This system includes a contour of joint tracking and contour of compensation of magnetic fields. The proposed system is stable. Calculation of dynamic error of system showed that error of positioning does not exceed permissible deviation of the electron beam from the joint plane.

Research on Target Information Fusion Identification Algorithm in Multi-Sky-Screen Measurement System

To solve the false targets influence identification problems in multi-sky-screen measurement system, this paper proposes multi-sensors fuzzy data fusion identification algorithm by using D–S data fusion recognition theory and the space and time relation that target pass through multi-sky-screen measurement system. According to space optical geometry of eight-sky-screen, this paper gives the calculation function of flight target location and target flight azimuth parameters, analyzes eight-sky-screens detection sensor output signal peak and signal pulse width characteristics, sets up target recognition propositional structures by using each detection screen’s output signal as a unit, researches eight-sky-screen detection target signal fusion identification processing algorithm, and derives the detection target signal fusion recognition calculation function based on support and weight values of multiple photoelectric detection sensor output signal characteristic. By using two target signals reasoning and calculation, the results verify the feasible and scientific of multi-sensors fuzzy data fusion algorithm and give the calculation process.

Mathematical model of time difference for Coriolis flow sensor output signals under gas-liquid two-phase flow

Abstract The features of Coriolis mass flow sensor output signal are analyzed, and a mathematical model of the time difference for the signals is built to evaluate the rationality and limitation of the proposed correction method when Coriolis mass flowmeter (CMF) is used to measure the gas-liquid two-phase flow. According to the experimental data of Coriolis mass flow sensor output signals under the gas-liquid two-phase flow condition, the time differences of the sensor output signals are extracted as a characteristic quantity to obtain the time difference sequence by adopting a digital zero-crossing detection method. The distribution pattern of the time difference sequence is analyzed with the probability density function, and the mathematical model of the time difference sequence is built by the correlation analysis. The mathematical model consists of a stable component and a fluctuating component. Correcting the stable component can improve the measurement accuracy of cumulative mass flow rate, and reducing the fluctuating component can enhance the measurement stability of instantaneous mass flow rate. Although the stable component cannot be completely corrected because its variation is nonlinear with the flow rate and drop in density, and the fluctuating component can only be reduced to a certain extent due to the real-time processing limitation of the instrument, CMF can provide relatively reliable measurement results of the liquid mass flow rate when the gas-liquid two-phase flow occurs.

DNA-magnetic bead detection using disposable cards and the anisotropic magnetoresistive sensor

A disposable card incorporating specific DNA probes targeting the 16 S rRNA gene of Streptococcus suis was developed for magnetically labeled target DNA detection. A single-stranded target DNA was hybridized with the DNA probe on the SPA/APTES/PDMS/Si as-prepared card, which was subsequently magnetically labeled with superparamagnetic beads for detection using an anisotropic magnetoresistive (AMR) sensor. An almost linear response between the output signal of the AMR sensor and amount of single-stranded target DNA varied from 4.5 to 18 pmol was identified. From the sensor output signal response towards the mass of magnetic beads which were directly immobilized on the disposable card surface, the limit of detection was estimated about 312 ng ferrites, which corresponds to 3.8 μemu. In comparison with DNA detection by conventional biosensor based on magnetic bead labeling, disposable cards are featured with higher efficiency and performances, ease of use and less running cost with respects to consumables for biosensor in biomedical analysis systems operating with immobilized bioreceptor.

Thermal MEMS flow meter for gaseous working fluids on the basis of the hot-wire thermoanemometric sensor

This paper describes the main principles of constructing innovative MEMS flow meters for gaseous working fluids. MEMS flow meter contains hot-wire thermoanemometrisc sensor which response to the temperature change caused by convective working fluid heat transfer from a hot-wire. The advantages of using hot-wire thermoanemometric sensors were analyzed. The main emphasis of this work is on speed, construction simplicity and small size of the sensor. The new approach to the solution of a problem of sensor output signal relation with the working fluid temperature is presented. This approach is based on adding an extra temperature sensor and a special scheme for thermal compensation to the hot-wire sensor. The temperature scale between temperature sensors (thermistors) corresponds to the flow speed and the flow rate.

The use of polyvinylidene fluoride (PVDF) films as sensors for vibration measurement: A brief review

ABSTRACTInformation about vibrating objects can be obtained by vibration measurements. Piezoelectric sensors made by piezoelectric ceramics, quartz, or organic piezoelectric materials, e. g. polyvinylidene fluoride (PVDF) have been adopted by many researchers to measure vibrations. Among these piezoelectric materials, PVDF has attracted much attention for its excellent properties such as outstanding chemical resistance, high thermal stability, low permitivities, low acoustic impedances, flexibility and membrane forming properties. In this paper, PVDF is introduced in brief. In addition, this paper briefly reviews the use of PVDF films as sensors for vibration measurement in the areas of portable medical detections, structural health monitoring, mechanical equipment vibration measurements and other applications. Meanwhile, some cases which have good low-frequency performances or novel features in structures will be especially introduced to provide helpful experiences for future applications. In the end, a spiral-shaped PVDF cantilever and a double-clamped PVDF beam of two piezoelectric energy harvesters are mentioned to provide ideas for reducing the resonant frequencies and enhancing the output signals of PVDF vibration sensors respectively. The idea of how to enhance the output signals of PVDF sensors for low frequency vibration measurements may be helpful to the development of geophone.

Design and experimental validation of an ultra-precision Abbe-compliant linear encoder-based position measurement system

The design and development of an Abbe-compliant linear encoder-based measurement system for position measurement with a targeted 20nm uncertainty (k=2) in machine tools and CMMs is presented. It consists of a linear scale and a capacitive sensor, mounted in line on an interface which is guided in the scale's measurement direction and driven by a linear motor based on the output signal of the capacitive sensor. The capacitive sensor measures the displacement of a target surface on the workpiece table. The functional point, which is the center of a tool or touch probe, is always aligned with the scale and capacitive sensor such that this configuration is compliant with the Abbe principle. Thermal stability is achieved by the application of a thermal center between the scale and capacitive sensor at the tip of the latter, which prevents both components to drift apart. Based on this concept, a prototype of a one-DOF measurement system was developed for a measurement range of 120mm, together with an experimental setup aimed at verifying the reproducibility of the system for changing ambient conditions of ±0.5°C and ±5%rh and the repeatability during tracking of a target surface over a short period of time. These experiments have shown that the measurement uncertainty of the one-DOF system is below 29nm with a 95% confidence level.

Investigation on the Output Signal of Rotational Speed Sensor for Different Flux Surfaces between Gear Wheel and Sensor

Rotational Speed Sensors are typically used to measure rotational speed in automotive application such as ABS (Anti-lock Braking System), ASR (Anti Slip Regulation) or Gear Box. In terms of application area, rotational speed sensors transmit very important signal from gear wheel to ECU (Electronic Control Units). The output signal of rotational speed sensor (RSS) may not provide exact solution in high speed situation because RSS is a kind of inductive sensor which has discharge and charge time. Thus, response time of RSS may lead a problem for exact speed measurement while the output signal is settling. In this study to evaluate different flux surfaces, both low speed @0.8RPM and high speed @3992 RPM, 6 experiments were performed for normal, convex and concave teeth setups. It has been seen that the output signal form of convex teeth setup is more appropriate than normal teeth setup and concave teeth setup for sinus signal.

Modeling, fabrication and plasma actuator coupling of flexible pressure sensors for flow separation detection and control in aeronautical applications

Preventing the flow separation could enhance the performance of propulsion systems and future civil aircraft. To this end, a fast detection of boundary layer separation is mandatory for a sustainable and successful application of active flow control devices, such as plasma actuators. The present work reports on the design, fabrication and functional tests of low-cost capacitive pressure sensors coupled with dielectric barrier discharge (DBD) plasma actuators to detect and then control flow separation. Finite element method (FEM) simulations were used to obtain information on the deflection and the stress distribution in different-shaped floating membranes. The sensor sensitivity as a function of the pressure load was also calculated by experimental tests. The results of the calibration of different capacitive pressure sensors are reported in this work, together with functional tests in a wind tunnel equipped with a curved wall plate on which a DBD plasma actuator was mounted to control the flow separation. The flow behavior was experimentally investigated by particle image velocimetry (PIV) measurements.Statistical and spectral analysis, applied to the output signals of the pressure sensor placed downstream of the profile leading edge, demonstrated that the sensor is able to discriminate different ionic wind velocity and turbulence conditions. The sensor sensitivity in the 0–100 Pa range was experimentally measured and it ranged between 0.0030 and 0.0046 pF Pa−1 for the best devices.

Sensor fault diagnosis and processing for a two-speed AMT for pure electric vehicles

In shifting process for the two-speed AMT (automated manual transmission) in this paper, the position of synchronizer sleeve is reflected by output signal of an angular displacement sensor, therefore, the normal operation of the sensor is the key to complete shifting accurately and reliably. To improve the fault-tolerant ability of two-speed AMT for electric vehicles, the operation principle of the shifting actuator and the shifting process of the two-speed AMT are analyzed. A signal revised strategy and a vehicle failure mode are proposed for the sensor signal drift and sensor fault respectively. A test bed based on dSPACE real time simulation was set up for the two-speed AMT and the sensor fault diagnosis and processing strategy was verified by experiment. The experiment results indicate that the proposed strategy can be achieved under the simulation of sensor signal drift and sensor fault, improving the reliability of the AMT.

Optimizing a new cuffless blood pressure sensor via a solid–fluid-electric finite element model with consideration of varied mis-positionings

The sizes of a newly-developed non-invasive, cuffless blood pressure sensor are successfully optimized for maximizing its output signal quality. The optimization is conducted via establishing a coupled solid---fluid-electric model and considering varied mis-positionings. The non-invasive, cuffless blood pressure sensor consists of a gel-capsule and a strain sensor in a number of parallel electrodes. Towards sensing blood pressure, the BP sensor is designed to sense the vibration of radial artery by converting the deformation of the sensor electrodes to electrical signals. In practical uses, it is inevitable that the sensor is not placed right on the location where maximum vibration of the artery occurs, thus undermining the signal quality of the sensor output signals for accurate BP estimates. This study is dedicated to optimize the sizes of sensor electrodes with a required level of robustness to be able to obtain quality signals with presence of reasonable mis-positionings. The optimization is made possible by first establishing a coupled fluid-mechanics-electric model to predict sensor output due to dynamic artery dilations, and then the sizes of sensor electrodes are successfully optimized for maximum sensor outputs with consideration of reasonable mis-positionings. The range of sensor mis-positions considered is between ?5 and +5 mm to cover all possible users in different heights, weights, ages, genders, etc. The optimal electrode length of the sensor is found to be 7 mm, while the accuracy of the predicted pressure levels are within ±7 mmHg, which conforms to the required accuracy of ±8 mmHg by The Association for the Advancement of Medical Instrumentation (AAMI).

Simulation Test System of Non-Contact D-dot Voltage Transformer

Abstract The development trend of future voltage transformer in smart grid is non-contact measurement, miniaturization and intellectualization. This paper proposes one simulation test system of non-contact D-dot transformer for voltage measurement. This simulation test system consists of D-dot transformer, signal processing circuit and ground PC port. D-dot transformer realizes the indirect voltage measurement by measuring the change rate of electric displacement vector, a non-contact means (He et al. 2004, Principles and experiments of voltage transformer based on self-integrating D-dot probe. Proc CSEE 2014;15:2445–51). Specific to the characteristics of D-dot transformer signals, signal processing circuits with strong resistance to interference and distortion-free amplified sensor output signal are designed. WIFI wireless network is used to transmit the voltage detection to LabVIEW-based ground collection port and LabVIEW technology is adopted for signal reception, data processing and analysis and other functions. Finally, a test platform is established to simulate the performance of the whole test system of single-phase voltage transformer. Test results indicate that this voltage transformer has sound real-time performance, high accuracy and fast response speed and the simulation test system is stable and reliable and can be a new prototype of voltage transformers.

Improve Static Performance Identification Of Inductive Proximity Sensor For a Mobile Robot

Nowadays, inductive proximity sensor and mobile robot are one of the most interesting topics attracting scientists. With enhancement techniques from using sensor for controlling mobile robots which can be developed more in the future. Additionally, measuring of static performance of inductive proximity sensor is also essential because the testing and navigation systems perform more exactly by result information from the experiment by assaying the output signal. In this paper, the hand-made measurement system is used to verify again the static performance of proximity sensor with ferrous, non-ferrous and alloy metal tape. Simultaneously, improve static properties of typical tape metal through the relationship between the output signal and the sensing distance of sensor. According to theoretical basis, the relationship of the static parameters can be determined such as: thickness of metal, sensing distance, dimension of metal, and so on. The testing results have shown the output signal of proximity sensor in the model and theory is not similar. The final data will accommodate some information about the relationship of the thickness of metal tape and the sensing distance of proximity sensor, the different affects of position sensor and optimum operation range of mobile robot.

Feature Patterns Extraction-Based Amplitude/Frequency Modulation Model for Vortex Flow Sensor Output Signal

To solve the key problem that vortex flowmeter is susceptible to be disturbed by pipe vibration, the collected data of the vortex flow sensor output signal are filtered, and the amplitudes of the filtered signal are extracted. The fluctuations of both the amplitude and frequency are analyzed and compared so as to study antistrong vibration interference digital signal processing methods for vortex flowmeter. The patterns of fluctuation features are extracted by calculating and analyzing the probability density function and the cycle differenced sequence. Combining with the features of the amplitude modulation and frequency modulation, the mathematical models of the vortex signal, vibration interference, and cofrequency signal are built, and the patterns between the frequency and model parameters are obtained. The effectiveness of the three types of signal models is verified through error analysis, then the reliability of the fluctuation patterns of signal amplitude and frequency is examined, which provides the basis for digital signal processing methods based on fluctuation features.

Research of Food Safety Detection Based on Multi-sensor Data Fusion Technology

This study presents a method for food safety testing based on multi-sensor data fusion, mainly to deal with food safety testing to detect the most common substances, these materials include: formaldehyde, heavy metals lead and cadmium and organ phosphorus and carbamate pesticides. Because it is more sensors, so the detection system will generate a lot of signals. Limited ability of the sensor output signals, these signals are often relatively weak and because the system will be applied to on-site testing and site environment is complex signal is easily influenced by many factors. System design related circuit, using a variety of chips, purify and amplify the signal processing of analog to digital conversion. The final article, but also on data fusion technology relevant circumstances were introduced to the relevant algorithm analysis shows. The experiment data shows that the system has a wide detection range and the configuration is simple with low detection cost which shows the method prompted can meet the engineering requirements of food safety detection.

High-Frequency Calibration of Piezoelectric Displacement Sensors Using Elastic Waves Induced by Light Pressure

In the study of ultrasound propagation in matter, displacement sensors are indispensable and of these, the most sensitive are piezoelectric sensors. In order to eliminate the intrinsic effects of the sensor from the measurements, the sensor has to be properly calibrated, which means that its transfer function has to be evaluated from a known sensor input signal and a measured sensor output signal. This has usually been done by comparing the sensor response signal to a known input signal, namely, an ultrasonic waveform, which can be theoretically calculated using mathematical models and numerical algorithms. Until now, the point-source-point-sensor model has been primarily used, while ultrasonic waves were induced mechanically either by a dropped ball or a capillary fracture. In this paper, a real-source-real-sensor model is presented. It provides a more faithful waveform construction and it enables the removal of the aperture effect from the calculated sensor transfer function, thus giving correct and universal sensor response characteristics. This was corroborated by high-frequency calibration measurements of the output signal of a Glaser-type conical sensor in two positions on both surfaces of a glass plate, while ultrasonic waves were induced by the radiation pressure of a nanosecond laser pulse.

Construction Of A Piezoelectric-Based Resonance Ceramic Pressure Sensor Designed For High-Temperature Applications

Abstract In this work the design aspects of a piezoelectric-based resonance ceramic pressure sensor made using low-temperature co-fired ceramic (LTCC) technology and designed for high-temperature applications is presented. The basic pressure-sensor structure consists of a circular, edge-clamped, deformable diaphragm that is bonded to a ring, which is part of the rigid ceramic structure. The resonance pressure sensor has an additional element – a piezoelectric actuator – for stimulating oscillation of the diaphragm in the resonance-frequency mode. The natural resonance frequency is dependent on the diaphragm construction (i.e., its materials and geometry) and on the actuator. This resonance frequency then changes due to the static deflection of the diaphragm caused by the applied pressure. The frequency shift is used as the output signal of the piezoelectric resonance pressure sensor and makes it possible to measure the static pressure. The characteristics of the pressure sensor also depend on the temperature, i.e., the temperature affects both the ceramic structure (its material and geometry) and the properties of the actuator. This work is focused on the ceramic structure, while the actuator will be investigated later.

Enhancement of oil particle sensor capability via resonance-based signal decomposition and fractional calculus

Abstract Oil particle sensors can provide valuable information about the conditions of mechanical devices by detecting the metallic particles falling from machine components into lubricating oil due to fatigue, corrosion and pitting. However, the vibration interferences and background noise in the signals from a particle sensor make it difficult to precisely detect the particle quantity and size, and thus lead to misleading detection results. To enhance the capabilities of oil particle sensors, resonance-based signal decomposition is employed in this study to separate the output signal of the oil particle sensor into two components, i.e., the high-resonance and the low-resonance components. Since the high- and the low-resonance components reflect the harmonic signal components and the impulse signal components contained in the original signal respectively, only the low-resonance component contains the particle signal contents. Then the fractional calculus technique is applied to extract the oil particle signature from the low-resonance component. In this way, the interferences can be eliminated and the particle signature can be reliably extracted. The performance of the proposed approach has been validated by both simulated and experimental data.

Circadian Intraocular Pressure Fluctuation and Disease Progression in Primary Angle Closure Glaucoma.

To document the continuous circadian intraocular pressure (IOP) fluctuation using a contact lens sensor during normal daily activities, and to study the relationship between IOP fluctuation and disease progression in primary angle closure glaucoma (PACG) eyes. Circadian IOP fluctuations were recorded by Sensimed Triggerfish sensors in 25 PACG eyes. The sensor output signals were smoothed using B-spline smoothing transform and described by functional data analysis. Glaucoma progression was documented with serial changes in mean deviation (MD) and visual field index (VFI) in Humphrey automated perimetry and retinal nerve fiber layer (RNFL) thickness. The signals were compared between the progressive and stable groups by permutation tests on functional t-statistic. Statistically significant differences were found from 2200 to 2300 and from 0700 to 0800 in gradients of the IOP fluctuation curve, as well as from 2300 to 2400 and 0800 to 0900 in curvatures of the IOP fluctuation curves, between the progressive MD and stable MD groups (P < 0.05). Significant gradient differences were also found from 1500 to 1600 and 0600 to 0800 between the progressive VFI and stable VFI groups, and from 2400 to 0100 and 0200 to 0300 between the progressive RNFL and stable RNFL groups (P < 0.05). Significant differences in circadian IOP fluctuation between progressive and stable PACG eyes were identified. Large IOP fluctuations may be associated with disease progression in PACG eyes.