Sensors For Industrial Applications Research Articles

A high-sensitive anisotropic magnetoresistive sensor based on hybrid Ta/NiFe/Ta/Al multilayer structure

High sensitivity is crucial for anisotropic magnetoresistive (AMR) sensors in industrial applications. In this paper, a high- sensitive AMR sensor based on magnetoresistive thin films with Ta/NiFe/Ta/Al four-layer structure is proposed and fabricated. Firstly, the structural parameters were optimized by finite element analysis. Secondly, thin film samples and AMR sensors were prepared. Through the analysis and characterization of reluctance change rate, hysteresis loop, x-ray diffraction and surface morphology and structure, the process parameters were optimized. Finally, the sensor was connected to the designed external circuit, and its technical parameters were tested in a magnetic field test system. The results show that the prepared AMR sensor performs well. It has a high sensitivity of 1.27 mV/V/Oe, a low bridge offset voltage of ±1.64 mV V−1, and a low temperature coefficient of sensitivity of −0.102%/°C. The results contribute to the future development of AMR magnetic field sensor chips.

Ultra-high piezoelectric properties and ultra-high Curie temperature of Li/Ce-doped La2Ti2O7 ceramics.

The demand for ultra-high-temperature piezoelectric sensors in industrial applications has witnessed a rapid upsurge. In this study, the piezoelectric properties of La2Ti2O7 (LTO) piezoelectric ceramics with a perovskite-like layered structure were enhanced by doping with Li/Ce ions. It was found that a remarkable 300% enhancement in the piezoelectric constant (d33) value was achieved in Li/Ce-doped LTO ceramics compared to their pristine counterparts, reaching 6.4 pC N-1 at room temperature with an ultra-high Curie temperature of 1408 °C. After annealing at 500 °C, the d33 value of the samples can be further improved to 7.4 pC N-1. Moreover, temperature-dependent resistivity measurements indicate that even at 1000 °C, the ceramics exhibit a high resistivity of 8.9 × 105 Ω cm. By combining X-ray diffraction, Raman spectra, transmission electron microscopy and piezoresponse force microscopy data, the enhanced piezoelectricity of the ceramics is attributed to local heterogeneity induced by Li/Ce doping. Our results unequivocally demonstrate the suitability of modified LTO ceramics for ultra-high-temperature piezoelectric applications.

An integrated approach to evaluate the measurement capability and acceptability of acoustic emission sensors

Acoustic emission (AE) is a pivotal technique in condition-based maintenance (CBM) and recent years have witnessed a significant surge in the deployment of AE sensors in industrial applications. With this increase in availability, there comes a substantial challenge: evaluating the measurement capability of sensors within specific applications. As such, this study identifies a critical need for a structured approach to evaluate the measurement capabilities of AE sensors and subsequently judge their acceptability against guideline criteria. To address this need, we present an integrated approach that systematically guides the capability evaluation of AE sensors, incorporating both qualitative and quantitative analyses. The qualitative analysis aims to scrutinize the diagnostic accuracy of sensors by assessing the detectability of features critical for diagnostics. The quantitative analysis leverages the Gage repeatability and reproducibility (Gage R&R) to statistically evaluate sensor characteristics. A comprehensive experimental study further investigates the impact of measurement sources on the sensors’ repeatability, and reproducibility. This study illustrates the qualitative findings regarding sensor’s diagnostic accuracy in both time and frequency domains, revealing promising performance in diagnostic-based evaluations. In quantitative analysis, we demonstrate the results of sensor capability in terms of repeatability and reproducibility, providing the variations of different sources in statistics-based evaluations. We thoroughly investigate the influence of significant factors, quantifying their contributions to the sensor’s measurement capability. Furthermore, we introduce metrics designed to assess sensor’s acceptability, according to explicit acceptance and rejection criteria. Our experimental results affirm that root mean square measurements are within acceptable ranges for both sensors, while spectral entropy (SE) measurements for PK15I sensor satisfy the acceptable level. For HZ136I sensor, however, SE measurements are deemed conditionally acceptable. Ultimately, the proposed approach provides a robust framework for the comprehensive evaluation of AE sensor measurement capabilities, offering invaluable guidance for sensor selection and enhancement in industrial applications.

Aluminum based high temperature thin film electrode system for wireless sensors

Self-sustained, wireless high-temperature stable sensors are developed, which are based on an aluminum alloy as the electrode metallization. Due to its cost-effectiveness accompanied by a high-temperature stability, this alloy substitutes and outperforms the commonly applied expensive Pt- and Ir-based metals. For the first time, a comprehensive structural, electrical and high-frequency characterization of these surface acoustic wave (SAW) sensors is shown. They are based on Catangasite (Ca3TaGa3Si2O14, CTGS) in combination with properly structured cover and barrier layers for the metallization. The frequency characteristics is determined up to 700 °C by ex situ and in situ methods. In addition, the morphology of the AlRu electrodes is analyzed after the thermal loadings and the temperature dependent sheet resistance is measured. The results reveal a reproducible and linear correlation between the applied temperature and the sheet resistance as well as the resonant frequency. In addition, hardly any degradation of the electrodes is detected after the thermal loadings. The observed high-temperature stability of the devices up to at least 700 °C demonstrates the large potential of the AlRu based SAW sensors as a cost-efficient alternative to expensive noble metal based sensors in industrial applications for the support of energy efficient operation.

Recent development of planar microwave sensor for material characterization of solid, liquid, and powder: a review

Microwave is the most popular sensor in industrial applications for detecting material characterization. Over the past decade, microwave sensor is high demand, especially in medical for detecting cancer in the human body, agriculture for detecting moisture of soil, and freshness in the food industry. The previous study has shown that the high demands of the microwave sensor in industrial applications make researchers always think of new ideas to design microwave sensors to improves accuracy and sensitivity. This paper reviews an investigation of material characterization of recent developments of a planar sensor for various contaminants and parameter value of solid, liquid, and powder as material under test (MUT). Planar resonator sensor enhances the weakness of conventional sensors in bulky size, required a large volume of samples, and high cost. This planar sensor will differentiate MUT properties based on scattering parameters at various operating frequencies. The framework presented in this review paper includes new developments in resonator structure as well as advanced design of potential future research work. Previous studies will be objectively analysed and compared in order to gain a better understanding of microwave resonant sensors and to develop innovative concepts to further enhance application research involving material characterization.

Controlling the kinematics of a spring-pendulum system using an energy harvesting device

This work focuses on vibration alleviation and energy harvesting in a dynamical system of a spring-pendulum. The structure of the pendulum is modified using an independent electromagnetic harvesting system. The harvesting depends on the oscillation of a magnet in a coil. An endeavor has been made to get both the energy harvesting and mitigation of vibration efficacy of the harvester. The governing kinematics equations are derived using Lagrange’s equations and are solved asymptotically using the multiple scales method to achieve the intended outcome as new and precise results. The resonance states are classified, and the influence of various parameters of the studied system is analyzed. Fixed points at steady states are categorized into stable and unstable. The time behavior of the solutions, the modified amplitudes, and phases are examined and interpreted in the light of their graphical plots. Zones of stability and instability are concerned, in which the system’s behavior is stable for a wide range of used parameters. This model has become essential in recent times as it uses control sensors in industrial applications, buildings, infrastructure, automobiles, and transportation.

Optimization of asymmetric reference structures through non-evenly layered synthetic antiferromagnet for full bridge magnetic sensors based on CoFeB/MgO/CoFeB

Industrial sensor applications rely on the implementation of full Wheatstone bridge architectures, demanding the development of low-cost and mass production methods of magnetic tunnel junctions (MTJ) based on CoFeB/MgO/CoFeB. In particular, monolithic bridge microfabrication has been demonstrated through the double deposition of MTJ stacks engineered by asymmetric reference layers with non-evenly layered synthetic antiferromagnet (SAF) structures. However, extending the standard double magnetic layered SAF into a triple magnetic multilayer system brings critical changes in the overall performance of the reference structure, which directly influences the magnetic stability of the device. Consequently, a theoretical model of a triple magnetic layered AF/SAF structure was developed to support the understanding of the magnetic response of the reference layers, aiming to improve the magnetic stability around zero field. A full MTJ Wheatstone bridge incorporating the optimized double and triple reference structures was microfabricated with a linear and hysteresis-free response. Furthermore, a high thermal endurance of both structures was verified through the measurement of the magnetotransport behavior of each type of MTJ structure within a reversible magnetic field range of ±2 kOe and a temperature sweep from room temperature up to 200 °C.

High-resolution PAT monitoring of sample preparation grinding by accelerometer sensors: the key to ensuring accuracy and long-term consistency

Industrial operations are often based on critical quality measures obtained for technical process control and/or to determine the value of raw materials and product streams. Process Analytical Technology (PAT) monitoring is applied to characterise, for example, raw materials, semi-finished as well as finished products. There is an active interest in approaches for “smart” online, real-time industrial sensor applications, especially where industrial operations involve high sample throughput and/or may involve hazardous substances demanding automation. State-of-the-art sample preparation procedures and equipment can deliver key performances indicators, often supplemented by sensor data that are used as proxy quality measures which helps to ensure measurement representativity and optimal process/product control. We here illustrate this industrial front-line arena by an example in which PAT accelerometer data are used for real-time monitoring of the efficiency of the automated grinding sample preprocessing process.

Wireless Readout of Multiple SAW Temperature Sensors

It has since long been known that surface acoustic wave (SAW) devices, resonators as well as delay lines, can be used as passive wireless sensors for physical quantities, like temperature and pressure, as well as gas sensors or identification-tags (ID-tags). The sensors are robust, work passively without a battery, can be applied at high temperatures, and provide a high resolution. Nevertheless, if the devices are used wirelessly in an industrial environment, several constraints have to be taken into account, especially when more than one quantity or device needs to be measured at the same time. The paper addresses the challenges that must be tackled when establishing multi-sensor-wireless-readout for industrial applications. Major issues here are the legal regulations for industrial, scientific and medical frequency bands (ISM-bands), as well as sampling time and costs, which impose severe restrictions to any system design. We describe several design approaches and their constraints. We successfully designed sensors based on reflective delay lines that allow the parallel readout of four independent temperature sensors in the 2.45 GHz ISM-band. These devices were fabricated and positively tested, demonstrating the applicability of SAW sensors for industrial applications.

Current-Mode Rail-to Rail Instrumentation Amplifier for General Purpose Instrumentation Applications

Instrumentation amplifiers are used extensively in bio-potential reading, industrial sensor applications, Wheatstone bridge amplifiers etc. In this work, a high input common-mode range instrumentation amplifier is presented. The amplifier is composed of two second generation current conveyors (CCII+) with common-mode input range close to supply swings and a differential difference current conveyor (DDCC) at the second stage with high voltage swing at the output. Also an optional DC servo loop is employed as a feedback to second stage for the removal of any possible DC offset voltage at the output which can be used for AC coupled applications. The simple design strategy with high input common-mode range and nearly rail-to-rail output stage together with increased bandwidth advantage of current-mode approach makes the proposed implementation desirable for many of the general purpose instrumentation applications. The design is made using 0.35μm AMS technology with 3V supply voltage. The operation is verified by HSPICE simulations.

Industrial mmWave Radar Sensor in Embedded Wafer-Level BGA Packaging Technology

We present highly integrated 60-GHz radar transceivers for industrial sensor applications. The bistatic and monostatic transceivers are implemented in the SiGe bipolar technology and packaged using the embedded wafer-level ball grid array technology that allows for direct embedding of the antennas in the package redistribution layer. In this way, very compact and efficient radar frontends comprising all millimeter-wave components can be implemented in an $8 \times 8$ mm2 package. These frontends were soldered on a standard low-cost printed circuit board based on FR4 material. For verification of the proposed frontends, an frequency-modulated continuous wave (FMCW) radar system was developed and set up within this paper. Theoretical considerations and simulations as well as corresponding measurements were carried out for the evaluation of the designed system. The demonstrator results of these embedded radar sensors show an excellent system performance at a high integration level.

Recent Developments of Magnetoresistive Sensors for Industrial Applications.

The research and development in the field of magnetoresistive sensors has played an important role in the last few decades. Here, the authors give an introduction to the fundamentals of the anisotropic magnetoresistive (AMR) and the giant magnetoresistive (GMR) effect as well as an overview of various types of sensors in industrial applications. In addition, the authors present their recent work in this field, ranging from sensor systems fabricated on traditional substrate materials like silicon (Si), over new fabrication techniques for magnetoresistive sensors on flexible substrates for special applications, e.g., a flexible write head for component integrated data storage, micro-stamping of sensors on arbitrary surfaces or three dimensional sensing under extreme conditions (restricted mounting space in motor air gap, high temperatures during geothermal drilling).

Performance and Sealing Material Evaluation in 6-axis Force-Torque Sensors for Underwater Robotics

In this paper, the effects of two different materials for the sealing on the performance of an innovative optoelectronic force/torque sensor for underwater robotic applications are investigated. The sensor has been designed to exhibit a considerable compliance in comparison with commercial F/T sensors for industrial applications, and optoelectronic components have been used as sensible elements for the development of the sensor, allowing a relatively simple and reliable implementation. These properties allow dealing with uncertain environments and an easy sensor integration in complex robotic systems, such as in robotic grippers for underwater applications.The paper presents the basic working principle and the design of the sensor together with experimental data to illustrate its main features. Finally, the use of the sensor as an intrinsic tactile sensor is investigated and experimentally validated, and the comparison of different materials for the rubber sealing in terms of their effects on the sensor performance is executed.

Review of Electrostatic Sensor Applications

Electrostatic sensors have a simple but robust structure, which can detect the electric charge from moving charged particles. Measurement of the dry particle mass flow rate, velocity, and concentration in a conveyor are the main areas of sensor application. This paper considers the measurement methods and techniques that utilize electrostatic sensors for instrumentation. The most significant applications of the sensor are reviewed and a newly developed technique in particle sizing using the spatial filtering method is explained. The results of the study re-emphasize the flexibility, reliability and cost-effective features of the electrostatic sensor for industrial applications.

A New Fiber Optic Spring

Optical sensors have attracted considerable attention in recent decades. Springs are used for a large variety of functions in industry including in sensor applications such as the measurement of force, acceleration, vibration, and pressure. In this study, a compression coiled spring and an optical ber cable were combined to form a new optical ber spring. The measurement part of the ber optic spring was constructed by using a 3 dB ber coupler and a ber polarization beam splitter/combiner. During the study, a diode laser was used and silicon detectors measured the variations of the polarization state intensity. The spring constant of the optical ber spring was obtained from decay of the free vibrations and Hooke's law. In conclusion, the new constructed ber optic spring can be used in some industrial sensor applications.

Applying Fuzzy Logic for Optimal Placement of XBOX Kinect Sensors for Industrial Applications

Automated acquisition of sensing data is an active research area in manufacturing domain. A great deal of research work has been focused on automated data acquisitionapplied to various subjects related to manufacturing operations such as safety, performance improvement, monitoring and layout planning. Laser scanners including Time of Flight cameras play a significant role in real time or near real time decision makings in manufacturing automation. To establish an automated sensing system in a work place, enough test data should be available regarding the performance characteristics. This paper investigates the performance of Microsoft XBOX Kinect on spatial modeling in large jobsites, and employs fuzzy logic to find optimal placement of Kinect sensors that gives the best resolution.

Applications of PZT Dielectric Ceramics in High-Energy Storage Systems

The barium and strontium titanate (BST) ceramics have been used with great success as excellent dielectrics in the construction of high voltage (HV) commercial ceramic capacitors with reduced dimensions because of their high dielectric constant. However, the main point of this paper is to investigate other type of ceramic known as PZT (Lead Zirconate Titanate) normally used as piezoelectric sensors in industrial applications. The idea herein is to use the PZT ceramics as HV dielectrics for applications in high-energy storage systems by de-poling their piezoelectric properties in order to avoid dielectric damage and losses at high frequencies. For this, de-poled PZT-4 ceramic samples (30 mm × 2 mm) were submitted to HV tests, in which their dielectric breakdown strength and dielectric constant variation with the applied voltage were assessed. These results obtained confirmed the use of PZT in applications that require reasonable dielectric constant stability (< 15 %) with voltage and HV dielectric breakdown (40 kV/cm) for compact high-energy storage devices.

Magnetic moment investigation by frequency mixing techniques

Gas turbines and other large industrial equipment are subjected to high-temperature oxidation and corrosion. Research and development of efficient protective coatings is the main task in the field. Also, knowledge about the depletion state of the coating during the operation time is important. To date, practical nondestructive methods for the measurement of the depletion state do not exist. By integrating magnetic phases into the coating, the condition of the coating can be determined by measuring its magnetic properties. In this paper, a new technique using frequency mixing is proposed to investigate the thickness of the coatings based on their magnetic properties. A sensor system is designed and tested on specific magnetic coatings. New approaches are proposed to overcome the dependency of the measurement on the distance between coil and sample that all noncontact techniques face. The novelty is a low cost sensor with high sensibility and selectivity which can provide very high signal-to-noise ratios. Prospects and limitations are discussed for future use of the sensor in industrial applications.

A neuro-coevolutionary genetic fuzzy system to design soft sensors

This paper addresses a soft computing-based approach to design soft sensors for industrial applications. The goal is to identify second-order Takagi–Sugeno–Kang fuzzy models from available input/output data by means of a coevolutionary genetic algorithm and a neuro-based technique. The proposed approach does not require any prior knowledge on the data-base and rule-base structures. The soft sensor design is carried out in two steps. First, the input variables of the fuzzy model are pre-selected from the secondary variables of a dynamical process by means of correlation coefficients, Kohonen maps and Lipschitz quotients. Such selection procedure considers nonlinear relations among the input and output variables. Second, a hierarchical coevolutionary methodology is used to identify the fuzzy model itself. Membership functions, individual rules, rule-bases and fuzzy inference parameters are encoded into each hierarchical level and a shared fitness evaluation scheme is used to measure the performance of individuals in such levels. The proposed methodology is evaluated by developing soft sensors to infer the product composition in petroleum refining processes. The obtained results are compared with other benchmark approaches, and some conclusions are presented.

Investigation into the packaging and operation of an electronic tongue sensor for industrial applications

PurposeThe purpose of this paper is to describe the packaging and operation of an electronic tongue sensor. The sensor will be used in an industrial setting and the packaging needs to withstand the harsh clean‐in‐place (CIP) routines that are commonly employed. A suitable epoxy, Loctite FP4450 HYSOL, was identified from a number of packaging materials. The sensor was validated by carrying out cyclic voltammetry in a number of reference solutions including sulphuric acid solution and ferrocyanide in potassium chloride solution, which gave well‐defined reduction and oxidation peaks that could be compared with the literature. The operation of the sensor in mixtures of salt and citric acid solutions was also investigated and it was seen that by applying a carefully selected voltage window and scan rate to each electrode, the sensor could distinguish between the different mixtures. Further experimentation and the application of principle component analysis have shown the sensor to have good repeatability.Design/methodology/approachThis paper concentrates on the ability of the sensor packaging to withstand a typical industrial CIP procedure. A number of packaging materials are investigated. In addition, the operation of the sensor has been investigated by using cyclic voltammetry.FindingsOne successful packaging material is Loctite 9461A&B HYSOL. Poly ether ether ketone also performs well after repeated CIP exposure. For ease of manufacture, Loctite FP4450 HYSOL is the epoxy of choice. An extensive matrix of test solutions was prepared from salt and citric acid powders. The aim was to investigate the sensor's ability to distinguish between increasing concentration levels of salt and citric acid and also to investigate how the sensor operates in mixtures of the solutions. By carefully choosing the applied voltage window and scan rate, the electrodes can distinguish between the mixturesOriginality/valueThis research work has highlighted a robust packaging material to withstand industrial CIP procedures.