Output Signal Of Sensor Research Articles

Self-Powered Pressure- and Vibration-Sensitive Tactile Sensors for Learning Technique-Based Neural Finger Skin.

Finger skin electronics are essential for realizing humanoid soft robots and/or medical applications that are very similar to human appendages. A selective sensitivity to pressure and vibration that are indispensable for tactile sensing is highly desirable for mimicking sensory mechanoreceptors in skin. Additionally, for a human-machine interaction, output signals of a skin sensor should be highly correlated to human neural spike signals. As a demonstration of fully mimicking the skin of a human finger, we propose a self-powered flexible neural tactile sensor (NTS) that mimics all the functions of human finger skin and that is selectively and sensitively activated by either pressure or vibration stimuli with laminated independent sensor elements. A sensor array of ultrahigh-density pressure (20 × 20 pixels on 4 cm2) of interlocked percolative graphene films is fabricated to detect pressure and its distribution by mimicking slow adaptive (SA) mechanoreceptors in human skin. A triboelectric nanogenerator (TENG) was laminated on the sensor array to detect high-frequency vibrations like fast adaptive (FA) mechanoreceptors, as well as produce electric power by itself. Importantly, each output signal for the SA- and FA-mimicking sensors was very similar to real neural spike signals produced by SA and FA mechanoreceptors in human skin, thus making it easy to convert the sensor signals into neural signals that can be perceived by humans. By introducing microline patterns on the top surface of the NTS to mimic structural and functional properties of a human fingerprint, the integrated NTS device was capable of classifying 12 fabrics possessing complex patterns with 99.1% classification accuracy.

Computational Neuroscience Applied in Surface Roughness Fiber Optic Sensor.

Computational neuroscience has been widely used in fiber optic sensor signal output. This paper introduces a method for processing the Surface Roughness Fiber Optic Sensor output signals with a radial basis function neural network. The output signal of the sensor and the laser intensity signal as the light source are added to the input of the RBF neural network at the same time, and with the ability of the RBF neural network to approach the non-linear function with arbitrary precision, to achieve the nonlinear compensation of the sensor and reduction of the effect of changes in laser output light intensity at the same time. The Surface Roughness Fiber Optic Sensor adopting this method has low requirements on the stability of the output power of laser, featuring large measuring range, high accuracy, good repeatability, measuring of special surfaces such as minor area, and the bottom surface of holed etc. The measurements were given and various factors that affect the measurement were analyzed and discussed.

Improving the accuracy of the micromechanical gyroscope by utilizing multiple sensing elements in the control system

The purpose of the study is to develop a method for reducing the random error of MMGs by simultaneously using multiple sensors by jointly processing their output signals. The results of the experimental study of the characteristics of the zero signal of the micromechanical gyroscope are presented. The output signal of the micromechanical angular velocity sensor is presented as a set of useful signal and white noise (random component). To increase the informativeness of the study of the output signal, their centering (compensation of the constant component) and integration were performed. In order to study the characteristics, realizations were made simultaneously with 7 micromechanical gyroscopes. Received 9 implementations of the zero signal of the sensor group. They indicate an increase in the variance of the integrated highly noisy signal. The results of sensor signal processing are presented in two methods. The first method of complex processing of a group of sensors with simultaneous removal of a signal from all at the same time, the second - in turn, the capture of a useful signal from two micromechanical gyroscopes. It is shown that statistical processing of the output signals of 7-10 micromechanical gyroscopes allows to reduce the average value of a random error and its standard deviation, ie to increase the measurement accuracy by 1.5 orders of magnitude. The method of increasing the accuracy of micromechanical angular velocity sensors by step-by-step paired complex processing of their output signal, which consists in two-step observation and approximation and correction of the output signal and measurement of angular velocity (input value) and complex (pair-wise) steam The method improves the accuracy of micromechanical gyroscopes by 10 times. The statistical characteristics of the signal are established. The efficiency of complex signal processing of the sensor group is shown to reduce the random component of the error.

An Inductive Debris Sensor for a Large-Diameter Lubricating Oil Circuit Based on a High-Gradient Magnetic Field

Wear is one of the main factors of machine failure. If abnormal wear was not detected in time during the operation of a mechanical system, it probably leads to catastrophic consequences. The wear debris in the lubricating oil circuit contains much information about equipment wear. Consequently, debris detection is regarded as an effective way to detect mechanical faults. In this paper, an inductive debris sensor based on a high-gradient magnetic field is presented for high-throughput lubricating oil circuits. The excitation coil of the sensor is driven by a constant current to generate a high-gradient magnetic field, and the induction coil is wound around the flow path. When wear debris cuts the magnetic line through the flow path, a corresponding induced voltage is generated. The experimental results show that the sensor output signal is linear with the drive current and the wear debris velocity. In addition, the shortest distance between the particles that the sensor output signals can be completely separated is 25 mm. When the distance is smaller, the induced signals are superimposed.

An Optical MEMS Acoustic Sensor Based on Grating Interferometer.

Acoustic detection is of great significance because of its wide applications. This paper reports a Micro-Electro-Mechanical System (MEMS) acoustic sensor based on grating interferometer. In the MEMS structure, a diaphragm and a micro-grating made up the interference cavity. A short-cavity structure was designed and fabricated to reduce the impact of temperature on the cavity length in order to improve its stability against environment temperature variations. Besides this, through holes were designed in the substrate of the grating to reduce the air damping of the short-cavity structure. A silicon diaphragm with a 16.919 µm deep cavity and 2.4 µm period grating were fabricated by an improved MEMS process. The fabricated sensor chip was packaged on a conditioning circuit with a laser diode and a photodetector for acoustic detection. The output voltage signal in response to an acoustic wave is of high quality. The sensitivity of the acoustic sensor is up to −15.14 dB re 1 V/Pa @ 1 kHz. The output signal of the high-stability acoustic sensor almost unchanged as the environment temperature ranged from 5 °C to 55 °C.

Implementasi Algoritma 2 Step Kalman Filter Untuk Mengurangi Noise Pada Estimasi Data Accelerometer

An accelerometer is a useful sensor in technological development. Currently, the accelerometer is found on smartphone devices, navigation devices, and wearable devices. However, processing the sensor output signal into data that can be interpreted is not easy. This is because the output of an accelerometer sensor has significant noise. In this study, the authors are interested in developing an estimation method using a Kalman Filter. Kalman filter is an estimator so it is expected that the sensor data are more resistant to noise interference. In this study, the author innovated the 2 step Kalman filter. The study was conducted because the use of 1 step still has noise on the estimation results. Based on the analysis of the algorithm simulation results, it can be concluded that the Kalman filter 2-step algorithm has good performance in estimating the accelerometer sensor output. When compared with the Kalman filter 1 step algorithm, the Kalman filter 2 step algorithm has a smaller average error estimation and is able to achieve a constant/stable condition faster than the Kalman filter 1 step method

Construction and investigation of a method for measuring the non-stationary pressure using a wavelet transform

Automated control systems badly need measurements of fast-changing non-stationary physical quantities in real time, or close to that. In this area, there is a separate group of tasks on measuring the non-stationary pressure in liquids and gases. This paper demonstrates that measuring the non-stationary pressure in real time, or close to that, represents a problem on restoring an input signal, which, in terms of mathematics, belongs to the class of ill-posed problems (according to J. Hadamard). We have derived a solution to the inverse problem of measurement that is based on a mathematical model for measuring transformation enabled by a pressure sensor. Based on this solution, we have constructed a measuring method, which implies the wavelet processing of the sensor's output signal. In this case, we suggest that such basic functions of wavelet transformation should be selected that are the modification of the pulse transition function of the sensor. This paper reports an experimental study into the feasibility of the developed method, based on the measurement of the simulated pressure pulse. A pressure pulse is simulated by dropping a ball of the calibrated mass onto the sensor's membrane. We have proposed a measurement scheme for determining the duration of touch between the ball and the membrane. Testing the accuracy of the method implies comparing the actual mass of the ball with that derived from the sensor's output signal. The proposed method has demonstrated high accuracy because the maximum relative error in determining the mass of the falling ball was only 0.65 %. The proposed method for measuring the non-stationary pressure could be used in control systems that require the high-speed dynamic correction of a measurement error. Specifically, these include control system in aerospace engineering, testing complexes, military technology, scientific research

A Novel Fabricating Process of Catalytic Gas Sensor Based on Droplet Generating Technology.

Catalytic gas sensors are widely used for measuring concentrations of combustible gases to prevent explosive accidents in industrial and domestic environments. The typical structure of the sensitive element of the sensor consists of carrier and catalyst materials, which are in and around a platinum coil. However, the size of the platinum coil is micron-grade and typically has a cylindrical shape. It is extremely difficult to control the amount of carrier and catalyst materials and to fulfill the inner cavity of the coil, which adds to the irreproducibility and uncertainty of the sensor performance. To solve this problem, this paper presents a new method which uses a drop-on-demand droplet generator to add the carrier and catalytic materials into the platinum coil and fabricate the micropellistor. The materials in this article include finely dispersed Al2O3 suspension and platinum palladium (Pd-Pt) catalyst. The size of the micropellistor with carrier material can be controlled by the number of the suspension droplets, while the amount of Pd-Pt catalyst can be controlled by the number of catalyst droplets. A bridge circuit is used to obtain the output signal of the gas sensors. The original signals of the micropellistor at 140 mV and 80 mV remain after aging treatment. The sensitivity and power consumption of the pellistor are 32 mV/% CH4 and 120 mW, respectively.

Automatic System to Count and Classify Bacteria Based on Magnetic Cytometry

Flow cytometry is a powerful technique to analyze cells in a solution. Magnetic flow cytometers combine the potential for cell detection and counting with the advantages of a lab-on-chip technology. In these devices, magnetic sensors are combined with magnetic particles as reporters and microfluidics for sample transport. Herein, a signal analysis method is used to aid the identification of the number of magnetically labeled bacteria associated with each detection event. Comparing the sensor output signal (pulse amplitude versus pulse-width analysis) with simulations, we have developed a reliable classification method, based on a MATLAB algorithm, to identify the number of magnetically labeled bacteria. Discrimination of the number of bacteria from the sensor event signatures improves the accuracy of the detection system.

Sideband sensitivity of fluxgate sensors theory and experiment

The relationship between electronic properties of racetrack fluxgate and the second harmonic sideband sensitivity of the sensor alone without electronics is discussed in this paper. We propose a new approach to calculate the sideband sensitivity based on inductance measurements of the fluxgate coils. In this approach, we take the current-dependent mutual inductance between primary and secondary coil into account. To calculate the sensitivity, the inductance and its current dependence are measured and fitted using the provided model. The results show the validity of the approach and can describe the output signal and sensitivity of the fluxgate sensor alone, separating it from influences of the electronics. This approach makes the separable optimization of fluxgate sensor and its electronics possible.

МЕТРОЛОГIЧНЕ ЗАБЕЗПЕЧЕННЯ ВИПРОБУВАНЬ ЕЛЕКТРОННИХ РЕГУЛЯТОРIВ ГТД – СТЕНД-IМIТАТОР ДВИГУННИХ ДАТЧИКIВ

Testing of electronic control systems (further “regulators”) FADEC for gas turbine engines in the manufacturer laboratory conditions is described. The main attention is devoted to the control of the metrological characteristics of the regulator measuring channels. The results of constructively separated sensor imitators application, what interacts with the controller, including DBSCT and vibration sensor, are presented in this article. It is shown the expediency and results of the stand application, which united all the imitators necessary for testing of serial production. Data on verifying imitators and ensuring accuracy coefficients is given. In the framework of testing the electronic regulators of gas turbine engines, JSC Element experts developed, manufactured and certified all the necessary specialized stands that provide both a full-fledged inspection in the test-laboratory of monitoring and functions checking and additionally checking of the metrological characteristics of the regulators measuring channels. For reduced testing time in the serial production of the RDTs-450M regulator, in addition to the previously used structurally isolated sensors imitators, a stand was designed and manufactured combining all the imitators necessary for measuring channels testing. This new imitator provided usability and reduced testing time. The simulators used for test procedure. These simulators provide output signals of real sensors. These signals check by standardized measuring equipment. Systematic verification use certified stands, which create a normalized influence on the input signal of measuring (pressure, vibration acceleration, shaft rotation angle are also available). Further improvement of the test equipment will consist in automating of procedures for checking the metrological characteristics of the regulators channels by creating of programmatically controlled simulators. The replacement of individual simulators with a specialized stand markedly increased the productivity of work on the calibration and verification of the regulators measuring channels.

Novel MPC‐Based Fault Tolerant Tracking Control Against Sensor Faults

AbstractThe problem of active fault‐tolerant tracking control with control input and system output constraints is studied for a class of discrete‐time systems subject to sensor faults. A time‐varying fault‐tolerant observer is first developed to estimate the real system state from the faulty sensor output and control input signals. Then by using the estimated state at each time step, a model predictive control (MPC)‐based fault‐tolerant tracking control scheme is presented to guarantee the desired tracking performance and the given input and output constraints on the faulty system. In comparison with many existing fault‐tolerant MPC methods, its main contribution is that the proposed state estimator is designed by the simple and online numerical computation to tolerate the possible sensor faults, so that the regular MPC algorithm without fault information can be adopted for the online calculation of fault‐tolerant control signal. The potential recursive infeasibility and computational complexity due to the faults are avoided in the scheme. Additionally, the closed‐loop stability of the post‐fault system is discussed. Simulative results of an electric throttle control system verify the effectiveness of the proposed method.

Study on measurement error of iron ore pipeline transportation flow based on weight function theory of electromagnetic flow sensor

An electromagnetic flow sensor applied to the flow measurement of iron ore pipeline transportation will incur a measurement error after being used for a period of time, and the error will increase continuously. In this paper, based on the weight function theory of electromagnetic flow sensors, the main cause of the error is proposed. Specifically, in the process of using the electromagnetic flow meter the insulation lining of the sensor is easily damaged because the measuring pipe of the sensor constantly collides with the solid phase of the fluid, leading to a change in the distribution of the weight function of the electromagnetic flow sensor, which, in turn, changes the contribution of the induced electromotive force generated by each medium in the pipe to the measuring electrode. This paper is based on the PDE computer numerical calculation method, and, according to the analysis of the weight function under different boundary conditions, the rule that the output signal of the electromagnetic flow sensor decreases with increasing insulation lining area is obtained. The computer numerical calculation method used in this paper can provide a new approach to the theoretical analysis of the weight function of electromagnetic flow sensors. Furthermore, the conclusion reached in this paper can provide a theoretical basis for the development and maintenance of electromagnetic flow sensors applied to the flow measurement of iron ore pipelines.

Cyclostationary mode of pyroelectric sensor

Periodically variable pyroelectric systems with a time–varying load resistance are investigated both theoretically and experimentally. The sensitive element of the system under consideration is periodically connected to the input of the measuring device. The processes of accumulation and redistribution of electric charges in this case are similar to those in pyroelectric vidicons. Theoretical analysis is based on the expansion of input time functions into a family of elementary signals, such as delta or unit step functions. In this case the response to an arbitrary signal can be calculated as a superposition of the elementary responses. Output signal of such sensors is represented by a periodical sequence of impulses under sinusoidal thermal excitation conditions, contrary to a sinusoidal signal in the case of stationary systems. Operating conditions under which the output signal amplitude exceeds the stationary response and is independent of the load resistance value are found.

Magnetostrictive whisker sensor application of carbon fiber-alfenol composites

Long strips of material cut from magnetostrictive Fe-Al (alfenol) and Fe-Ga (galfenol) rolled sheets with a preferred orientation are flexible yet have a high elastic modulus. They resemble animal whiskers and are effective as flow sensors, responding with local changes in magnetization due to bending stresses induced from the drag force during fluid flow. Both tensile and compressive stresses are simultaneously applied on opposite sides of the whisker neutral axis when the whisker bent, and thus the magnetostrictive whisker sensor must be able to withstand the range of tensile and compressive stress loadings caused as the whisker bends. In this study, we investigate application-related properties of alfenol and galfenol thin sheets and carbon fiber composite-coated sheets for use in whisker flow sensors. Being able to reduce sensor thickness is important for improving flexibility as the sensors deflect. The net voltage changes in the Hall sensor were proportional to the applied tip force. Magnetostriction is strongly dependent on texture development, and this was explored for several sample thicknesses in the two alloys. Goss, (011) [100], single grain was well developed in the both of 0.32- and 0.45 mm thick sheets, while the 0.20 mm thick sample shows {113} grain growth in galfenol. For alfenol, the Goss grain was globally grown in the whole sample with the overall thicknesses. For utilization of these sensors for real situations, carbon fiber was added to the alfenol whiskers as a protective layer. Bending experiments were performed on a carbon fiber-alfenol composite with a Hall sensor to see if magnetomechanical transduction was impaired. We observed that the Hall sensor output signal from the composite was improved by about 75% from that of a bare alfenol strip. Finite element modelling showed that the composite induced more internal stresses on the alfenol strip with the same degree of bending.

Fabrication and Characterization of Bending- Independent Capacitive CMOS Pressure Sensor Stacks

Abstract Artificial limbs, equipped with miniaturized tactile sensors, can handle objects with more dexterousness. Next to detecting forces, the sensor devices are also able to measure temperature. With this additional information, the touched objects can be better characterized. As such sensors, active CMOS-based capacitive pressure sensors are used in this work. The Sensors are thinned to 20-30 μm target thickness to make them bendable. One challenge of such thin sensors is the strong dependence of the output signal upon bending. To compensate this dependency, two sensors were mounted back to back. This allows a numerical adjustment of the two characteristic sensor output signals to mechanical stress curves. After electrically contacting of the stacks with a 15 μm thin polyimide foil substrate, the bending dependence of the stacks was characterized with a four-point bending procedure. By this characterization the dependency of the pressure sensor output signal on the height of mechanical stress was determined. Both sensor output signals show an inverted behavior under the same mechanical stress which confirmed prior simulation results with the same setup. Based on this information, a numerical method for compensating the bending dependence was successfully proven.

Debonding detection for rectangular CFST using surface wave measurement: Test and multi-physical fields numerical simulation

Abstract The interfacial debonding detection approach for concrete-filled steel tubular (CFST) members using surface-mounted piezoelectric-lead-zirconate-titanate (PZT) actuators and sensors is experimentally and numerically investigated. In this study, an interfacial debonding detection approach using surface wave measurement with PZT patches is propoed firstly and experimental investigation on the feasibility of the proposed approach with two CFST specimens with different levels of interface debonding defects is carried out. For comparison, a PZT sensor is also embedded in concrete core to measure the stress wave traveling from the surface-mounted PZT actuator. Experiment results indicate that the voltage amplitude of the embedded PZT sensor representing the wave propagation from the steel plate into the concrete core decreases due to the existence of interfacial debonding defect, but the output signal of the surface-mounted PZT sensor increases accordingly when interface debonding occurs. Moreover, the increment of surface-mounted PZT sensor measurement is related to the dimension of the interface debonding defects. The experimental finding implies that the interface debonding is detectable using surface wave measurement. In order to investigate the mechanism of the proposed approach, numerical study on the wave propagation process in CFSTs is further discussed by using three-dimensional (3D) solid element models and two-dimensional (2D) plane strain models, respectively. Finally, in order to consider the effect of nonhomogeneous meso-scale structure of concrete on the wave propagation, a random aggregate method (RAM) is employed to model the concrete core and multi-physical fields coupling numerical analysis on stress wave propagation of the CFST member with different interface debonding defects is performed. The numerical findings meet well with the experimental observations and the results indicate that the interface debonding of CFST can be detected efficiently using surface wave measurement.

Accuracy Improvement of Rotational Speed Sensors by Novel Signal Processing Method

A novel signal processing method is proposed for determining the rotational speed more accurately. In this method, the periodic output signal of a rotational speed sensor is filtered and then sampled in a defined time window. The sampled discrete signal is further filtered to improve its Signal-to-Noise Ratio (SNR). The rotational speed is derived by a precise determination of the signal frequency of the periodic signal under using Discrete Fourier Series (DFS) and iterative Self-Correction and optimization algorithms. From the experimental results, an accuracy of about 0.2% can be achieved. This method can be used in all kinds of rotational speed sensors and encoders with analogue signal output.

Experimental and numerical research on damage localization in plate-like concrete structures using hybrid approach

This paper presents an experimental–numerical analysis of damage localization of concrete plate-like elements on the basis of hybrid approach. The proposed hybrid approach uses the fast discrete wavelet transform, energy approach, and time of flight criterion for the purpose of localization of single and multidamage problems inside or on the periphery of concrete elements. Verification of the proposed damage localization approach has been performed under laboratory conditions using a laser scanning-based system with piezoelectric excitation of the wave propagation. Numerical simulation of the wave propagation is performed using the explicit finite element method using 3D models with linear-elastic material model of concrete with Rayleigh damping. The Rayleigh damping coefficients are determined on the basis of experimental data and implemented in numerical models. Validation of the numerical model is conducted, based on the comparison with sensor output signals obtained through experimental measuring and a very good agreement of results is obtained. The proposed hybrid approach to damage localization is verified using 15 different models/specimens, varying the number, shape (circular or notched), and position of damage, as well as the number and placement of actuators/sensors. For all the analyzed scenarios, the hybrid approach successfully localized the damage even for the least number of used sensor positions. In the models with the circular damage, the damage image created on the basis of the hybrid approach is almost identical to the actual shape of the damage, indicating a good potential of the method for damage localization.

Oscillator Phase Noise Suppression in Surface Acoustic Wave Sensor Systems

Surface acoustic wave (SAW) sensors are widely used in different fields of application. In order to maximize the limit of detection of such sensor systems, it is of high importance to understand and to be able to quantify the relevant noise sources. A straightforward approach to detect the desired phase information of SAW sensors is to compare the sensor output signal with a reference signal. In this paper, the effect of decorrelation of oscillator phase noise as a function of delay time and offset frequency is discussed and analyzed. An analytical expression is derived which describes the degree of phase noise suppression in heterodyne readout systems. The model is verified by various measurement series, showing a degree of phase noise suppression of −100 dB for an offset frequency of 1 Hz and for a decorrelation time of 1500 ns which represents a typical time delay of SAW sensors. Although the effect is analyzed with respect to SAW sensors, the results are basically applicable to all kinds of phase sensitive sensors.