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18 pages, 15718 KiB

Open AccessArticle

Optimizing Calibration for a Capacitance-Based Void Fraction Sensor with Asymmetric Electrodes under Horizontal Flow in a Smoothed Circular Macro-Tube

by Moojoong Kim, Kanta Komeda, Jongsoo Jeong, Mizuki Oinuma, Tetsuya Sato and Kiyoshi Saito

Sensors 2022, 22(9), 3511; https://doi.org/10.3390/s22093511 - 5 May 2022

Cited by 9 | Viewed by 2328

Abstract

In this study, a technique that uses a capacitance sensor with an asymmetric electrode to measure the void fraction of a refrigerant was developed. It is known that the void fraction and flow pattern affect the measured capacitance. Therefore, the relationship between the [...] Read more.

In this study, a technique that uses a capacitance sensor with an asymmetric electrode to measure the void fraction of a refrigerant was developed. It is known that the void fraction and flow pattern affect the measured capacitance. Therefore, the relationship between the void fraction and capacitance is not linear; hence, a calibration method for obtaining accurate measurements is necessary. A calibration method was designed in this study based on repeated capacitance measurements and the bimodal temporal distribution to calibrate the atypical and repetitive flow patterns of slug flow and its transition to the intermittent flow regime. The calibration method also considers the weighted-average relation for the gradual transition of the intermittent to annular flow pattern according to the change from low to high quality. The proposed method was experimentally analyzed under the conditions of R32 refrigerant, a tube inner diameter of 7.1 mm, saturation temperature of 25 °C, mass flux of 100–400 kg m⁻² s⁻¹, and vapor quality of 0.025–0.900, and it was validated using a quick-closing valve (QCV) system under identical conditions. A relative error of 2.99% was obtained for the entire system, indicating good agreement between the proposed and QCV-based methods. Full article

(This article belongs to the Special Issue Sensors and Methods for Dynamic Measurement)

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36 pages, 8022 KiB

Open AccessArticle

Measurement of Sea Waves

by Giovanni Battista Rossi, Andrea Cannata, Antonio Iengo, Maurizio Migliaccio, Gabriele Nardone, Vincenzo Piscopo and Enrico Zambianchi

Sensors 2022, 22(1), 78; https://doi.org/10.3390/s22010078 - 23 Dec 2021

Cited by 33 | Viewed by 11777

Abstract

Sea waves constitute a natural phenomenon with a great impact on human activities, and their monitoring is essential for meteorology, coastal safety, navigation, and renewable energy from the sea. Therefore, the main measurement techniques for their monitoring are here reviewed, including buoys, satellite [...] Read more.

Sea waves constitute a natural phenomenon with a great impact on human activities, and their monitoring is essential for meteorology, coastal safety, navigation, and renewable energy from the sea. Therefore, the main measurement techniques for their monitoring are here reviewed, including buoys, satellite observation, coastal radars, shipboard observation, and microseism analysis. For each technique, the measurement principle is briefly recalled, the degree of development is outlined, and trends are prospected. The complementarity of such techniques is also highlighted, and the need for further integration in local and global networks is stressed. Full article

(This article belongs to the Special Issue Sensors and Methods for Dynamic Measurement)

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17 pages, 8294 KiB

Open AccessEditor’s ChoiceArticle

Filtering Biomechanical Signals in Movement Analysis

by Francesco Crenna, Giovanni Battista Rossi and Marta Berardengo

Sensors 2021, 21(13), 4580; https://doi.org/10.3390/s21134580 - 4 Jul 2021

Cited by 50 | Viewed by 7107

Abstract

Biomechanical analysis of human movement is based on dynamic measurements of reference points on the subject’s body and orientation measurements of body segments. Collected data include positions’ measurement, in a three-dimensional space. Signal enhancement by proper filtering is often recommended. Velocity and acceleration [...] Read more.

Biomechanical analysis of human movement is based on dynamic measurements of reference points on the subject’s body and orientation measurements of body segments. Collected data include positions’ measurement, in a three-dimensional space. Signal enhancement by proper filtering is often recommended. Velocity and acceleration signal must be obtained from position/angular measurement records, needing numerical processing effort. In this paper, we propose a comparative filtering method study procedure, based on measurement uncertainty related parameters’ set, based upon simulated and experimental signals. The final aim is to propose guidelines to optimize dynamic biomechanical measurement, considering the measurement uncertainty contribution due to the processing method. Performance of the considered methods are examined and compared with an analytical signal, considering both stationary and transient conditions. Finally, four experimental test cases are evaluated at best filtering conditions for measurement uncertainty contributions. Full article

(This article belongs to the Special Issue Sensors and Methods for Dynamic Measurement)

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24 pages, 4461 KiB

Open AccessArticle

Sea Spectral Estimation Using ARMA Models

by Marta Berardengo, Giovanni Battista Rossi and Francesco Crenna

Sensors 2021, 21(13), 4280; https://doi.org/10.3390/s21134280 - 23 Jun 2021

Cited by 14 | Viewed by 2273

Abstract

This paper deals with the spectral estimation of sea wave elevation time series by means of ARMA models. To start, the procedure to estimate the ARMA coefficients, based on the use of the Prony’s method applied to the auto-covariance series, is presented. Afterwards, [...] Read more.

This paper deals with the spectral estimation of sea wave elevation time series by means of ARMA models. To start, the procedure to estimate the ARMA coefficients, based on the use of the Prony’s method applied to the auto-covariance series, is presented. Afterwards, an analysis on how the parameters involved in the ARMA reconstruction procedure—for example, the signal time length, the number of poles and data used—affect the spectral estimates is carried out, providing evidence on their effect on the accuracy of results. This allowed us to provide guidelines on how to set these parameters in order to make the ARMA model as accurate as possible. The paper focuses on mono-modal sea states. Nevertheless, examples also related to bi-modal sea states are discussed. Full article

(This article belongs to the Special Issue Sensors and Methods for Dynamic Measurement)

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14 pages, 5864 KiB

Open AccessArticle

Experimental Investigation on a Bladed Disk with Traveling Wave Excitation

by Luigi Carassale and Elena Rizzetto

Sensors 2021, 21(12), 3966; https://doi.org/10.3390/s21123966 - 8 Jun 2021

Cited by 11 | Viewed by 2154

Abstract

Bladed disks are key components of turbomachines and their dynamic behavior is strongly conditioned by their small accidental lack of symmetry referred to as blade mistuning. The experimental identification of mistuned disks is complicated due to several reasons related both to measurement and [...] Read more.

Bladed disks are key components of turbomachines and their dynamic behavior is strongly conditioned by their small accidental lack of symmetry referred to as blade mistuning. The experimental identification of mistuned disks is complicated due to several reasons related both to measurement and data processing issues. This paper describes the realization of a test rig designed to investigate the behavior of mistuned disks and develop or validate data processing techniques for system identification. To simplify experiments, using the opposite than in the real situation, the disk is fixed, while the excitation is rotating. The response measured during an experiment carried out in the resonance-crossing condition is used to compare three alternative techniques to estimate the frequency-response function of the disk. Full article

(This article belongs to the Special Issue Sensors and Methods for Dynamic Measurement)

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25 pages, 2316 KiB

Open AccessArticle

Evaluating Martial Arts Punching Kinematics Using a Vision and Inertial Sensing System

by Karlos Ishac and David Eager

Sensors 2021, 21(6), 1948; https://doi.org/10.3390/s21061948 - 10 Mar 2021

Cited by 26 | Viewed by 9698

Abstract

Martial arts has many benefits not only in self-defence, but also in improving physical fitness and mental well-being. In our research we focused on analyzing the velocity, impulse, momentum and impact force of the Taekwondo sine-wave punch and reverse-step punch. We evaluated these [...] Read more.

Martial arts has many benefits not only in self-defence, but also in improving physical fitness and mental well-being. In our research we focused on analyzing the velocity, impulse, momentum and impact force of the Taekwondo sine-wave punch and reverse-step punch. We evaluated these techniques in comparison with the martial arts styles of Hapkido and Shaolin Wushu and investigated the kinematic properties. We developed a sensing system which is composed of an ICSensor Model 3140 accelerometer attached to a punching bag for measuring dynamic acceleration, Kinovea motion analysis software and 2 GoPro Hero 3 cameras, one focused on the practitioner’s motion and the other focused on the punching bag’s motion. Our results verified that the motion vectors associated with a Taekwondo practitioner performing a sine-wave punch, uses a unique gravitational potential energy to optimise the impact force of the punch. We demonstrated that the sine-wave punch on average produced an impact force of 6884 N which was higher than the reverse-step punch that produced an average impact force of 5055 N. Our comparison experiment showed that the Taekwondo sine-wave punch produced the highest impact force compared to a Hapkido right cross punch and a Shaolin Wushu right cross, however the Wushu right cross had the highest force to weight ratio at 82:1. The experiments were conducted with high ranking black belt practitioners in Taekwondo, Hapkido and Shaolin Wushu. Full article

(This article belongs to the Special Issue Sensors and Methods for Dynamic Measurement)

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15 pages, 11400 KiB

Open AccessArticle

Supersensitive Detector of Hydrosphere Pressure Variations

by Grigory Dolgikh, Sergey Budrin, Stanislav Dolgikh and Aleksandr Plotnikov

Sensors 2020, 20(23), 6998; https://doi.org/10.3390/s20236998 - 7 Dec 2020

Cited by 13 | Viewed by 3158

Abstract

This paper presents an instrument based on an equal-arm Michelson interferometer and a frequency-stabilized helium-neon laser. It is designed to record hydrosphere pressure variations in the frequency range from 0 (conventionally) to 1000 Hz, with accuracy of 0.24 mPa at sea depths of [...] Read more.

This paper presents an instrument based on an equal-arm Michelson interferometer and a frequency-stabilized helium-neon laser. It is designed to record hydrosphere pressure variations in the frequency range from 0 (conventionally) to 1000 Hz, with accuracy of 0.24 mPa at sea depths of up to 50 m. The operating range of the instrument can be increased by order of magnitude by improving the registration system speed, and accuracy can be enhanced by using larger diameter membranes and/or their smaller thickness. The paper demonstrates some experimental results obtained on the supersensitive detector of hydrosphere pressure variations, confirming its high performance in the infrasonic and sonic ranges. Full article

(This article belongs to the Special Issue Sensors and Methods for Dynamic Measurement)

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17 pages, 1928 KiB

Open AccessArticle

Washing Machine Dynamic Model to Prevent Tub Collision during Transient State

by Beatriz Sánchez-Tabuenca, Carmen Galé, Juan Lladó, Cristian Albero and Roberto Latre

Sensors 2020, 20(22), 6636; https://doi.org/10.3390/s20226636 - 19 Nov 2020

Cited by 5 | Viewed by 3431

Abstract

In horizontal-axis washing machines, the front gasket as well as the damping system are crucial owing to the possible collision of the tub with the housing during the transient period. However, most dynamic models for predicting tub motion focus on the steady state [...] Read more.

In horizontal-axis washing machines, the front gasket as well as the damping system are crucial owing to the possible collision of the tub with the housing during the transient period. However, most dynamic models for predicting tub motion focus on the steady state and consider only the suspension system without including the gasket. We conducted an experimental study to analyze the effect of the gasket on the transient motion of the tub. The results obtained indicate the necessity of implementing the gasket in the multibody model of a washing machine to accurately predict the tub behavior during this period. The gasket model is formed by a combination of Voigt elements. Stiffness parameters are determined using a load cell, and damping factors are estimated using a process that integrates Adams/View, Matlab optimization algorithms, and displacement measurements that are taken using accelerometers. A D-optimal design used to predict the effect of the gasket parameters reveals that the tub displacement is most sensitive to the changes in linear stiffness in the transversal direction. Finally, the model of the gasket provides a better approach for predicting the tub movement during resonance that can be used in the design phase to avoid tub collision. Full article

(This article belongs to the Special Issue Sensors and Methods for Dynamic Measurement)

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19 pages, 5785 KiB

Open AccessArticle

A Non-Linear Temperature Compensation Model for Improving the Measurement Accuracy of an Inductive Proximity Sensor and Its Application-Specific Integrated Circuit Implementation

by Li Wang, Hui-Bin Tao, Hang Dong, Zhi-Biao Shao and Fei Wang

Sensors 2020, 20(17), 5010; https://doi.org/10.3390/s20175010 - 3 Sep 2020

Cited by 7 | Viewed by 3783

Abstract

The non-linear characteristic of a non-contacting Inductive Proximity Sensor (IPS) with the temperature affects the computation accuracy when measuring the target distance in real time. The linear model based method for distance estimation shows a large deviation at a low temperature. Accordingly, this [...] Read more.

The non-linear characteristic of a non-contacting Inductive Proximity Sensor (IPS) with the temperature affects the computation accuracy when measuring the target distance in real time. The linear model based method for distance estimation shows a large deviation at a low temperature. Accordingly, this paper presents a non-linear measurement model, which computes the target distance accurately in real time within a wide temperature range from

- 55 ° C

to

125 ° C

. By revisiting the temperature effect on the IPS system, this paper considers the non-linear characteristic of the IPS measurement system due to the change of temperature. The proposed model adopts a non-linear polynomial algorithm rather than the simple linear Look-Up Table (LUT) method, which provides more accurate distance estimation compared to the previous work. The introduced model is fabricated in a 0.18

μ

m Complementary Metal Oxide Semiconductor (CMOS) process and packaged in a CQFN40. For the most commonly used sensing distance of 4 mm, the computed distance deviation of the Application-Specific Integrated Circuit (ASIC) chips falls within the range of

[- 0.2, 0.2]

mm. According to the test results of the ASIC chips, this non-linear temperature compensation model successfully achieves real-time and high-accuracy computation within a wide temperature range with low hardware resource consumption. Full article

(This article belongs to the Special Issue Sensors and Methods for Dynamic Measurement)

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