• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.1
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• pp.46-55
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• 2006

This paper presents the control method for the hybrid actuator comprising a DC motor and an MR brake. Generally, a DC motor as an active actuator has a small power to weight ratio and goes unstable with higher force control gain due to its saturation limit. In order to cope with this instability and make the transparency higher, this paper proposes a hybrid actuator which consists of a DC motor and an MR brake as a passive actuator and its force control method based on network theory. A DC motor actively produces the output corresponding to the signs of the input currents. On the other hand, an MR brake passively resists against the external load independent of the sign changes of the input currents. This characteristics is widely known as 'passive' This paper suggests a force control method based on passivity concept in network theory for the hybrid actuator and verified its performance and stability through the experiments.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.115-121
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• 2001

In micro automation technology, the concurrent realization of a high resolution and a large operating rage has been achieved by a dual actuator, usually called by piggy-back system, conventionally. But, because of its manufacturing cost, the complexity of control, and the limit of overall bandwidth, the contract-free and single servo actuators have been suggested with specific applications. In this paper, we suggest a novel non-contact surface actuator suing combination of the Lorentz force and the magnetized force, and discuss the actuating principles including an analytical approach. Differently from the existing planar system, an operating range of the suggested system can be expanded by an additional attachment of active elements. Therefore, it is estimated to be suitable for the next-generation moving system.

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.306-308
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• 2006

Numerical simulations were carried out of the effects of momentum and heat produced by a plasma actuator on neutral flow. Momentum and heat generated during plasma discharge were modeled as a body force and heat source using results of experiments and DSMC of particle. These force and heat model were inserted into a Navier-Stokes equation and the flow around the plasma actuator could be explored by solving fluid dynamics only. Fluid simulation showed that force produced in DSMC generated a jet flow in the vicinity of the plasma actuator and heat accounted for density change.

• Journal of Drive and Control
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• v.9 no.2
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• pp.8-14
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• 2012

Electro-hydraulic spring return actuator(ESRA) is utilized for air conditioning facilities in a nuclear power plant. It features self-contained, hydraulic power that is integrally coupled to a single acting hydraulic cylinder and provides efficient and precise linear control of valves as well as return of the actuator to the de-energized position upon loss of power. In this paper, the algebraic equations of ESRA at steady-state have been developed for the analysis of static characteristics that includes control pressure and valve displacement of pressure reducing valve, flow force on flapper as well as its displacement over the entire operating range. Also, the effect of external load on piston deviation is investigated in terms of linear system analysis. The results of static characteristics show the unique feature of force balance mechanism and can be applied to the stable self-controlled mechanical system design of ESAR.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.137-140
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• 2008

The purpose of PEEP is to increased effect reparation in lung. Recently trend of technology is possible to have multi-level or to control freely for variety breathing pattern or breathing mode. Those new technology need some issue like electronic controlled actuator(solenoid), PEEP valve of special structure and control software in micro controller. This paper brief to develop actuator(solenoid) and PEEP valve. This development is to make commercial product of MEKICS.Co.LTD Electronic controlled actuator(Solenoid) is to make force depend on current in linear. And force is convert to pressure in PEEP valve. Major technical issue are how to make the valve with continuous force even dough moving and how to optimize to convert force - pressure.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.595-602
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• 2013

An air circuit breaker (ACB) with novel double-breaker contact and permanent magnet actuator (PMA) is presented. Three-dimensional (3-D) finite element method (FEM) is employed to compute the electro-dynamic repulsion forces, including the Holm force and Lorentz force, which are acting on the static and movable contacts. The electro-dynamic repulsion forces of different contact pieces are computed, illustrating there is an optimal number of contact pieces for the ACB being studied. The electro-dynamic repulsion force of each contact, which varies from the outer position to the inner position, is also computed. Finally, the contacts of the double-breaker are manufactured according to the analyzed results to validate the simulations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.775-779
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• 2001

In optical disk drive (ODD), disk rotation speed has been increasing rapidly to achieve high data transfer rate. High servo bandwidths for focusing and tracking actuator are required to follow dynamic disturbance by high rotation speed in ODD. However, the servo bandwidth is significantly limited by some vibration modes which are induced by the flexibility of moving part. In this work, the vibration modes affecting bandwidth of actuators are suppressed by modifying actuating force by VCM. For this, the relation between the horizontal component of the actuating force and vibration mode is analyzed and force characteristic affecting to vibration mode is obtained through electromagnetic and structural analysis using simulation program.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1216-1228
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• 2016

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.147-154
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• 2005

A precision hi-directional actuator for a high precision leveling system with $Z{\Theta}_x{\Theta}_y$ motions is proposed and designed in this paper. The actuator is composed of a force generation structure, a guide mechanism, and a symmetric structure. At first, its driving force is generated by a change of flux in air gaps by permanent and changeable flux. The permanent flux is generated by a permanent magnet. The changeable flux is created by variable current flowing through coil. The combination of permanent and changeable flux makes various flux densities in air gaps between moving part and fixed yokes. And then, the difference between flux densities in lower and upper gaps creates forces fur the $bi-direction({\pm}z)$ motion. The guide mechanism of this actuator is composed of two circular plates and one shaft. Reducing motions generated by forces except z-motion, these circular plates endow the actuator with high stiffness for fast settling time. And the function of the shaft is to transfer motion to an object. At last, total body has a symmetric structure to be stable on thermal error. The actuator is designed by MAXWELL 2D and ProMECHANICA. The designed actuator is evaluated by 8nm laser doppler vibrometer, dynamic signal analyzer, and simple PID controller.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.8
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• pp.743-748
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• 2015

This paper reports the enhanced fabrication and characterization of a $3{\times}3$ array tactile actuator composed of cellulose acetate. The array tactile actuator, with dimensions of $15{\times}15{\times}1mm^3$, consists of 9 pillar-supported cells made from a cellulose-acetate molding. The fabrication process and performance test along with the results for the suggested actuator are explained. To improve the cell-array fabrication, a laser cut was adopted after the molding process. The displacement of the unit cell increased the input voltage and frequency. Various top masses are added onto the actuator to mimic the touch force, and the acceleration of the actuator is measured under actuation. When 2 kV is applied to the actuator, the maximum acceleration is 0.64 g, which is above the vibrotactile threshold. The actuation mechanism is associated with the electrostatic force between the top and bottom electrodes.