Search

Monitoring the degradation of induction motors is an essential concern for industries, especially when there are high costs related to maintenance and their stops. Nowadays, there are many non-invasive ways to monitor the health status of induction motors, including sensors to measure temperature, magnetic field, vibration, current, and power. However, installing these sensors may not be a simple task since intrusive procedures such as engine disassembling, wire separation, and engine interruption are commonly observed. Thus, we propose MUCLA (Multiphase Clamp and Tracking - patent pending) as a new device and methodology for monitoring motor degradation by analyzing its stator current. MUCLA introduces a non-invasive current sensors array on a proposed clamp in the hardware perspective, while a spectral tracking methodology refers to our novelty in the software viewpoint. For end-users, the main MUCLA contribution relies on the combination of the simplicity of installation and the possibility of using the proposed device even when considering Variable-Frequency Drive powered engines. The results obtained with both simulation and practical tests show encouraging results over different input workloads and emulated degradation. Compared to the current initiatives, we can classify MUCLA as a better solution for industrial plants in terms of installation time, installation complexity, and cost.

Monitoring the degradation of induction motors is an essential concern for industries, especially when there are high costs related to maintenance and their stops. Nowadays, there are many non-invasive ways to monitor the health status of induction motors, including sensors to measure temperature, magnetic field, vibration, current, and power. However, installing these sensors may not be a simple task since intrusive procedures such as engine disassembling, wire separation, and engine interruption are commonly observed. Thus, we propose MUCLA (Multiphase Clamp and Tracking - patent pending) as a new device and methodology for monitoring motor degradation by analyzing its stator current. MUCLA introduces a non-invasive current sensors array on a proposed clamp in the hardware perspective, while a spectral tracking methodology refers to our novelty in the software viewpoint. For end-users, the main MUCLA contribution relies on the combination of the simplicity of installation and the possibility of using the proposed device even when considering Variable-Frequency Drive powered engines. The results obtained with both simulation and practical tests show encouraging results over different input workloads and emulated degradation. Compared to the current initiatives, we can classify MUCLA as a better solution for industrial plants in terms of installation time, installation complexity, and cost. [ABSTRACT FROM AUTHOR]

Contactless Human to Machine Interface (HMI) is an indispensable technology for handling the machine or equipment in a pandemic situation where the virus can spread through direct contact. The contactless hand gesture sensor is an essential part needed for the HMI system as previously mentioned. Several hand gestures with a similar Doppler response will become problems in applying Doppler radar as a hand gesture sensor that requires a more complex recognition method. This paper proposes spatial diversity implementation for obtaining more accurate hand gesture features to cope with this problem. Array radar was selected as a sensor configuration to create the spatial diversity feature. In this paper, an array configuration of four Continuous Wave (CW) radars is proposed as a contactless sensor for hand gestures. Peak detection based on cross-correlation was employed to determine the time position of the hand gesture Doppler response detected by each CW radar. The time position pattern then becomes a feature of each hand gesture used. The CW radar array is realized with an operating frequency of 10 GHz by using the HB 100 as a CW radar component. The experimental results show that the proposed method can distinguish the hand gesture feature with an accuracy of 96.6 % at a sensing distance of 50 cm. It can differentiate the hand gesture pairs that have the opposite direction movement with a similar Doppler effect, and also requires simple data processing for recognizing different hand gestures. [ABSTRACT FROM AUTHOR]

This article presents a novel technique to remove the radar self-motion effects (RSMs) for an accurate detection of human vital signs. As opposed to the commonly used techniques, the proposed approach does not require any additional sensor, and instead, it extracts the RSM from the signals reflected by stationary clutters. Since the proposed technique requires to accurately identify the clutter range, two procedures for its automatic identification are proposed, aimed to detect both small and large radar motions. Besides allowing precise and reliable vital sign detection, it provides a compact, lightweight, comfortable, and cost-effective solution since potentially intrusive additional sensors are not required. Simulations have been carried out for validating the proposed approach, with an insight on the influence of different clutter radar cross sections on the sensitivity. Moreover, the effectiveness of the RSM cancellation has been experimentally demonstrated, showing its suitability for different applications, e.g., radar on moving platforms, vibrating tools, handheld devices, unmanned aerial vehicles, and cars. [ABSTRACT FROM AUTHOR]

Intelligent surveillance systems are widely used in several critical areas as airports, ATM, and bank agencies to ensure more security and more safety. The need for an intelligent behavior recognition system is still increasing. Traditional approaches based on access to restricted places or suspected actions as theft, scam, and loitering are insufficient to identify suspect behavior. These actions do not represent a real key of suspects. Novel trends attempt to extract behaviors from involuntary actions as face gestures, face characteristics, and feeling features. This paper is motivated not only by the limits of the traditional approaches but also by the complexity of intelligent algorithms. In this context, the present paper uses face features to recognize the feeling of fear like a suspect behavior. Indeed, this feeling represents the main characteristic of a suspicious person under crime as announced by several psychologist scientists. The fear feeling is usually followed by an increase in heart rate beats. This paper describes the recognition of fear feeling using a camera as a contactless sensor. Frequencies associated with face based-video are used to estimate the heart rate according to the fusion of three techniques: bandpass filter, Eulerian transformer, and Lagrangian transformer. The proposed algorithm benefits from the advantages of each technique, but it is challenged by the Real-Time exigence. For this purpose, a Raspberry PI3 board is used in relation to Raspbian Operating System to ensures Real-Time criteria. The proposed is trained according to CK+ dataset. In this paper, contributions attempt to ensure not only a high recognition rate using a non-complex algorithm but also guarantee a real-time computation. Results reveal that the proposed algorithm has the best heart rate estimation in comparison with traditional methods. Hardware results justify the success of the proposed design in terms of resource requirements.

This paper presents the real-time monitoring of a grapevine’s water content that flows up through the xylem tissue by means of a frequency-modulated continuous-wave radar. The application of an optimization process, based on the super-resolution multiple signal classification algorithm, has enabled the reduction of the bandwidth required to discern the xylem water content and, thus, the operating frequency, achieving a depth resolution of at least 3 mm. This design advantage has resulted in a significant step forward toward a real life application, allowing the use of fully-integrated off-the-shelf components in order to implement a completely portable low-power cost-effective radar at 23.1 GHz with a 3.4-GHz bandwidth. The sensor performance has been evaluated by means of three different experiments: irrigation cycles, day/night cycles, and comparison between irrigation cycles at different temperatures. From the experimental results, it is possible to assert that the contactless sensor presented in this paper is very sensitive to changes in the plant’s water content, differentiating between daytime and nighttime. In addition, it has been proven that temperature has a noticeable influence over the evapotranspiration, observing negative drying slopes of 5.62 and 6.28 mV/cycle at 23 °C and 26 °C, respectively. [ABSTRACT FROM AUTHOR]

Torque is one of the mighty core parameters of rotating machinery, and it has profound implications for the success of many engineering and industrial manufacturing activities. To date, more and more torque sensors are being researched and manufactured to meet the requirements of torque measurements in all of the engineering sectors that rely on accurate measurement of torque parameters for their success. A direct implication of these constantly growing developments is the recent development of various torque sensors, which operate based on more than ten different principles. Although several measurement principles have been created, torque sensors themselves can only be divided into two categories based on whether they come into contact with the rotating objects being measured (contact sensors) or do not have any point of contact with these objects (contactless sensors). In this paper, the concept of contactless sensors for torque measurement is redefined and the major classes of torque sensors (i.e., contactless sensors based on the laser Doppler effect, laser speckle effect, and optical coherence vibrometer, etc.) are introduced outlining the main progress, challenges, and future directions involving torque measurement applications. As the key to the success of torque measurement systems, some advanced signal processing techniques that are commonly used to enhance the accuracy of the torque measurement data are also introduced. [ABSTRACT FROM AUTHOR]

Abstract The dynamical properties of the main spindle of a milling machine can have essential effect on the stability of milling processes. These dynamical properties often change with the rotational speed of the spindle, e.g. the stiffness and damping properties of the angular contact bearings of the spindle vary significantly with the spindle speed. Our study focuses on the development of measurement devices which enable us to measure the dynamical properties of rotating spindles with high accuracy. The concept of the Fotonic Beam Reduction (FBR) laser sensor is presented, which is applied to measure the displacement of rotating milling tools in a contactless way. In order to determine the frequency response function (FRF) of the spindle, a ball shooter is constructed. The impulse generated by the bullet on the target is analysed experimentally. A force sensor is utilized to estimate the time interval of the impacting between bullet and surface. It is shown that the repeatability of the impact is very good, and the generated impulse can excite the natural frequencies up to 30 kHz. The FBR sensor with the ball shooter is applied to identify the FRF of a milling spindle versus its rotational speed. The variation of the vibration frequencies is demonstrated by means of the experiments. [ABSTRACT FROM AUTHOR]

Energy-harvesting passive RFID (radio frequency identification) tags provide countless possibilities as so-called smart tags. Smart tags can communicate with existing RFID readers or interrogators while providing a battery-less platform for internal and external sensors to enrich available information about the environment and smart tag it. A reduced cost and size as well as an increased lifespan and durability of battery-free smart tags offer improvements in areas such as transportation and product tracking. Battery-free smart tags can ideally support arbitrarily complex sensor measurements, but in reality energy limitations can introduce great reductions in operating range and thus application range. In this work, we present an example application of a smart tag with a passive HF (high-frequency) RFID tag IC (integrated circuit) and MEMS (micro electro-mechanical structure) sensor. A standard HF RFID reader connected to a PC (personal computer) allowed the RF (radio frequency) field to power and communicate with the smart tag. A Kalman filter, implemented on a PC, was used to correct and improve the raw sensor data of smart tag orientation. Measurement results showed that the MEMS sensor on the smart tag could be powered for continuous operation and that raw smart tag orientation data could be read while in the RF field of a standard HF RFID reader, but at a limited range. [ABSTRACT FROM AUTHOR]

A passive contactless sensor is presented for monitoring resistivity in porous materials. Electrical resistivity (ER) is an important indicator of water and ion content in porous materials, especially man-made and natural composites such as concrete and soil. The ER sensor is small, battery-free and is energised and queried wirelessly for data by a radio-frequency identification (RFID) reader or a near-field communication (NFC) enabled mobile device (a tablet or Smartphone). By applying Topsøe coefficients and a calibration function to the sensor output, the ER of the material is reliably estimated. Experimental results in the laboratory with a model aggregate material (sand) wetted with sodium chloride solutions demonstrate excellent agreement between the new sensor and a standard laboratory conductivity meter. Embedded ER sensors can provide long-term and repeatable data from soil, concrete and similar porous materials where ER is an accepted proxy for water and ion content. We think that passive contactless resistivity sensors will become commonplace as the Internet of Things (IoT) develops in the construction and precision agriculture sectors, and as the demand for long-lived, battery-free sensors increases. [ABSTRACT FROM AUTHOR]

In this article, we demonstrate how intervention using basic technology has improved the manufacturing of the beads from the stems of Holy Basil (Tulasi). This has helped the convenience, productivity and income of those women in the villages who typically make the beads in the Brij area (Mathura, Brindavan and nearby districts) of Rajasthan state in India. Later, it was experimented with a new stem holder and a contactless sensor to improve the vibration of the device and the inconvenience of replacing the mechanical switch frequently. As a result, there is overall improvement in the performance of the device. [ABSTRACT FROM AUTHOR]

SUMMARY By electrically connecting and placing an InAs deep quantum well (DQW) Hall element as a magnetic sensor chip and an Si IC linear amplifier in a small plastic package, a very small InAs DQW linear hybrid Hall IC (InAs DQW LHHIC) with a high magnetic field sensitivity has been developed. The output voltage of the hybrid Hall IC showed a very small temperature coefficient of 0.02%/°C and the response time was very low, less than 3 μs. By using this InAs DQW LHHIC, practical current sensors with high sensitivity, high accuracy, and temperature stability have been developed. [ABSTRACT FROM AUTHOR]

Development of plough control system using ultrasound equipment of distance measurement is presented. The experimental results confirm the efficiency of tractor performance with contactless sensor of soil profile copying.

The theoretical fundamentals of construction of a contactless sensor of penetration in arc and plasma welding, the functional circuit of the sensor, the design and external appearance, and also the advantages of the sensor are described. [ABSTRACT FROM AUTHOR]

In this study, the thermal stability of the in-plane uniaxial anisotropy field of Fe32Co44Hf12N12/Ti50N50 multilayer films was investigated from room temperature up to 500^\circC with regard to contactless high-frequency sensor applications. The uniaxial anisotropy field of about \mu0Hu\approx 5\ mT was thermally induced by annealing the films in a static magnetic field of 50 mT in vacuum for one hour either at an annealing temperature of Ta=400^{\circ}C or Ta=600^{\circ}C. The films which were annealed at Ta=600^{\circ}C show a clear distinction between the easy and hard axis of polarization up to temperatures of 500^\circC. Hence, the uniaxial anisotropy, thermally induced at Ta=600^{\circ}C, is stable at working temperatures up to 500^\circC. In contrast, films with a uniaxial anisotropy induced at Ta=400^{\circ}C show a different behavior. Here, hysteresis loop measurements indicate that above a working temperature of 200^\circC the uniaxial anisotropy field turns away from its direction at room temperature. In conclusion, only the Fe32Co44Hf12N12/Ti50N50 multilayer films with a uniaxial anisotropy field induced at Ta=600^{\circ}C promise a great potential for contactless high-frequency sensor applications up to 500^\circC. [ABSTRACT FROM AUTHOR]

This paper deals with the possibilities of contactless stress measuring inside a material. Conventional strain gauge measuring methods cover surface stress measuring, however measuring inside in material is widely limited. Magnetic microwires give us the ability to create a build-in sensor inside the material without its structure violation. Moreover, sensor can measure several parameters simultaneously, what makes this technology very interesting for many applications. [ABSTRACT FROM AUTHOR]

Abstract: A principle for contactless interrogation of passive micromechanical resonator sensors is proposed. The principle exploits an external primary coil electromagnetically air-coupled to a secondary coil which is connected to a conductive path on the resonator. The interrogation periodically switches between interleaved excitation and detection phases. During the excitation phase the resonator is driven into vibrations, while in the detection phase the excitation signal is turned off and the decaying oscillations are contactless sensed. The principle advantageously avoids magnetic properties required to the resonator, thereby ensuring compatibility with standard silicon microfabrication processes. The principle has been implemented on a MEMS SOI microcantilever resonator sensor with mechanical resonant frequency of 10.186kHz and has been demonstrated to work over a distance of up to 1cm. Tests based on the deposition and evaporation of a water droplet have demonstrated the capability to sense physical and chemical quantities which affect either the resonant frequency or the quality factor of the resonator. [Copyright &y& Elsevier]

Abstract: A principle for contactless interrogation of passive micromechanical resonator sensors is proposed, in which an external primary coil is electromagnetically air-coupled to a secondary coil connected to a conductive path on the resonator. The interrogation periodically switches between interleaved excitation and detection phases. During the excitation phase the resonator is driven into vibrations, while in the detection phase the excitation signal is turned off and the decaying oscillations are contactless sensed. The principle advantageously avoids magnetic properties required to the resonator, thereby ensuring compatibility with standard microfabrication processes. Results are reported on the successful implementation on a MEMS SOI microcantilever resonator working as a mass sensor for which the deposition and evaporation of a water droplet have been detected. [ABSTRACT FROM AUTHOR]

Abstract: Wearable devices are used to record several physiological signals, providing unobtrusive and continuous monitoring. These systems are of particular interest for applications such as ambient-assisted living (AAL), which deals with the use of technologies, like brain–computer interface (BCI). The main challenge in these applications is to develop new wearable solutions for acquisition of electroenchephalogram (EEG) signals. Conventional solutions based on brain caps, are difficult and uncomfortable to wear. This work presents a new optical fiber biosensor based on electro-active gel – polyacrylamide (PAAM) hydrogel – with the ability to measure the required EEG signals and whose technology principle leads to contactless electrodes. Experiments were performed in order to evaluate the electro-active properties of the hydrogel and its frequency response, using an electric and optical setup. A sinusoidal electric field was applied to the hydrogel while the light passes through the sample. An optical detector was used to collect the resultant modulated light. The results have shown an adequate sensitivity in the range of μV, as well as a good frequency response, pointing the PAAM hydrogel sensor as an eligible sensing component for wearable biopotential recording applications. [Copyright &y& Elsevier]

Abstract: This paper proposes an optical and electrical layered sensor as a new contactless sensor for material identification. In the proposed sensor, the optical properties of the material are measured by a light emitting diode (LED) and a phototransistor, and the electrical properties are measured by indium tin oxide (ITO) film electrodes with the transparent conductive properties arranged on the surfaces of the LED and phototransistor. Therefore, the optical and electrical properties of the material can be simultaneously measured by the single sensor. To test the sensor experimentally, six material samples – clear, white, and black acrylic, clear glass, white polytetrafluoroethylene (PTFE), and silver aluminium – were prepared, and identification of their sample materials and detection of distance between the sensor and the surface of material were demonstrated by using measurement values of the optical and electrical properties in the proposed sensor. In addition, the measurement values of optical properties with and without ITO film electrodes and those of electrical properties using the ITO film electrodes and the stainless steel film electrodes were compared. The results suggested that it is possible to measure both optical and electrical properties using the proposed sensor, although there are still some problems that must be addressed. [Copyright &y& Elsevier]

This paper presents a capacitive angular-position sensor with a contactless electrically floating conductive rotor and an interface electronic circuit that is designed to maximize the performance/cost ratio. The sensor includes two separate and independent measurement sections that sense the same angle and provide redundancy in critical applications. The electronic interface is based on a relaxation oscillator that, for each of the two sections, measures an appropriate quantity that relates capacitance ratio to angular position and provides a dc output voltage that varies ratiometrically with respect to the supply voltage. The sensor was built in a version with ±11° measuring range for each section. Experimental tests showed a linearity better that 1% of the span. [ABSTRACT FROM AUTHOR]

Using a camera as an optical sensor to monitor physiological parameters has garnered considerable research interest in biomedical engineering in recent decades. Researchers have explored the use of a camera for monitoring a variety of physiological waveforms, together with the vital signs carried by these waveforms. Most of the obtained waveforms are related to the human respiratory and cardiovascular systems, and in addition of being indicative of overall health, they can also detect early signs of certain diseases. While using a camera for noncontact physiological signal monitoring offers the advantages of low cost and operational ease, it also has the disadvantages such as vulnerability to motion and lack of burden-free calibration solutions in some use cases. This study presents an overview of the existing camera-based methods that have been reported in recent years. It introduces the physiological principles behind these methods, signal acquisition approaches, various types of acquired signals, data processing algorithms, and application scenarios of these methods. It also discusses the technological gaps between the camera-based methods and traditional medical techniques, which are mostly contact-based. Furthermore, we present the manner in which noncontact physiological signal monitoring use has been extended, particularly over the recent years, to more day-to-day aspects of individuals' lives, so as to go beyond the more conventional use case scenarios. We also report on the development of novel approaches that facilitate easier measurement of less often monitored and recorded physiological signals. These have the potential of ushering a host of new medical and lifestyle applications. We hope this study can provide useful information to the researchers in the noncontact physiological signal measurement community.