Inductive Sensor Research Articles

A Survey Paper on Automated Waste Segregator Based on Internet of Things Technology

Municipal solid waste, commonly known as garbage, is a waste category comprising of items that are discarded. The waste that is involved is very flagrant, we approach a system called as Involuntary Solid Waste Segregator (ISWS), where the segregation of the waste like metal, glass and plastic, organic and sanitary napkins are carried out. To segregate the metallic waste, a magnetic field is generated with inductive sensor, for glass and plastic and organic waste used capacitive sensor, infrared sensors respectively. Once the waste segregated is amassed in a trash can and the amount is monitored in a server by Internet of things (IoT).

A wireless battery-less and moisture-resistant packaged glucose sensing system employing hydrogel-based inductive sensing technique and low-power ASIC for long-term glucose monitoring

A wireless and battery-less glucose sensing system has been demonstrated for future long-term implantable glucose monitoring. The proposed glucose sensing system employs an oscillator-based inductive sensor that detects a volumetric change of a glucose-sensitive hydrogel. A robust 3D-printed moisture-resistant package is used to encapsulate the sensing system for in-vitro characterization. An application-specific integrated circuit (ASIC) is designed to enable in-situ temperature characterization as well as system miniaturization. The overall system dissipates 600 μW and exhibits a dimension of 6 mm × 6 mm x 25 mm. A rotation-insensitive wireless powering scheme has been demonstrated to reliably deliver power to a tube-shaped implantable system. The prototype sensor operated at 190 MHz can be wirelessly powered by a 6.78 MHz RF power source over a distance of 2 cm. The sensor achieves a glucose sensing resolution of 0.025–0.055 mM within a typical physiological glucose concentration between 4 mM and 10 mM at a typical human body temperature of 37 ºC. The prototype sensor has demonstrated a reliable in-vitro operation for 60 days without noticeable performance degradation.

Efficient metrics for the detection of partial discharges under steep-fronted voltage pulses

The increasing use of power electronic inverters in electrical drives is leading to the unexpected inception of partial discharges (PD) within the insulation system of electric machine stator windings. Unfortunately, the short rise and fall times of such voltages, below 100 nanoseconds in most cases, create high-magnitude conducted and radiated interferences that affect the measurements. Detecting partial discharges in these systems with inductive or electromagnetic sensors turns to be an important challenge, especially when interference and partial discharges share the same bandwidth. In this work, the authors propose a technique to detect the occurrence of PD in such systems, even when they are masked by disturbances. The proposed technique combines an analog high-pass filter stage and a digital band-pass to select a proper spectral interval. The resulting signal is converted to the base-band, where two metrics based on the peak-to-average power ratio are proposed. Experimental results obtained with the signals acquired with two antennas show that both proposed metrics exhibit a significant increase, about ten times greater, when the applied voltage exceeds the PD inception voltage. These contributions define new markers for the detection of PD events created by pulsed voltages with overlapped overshoots with promising results.

Manufacturing of Pure Iron by Cold Rolling and Investigation for Application in Magnetic Flux Shielding.

The presented work investigates a novel method to manufacture 98.8% pure iron strips having high permeability and better saturation flux density for application in magnetic flux shielding. The proposed method uses electro-deposition and cold rolling along with intermediate annealing in a controlled environment to manufacture 0.05–0.5 mm thick pure iron strips. The presented approach is inexpensive, has better control over scaling/oxidation and requires low energy than that of the conventional methods of pure iron manufacturing by pyrometallurgical methods. Important magnetic and mechanical properties of the pure iron are investigated in the context of the application of the material in magnetic shielding. Magnetic properties of the material are investigated by following IEC60404-4 standard and toroidal coil test to determine hysteresis curve, magnetic permeability and core losses. The microstructure is investigated with an optical microscope and scanning electron microscopy to study grain size and defects after cold rolling and annealing. The properties derived from the experimental methods are used in finite element analysis to study the application of the material for static, low-frequency and high-frequency magnetic shielding. Theoretical simulation results for magnetic shielding around a current-carrying conductor and micro-electromechanical inductive sensor system are discussed. Further shielding performance of the material is compared with that of the other candidate materials, including that of Mu-metal and electrical steel. It is demonstrated that the pure iron strips manufactured in the present study can be used for magnetic shielding in the case of low-frequency applications. In the case of high-frequency applications, a conducting layer can be combined to ensure the required shielding effectiveness in the case of Class 2 applications.

Embedded Soft Inductive Sensors to Measure Arterial Expansion of Tubular Diameters in Vascular Phantoms

Measuring diameter change in flexible tubular structures embedded in opaque material is challenging. In this article, we present a soft braided coil embedded in an elastomer tube as a method to continuously measure such a change in diameter. By measuring the inductance change in the braided coil, we estimate the instantaneous diameter with a simple inductance model. In applying this method, we demonstrate that diameter waves in a vascular phantom, a model of a radial artery embedded in a viscoelastic wrist structure, can be recorded continuously. Four sensors were made, and their ability to measure physiologically relevant simulated pulse waves was assessed. Several pressure pulse profiles were generated using a precision digital pump. Inductance of the coil was measured simultaneously as the change in diameter was recorded using an optical laser/mirror deflection measurement. One sensor was then embedded in a vascular phantom model of the human wrist. The diameter of the simulated radial artery was recorded via ultrasound and estimated from coil inductance measurements. The diameter estimates from the inductance model corresponded well with the comparator in both experimental setups. We demonstrate that our method is a viable alternative to ultrasound in recording diameter waves in artery models. This opens opportunities in empirical investigations of physiologically interesting fluid-structure interaction. This method can provide new ability to measure diameter changes in tubular systems where access is obstructed.

A low-cost wheel slip measurement device for agricultural tractors

Tractor wheel slip affects the traction of a tractor, fuel efficiency and tyres adversely, along with compaction of the soil. Tractor operators cannot sense the slip unless it continues for some significant time. In the present study, a low-cost slip measuring device and an indicator were developed at ICAR-IARI, New Delhi (2018) and installed on the tractor dashboard for the operator’s information. It warns the operator about slip both by visual and auditory signals to adjust the driving accordingly. In this study, four different sensors (Inductive proximity sensor, IR sensor, Hall effect sensor, and Photo-electric sensor) were tested for measurement of rotational speed under different working conditions of light and dust. Hall effect sensor was found the best for all the operational conditions. So, a low-cost slip measuring device was developed with the Hall effect sensor integrated with a microcontroller as a retrofit for tractors. The device was mounted on the tractor, and field experiments were conducted. The results obtained from the developed device showed that the values were statistically close to actual values.

Hybrid Magnetic-Inductive Angular Sensor with 360° Range and Stray-Field Immunity.

Magnetic and inductive sensors are the dominant technologies in angular position sensing for automotive applications. This paper introduces a new angular sensor: a hybrid concept combining the magnetic Hall and inductive principles. A magnetic Hall transducer provides an accurate angle from 0° to 180°, whereas an inductive transducer provides a coarse angle from 0° to 360°. For this novel concept, a hybrid target with a magnetic and inductive signature is also needed. Using the two principles at the same time enables superior performances, in terms of range, compactness and robustness, that are not possible when used separately. We realized and characterized a prototype. The prototype achieves a 360° range, has a high accuracy and is robust against mechanical misalignments, stray fields and stray metals. The measurement results demonstrate that the two sensing principles are completely independent, thereby opening the doors for hybrid optimum magnetic–inductive designs beyond the usual trade-offs (range vs. resolution, size vs. robustness to misalignment).

Inductive proximity sensors within a ceramic package manufactured by material extrusion of binder-coated zirconia

The embedding of electric components into additively manufactured structures offers enormous potential for extending the functionality and applications of parts produced by additive manufacturing (AM). However, the production of electric components embedded with 3D-printed ceramic structures has been a significant challenge due to the complexity of the manufacturing process and the high-temperature post-processing it requires. In the present study, an inductive proximity sensor with a 3D-printed ceramic housing and embedded sensing elements was designed and produced using a hybrid manufacturing process in which the printing process is paused and a sensing element is embedded into the printed structure. Sensing elements materials were carefully selected and intra-sensor structures were developed to ensure that the sensing element would survive in a high-temperature sintering environment. In the developed process, binder-coated zirconia containing 87 wt% was used as feedstock in a piston-based material extrusion process to fabricate the ceramic housing for the sensor, and platinum wire was used in the sensing element. The subsequent debinding and sintering processes achieved a nearly fully dense ceramic housing that protects the sensor in harsh environments. The successfully fabricated sensor was tested by measuring the change of distance between the inductive and metallic target and determining if the changes in distance would alter the inductance of the sensor. Results show that the sensing element maintains functionality throughout each fabrication step, and the fully packaged sensor also demonstrates the ability to work properly at high temperatures (in the range of 200–400 °C). At a frequency of 2 MHZ and a voltage of 1 V, the inductive sensor has a measurement range of approximately 7.0 mm. Additive manufacturing of the sensor housing enabled precise control of the geometry, dimensions, and infill density. Because the developed methodology allows for control of the type and structure of the sensing element, it can be used in the manufacture of a wide variety of sensors or smart components.

Research on High Sensitivity Oil Debris Detection Sensor Using High Magnetic Permeability Material and Coil Mutual Inductance.

Metallic contaminants (solid) are generated by friction pair, causing wear of equipment by enters the lubricating system. This poses a great potential threat to the normal operation of such machines. The timely analysis and detection of debris can lead to the avoidance of mechanical failures. Abnormal wear in machinery may produce debris exceeding 10 μm. The traditional inductance detection method has low sensitivity and cannot meet the actual detection requirements. To boost the sensitivity of the inductance sensor, the mutual inductance of coils and the strong magnetic conductivity of permalloy was utilized to design a high sensitivity inductance sensor for the detection of debris in lubricating oil. This design was able to detect 10–15 μm iron particles and 65–70 μm copper particles in the oil. The experimental results illustrate that low-frequency excitation is the best for detecting ferromagnetic particles, while high-frequency excitation has the best effect for detecting non-ferromagnetic particles. This paper demonstrates the significant advantages of coil mutual inductance, and strong magnetic conductivity of permalloy in improving the detection sensitivity of oil debris sensors. This will provide technical support for wear detection in mechanical equipment and fault diagnosis.

Sensitivity Optimisation of a Main Marine Diesel Engine Electronic Speed Governor

Electronic speed governors have become widespread on marine diesel engines. In comparison with hydromechanical ones, they have an additional setting parameter – input signal sensitivity. This parameter allows changing the response of governors to high-frequency disturbances. In camshaft diesel engines, such disturbances are generated when the cams run over fuels pump push rods, while in ME (MAN Energy Solutions) or RT-flex (Wärtsilä) engines they result from the use of inductive sensors with a serrated tape on the diesel shaft for speed measurement. If the engine is used as a main engine on vessels, the governor’s sensitivity additionally allows governors to vary the response to propeller shaft resistance moment fluctuations in sea waves conditions. In practice the value of sensitivity of electronic speed governors of main marine engines is selected intuitively. As a result, the adjustment of governors doesn’t provide satisfactory stability of speed modes at the change of sea conditions. The study aims to develop a methodology for adjusting the sensitivity of main engines electronic speed governors with considering the stochasticity of the load on the diesel engine in sea waves state. The study was carried out using the systems of automatic speed control model, which is based on the assumption of relatively small deviations of diesel engine shaft rotation speed and load parameters at sea waves conditions. Considering the character and magnitude of change of load on diesel engine at sea waves conditions depend on many variables of external conditions (waves levels, course of a vessel in relation to wind-wave conditions, wind gusts, vessel’s loading condition, given speed of a vessel), any set value of sensitivity of electronic speed governors appears to be optimum only for a particular case of vessel movement in sea waves state. The scientific novelty is defined by the fact that recommendations on the choice of governor sensitivity are determined with considering stochasticity of propeller shaft resistance moment fluctuations at sea waves conditions, that increased accuracy, and validity of recommendations. The practical significance of the research consist in the increase of stability of speed modes of the main engine with electronic speed governor at various sea waves conditions

3D Printed Spring‐Type Electronics with Liquid Metals for Highly Stretchable Conductors and Inductive Strain/Pressure Sensors

AbstractThe spring structure is stretchable and resilient, enabling electronic devices to be highly stretchable and durable. However, spring objects composed of only soft materials cannot be maintained without a supporting rod inside the coil owing to self‐weight deformation. Therefore, a design strategy should be investigated. In this study, self‐maintaining spring structures with soft materials are designed using physical simulations and soft spring‐type electronic devices (a stretchable conductor, strain sensor, and pressure sensor) with little hysteresis are developed. The spring‐type electronic devices consist of a core–sheath structure, which is a core channel filled with liquid metal and a 3D‐printed elastomeric sheath. The spring‐type conductor can be stretched with a small force (1.25 N) and has a negligible resistance change for up to 400% strain and ≈5.5% resistance increase at 640% strain. Moreover, the inductance induced by the coil structure monotonically decreases in the range of 200% stretching. The device also has high durability with little change in the electrical characteristics during 1000 cycles of 100% stretching. Furthermore, an inductive pressure sensor can measure <250 Pa (50 mN) by compressing the spring. Spring‐type electronic devices composed of soft materials contribute to highly durable and stretchable sensors for robotic applications.

A Novel Inductive Angular Displacement Sensor With Multi-Probe Symmetrical Structure

This articledevelops a novel probe-type inductive angular displacement sensor based on time-grating, which is suitable for large-diameter hollow rotary table position detection of the heavy-duty machine tools. It abandons the traditional sensor precise marking lines in spatial domain, and integrates the tested mechanical component with the sensor, which realizes the angular displacement measurement directly. The sensor is divided into three parts: 1) a permalloy probe, which is adopted the simple structure to reduce the assembly errors; 2) a 45-steel rotor, which is a standard spur gear in a heavy-duty machine tool rotary table transmission system; 3) three groups of copper coils, which include sinusoidal coils, cosine coils and inductive coils. The theoretical model of angular displacement measurement is derived by means of mathematical equation in detail. Then the feasibility of the sensor structure is verified by finite element simulation. After that, a sensor prototype is built and tested in the laboratory, showing that the sensor has an original error of ±0.018° (approximately ± <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$64^{\prime \prime }$ </tex-math></inline-formula> ) over a full 360° range. The error analysis found that the systematic error is the main component. As a result, the mechanical structure and angular displacement algorithm of the sensor are optimized, which can significantly reduce the original errors of the sensor. After optimization, the final accuracy of the sensor is within ±0.0012° (approximately ± <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.4^{\prime \prime }$ </tex-math></inline-formula> ) in the range of 0°–360°.

A novel inductive angular displacement sensor based on time-grating

The paper proposes a novel inductive angular displacement sensor to measure large-diameter hollow rotating mechanical components in large science facilities. The sensor design includes a stator, a rotor with two layers of windings. The stator is fabricated according to the dimension of the rotor, which is the large-diameter hollow rotary mechanical components. Based on the principle of electromagnetic induction, the theoretical model of the proposed sensor is acquired by mathematical equations in detail. The proposed sensor design ensures integration of the large-diameter hollow rotating mechanical components with the stator, and solves the problem that the sensors cannot be coaxially installed in the closed-loop control process of large mechanical rotating parts. The performance of the sensor is evaluated by tests of the prototype sensor fabricated by printed circuit board technology, which manifests the effectiveness of the proposed sensor. The results demonstrate the value of original dynamic relative error is ±97.6″ over 0°–360° range, and the measurement error mainly includes first-order and second-order harmonic components. Therefore, the original errors are reduced by optimizing the angular displacement algorithm of the sensor, optimized results demonstrate the final relative accuracy of the sensor is ±3.5″ over the 0°–360° measurement range.

Sensor Technology Options for Municipal Solid Waste Characterization for Optimal Operation of Waste-to-Energy Plants

Reuse, refurbishing, and recycling are the most sustainable options for handling waste materials. However, for municipal solid waste (MSW) that is highly heterogenic, crude, contaminated, and decrepit, thermal conversion in waste-to-energy (WtE) plants is an option. In such plants, the fuel quality of MSW is difficult to predict and the substantial changes expected are challenging for incineration stability. Development of new online sensor technologies for monitoring waste properties prior to incineration is therefore needed. Sensors may contribute to increase WtE process stability, as well as reducing the probability of incineration stops or emissions exceeding legal limits. In this work, the operating principles of potential sensor systems for waste monitoring are categorized and assessed to be implemented for providing parameters for process control or indicators for process alarms in the waste incineration process. For transmissive settings, the use of inductance and hard X-ray sensors are most promising, whereas for reflective settings, utilization of photonic, inductive, soft and hard X-ray, as well as low-frequency radiowave sensors, are most promising. The analytic capacity of single-point measurements with inductance, radiowave, photonic, or X-ray sensors are limited to providing indicators for process alarms, whereas spectral imaging with X-ray or photonic techniques are feasible for providing parameters for both process control and indicators for process alarms. The results obtained in this sensor assessment will be important as a first step in guiding the evolution of monitoring waste properties in the WtE industry to increase repeatability, performance of energy production, and manual labor safety in controlling the waste incineration.

Change in blocking temperature of nanoparticle array deposited on magnetoresistive sensor

Here we present the effect of ferromagnetic magnetoresistive sensor on magnetic susceptibility of nanoparticles (NPs) deposited on its surface. Deposition of the CoFe2O4 nanoparticles on the CoFeB/Ta/CoFeB platform, comprising thin ferromagnetic layers, changes the blocking temperature of the NPs. The magnetic dipole interaction between the NPs and the platform affects the frequency and field dependences of the blocking temperature of the NPs, because the effective energy barrier of magnetization reversal is higher than in NPs deposited on a diamagnetic substrate. Obtained results demonstrate backward effect of the sensor on the analyzing NPs array. An allowance of this effect is important for the correct application of a magnetoresistive and low frequency inductive sensors in medicine and biology.

Non-invasive laparoscopic detection of small tumors of the digestive tract using inductive sensors of proximity

The precise location of gastric and colorectal tumors is of paramount importance for the oncological surgeon as it dictates the limits of resection and the extent of lymphadenectomy. However, this task proves sometimes to be very challenging, especially in the laparoscopic setting when the tumors are small, have a soft texture, and do not invade the serosa. In this view, our research team has developed a new instrument adapted to minimally-invasive surgery, and manipulated solely by the operating surgeon which has the potential to locate precisely tumors of the digestive tract. It consists of an inductive proximity sensor and an electronic block encapsulated into an autoclavable stainless-steel cage that works in tandem with an endoscopic hemostatic clip whose structure was modified to increase detectability. By scanning the serosal side of the colon or stomach, the instrument is capable to accurately pinpoint the location of the clip placed previously during diagnostic endoscopy on the normal bowel mucosa, adjacent to the tumor. In the current in-vivo experiments performed on large animals, the modified clips were transported without difficulties to the point of interest and attached to the mucosa of the bowel. Using a laparoscopic approach, the detection rate of this system reached 65% when the sensor scanned the bowel at a speed of 0.3 cm/s, and applying slight pressure on the serosa. This value increased to 95% when the sensor was guided directly on the point of clip attachment. The detection rate dropped sharply when the scanning speed exceeded 1 cm/s and when the sensor-clip distance exceeded the cut-off value of 3 mm. In conclusion, the proposed detection system demonstrated its potential to offer a swift and convenient solution for the digestive laparoscopic surgeons, however its detection range still needs to be improved to render it useful for the clinical setting.

Low-Cost Inductive Sensor and Fixture Kit for Measuring Battery Cell Thickness Under Constant Pressure

This study investigates the application of inductive proximity sensors for accurately measuring battery expansion. Previous research has obtained high accuracy sensing using strain gauges, displacement sensors, and load cells, but has been limited by sensor cost. A proximity sensor based on changes in mutual inductance with a metal target sensor benefits from low cost, high accuracy, simple design, and ease of installation, calibration, and measurement; all allowing for better scalability for testing many cells simultaneously. Initial testing demonstrated that the inductance sensor readings were linearly proportional to displacement at multiple cycling temperatures. Further tests were conducted comparing the performance of the inductance sensor with highly accurate displacement sensors (1µm at $2000). Our sensor demonstrates a 3.2 µm maximum error at less than $20 cost, highlighting the cost-effectiveness of the proposed sensor. Thus, the proposed sensing platform will enable low-cost, high throughput testing of cell expansion.

Capacitive–Inductive Magnetic Plug Sensor With High Adaptability for Online Debris Monitoring

A capacitive&#x2013;inductive magnetic plug sensor for online condition monitoring is proposed in this article, which can achieve particle counting, debris measurement, and wear rate estimation. The sensor can detect capacitance and inductance parameters, the coil is the outer electrode to detect the dielectric change in capacitance mode, and the coil directly induces magnetic field disturbance in inductance mode. Through introducing a reference unit, Wheatstone bridge circuits are constructed to enhance the response to debris and reduce the interference of oil temperature and viscosity. A postprocessing circuit with filtering and amplifying functions is adopted to improve accuracy. The sensor output characteristics and debris position effect are studied through the experiment. The comprehensive analysis of the detection results in two modes can improve sensor adaptability and overcome the deficiency of low reliability based on a single detection method. This sensor can provide more accurate debris information for the fault diagnosis of hydraulic equipment and is of great significance for intelligent maintenance.

A Double Lock-in Amplifier Circuit for Complex Domain Signal Detection of Particles in Oil

The detection of metal particles in oil is of great significance to the fault diagnosis of mechanical equipment. Real domain detection methods cannot simultaneously identify the sizes and materials of particles. Because a metal particle in an alternating magnetic field induces a complex domain signal whose strength relates to the particle properties, this paper introduces a double lock-in amplifier circuit (DLAC) into a triple-coil inductive particle sensor to detect the complex domain signal under noise interference conditions. Furthermore, various sizes of red copper, brass, aluminum, iron, and type 403 steel particles are chosen as the experimental materials. For the first time, the complex domain signals induced by the five kinds of particles are detected. Hence, in the complex plane, a method is proposed to identify the size and material of a particle based on the amplitude and phase of these signals. With the high sensitivity and strong antinoise ability of the DLAC, this system can detect 25 μm iron particles and 70 μm copper particles. This study presents a new strategy for the online detection of particles in oil.

The Effect of COVID-19 Pandemic on Emitted PM2.5 in Urban Road Networks: Using Loop Data and Kriging Method for Passenger Cars in the Central Part of the City of Lodz

In this paper, the effect of the COVID-19 pandemic on the emission of PM2.5 generated by passenger cars is investigated. First, traffic data collected from the inductive loop sensors is analyzed. Second, the traffic flow for the whole network system is estimated using an isometric transformed network and the Euclidean space, and the representative one is selected. Then, an emission model is presented for measuring the level of PM2.5 emissions by the passenger cars, and the integration process is given. Finally, the model is implemented on the central part of the city of Lodz, and the value of emissions before and after the COVID-19 pandemic is measured. Finally, the outputs and the process of the model calibration are depicted. Results show that before the pandemic, PM2.5 pollution was highly concentrated in the center and peripheral parts of the area under consideration, and it would gradually drop outside rush hours and grow at peak hours. After the lockdown, the pollution load throughout the whole area, and across its central parts in particular, decreased dramatically. Outputs also illustrate that restrictions not only lower the car-induced PM2.5 but also have a significant effect on the impact zones, areas affected by the pollutants. Another finding is that although the COVID-19 outbreak clearly poses a serious threat to life and health, it has had an exceptionally positive impact on the natural environment, becoming an unconventional mechanism for its restoration.