Whisker-Like Position Sensor for Measuring Physiological Motion

A static frequency converter start-up control strategy for pumped-storage power unit is presented. And rotor position detecting without position sensor is realized according to voltage and magnetism equations of ideal synchronous motor mathematics model. The mechanism and implementation method of initial rotor position determination and rotor position estimation under low frequency without position sensor are expounded and validated by simulations. Based on the mentioned control strategy, first set of a static frequency converter start-up device in China for large-scale pumped-storage unit is developed, which is applied to start-up control test in the 90 MW generator/motor of Panjiakou Pumped-storage Power Plant. Test results show that rotor position detecting, pulse commutation, natural commutation, and unit synchronous procedure control of static start-up are all proved. The outcomes have been applied in running equipment, which proves the feasibility of mentioned method.

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Movement Control Method of Magnetic Levitation System Using Eccentricity of Non-Contact Position Sensor

Applied Sciences ◽

10.3390/app11052396 ◽

2021 ◽

Vol 11 (5) ◽

pp. 2396

Author(s):

Jong Suk Lim ◽

Hyung-Woo Lee

Keyword(s):

Motor System ◽

Control Method ◽

Magnetic Levitation ◽

Movement Control ◽

Position Sensor ◽

Semiconductor Wafer ◽

Control Command ◽

Levitation System ◽

Magnetic Levitation System ◽

Contact Position

This paper presents a method of utilizing a non-contact position sensor for the tilting and movement control of a rotor in a rotary magnetic levitation motor system. This system has been studied with the aim of having a relatively simple and highly clean alternative application compared to the spin coater used in the photoresist coating process in the semiconductor wafer process. To eliminate system wear and dust problems, a shaft-and-bearing-free magnetic levitation motor system was designed and a minimal non-contact position sensor was placed. An algorithm capable of preventing derailment and precise movement control by applying only control without additional mechanical devices to this magnetic levitation system was proposed. The proposed algorithm was verified through simulations and experiments, and the validity of the algorithm was verified by deriving a precision control result suitable for the movement control command in units of 0.1 mm at 50 rpm rotation drive.

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Influence of the Magnetic Field of the Overhang Parts of the Micromotor Winding on the Rotor Position Sensor

2020 IEEE Problems of Automated Electrodrive. Theory and Practice (PAEP) ◽

10.1109/paep49887.2020.9240855 ◽

2020 ◽

Author(s):

Igor Petukhov ◽

Konstantin Akinin ◽

Anton Filomenko

Keyword(s):

Magnetic Field ◽

Position Sensor ◽

Rotor Position ◽

The Magnetic Field

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Imaging coronary plaques using 3D motion-compensated [18F]NaF PET/MR

European Journal of Nuclear Medicine and Molecular Imaging ◽

10.1007/s00259-020-05180-4 ◽

2021 ◽

Author(s):

Johannes Mayer ◽

Thomas-Heinrich Wurster ◽

Tobias Schaeffter ◽

Ulf Landmesser ◽

Andreas Morguet ◽

...

Keyword(s):

Attenuation Correction ◽

Free Breathing ◽

Cardiac Motion ◽

Water Fraction ◽

3 Dimensional ◽

Background Ratio ◽

Motion Models ◽

Physiological Motion ◽

Atherosclerosis Imaging ◽

Novel Applications

Abstract Background Cardiac PET has recently found novel applications in coronary atherosclerosis imaging using [18F]NaF as a radiotracer, highlighting vulnerable plaques. However, the resulting uptakes are relatively small, and cardiac motion and respiration-induced movement of the heart can impair the reconstructed images due to motion blurring and attenuation correction mismatches. This study aimed to apply an MR-based motion compensation framework to [18F]NaF data yielding high-resolution motion-compensated PET and MR images. Methods Free-breathing 3-dimensional Dixon MR data were acquired, retrospectively binned into multiple respiratory and cardiac motion states, and split into fat and water fraction using a model-based reconstruction framework. From the dynamic MR reconstructions, both a non-rigid cardiorespiratory motion model and a motion-resolved attenuation map were generated and applied to the PET data to improve image quality. The approach was tested in 10 patients and focal tracer hotspots were evaluated concerning their target-to-background ratio, contrast-to-background ratio, and their diameter. Results MR-based motion models were successfully applied to compensate for physiological motion in both PET and MR. Target-to-background ratios of identified plaques improved by 7 ± 7%, contrast-to-background ratios by 26 ± 38%, and the plaque diameter decreased by −22 ± 18%. MR-based dynamic attenuation correction strongly reduced attenuation correction artefacts and was not affected by stent-related signal voids in the underlying MR reconstructions. Conclusions The MR-based motion correction framework presented here can improve the target-to-background, contrast-to-background, and width of focal tracer hotspots in the coronary system. The dynamic attenuation correction could effectively mitigate the risk of attenuation correction artefacts in the coronaries at the lung-soft tissue boundary. In combination, this could enable a more reproducible and reliable plaque localisation.

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Modeling Linear Position Sensor Dependence On Planar Rotation

1997 IEEE International Magnetics Conference (INTERMAG'97) ◽

10.1109/intmag.1997.597395 ◽

2005 ◽

Author(s):

J. Ish-Shalom

Keyword(s):

Position Sensor ◽

Planar Rotation

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Vibration Monitoring for Position Sensor Fault Diagnosis in Brushless DC Motor Drives

Energies ◽

10.3390/en14082248 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2248

Author(s):

Dimitrios A. Papathanasopoulos ◽

Konstantinos N. Giannousakis ◽

Evangelos S. Dermatas ◽

Epaminondas D. Mitronikas

Keyword(s):

Fault Diagnosis ◽

Harmonic Component ◽

Motor Drives ◽

Brushless Dc Motor ◽

Position Sensor ◽

Sensor Faults ◽

Sensor Fault ◽

Brushless Dc ◽

Non Invasive ◽

Dc Motor Drives

A non-invasive technique for condition monitoring of brushless DC motor drives is proposed in this study for Hall-effect position sensor fault diagnosis. Position sensor faults affect rotor position feedback, resulting in faulty transitions, which in turn cause current fluctuations and mechanical oscillations, derating system performance and threatening life expectancy. The main concept of the proposed technique is to detect the faults using vibration signals, acquired by low-cost piezoelectric sensors. With this aim, the frequency spectrum of the piezoelectric sensor output signal is analyzed both under the healthy and faulty operating conditions to highlight the fault signature. Therefore, the second harmonic component of the vibration signal spectrum is evaluated as a reliable signature for the detection of misalignment faults, while the fourth harmonic component is investigated for the position sensor breakdown fault, considering both single and double sensor faults. As the fault signature is localized at these harmonic components, the Goertzel algorithm is promoted as an efficient tool for the harmonic analysis in a narrow frequency band. Simulation results of the system operation, under healthy and faulty conditions, are presented along with the experimental results, verifying the proposed technique performance in detecting the position sensor faults in a non-invasive manner.

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Application of the MEMS Accelerometer as the Position Sensor in Linear Electrohydraulic Drive

Sensors ◽

10.3390/s21041479 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1479 ◽

Cited By ~ 1

Author(s):

Dominik Rybarczyk

Keyword(s):

High Price ◽

Second Phase ◽

Position Sensor ◽

Microelectromechanical System ◽

Mems Accelerometer ◽

Drive Control ◽

Electrohydraulic Drive ◽

Preliminary Research ◽

Two Phases ◽

Correction Phase

Various distance sensors are used as measuring elements for positioning linear electrohydraulic drives. The most common are magnetostrictive transducers or linear variable differential transformer (LVDT) sensors mounted inside the cylinder. The displacement of the actuator’s piston rod is proportional to the change in the value of the current or voltage at the output from the sensor. They are characterized by relatively low measurement noise. The disadvantage of presented sensors is the need to mount them inside the cylinders and the high price. The article presents preliminary research on the replacement of following sensors and the use of a microelectromechanical system (MEMS) accelerometer as a measuring element in the electrohydraulic drive control system. The control consisted of two phases: at first, the signal from the acceleration sensor was analyzed during the actuator movement, based on the value determined from the simplified model implemented on the controller. In the range of motion in which the dynamics were the lowest, the signal was integrated and the obtained value was used in the second phase of motion. In the correction phase, a new set point was determined. Conducting the research required building a dedicated research stand. The author conducted the simulation and experimental research.

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