scholarly journals Extreme membrane position detection and pump output estimation in pulsatile VADs

2022 ◽  
Vol 73 ◽  
pp. 103409
Author(s):  
Alicja Siewnicka ◽  
Bartłomiej Fajdek ◽  
Krzysztof Janiszowski
Keyword(s):  
Position Detection ◽  
Pump Output

Recent Challenges and Advances in the Sensorless Commutation of Brushless DC Motors

2020 ◽  
Vol 13 ◽  
Author(s):  
Umesh Kumar Soni ◽  
Ramesh Kumar Tripathi
Keyword(s):  
Initial Position ◽  
Position Estimation ◽  
Current Response ◽  
Flux Linkage ◽  
Brushless Dc Motors ◽  
Position Sensing ◽  
Brushless Dc ◽  
Dc Motors ◽  
Reverse Torque ◽  
Position Detection

Background: Brushless DC motors are highly efficient motors due to its high torque to weight ratio, compact design, high speed operating capability and higher power density. Conventional Hall sensor based rotor position sensing is affected by the heating, vibration, interference and noise. Objective: The innovative, cost effective and easily implementable sensorless techniques are essential in order to achieve high efficiency, reduced current and reduced torque pulsations. Further, a delay free, high load fast startup is also important issue. Methods: In this paper an extensive review of various techniques based on the detection of freewheeling diode current, phase back EMF zero crossoing point detection, back EMF integration method and third harmonic back EMF was done. The study and effect of various PWM strategies on back EMF detection was studied. Later on the sensorless schemes based on flux linkage estimation and flux linkage increment were introduced. The load torque observers, unknown input observers, sliding mode observers, L∞-induced observers, H ∞ - deconvolution filter for back EMF estimation were also reviewed. As the brushless DC motors have no back EMF at starting and for back EMF based commutation a minimum speed is required for sufficient back EMF. Therefore various strategies of open and close-loop reduced current startup have been studied to achieve effective commutation without reverse torque. Initial position detection (IPD) schemes, which are mostly based on saliency and current response to inductance variation, is effective where reverse torque is strictly prohibited. A detailed review of these initial position detection techniques (IPD) has also been presented. Results: The detailed mathematical and graphical analysis has been presented here in order to understand the working of the state-of-art sensorless techniques. Conclusion: The back EMF detection using direct and indirect methods of terminal voltage filtering have the problem of delay and attenuation, PWM noise, freewheeling diode spikes and disturbance in detected back EMFs is a drawback. The parameter detuning, underestimation and overestimation, offset problem, system noise and observer gain variation etc. limit the applicability of observer based technique. Therefore, a more robust and precise position estimation scheme is essential.

Application of 3D-printed magnets for magnetic position detection systems

2017 ◽  
Author(s):  
M. Ortner ◽  
C. Huber ◽  
N. Vollert ◽  
J. Pilz ◽  
D. Suss
Keyword(s):  
Detection Systems ◽  
Position Detection ◽  
3D Printed

The Improvement of the Spin Coater and its Patented Project Design

2013 ◽  
Vol 706-708 ◽  
pp. 1631-1634
Author(s):  
Nai Gen Li ◽  
Ke Gao Liu ◽  
Yong Xu
Keyword(s):  
Project Design ◽  
Exhaust Pipe ◽  
Motor Shaft ◽  
Coating Technology ◽  
Technology Project ◽  
Speed Controller ◽  
Power Switch ◽  
Control Switch ◽  
Pump Output ◽  
The Face

A rotary spin-coating technology project is provided by the utility model patent in this work. It includes vacuum pump and chassis, speed display, power switch, suction piece switch, start switch and the speed control switch on the chassis panel, motor and speed controller in the chassis connected to the outside of the chassis bracket, the bracket beams fixed hanging umbrella cover, the ring hood under the umbrella cover on top of the face, the piece prop and tachometer probe in the ring hood, the chip tray fixed extended chassis top surface motor shaft, there is a solution injection tube on the top of the sheet tray in project; it has an annular heater chip at the bottom of the tray within the annular cover sheet around the motor shaft; In addition, there is an ultrasonic humidification pump, the pump output of the ultrasonic humidification communicating through the humidifying tubes with the annular cover. In above mentioned the annular cover connected to the exhaust pipe and the annular cover interior chamber. A temperature sensor is at the inside of the annular cover, and a temperature display panel on the panel of the chassis.

scholarly journals The nanofluidic confinement apparatus: studying confinement-dependent nanoparticle behavior and diffusion

2018 ◽  
Vol 9 ◽  
pp. 301-310 ◽  
Author(s):  
Stefan Fringes ◽  
Felix Holzner ◽  
Armin W Knoll
Keyword(s):  
Polymer Surface ◽  
Diffusion Constant ◽  
Numerical Aperture ◽  
Lateral Diffusion ◽  
Vertical Position ◽  
Detection Accuracy ◽  
Illumination Time ◽  
Electroviscous Effect ◽  
Position Detection ◽  
Hydrodynamic Effects

The behavior of nanoparticles under nanofluidic confinement depends strongly on their distance to the confining walls; however, a measurement in which the gap distance is varied is challenging. Here, we present a versatile setup for investigating the behavior of nanoparticles as a function of the gap distance, which is controlled to the nanometer. The setup is designed as an open system that operates with a small amount of dispersion of ≈20 μL, permits the use of coated and patterned samples and allows high-numerical-aperture microscopy access. Using the tool, we measure the vertical position (termed height) and the lateral diffusion of 60 nm, charged, Au nanospheres as a function of confinement between a glass surface and a polymer surface. Interferometric scattering detection provides an effective particle illumination time of less than 30 μs, which results in lateral and vertical position detection accuracy ≈10 nm for diffusing particles. We found the height of the particles to be consistently above that of the gap center, corresponding to a higher charge on the polymer substrate. In terms of diffusion, we found a strong monotonic decay of the diffusion constant with decreasing gap distance. This result cannot be explained by hydrodynamic effects, including the asymmetric vertical position of the particles in the gap. Instead we attribute it to an electroviscous effect. For strong confinement of less than 120 nm gap distance, we detect the onset of subdiffusion, which can be correlated to the motion of the particles along high-gap-distance paths.

Research on the Pose Detection and Control Methods of Robot with Series-Parallel Structure

2013 ◽  
Vol 303-306 ◽  
pp. 1685-1690 ◽  
Author(s):  
Dong Yang ◽  
Tie Jun Li ◽  
Jin Yue Liu ◽  
Hai Wen Zhao
Keyword(s):  
Structural Features ◽  
Hybrid Structure ◽  
Parallel Structure ◽  
Sensing Systems ◽  
Position Detection ◽  
Pose Detection ◽  
Building Environment ◽  
Automated Installation ◽  
And Control ◽  
Structured Light Vision

Aiming at the load requirements, positioning accuracy and workflow of building panels installed robot, developed a 6 DOF of a series-parallel hybrid structure installed robot. According to the structural features of parallel mechanism to the installation manipulator, designed a robot attitude sensing system based on the inclination and laser ranging sensor information feedback; according to the characteristics of the building environment, proposed the position detection method of panels to be installed based on the structured light vision; constructed the control system of the installation manipulator, and used teaching mode to achieve robot control and system calibration. The experimental data prove that, the control and sensing systems of panels installed robot, overcome the complexity of the building environment and the diversity of installation object, and can achieve the automated installation of building panels.

scholarly journals Binary Large Object-Based Approach for QR Code Detection in Uncontrolled Environments

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Omar Lopez-Rincon ◽  
Oleg Starostenko ◽  
Vicente Alarcon-Aquino ◽  
Juan C. Galan-Hernandez
Keyword(s):  
Recognition Rate ◽  
Qr Code ◽  
Large Object ◽  
Position Detection ◽  
Object Based ◽  
Geometrical Features ◽  
Particular Solution ◽  
Variable Illumination ◽  
Low Performance ◽  
Iterative Filtering

Quick Response QR barcode detection in nonarbitrary environment is still a challenging task despite many existing applications for finding 2D symbols. The main disadvantage of recent applications for QR code detection is a low performance for rotated and distorted single or multiple symbols in images with variable illumination and presence of noise. In this paper, a particular solution for QR code detection in uncontrolled environments is presented. The proposal consists in recognizing geometrical features of QR code using a binary large object- (BLOB-) based algorithm with subsequent iterative filtering QR symbol position detection patterns that do not require complex processing and training of classifiers frequently used for these purposes. The high precision and speed are achieved by adaptive threshold binarization of integral images. In contrast to well-known scanners, which fail to detect QR code with medium to strong blurring, significant nonuniform illumination, considerable symbol deformations, and noising, the proposed technique provides high recognition rate of 80%–100% with a speed compatible to real-time applications. In particular, speed varies from 200 ms to 800 ms per single or multiple QR code detected simultaneously in images with resolution from 640 × 480 to 4080 × 2720, respectively.

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