• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.537-544
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• 2015

This paper provided two types of design method on moving core type LOA and one type of design method on moving coil type LOA, and compared and examined each of its characteristics. In order to conduct parametric design process, voltage equation was used to schematize Lmin/K and L/M map, and the schematized map was used to determine Lmin, K or L, M. In order to meet requirements such as thrust force and input voltage and to satisfy the target values of Lmin, K or L, M, the types and sizes of each type were designed using geometry design process. 2-FEA was conducted for each of the designed model. After examining thrust force based on the location of the mover, Type-1 showed radical change in thrust force as movers moved, and Type-2 and Type-3 showed constant appearance of thrust force. The total volume of the designed LOA model was compared to select the model with highest thrust force density. Also, the weight of the mover for each model was compared in order to select the model that was predicted to have highest mechanical responsiveness and stroke characteristics.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.317-319
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• 1996

In this paper, an active vibration control system using a voice coil type linear oscillating actuator(LOA) is studied to suppress structural vibration. Being compared with a hydraulic actuator, a LOA has simplified structure and requires a few elements in the driving system, so it has lots of merits with respect to economics and maintenance. The general mathematical dynamic model to obtain the algorithm for the realization of vibration active control system is treated. Actually, the performance test of the control system using LOA is carried out on a steel test structure under sinusoidal and white noise excitation. From this test it is conformed that acceleration level of test structure is reduced near the resonance region. In the future research on the application to large structures will be studied.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.844-846
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• 1998

In this study, Brass endcap with 2, 3, 5, and 7mm contact surface and 0.6, 0.9, 1.2, 1.5mm conical cavity depths was fabricated by the punch die while keeping the cavity diameter constant 9.25mm then displacement characteristics of the cymbal actuators with each of brass endcap thickness were measured under an applied voltage $60V_{max}$. Dispacement increased with increasing contact surface and resonant frequency decreased with increasing contact surface, cymbal actuator with 7mm contact surface and 1.5mm endcap cavity depth exhibits $35.89{\mu}m$ displacement and 18.8kHz resonant frequency, displacement increased with increasing endcap cavity depth while contact surface was kept constant at 3mm and Below a endcap thickness of 0.2mm, Differences in displacement between 1.2mm and 1.5mm cavity depth appeared at $0.18{\mu}m$. that is, displacement of cymbal actuator with 1.2mm over cavity depth saturated nearly.

• Membrane Journal
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• v.14 no.2
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• pp.142-148
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• 2004

This paper presents the enhancement of oxygen transfer efficiency using vibrating intravascular lung assist device (VIVLAD) for patients having chronic respiratory problems. The flow rate was controlled by the pump and monitored by a built-in flow meter. The vibration apparatus was composed of a piezo-actuator, a function generator, and a power amplifier. Gas flow rates of up to 6 L/min through the 120-cm-long hollow fibers have been achieved by exciting a piezo-actuator. The output PVDF sensor and FRF (frequency response function) were investigated by various frequency in VIVLAD. As a result, the maximum oxygen transfer rate was found to occur with maximum amplitude and the transfer of vibration to the hollow fiber membranes. It was excited by the frequency band of 35 Hz at various distilled water flow rates, and various module types.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1083-1089
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• 2010

Shape memory alloys (SMAs) are smart materials. The unique characteristics of SMAs enable the production of large force and displacement. Hence, SMAs can be used in many applications such as in actuators and active structural acoustic controllers; the SMAs can also be used for dynamic tuning and shape control. A SMA torque tube actuator consisting of SMA tubes and superelastic springs is proposed, and the behaviors of the actuator are investigated. From the results of heat transfer analysis, it is proved that the SMA torque tube actuator with both resistive heating of SMA itself and a separate conventional heating rod in the tube core has good performance. The behavior of an actuator system was analyzed by performing a contact analysis, and the twisting motion was noticed when checking the actuation. 3D SMA nonlinear constitutive equations were formulated numerically and implemented by performing a nonlinear analysis by using Abaqus UMAT.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.175-181
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• 2023

In offshore plants, various equipments including cranes and davits are used for safety management. Hydraulic cylinder type actuators are mainly used for luffing operations such as cranes and davits. However, in the case of a cylinder using hydraulic pressure, a separate power pack is required to supply hydraulic pressure. When used for a long time, maintenance costs such as sticking of hydraulic valves, contamination of hydraulic oil and deterioration of hydraulic hoses occur. In addition, a lot of hydraulic oil is used in the handling of cranes and davits, which causes marine pollution due to management problems. As a result, as interest in marine pollution prevention has increased recently, interest in actuators that do not use hydraulic pressure is also increasing. Therefore, in this study, we intend to develop a davit with an electric cylinder type actuator that uses electricity rather than hydraulic pressure by the SOLAS regulation. In other words, the conceptual design of the davit driven through the linear motion of the ball screw using electricity is performed, and the structural safety of the drive is also reviewed so that it can be utilized in the industrial field.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.653-656
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• 2001

This paper describes the design and the analysis of permanent magnetic actuator "Magnetic Switch" using classical method and 2D finite element method. The classical method gives an outline of permanent magnet size and analysis is carried out by finite element method. Therefore we make use of the result in specific detail site of magnet. The transient state is simulated in order to calculate the response time of "Magnetic Switch". The simulation is based upon a step-by-step integration of the electric circuit equations and the tore movement. The contactor uses a permanent magnet for maintaining the closed state. The presented solution takes account of non-linear magnetic material property and spring force controlled by core position. The dynamic response of "Magnetic Switch" is predicted by the simulation agrees closely with the required condition.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.9
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• pp.1648-1654
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• 2007

In this paper, we consider the design of $H_\infty$ high-gain state feedback control for time-delayed linear systems with limited actuator capacities. The high-gain control means that the control permits the predetermined degree of saturation. Based on new Lyapunov-Krasovskii functional, we derive a result in the form of matrix inequalities. The matrix inequalities are consisted of LMIs those confirm the positive definiteness of Lyapunov- Krasovskii functional, satisfaction of predetermined degree of saturation, reachable set and $L_2$ gain constraint. The result is dependent on the bound of time-delay and its rate, predetermined degree of saturation, actuator capacity, and the allowed size of disturbances. Finally, we give a numerical example to show the effectiveness and usefulness of our result.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.4
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• pp.620-626
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• 1994

As the electrostrictive actuator for optic control, PZN-BT-PT ceramics were investigated for the influences of sintering conditions on the structural, electrostrictive properties and the optical properties of Fabry-perot Interferometer using eletrostrictive ceramics. The specimen SS15T, sintered 1hr at 1150$^{\circ}C$, is sutible for eletrostrictive actuator because its piezoelectric constants(dS131T) and strain(XS131T) at dc 10kV/cm had the higest value of 175${\times}$10S0-12TC/N, -255${\times}$10S0-6TΔl/l respectively. As the dc electric field increased, the interference effect of Fabry-Perot Interferometer was increased. The most intense interference fringe and the maximum power of 160${\mu}$W were observed at dc 6kV/cm. Thus it was considered that specimen SS15T could be used as the electrostrictive actuator for optic control.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.61-66
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• 2011

The purpose of this paper is to design a hydraulic actuator to operate under high pressure conditions. The flow characteristics under design conditions of hydraulic actuator were numerically conducted by commercial fluid dynamic code(ANSYS CFX V11). The numerical analysis was performed by transient technique according to the variation of stroke times, which was changed from 0 to 1 second by interval of 0.01. Turbulence model, $k-\omega$ SST was selected to secure more accurate prediction of hydraulic oil flow. The ICEM-CFD 11 and CFXMesher, reliable grid generation software was also adapted to secure high quality grid necessary for the reliable analysis. According to the simulation results, the flow rate which was supplied to the hydraulic actuator was 30.4l/min. These results are in good agreement with design results within 3.5% error.