• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.557-562
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• 2017

In this paper, we show the design of a rotary joint transition for the X-band channel in a rotatable microwave communication system. The transition seems complicated to make a channel between two coaxial cables through a cylindrical waveguide. To make a broad-band performance in the X-band with low insertion loss and return loss given the constraint on the length and radius of this complicated-looking cylindrical structure, Genetic Algorithm optimization is adopted to check the validity of an intensive parametric study in the design. The structure is fabricated and tested to show how valid the design method is as well as good frequency responses.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.705-707
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• 2018

Rotary Inverted Pendulum 은 제어분야에서 비선형 제어 시스템을 설명하기 위해 자주 사용되어왔다. 본 논문은 강화학습 에이전트의 환경으로써 Rotary Inverted Pendulum 을 도입하였다. 이를 통해서 강화학습이 실제 세계에서의 복합적인 문제를 해결할 수 있음을 보인다. 강화학습 에이전트의 가상 환경과 실제 환경을 맵핑시키기 위해서 Ethernet 연결 위에 MQTT 프로토콜을 사용하였으며 이를 통해서 경량화된 IoT 분야에서의 강화학습의 활용도를 조명한다.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.320-322
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• 2010

저용량 에어컨의 압축기에 많이 사용되는 Single rotary 방식은 하나의 피스톤만을 채용하여 가격적인 면에서 큰 이점을 가진다. 그러나, 압축기 모터가 1회전할때 마다 압축과 토출을 단 1회 거치게 되므로, 부하변동을 심하여 진동이 많이 발생하는 단점이 있다. 이러한 단점을 보완하기 위하여 Single rotary를 사용하는 에어컨 제품에서는 저속에서의 운전을 회피하거나 하나의 운전점에 대한 전향보상기를 채용하여 진동을 저감시켜 왔다. 본 논문에서는 모든 운전점에서 보상이 가능하도록 압축과 토출로 인한 부하의 패턴에서 각 주파수 성분을 분석하여 자동으로 부하 토크를 보상하는 알고리즘을 제안한다. 제안된 방법은 가장 영향이 큰 1차와 2차 주파수 성분의 속도 리플의 양을 FFT 하고, 그 양이 작아지는 방향으로 부하 토크를 전향 제어방식으로 인가하는 방식이다. 제안된 방식을 이용하여 저속 운전에서 진동이 저감 되는것을 실험을 통하여 보였다.

• Progress in Superconductivity and Cryogenics
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• v.8 no.1
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• pp.54-58
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• 2006

Stirling cryocooler is relatively compact, reliable, commercially available. and uses helium as a working fluid. Over the past decade and a half, there has been rapid development of Stirling cryocooler, mainly for military and space applications. Stirling cryocoolers have been widely used lot the cooling of infrared sensors and high temperature superconducting filters to the temperature of the liquid nitrogen. The Stirling cryocooler with the rotary compressor is applicable to the cooling device for the compact mobile thermal imaging system, because the cryocoolers have the compact structure and light weight. In this paper, integral Stirling cryocooler is designed, manufactured and fabricated, and performance characteristics are investigated. This cooler delivers approximately 0.6W cooling at 80K for 20W of input power from 24V DC power supply.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.219-224
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• 2005

In order to investigate transient behaviour of the CRW(Canard Rotor Wing) type UAV(Uninhabited Aerial Vehicle) propulsion system during flight mode transition considering flow control valve operation, the propulsion system was modelled using SIMULINK commercial program. For transient simulation of the main engine system, the ICV(Inter-Component Volume) method was applied. The valve system is to control the gas flow of the rotary duct system and the main duct system, and the analysis was performed with an assumption that the total gas mass flow of the main engine is the same as summation of the rotary duct flow and the main duct flow, and with consideration of valve loss, flow rate and effective area in valve angle variation. The performance analysis was carried out during flight mode transitions from the rotary flight mode to the fixed wing flight mode and vice versa mode at altitude of 1Km, flight Mach number 0.1 and maximum engine rpm.

• Journal of the Korea Safety Management & Science
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• v.6 no.2
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• pp.231-239
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• 2004

To keep an enterprise's competitiveness on the condition of the automatic manufacturing system such as FA, FMS and CIM, all the maintenance problems should be considered seriously in not only in production and maintenance but also in related industrial productivity. This paper presents the study of equipment reliability improvement for rotary-machine vibration analysis. Based on these analyses, the maintenance management information system, and the machinery condition diagnosis technique are studied by using of the real-time diagnostic. Therefore, it is expected to improve the efficiency of business processes in the production and safety when we use this system.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.12
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• pp.119-124
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• 2010

In this paper, thermal stabilization design of a new concept compact machining center has been investigated. A new concept machining center adopted a new X-axis as a NC rotary table. A New concept compact machining center is designed that spindle speed, feed rate and NC Rotary table speed are 12,000rpm, 60m/min and 110rpm each. The analysis is carried out by using FEM simulation Solidworks, CATIA and ANSYS. This paper is focused on the thermal deformation according to temperature distribution of a spindle system and feed drive system. Heat transfer analysis is performed according to heat source and atmosphere contact parts. As a result, this compact machining center is designed as a thermally stable structure.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2240-2242
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• 2001

A rotary double inverted pendulum, the nonlinear system has a regulation problem. In this paper, we linearize the nonlinear system at the upright equilibrium position. The linearized system can be expressed in state space. To maintain the upright position, we design a feedback controller using LQR(Linear Quadratic Regulator) algorithm. Then we simulate the system with third-order Adams Bashforth Moulton Method. The simulated result shows that the applied algorithm is effective for the regulation problem.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.934-937
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• 2005

It is not efficient and scarcely out of the question to use commercial expensive electron beam lithography system widely used for semiconductor fabrication process for the manufacturing application field of various devices in the small business scope. Then scanning electron microscope based electron beam machining system is maybe regarded as a powerful model can be used for it simply. To get a complete suite of thus proper system, proper chamber with high vacuum condition is necessarily required more than anything else to modify scanning electron microscope. In this study, special chamber unit using rotary pump and diffusion pump to obtain high vacuum degree was designed and manufactured and various evaluation tests fur recognize the vacuum characteristic were accomplished.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.3
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• pp.127-132
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• 2005

In order to investigate transient behavior, of the CRW(Canard Rotor Wing) type UAV(Uninhabited Aerial Vehicle) propulsion system during flight mode transition considering flow control valve operation, the propulsion system was modelled using SIMULINK commercial program. The valve system is to control the gas flow of the rotary duct system and the main duct system, and the analysis was performed with an assumption that the total gas mass flow of the main engine is the same as summation of the rotary duct flow and the main duct flow, and with consideration of valve loss, flow rate and effective area in valve angle variation. The performance analysis was carried out during flight mode transitions from the rotary flight mode to the fixed wing flight mode and vice versa mode at altitude of 1km, flight Mach number 0.1 and maximum engine rpm.