• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.861-866
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• 2011

This paper described the hybrid power generation using ocean wave that consists of linear power generation system and vibrational power generation system. The linear power generation system is made up of the winding coil, the permanent magnet and it is performed stable generation regardless of the wave frequency using directly the ocean wave velocity. And the vibration power generation system consists of the winding coil, the permanent magnet and spring. When the vibration system natural frequency in the vibrational power generation system is tuned to the ocean wave frequency, the relative velocity of between the winding coil and the permanent magnet is faster than the velocity of ocean wave up and down motion, then we can obtain more the electric power. Therefore, in this paper, the proposed hybrid power generation using ocean wave have merits that obtaining the more electric energy in resonance frequency and carrying out stable generation even over the range of resonance frequency.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.1
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• pp.45-52
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• 2016

One commercial package for magnetic analysis was used to apply repulsive forces of permanent magnetics to bicycle cushion system. Reliabilities of finite element analysis were acquired by comparing with those of experimental measurements. Equivalent spring stiffnesses corresponding to various sizes of magnetics were implemented into the bicycle dynamic model with three degree of freedom. Input force caused at front and rear wheels due to road unevenness was considered in the dynamic model. Dynamic behaviors were observed in terms of vertical displacements of the rider and the front reach as well as pitching displacement of the mass center when the bicycle ran over half-triangular bump. The methodology suggested in this paper by the finite element analysis and numerical model will be an useful tool for more accurate prediction of cushion design for any vehicle system if magnetic forces are utilized.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.25-27
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• 2002

중저압 차단기(Medium Voltage Circuit Breakers)의 최근 개발 동향은 전동 스프링 조작방식에서 마그네틱 액추에이터(Magnetic Actuator) 방식으로 전환되는 추세이다. 마그네틱 액추에이터는 동작 시판과 제어가 용이하고 부품수가 감소하여 신뢰성과 반복성이 뛰어나다.[1] 본 논문에서는 2코일형 마그네틱 액추에이터에 대해서 유한요소 모델링 하였고, 플랜져(plunger)의 이동 거리에 따른 액추에이터의 전자력 변화를 해석하였다. 또한 Time stepping 방식으로 외부 회로와 결합하여 유한요소 과도 해석을 하였다.

• Journal of Korea Multimedia Society
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• v.14 no.1
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• pp.133-143
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• 2011

This paper proposes a mobile navigation system which haptically presents the way to go to visually impaired persons. In order to convey the tactile information to the visually impaired persons, we develop a new tactile module with a solenoid, a permanent magnet and an elastic spring. Furthermore, we suggest 2D vibration flow which originates from one point and gradually propagates to other points on a surface of the haptic navigation system. The tactile module and the vibration flow method are incorporated into the proposed haptic navigation system and they stimulate the user's finger pad and palm, respectively. We conduct experiments to investigate that the proposed navigation system haptically provides the direction to the users. From the experimental results, we verify that the proposed system can generate enough tactile sensation to guide the direction to go in real-time.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.577-579
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• 2001

본 논문에서는 공진을 이용한 일정 진폭과 일정 주파수용 가진기 구동 시스템의 구현을 위한 제어기와 시스템에 대한 동적 해석을 수행하였다. 제안된 가진기 시스템의 엑츄에이터는 영구자석형 횡자속 선형 전동기(TFLM)가 적용되었고 가진기의 이동자에는 공진용 스프링을 장착하였다. 이로써 TFLM의 구조적인 장점인 고출력과 공진을 통한 에너지의 고효율의 장점을 갖는 전동식 가진기 시스템을 구현할 수 있게 되었다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.966-967
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• 2008

2kW급 선형 압축기용 액츄에이터로 직선 왕복 운동을 동작하게 하기 위하여 2상 영구자석형 횡자속 선형 전동기(Permanent Magnet Transverse Flux Linear Machine; PM-TFLM)와 스프링을 조합하여 선형 공진 시스템을 구성하였다. 선형전동기의 이동자를 공진점부근에서 왕복 운동을 하기 위해서 빠른 왕복 운전과 적절한 운전 알고리즘이 필요하게 된다. 먼저 2상으로 이루어진 PM-TFLM의 순시 토오크 제어를 위하여 벡터 제어 알고리즘을 설계하여 구현하고 피스톤, 스피링 및 부하에 따라 운전제어를 수행하는 방법에 대하여 연구를 하였다. 종래의 3상 교류 전동기의 순시 토오크 제어에 적용하는 벡터제어 알고리즘을 2상 PM-TFLM에 적용하여 그 타당성을 보이고 빠른 왕복운전을 안정적으로 수행함을 실험을 통하여 입증하였다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.4 s.316
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• pp.42-47
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• 2007

To reduce the chattering errors of reed switch sensors in the automatic remote measurement of water meter a reed switch sensor was analyzed and improved. The operation of reed switch sensors can be described as a mechanical contact switch by approximation of permanent magnet piece to generate an electrical pulse. The reed switch sensors are used mostly in measurement application to detect the rotational or translational displacement. To apply for water flow measurement devices, the reed switch sensors should keep high reliability. They are applied for the electronic digital type of water flow meters. The reed switch sensor is just mounted simply on the conventional mechanical type flow meter. A small magnet is attached on a pointer of the water meter counter rotor. Inside the reed sensor two steel leaf springs make mechanical contact and apart repeatedly as rotation of flow meter counter. The counting electrical contact pulses can be converted as the water flow amount. The MCU sends the digital flow rate data to the server using the wireless communication network. But the digital data is occurred difference or won by chattering noise. The reed switch sensor contains chattering error by it self at the force equivalent position. The vibrations such as passing vehicle near to the switch sensor installed location causes chattering. In order to reduce chattering error, most system uses just software methods, for example using filter algorithm and also statistical calibration methods. The chattering errors were reduced by changing leaf spring structure using mechanical characteristics.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.99-105
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• 1994

In this study, the transverse and the torsional vibration analyses of a precision dynamic drive system with the magnetic coupling are accomplished. The force of the magnetic coupling is regarded as an equivalent transverse stiffness, which has a nonlinearity as a function of the gap and the eccentricity between a driver and a follower. Such an equivalent stiffness is calculated by and determined by the physical law and the calculated equivalent stiffness is modelled as the truss element. The form of the torque function transmitted through the magnetic coupling is a sinusoidal and such an equivalent angular stiffness, which represents the torque between a driver and a follower, is modelled as a nonlinear spring. The main spindle connected to a follower is assumed to a rigid body. And then finally we have the nonlinear partial differential equation with respect to the angular displacements. Through the procedure mentioned above, we accomplish the results of the torsional vibration analysis in a spindle system with the magnetic coupling.