Design and research of a novel non-contact vertical inductive torque sensor
TL;DR: In this paper, a non-contact vertical inductive torque sensor was built and investigated, and the effect of different rotors on the nonlinear characteristics of the sensor was analyzed based on the simulation results.
About: This article is published in Measurement.The article was published on 2021-06-01. It has received 6 citations till now. The article focuses on the topics: Torque sensor & Rotor (electric).
Citations
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DOI•
TL;DR: In this article , the authors presented a theoretical study of an absolute, ratiometric inductive position sensor (IPS) based on eddy currents and showed that the best choice is to have a rectangular target and rectangular receivers.
Abstract: This article presents a theoretical study of an absolute, ratiometric inductive position sensor (IPS) based on eddy currents. The aim is to describe the working principle of the sensor, having as key components a transmitting coil, the receiving coils, and the conductive target, by introducing area-of-overlap functions. We show that each target–receiver pair needs the adoption of a different reconstruction formula for the identification of the target position, whereas in the literature the usual inverse tangent function is applied for every possible pair. Then, we seek the target–receiver pair that maximizes the amplitude of the induced voltages on the receivers. The results show that to achieve the maximum value of the induced voltages, the best choice is to have a rectangular target and rectangular receivers. To verify the theory, a simulation and optimization method has been applied to the rectangular receiver coils on two rotary IPS realized with printed circuit board (PCB) technology. Measurements performed on the prototypes have shown an increment of the induced voltage of more than 57% with respect to the commonly used sinusoidal receivers. However, a linearity error of 1.5%FS is obtained by using the inverse tangent reconstruction formula. When using the formula provided by the theory, the linearity error becomes 0.6%FS for the nonoptimized prototype and below 0.15%FS for the optimized one.
TL;DR: In this article , the authors presented a theoretical study of an absolute, ratiometric inductive position sensor (IPS) based on eddy currents and showed that the best choice is to have a rectangular target and rectangular receivers.
Abstract: This article presents a theoretical study of an absolute, ratiometric inductive position sensor (IPS) based on eddy currents. The aim is to describe the working principle of the sensor, having as key components a transmitting coil, the receiving coils, and the conductive target, by introducing area-of-overlap functions. We show that each target–receiver pair needs the adoption of a different reconstruction formula for the identification of the target position, whereas in the literature the usual inverse tangent function is applied for every possible pair. Then, we seek the target–receiver pair that maximizes the amplitude of the induced voltages on the receivers. The results show that to achieve the maximum value of the induced voltages, the best choice is to have a rectangular target and rectangular receivers. To verify the theory, a simulation and optimization method has been applied to the rectangular receiver coils on two rotary IPS realized with printed circuit board (PCB) technology. Measurements performed on the prototypes have shown an increment of the induced voltage of more than 57% with respect to the commonly used sinusoidal receivers. However, a linearity error of 1.5%FS is obtained by using the inverse tangent reconstruction formula. When using the formula provided by the theory, the linearity error becomes 0.6%FS for the nonoptimized prototype and below 0.15%FS for the optimized one.
TL;DR: In this article , a technique of differential rectification is proposed for three-phase coil based inductive angle sensors so that the amplitude difference between any two of the amplitudes of 3-phase coils is output for further signal processing.
Abstract: A technique of differential rectification is proposed for three-phase coil based inductive angle sensors so that the amplitude difference between any two of the amplitudes of three-phase coils is output for further signal processing. A 3-to-6 multiplexer, a low pass filter, and a 6-to-2 multiplexer are designed for the proposed technique, which is used for differential rectification, turning rectified signals into DC levels, and transmitting DC levels to the output of differential rectifiers, respectively. This differential rectification could suppress 3rd harmonic noise and common-mode noise, in order to improve the accuracy of angle calculation. The circuit of the proposed differential rectifier is given and simulation results shown in this manuscript verify the proposed circuit is feasible for three-phase coil based inductive angle sensors.
DOI•
TL;DR: In this article , a novel design of multi-period bipolar inductive absolute angle sensor is proposed, which is composed of stator and rotor, and an inner and outer fan-shaped bipolar pattern is designed and fabricated on the rotor.
Abstract: In this study, a novel design of multiperiod bipolar inductive absolute angle sensor is proposed. The sensor structure is composed of stator and rotor. An inner and outer fan-shaped bipolar pattern is designed and fabricated on the rotor. The receiving coils and signal processing circuits are on the stator. When alternating current is applied to the excitation coil, the eddy current is generated in the rotor. The induced voltage of two adjacent receiving coils is in the form of cosine, when the rotor rotates above the receiving coil. There are two groups of receiving coils in the sensor. One group is composed of eight loops, corresponding to the 45° fan-shaped pattern at the outer edge, and the other group is composed of two loops, corresponding to the 180° fan-shaped (semicircular) pattern at the center. The coil with more loops provides high measurement accuracy and the coil with a small number of loops provides the identification of the number of cycles. The results show that the measurement error is 0.04° and the resolution is better than 0.005° in the range of 0°–360°. Through the multiperiod bipolar pattern proposed in this article, a high accuracy absolute position measurement can be realized.
TL;DR: In this paper , a two-dimensional planar spiral excitation coil is modelled using ANSYS Maxwell software and the two-factor, five-level central composite deign principle is selected to establish a multivariate quadratic model by Response Surface Methodology (RSM).
Abstract: Planar coil is usually used as a basic element in various research fields. This paper models a sensor equivalent circuit by taking the planar spiral excitation coil as an optimization object according to the electromagnetic coupling principle. The influence of coil electrical parameters on the coupling efficiency is analysed. The present result shows that the excitation coil should be small size, large inductance and high-quality factor. A two-dimensional planar spiral coil is modelled using ANSYS Maxwell software. The coil structure parameters with significant influence on the coil quality factor are chosen by the single factor experiment. The two-factor, five-level central composite deign principle is selected to establish a multivariate quadratic model by Response Surface Methodology (RSM). Then the paper implemented Grey Wolf Optimizer (GWO) to optimize response surface model, and obtained the optimal coil structure parameters. The conclusion was drawn that the inductance and quality factor of the optimized coil increase from 27.031 μH and 161.293 to 43.171 μH and 175.537, respectively. Compared to the control coil, the inductance is 1.597 times as the original coil and the quality factor is increased by 8.8%.
References
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TL;DR: An overview of the fundamentals and main variables of eddy current testing is included, and the state-of-the-art sensors and modern techniques such as multi-frequency and pulsed systems are described.
Abstract: Non-destructive techniques are used widely in the metal industry in order to control the quality of materials. Eddy current testing is one of the most extensively used non-destructive techniques for inspecting electrically conductive materials at very high speeds that does not require any contact between the test piece and the sensor. This paper includes an overview of the fundamentals and main variables of eddy current testing. It also describes the state-of-the-art sensors and modern techniques such as multi-frequency and pulsed systems. Recent advances in complex models towards solving crack-sensor interaction, developments in instrumentation due to advances in electronic devices, and the evolution of data processing suggest that eddy current testing systems will be increasingly used in the future.
683 citations
TL;DR: This paper presents an integrated optical sensor based upon the heterogeneous integration of an InGaAs-based thin-film photodetector with a digital microfluidic system, the first step toward the heterogeneity integration of entire planar optical sensing systems on this platform.
Abstract: The advent of digital microfluidic lab-on-a-chip (LoC) technology offers a platform for developing diagnostic applications with the advantages of portability, increased automation, low-power consumption, compatibility with mass manufacturing, and high throughput. However, most digital microfluidic platforms incorporate limited optical capabilities (e.g., optical transmission) for integrated sensing, because more complex optical functions are difficult to integrate into the digital microfluidic platform. This follows since the sensor must be compatible with the hydrophobic surfaces on which electrowetting liquid transport occurs. With the emergence of heterogeneous photonic component integration technologies such as those described herein, the opportunity for integrating advanced photonic components has expanded considerably. Many diagnostic applications could benefit from the integration of more advanced miniaturized optical sensing technologies, such as index of refraction sensors (surface plasmon resonance sensors, microresonator sensors, etc.). The advent of these heterogeneous integration technologies, that enable the integration of thin-film semiconductor devices onto arbitrary host substrates, enables more complex optical functions, and in particular, planar optical systems, to be integrated into microfluidic systems. This paper presents an integrated optical sensor based upon the heterogeneous integration of an InGaAs-based thin-film photodetector with a digital microfluidic system. This demonstration of the heterogeneous integration and operation of an active optical thin-film device with a digital microfluidic system is the first step toward the heterogeneous integration of entire planar optical sensing systems on this platform.
156 citations
TL;DR: Magnetic and magnetostrictive sensor configurations are compared and contrasted in terms of application, sensitivity, and implementation issues as discussed by the authors, and compared to other common sensor configurations as appropriate.
Abstract: As sensors become integrated in more applications, interest in magnetostrictive sensor technology has blossomed. Magnetostrictive sensors take advantage of the efficient coupling between the elastic and magnetic states of a material to facilitate sensing a quantity of interest. Magnetic and magnetostrictive theory pertinent to magnetostrictive sensor technology is provided. Sensing configurations are based on the utilization of a magnetostrictive element in a passive, active, or combined mode. Magnetostrictive sensor configurations that measure motion, stress or force, torque, magnetic fields, target characteristics, and miscellaneous effects are discussed. The configurations are compared and contrasted in terms of application, sensitivity, and implementation issues. Comparisons are made to other common sensor configurations as appropriate. Experimental and modeling results are described when available and schematics of the configurations are presented.
143 citations
TL;DR: This paper presents a capacitive rotary encoder for both angular position and angular speed measurements based on the quadrature demodulation and the coordinate rotational digital computer algorithm.
Abstract: This paper presents a capacitive rotary encoder for both angular position and angular speed measurements. The encoder is mainly composed of three parts: the transmitting segments; a pair of reflecting electrodes; and a pair of receiving electrodes. The transmitting segments together with four mutual quadrature carrier voltages provide a modulated electric field. The reflecting electrodes, which are patterned sinusoidally can encode the angular position to a phase/frequency modulated signal based on quadrature modulation. The modulated signal is then digitally decoded to the angular position in a field programmable gate array processor based on the quadrature demodulation and the coordinate rotational digital computer algorithm. Through a universal serial bus, the digital angular position is transmitted to a computer for further analysis in National Instruments' LabVIEW software. A prototype of the capacitive encoder shows that its precision is better than 0.006° and the resolution is 0.002°. The dynamic nonlinearity is evaluated at ±0.4° when the rotor is rotating at 1000 r/min.
77 citations
TL;DR: In this article, an absolute capacitive angular-position sensor with a contactless rotor is presented, which is mainly composed of three parts: the capacitive sensing element, a signal processor, and a microcontroller.
Abstract: This paper presents an absolute capacitive angular-position sensor with a contactless rotor. The sensor is mainly composed of three parts: the capacitive sensing element, a signal processor, and a microcontroller. The electrically floating rotor can be either conductive or dielectric. For the dielectric material, we chose plastic, and for the conductive rotor, we chose aluminum. The sensing element has a redundant structure, which reduces mechanical nonidealities. The signal processor has a multicapacitance input and a single output, which is a period-modulated square-wave voltage. The microcontroller acquires output data from the processor and sends them to a PC, which calculates the rotor position. Theoretical analysis, supported by experimental results, show that the sensitivity to mechanical nonidealities of the sensing element is higher in the case of a conductive rotor. The resolution of the capacitive angular-position sensor over the full range (360/spl deg/) was better than 1". The measured nonlinearity was /spl plusmn/ 100" and /spl plusmn/ 300" for the dielectric and the conductive rotor, respectively.
75 citations