• Title, Summary, Keyword: driving coils

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Modeling of 3-stage Electromagnetic Induction Launcher

  • Kwak, Daehwan;Kim, Young Bae;Kim, Jong Soo;Cho, Chuhyun;Yang, Kyung-Seung;Kim, Seong-Ho;Lee, Byung-Ha;An, Sanghyuk;Lee, Young-Hyun;Yoon, Seok Han;Koo, In Su;Baik, Yong Gi;Jin, Yun Sik
    • Journal of Magnetics
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    • v.20 no.4
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    • pp.394-399
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    • 2015
  • Electromagnetic Induction Launchers (EIL) have been receiving great attention due to their advantages of non-contact between the coils and a projectile. This paper describes the modeling and design of 3-stage EIL to accelerate a copper projectile of 50 kg with 290 mm diameter. Our EIL consists of three independent driving coils and pulsed power modules to generate separate driving currents. To find efficient acceleration conditions, the appropriate shape of the driving coils and the position of the projectile have been calculated by using a finite element analysis (FEA) method. The results showed that the projectile can be accelerated more effectively as the gap between the coils is smaller; a final velocity of 45 m/s was obtained. The acceleration efficiency was estimated to be 23.4% when a total electrical energy of 216 kJ was discharged.

Inductive Micro Displacement Detecting System with High Sensitivity and Low Linearity Error

  • Park, Dong-June;Park, In-Mook;Kim, Soo-Hyun
    • International Journal of Precision Engineering and Manufacturing
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    • v.2 no.3
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    • pp.54-60
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    • 2001
  • A newly designed inductive micro displacement detecting system is presented. The proposed inductive system consists of driving coils, position-detecting coils, cores, and closed-loop formed magnetic blocks. The cores and magnetic blocks are made of Mn-Zn ferrite. When AC sine wave is applied to the driving coils, the time derivative flux is generated within the system, and then induced voltages arise in the position-detecting coils according to the core\`s position. Putting the cores to be moved proportionally to the input displacement, the induced voltage is proportional to input displacement. The parameters that affect the system characteristics are turn ratio, air-gap size, excitation frequency, overlap area, load resistance, capacitance effect, and so forth. Based on the experimental results, the system parameters are selected in such a way as to have high sensitivity ad stable responses. The sensitivity of the proposed inductive displacement-detecting system is greater than 2800mV.V-1mm-1 and the linearity error is below $\pm$0.10% in the range of $\pm$200㎛.

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Standardized Design of the Transmitting Coils in Inductive Coupled Endoscope Robot Driving Systems

  • Ke, Quan;Jiang, Pingping;Yan, Guozheng
    • Journal of Power Electronics
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    • v.17 no.3
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    • pp.835-847
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    • 2017
  • A transmitting coil with an optimal topology and number of turns can effectively improve the performance of the wireless power transfer (WPT) systems for endoscope robots. This study proposes the evaluation parameters of the transmitting coils related to the performance of the WPT system to standardize the design of the transmitting coils. It considers both the quality factor of transmitting coils and the coupling factor between the two sides. Furthermore, an analytical model of transmitting coils with different topologies is built to exactly estimate the evaluation parameters. Several coils with the specified topologies are wound to verify the analytical model and the feasibility of evaluation parameters. In the case of a constant power received, the related evaluation parameters are proportional to the transfer efficiency of the WPT system. Therefore, the applicable frequency ranges of transmitting coils with different topologies are determined theoretically. Then a transmitting coil with a diameter of 69 cm is re-optimized both theoretically and experimentally. The transfer efficiency of the WPT system is increased from 3.58% to 7.37% with the maximum magnetic field intensity permitted by human tissue. Finally, the standardized design of the transmitting coil is achieved by summing-up and facilitating the optimization of the coils in various situations.

Coil Gun Electromagnetic Launcher (EML) System with Multi-stage Electromagnetic Coils

  • Lee, Su-Jeong;Kim, Ji-Hun;Song, Bong Sob;Kim, Jin Ho
    • Journal of Magnetics
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    • v.18 no.4
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    • pp.481-486
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    • 2013
  • An electromagnetic launcher (EML) system accelerates and launches a projectile by converting electric energy into kinetic energy. There are two types of EML systems under development: the rail gun and the coil gun. A railgun comprises a pair of parallel conducting rails, along which a sliding armature is accelerated by the electromagnetic effects of a current that flows down one rail, into the armature and then back along the other rail, but the high mechanical friction between the projectile and the rail can damage the projectile. A coil gun launches the projectile by the attractive magnetic force of the electromagnetic coil. A higher projectile muzzle velocity needs multiple stages of electromagnetic coils, which makes the coil gun EML system longer. As a result, the installation cost of a coil gun EML system is very high due to the large installation site needed for the EML. We present a coil gun EML system that has a new structure and arrangement for multiple electromagnetic coils to reduce the length of the system. A mathematical model of the proposed coil gun EML system is developed in order to calculate the magnetic field and forces, and to simulate the muzzle velocity of a projectile by driving and switching the electric current into multiple stages of electromagnetic coils. Using the proposed design, the length of the coil gun EML system is shortened by 31% compared with a conventional coil gun system while satisfying a target projectile muzzle velocity of over 100 m/s.

An Open Bridcage RF coil for Magnetic Rresonance Imaging (자기공명영상을 위한 개방형 새장 고주파코일)

  • Lee, S.Y.;Yi, J.H.;Yi, W.;Mun, C.W.;Cho, M.H.
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.5
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    • pp.42-47
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    • 1998
  • Bridcage RF coil is one of the most widely used RF coils in MRI. In order to use birdcage RF coils in open MRI systems, an open tructured birdcage RF coil has been investigated. By opening the ring structure of an original birdcage RF coil and driving the coil at two opening ends, the original birdcage RF coil can be modified to an open structured coil. In order to improve magnetic field uniformity of the open birdcage RF coil, driving voltage phases at the two opening ends can be controlled to be in-phase or out-of-phase each other. Operating frequency of the open birdcage RF coil has been theoretically derived, and the theoretical derivation has been verified by experiments.

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An Inductive Micro Position Sensign System and Analysis of its Response Characteristics (인덕턴스형 미소 변위 측정 시스템과 응답 특성의 분석)

  • Choi, Dong-Jun;Choi, In-Mook;Kim, Soo-Hyun
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.3
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    • pp.189-194
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    • 2001
  • This paper presents a mew design of an inductive position sensing system with high sensitivity. The designed system consists of the driving coils, position-detecting coils, and closed loop formed magnetic blocks. To obtain high sensitivity we design a symmetric and closed loop type measuring system with small air-gaps. The elements that affect the system characteristics are turn ratio, excitation frequency, air-gap size, capacitance effect, and load resistance. By experimental investigation, the influences of these elements are examined and the system parameters are selected. The sensitivity of the newly designed system is greater than 2800mV/(V mm) and the linearity error is below${\pm}0.01%; in; the; range; of; {\pm}200{\mu}m$.

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Design of A Simple Disk-type 3-DOF Actuator (단순 원판형 평면 3자유도 액추에이터 설계)

  • Bach, Du-Jin;Kim, Ha-Yong;Kim, Seung-Jong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.3
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    • pp.334-340
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    • 2005
  • A disk-type 3-DOF actuator which has new principle and very simple structure is proposed. Also it utilizes the relation of bias and control fluxes produced by permanent magnets and coils, respectively, like other conventional electromagnetic actuators, but its main feature is that both the coils and permanent magnets are fixed in the stator, which makes it easy to design the shape of moving part. Operating principle is that a moving disk is driven by reaction force of Lorentz force acting on the fixed equivalent coil. Simple analytic approach and FEM analysis are performed to determine the design parameters so as to increase the driving force and distance. And some experimental results show the feasibility of the proposed actuator.

The generation of Uniform High Density Plasma of Inductively Coupled Plasma Etcher Enhanced by Alternating Axial Magnetic Field (축방향 자기장의 주기적 단속을 이용한 유도결합형 플라즈마 식각장비의 고품위 플라즈마 형성)

  • 정재성;김철식
    • Proceedings of the IEEK Conference
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    • pp.589-592
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    • 1998
  • The performance of inductively coupled plasma (ICP) is enhanced by axial magnetic field driven by alternating current Helmholtz coils in this work. Langmuir pobe is used to characterize the plasma, and the etching performance is demonstrated with phororesist stripping process. It is shown that its density and uniformity depends on the frequency of driving current to the magnetic field.

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Driving silicon membrane with electromagnetic force (전자력을 이용한 실리콘 막의 구동)

  • Kim, Yong-Sung;Ahn, Si-Hong;Kim, Yong-Kweon
    • Proceedings of the KIEE Conference
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    • pp.1020-1022
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    • 1998
  • Silicon membrane to be used for micropump is fabricated and the deflection of the membrane driven by the electromagnetic force is measured. Silicon and glass are anodic bonded and Si is thinned. Silicon membrane is fabricated by the glass etching. The gold pattern can be protected against HF by the washing and fixing process under the glass etching process. The electromagnetic force is gained by the magnetic field driven by the current flowing through two coils. Deflection of the silicon membrane has a tendency of increasing with the increase of the driving current.

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The Development of Chestpiece Detecting Techniques for Physical Assessment Trainer (청진 훈련 모형용 청음판 검출 알고리즘 개발)

  • Chang, In Bae;Oh, Soo Hwan;Lee, Young Seok
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.6
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    • pp.527-534
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    • 2014
  • The control system of human torso model and driving system of stethoscope for physical assessment trainer are developed. The detecting characteristics of circular pickup coil which is driven by square wave voltage signal with resonance frequency of LC circuits are investigated and it is confirmed that the pickup coil can detect the existence of chestpiece near the coil region. The control system of human torso model is composed of 8 channel pickup coils, Mp3 and Bluetooth module. The driving system of stethoscope is composed of chestpiece with contact switch and Bluetooth headset. The chestpiece detecting algorithm check the contact of chestpiece with human body model first and excite the pickup coil sequentially to find the location. The proposed system can be applied the physical assessment trainer.