• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.141-148
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• 2003

In the recently, the necessity of the hybrid type linear stepping motor(HLSM) of linear motion digital actuator has been increased in the various fields of the automatic control system. The HLSM is directly performed without any converting mechanism. Therefore, the HLSM is better advantaged in the efficiency and economical view than a rotary stepping motor. In this paper, we have designed an optimum tooth shape by the 2D finite element method(FEM) to develop the HLSM with longitudinal flux machine(LFM) type, and calculated the thrust force and normal force. And we have manufactured the prototype of it, and have experimented the thrust force characteristics of it.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.30-32
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• 2002

선형동기전동기는 고추력, 고정밀 운전을 요하는 시스템에 많이 사용되고 있는데, 추력 증가에 따른 추력 리플의 증가는 고정밀 위치제어에 어려움을 주기도 한다. 철심형 선형동기전동기에서는 자석 배열과 철심 치형상의 상호 관계에 의해 발생하는 디텐트력의 영향이 매우 크므로 이를 저감하기 위한 철심 구조의 설계가 필요하다. 본 논문에서는 실제 제작성을 고려하여 치와 철심부의 챔퍼링, 길이 변경, 자석 배열의 스큐 적용 등을 통해 선형동기전동기의 디텐트력을 저감하기위한 설계법을 제시하고 그 효과를 시험기의 제작 및 실험을 통해 증명하였다.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.468-472
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• 2003

MRE-1 dual thruster module(DTM) which will be installed to the present under development KOMPSAT(Korea Multi-Purpose Satellite) can provide reliable and cost-effective means of propulsive control for attitude and maneuvering control system. Thruster heat shield, one of the main components of DTM, is designed to intercept the radiative heat exchange between thruster and satellite during firing. The inside diameter of the current configuration will be decreased a little compared with that of the previous one due to manufacturing method change. Therefore, the possibility of interference between thruster and heat shield due to configuration change is investigated through structural analysis and their results are described in this paper.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.10
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• pp.738-746
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• 2019

Instead of hydraulic actuation systems, an electromechanical actuation system is more efficient in terms of weight, cost, and test evaluation in the thrust vector control of the 7-ton gimbal engine used in the Korea Space Launch Vehicle-II(KSLV-II) $3^{rd}$ stage. The electromechanical actuator is a kind of servo actuator with position feedback and uses a BLDC motor that can operate at high vacuum. In the case of the gimballed rocket engine, a synthetic resonance phenomenon may occur due to a combination of a vibration mode of the actuator itself, a bending mode of the launcher structure, and an inertial load of the gimbals engine. When the synthetic resonance occurs, the control of the rocket attitude becomes unstable. Therefore, the requirements for the stiffness have been applied in consideration of the gimbal engine characteristics, the support structure, and the actuating system. For the 7-ton gimbal engine of the KSLV-II $3^{rd}$ stage, the stiffness requirement of the actuation system is $3.94{\times}10^7N/m$, and the direct drive type electromechanical actuator is designed to satisfy this requirement. In this paper, an equivalent stiffness analysis model of a direct drive electromechanical actuator designed based on the stiffness requirements is proposed and verified by experimental results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.1
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• pp.35-42
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• 2020

Electromechanical Actuator(EMA) for flight vehicles generally serves to control the fin deflection angle or the thrust vector angle. This paper deals with design and development of EMA for both aerodynamic control and thrust vector control. In this paper, a novel compact EMA is proposed that can simultaneously control both the tail fin and the jet vane with one actuator and detach the jet vane after vertical launch and rapid turn of the flight vehicle so as to increase efficiency during flying to target. To do this, we designed the EMA using a push-push link mechanism and derived a mathematical model. The mathematical model is validated by comparing simulation result and experimental data. The performance and reliability of the proposed EMA have been verified through performance test, environmental test and ground test. The proposed EMA is expected to be useful as an EMA for flight vehicles because of its simple and compact structure, as well as its performance and reliability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.5
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• pp.68-73
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• 2005

This paper presents the characteristics analysis of an electromagnetic pump using the linear induction motor(LIM). The electromagnetic pump can be used to transfer the molten metals by the electromagnetic force of LIM. The characteristics of the pump are analyzed solving a hydrodynamic equation with an electromagnetic one.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.744-745
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• 2008

IT기기, 통신시기, 반도체 기기 등은 점점 더 고성능화되면서 속도도 빨라지고 기능도 추가되는 추세이다. 이러한 IT기기들은 속도와 더불어 열문제는 더욱더 크게 강조되고 있는 실정이며 개인용으로 많이 사용하고 있는 PC의 경우 더 이상 속도를 높이지 못하고 있는 실정이다. 이러한 열문제는 100W까지는 Heat pipe 등으로 냉각이 가능하였으나 거의 한계수준에 도달한 상황이다. 이러한 상황에서 일부 메니아들은 빠른 속도의 통신이나 작업을 위해서 수냉식 전용 냉각기를 설치하여 현재의 기능보다 더 좋은 환경에서 사용하고자 하고 있다. 본 연구에서는 수냉식 냉각기보다 더 큰 열용량을 가진 CPU의 냉각을 위해서 냉매 압축기를 적용하고자 하였으며 냉매 압축기에 사용하기 위한 선형압축기를 개발하고자 하였다. 즉 선형압축기에 의해서 압축된 냉매를 사용하여 CPU를 냉각하기 위해서 본 연구를 시작하였다. 본 연구에서는 선형전동기를 공진구동형 스프링을 장착하여 50-100Hz로 공진구동하는 액추에이터를 제작하여 그 특성을 알아보았다. 먼저 제자과정과 제작후 추력과 공진구동 설계 및 공진구동시 전기적, 기계적 특성변화를 확인하였으며 피스톤과 실린더 및 흡입밸브와 배기밸브 등을 장착하여 선형압축기로서 시운전까지 수행하였다.

• Journal of Aerospace System Engineering
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• v.16 no.5
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• pp.26-34
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• 2022

The propulsion system of geostationary orbiting satellites is typically used to raise the orbit into a transfer orbit, maintain the orbital position in the south/north, east/west direction in regular operation, and accumulate momentum in the south/north and east/west direction. Recently, when an electric propulsion system is used in a geostationary orbit satellite, the payload capacity can be increased by about 40% compared to a chemical propulsion system. However, despite these advantages, using an electric propulsion system has several limitations that should apply to all geostationary orbiting satellites. This paper discusses the operational constraints to consider when developing an indigenous geostationary satellite using a fully electric propulsion, radiation exposure, and control mechanism design due to unit displacement and floating ground-design. A high-voltage control unit for electric drives were analyzed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.130-141
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• 2008

This paper presents the flow characteristics in the fluid circulation loop using the tubular type linear induction motor(TLIM) electromagnetic pump. A TLIM of thrust 40[N] is analyzed using the equivalent and genetic algorithm for the system The flow characteristics are analyzed by coupling the Maxwell equations with the Navier-Stokes equation with the thrust. The analysis algorithm is developed for analyzing the liquid metal flow in the system for laminar and turbulent flow. And the effect of thrust is analyzed for the flow characteristics.

• Bulletin of the Korean Space Science Society
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• 2007.10a
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• pp.45.2-45.2
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• 2007