• International Journal of Precision Engineering and Manufacturing
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• 제9권3호
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• pp.72-74
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• 2008

We investigate the effect of mechanical damping and electrical conductivity on the dynamic performance of a new electromagnetic engine valve actuator that employs a permanent magnet. The key dynamic performance factors are the transition time and the landing velocity of the armature. Two-dimensional dynamic finite element analyses are performed to simulate a coupled system. The results show that mechanical damping and electrical conductivity have similar effects on the dynamic performance of the engine valve actuator. Subsequently, it is possible to replace the role of mechanical damping by controlling the electrical conductivity through the thickness and number of steel core laminations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3295-3297
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• 1999

This paper presents the fabrication of an electromagnetic micro actuator consisting of a Parylene diaphragm with a spiral copper coil and a permanent magnet. The copper coil is fabricated by electroplating and patterning. The frequency response of the actuator are obtained using a laser vibrometer. When the input voltage is 3 V, the DC deflection is 5 ${\mu}m$, and the resonance frequency is about 35 Hz. Also, the mechanical sensitivity of the actuator diaphragm is 69 ${\mu}m/V$.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.743-748
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• 2007

This paper describes a lens transmissive type tilting actuator for a projection TV. An electromagnetic analysis and a structural analysis of the tilting actuator system is necessary to design a tilting actuator for a projection TV. The tilting actuator is composed a permanent magnet, coil and yoke as the electromagnetic components and it needs a driving hinge part as the mechanical component. The design of the tilting actuator for the projection TV is performed by the following procedure. Firstly, a magnetic flux density of the tilting actuator system is analyzed by a mathematical theory and an electromagnetic FEM. Secondary, a magnetic circuit method is used to determine tilting force. Thirdly, the structural FEM is carried out with an FE model of a lens-transmissive type tilting actuator and then the prototype of the model is manufactured. The characteristic of the prototype is experimentally observed. Finally, a design for a new hinge configuration is suggested for better performance.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권7호
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• pp.370-378
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• 2002

As resent trends in structural construction have been to build taller and larger structures than any time in the past, they have had high flexibility and low damping that can cause large vibration response under severe environmental loading such as earthquakes, winds, and mechanical excitations. The damper with mass and spring is one approach to safeguarding the structure against excessive vibrations. In this paper, the lumped electrical circuit approach of mass/spring system is used to model the mechanical aspects according to the frequency. Therefore, the mass/spring system can be dealt with here and linked with the equivalent circuit of electric linear oscillatory actuator(LOA). Analysis models are two types of vibration control system, active mass damper(AMD) and hybrid mass damper(HMD). AMD consists of the moving coil LOA with mass only The LOA of HMD with mass and spring is composed of the fixed coil and the movable permanent magnet(PM) field part. The PM field part composed magnet modules and iron coke, is the damper marts itself. We Present the motional resistance and reactance of mass/spring system and the system impedance of AMD and HMD according to the frequency.

• 대한기계학회논문집A
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• 제25권11호
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• pp.1863-1872
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• 2001

In this Paper, we suggest the precision stage using a novel non-contact planar actuator that utilizes an interaction between an array type of air-core solenoids and permanent magnets. The former with axes arranged in the mutually orthogonal direction is fixed on the stator and the latter with the same polar direction is attached below the stage. The promising magnetic structure has little uncertainty such as hysteresis loss caused by ferromagnetic material, then it is simple to quantify the magnetic phenomenon. And all the magnetic forces are transmitted through narrow air-gap between the coil and the permanent magnet, therefore the structure can be highly compacted. Furthermore, the stage or plate can be perfectly isolated from the stator without any wire connection, leading to diminish the generating possibility of wear particles due to mechanical contact. Then. it is estimated that the proposed operating principle is very suitable for work requiring high accuracy and cleanness. or general-purpose nano stage. The main issues rebated to the plate driving are discussed here.

• 대한기계학회논문집A
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• 제31권5호
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• pp.578-585
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• 2007

A vacuum circuit breaker (VCB) with permanent magnet actuator (PMA) has been studied in this study. Electromagnetic field analysis and dynamic simulations have been carried out for optimal design of VCB by using commercial software Maxwell and ADAMS. This simulation model can be an effective method for the VCB, which has non-linear output force of PMA, friction, and impact for operations. An experiment has been conducted to evaluate correctness of the simulated model. By using this evaluated model, the displacement and velocity characteristics of the VCB have been simulated with following conditions : (1) The different output forces of PMA have been applied, (2) The friction conditions in follow lever shaft and moving part have been changed, (3) The mass conditions of moving part have been changed. The simulated results shows that the velocity characteristics are mainly determined by the output force of PMA. The effects due to the changes of friction conditions against the dynamic characteristics was small, and the mass conditions of the moving parts affect the velocity and a bouncing phenomenon of VCB. From these results, the optimal design conditions for the VCB have been derived.

• 한국기계가공학회지
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• 제7권2호
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• pp.31-37
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• 2008

In this paper, we analyzed the dynamic behavior of magnetic fluid in a circular pipe with multiple permanent magnets. Magnetic fluid react on magnetic field against the normal fluid. In other words, magnetic fluid flow has the electromagnetism and fluid mechanics. So magnetic fluids has studied about the fluids properties and experiment. In this paper we studied the magnetic fluids velocity and pressure distribution for the novel type actuator. Because the velocity and pressure distribution is the important element of the magnetic fluids flow. First, we analyzed the Maxwell equation for the multiple permanent magnet and then concluded the governing equations for the magnetic fluid flow using the equation of Navier-Stokes. And, we simulated the dynamic behavior of magnetic fluid flow using the FEM(Finite Element Method). And we illustrated the relation between magnetic field and dynamic behavior of magnetic fluid flow.

• International Journal of Automotive Technology
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• 제8권4호
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• pp.429-436
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• 2007

In this study, we improved control performance of an EMV (electromechanical valve) system using a PM/EM (permanent magnet/electromagnet) hybrid EMA (electromagnetic actuator) and showed the feasibilities of both soft landing and fast transition of the EMV system using a simple PID control. The conventional EMV systems using only EM show significant nonlinear characteristics. Therefore, it is very difficult to control the valve position and several complex control schemes are used. This paper focused on the control performance improvement using a PM/EM hybrid actuator. In particular, a PM is used as a key design parameter such as a bias current of a magnetic bearing in order to improve the linear characteristic of the actuator, although most PM/EM hybrid actuators use a PM as a power saver during valve-open and -closed states. First, a FE (finite element) analysis was performed to confirm its linear static force characteristics. Then, both a test rig and a valve control system were built in order to prove experimentally the control performance improvement of the actuator. Finally, feasibilities of both soft landing and fast transition of the system were shown experimentally through gain-scheduled PID (proportional derivative integral) control.

• Journal of Magnetics
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• 제12권2호
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• pp.89-92
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• 2007

The authors propose a magnetic actuator for use as a navigation system for capsule endoscopes. The actuator is composed of a capsule dummy, a permanent magnet inside the capsule, and an external spiral structure. The device rotates and propels wirelessly when exposed to an external rotational magnetic field. In this study we measured the effect of the spiral shape on the velocity and thrust force properties. According to our experimental results, the actuator obtained a maximum velocity and thrust force when the spiral angle was set at 45 degrees, the number of spirals was set at 4, and the spiral-height was set at 1-mmf. We also conducted a motion test in the large intestine of a pig placed on a 30 degrees slope. The actuator passed through a 700 mm length of the intestine in about 300 s. The device also managed to travel up and down the 30 degrees slope with no difficulty whatsoever. Our results demonstrate the great potential of this actuator for use as a navigation system for capsule endoscopes.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.741-745
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• 2001

Reliability and safety of steer-by-wire concepts can be achieved by redundant designs. This paper discusses the design of a fault tolerant concept for a force feedback actuator with a standard three-phase PMSM. In contrast to usual drives, the phases of the machine are separated electrically. This design allows driving the machine with two instead of three phases in case of a fault. A superimposed torque controller adjusts the influence of fault currents and torque harmonics in two-phase operation and guarantees smooth torque at the steering wheel