• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.18-24
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• 2004

A fuel spiking test was performed to measure the surge margin of the compressor in a gas turbine engine. During the test, fuel spiking signal is superposed on the engine controller demand signals and the combined signals are used to control a fuel control valve. For the superposition, a subsystem composed of a fuel controller and a function generator is used. The real engine test was performed at the Altitude Engine Test Facility (AETF) in Korea Aerospace Research Institute (KARI). In the preliminary test, the fuel spiking signals are in good agreement with the dynamic pressure at the fuel line and at the compressor discharge point. After the preliminary test, a fuel spiking test to measure the surge point at a specific engine speed was performed. The test results show that the fuel spiking test is very effective in the measurement of surge.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2428-2434
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• 2012

This paper describes the control of a solenoid valve of ESC(Electronic Stability Control) with hydraulic modulator in braking system. ESC ECU(Electronic Control Unit) to control the high-frequency control and slope control method was applied, the surge pressure and EMI(electromagnetic interference) reduction characteristics were studied. The stage of ECU output was added the slope shaping function to reduce electromagnetic emission at higher frequencies. Measurements show that this high frequency ECU manages to reduce the surge pressure and electromagnetic emission by the control of solenoid valve. In conclusion, by using the results of this study for the high frequency ECU control, we could expect enhancement of braking system performance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.37-37
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• 1998

중형항공기용 터보펜 엔진의 성능모사와 LQR 제어기 설계에 대한 연구를 수행하였다. 동적 성능모사를 설계점으로 선정한 지상최대이륙조건과 탈설계점으로 선정한 최대상승조건과 순항조건에 대하여 Step 증가, Ramp 증가, Ramp 감소, Step증가 후 Ramp 감소의 4가지 연료공급에 조건에 대하여 수행되었다. 성능모사 결과 모든 비행조건에서 연료를 Step 증가시킬 경우 고압터보빈의 입구온도가 제한온도인 3105$^{\circ}$R을 초과함을 확인하였고, 최대 상승조건에서 연료를 Step 증가시킬 경우가 4.5초 이내에 Ramp 증가시킬 경우 고압압축기에 서지가 발생함을 확인하였다. 따라서 고압터어빈의 오버슈트와 고압압축기의 서지를 동시에 제어할 수 있는 다변수 제어기의 설계가 필요함을 확인하였다.

• Journal of Advanced Navigation Technology
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• v.15 no.3
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• pp.449-455
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• 2011

In this paper, Proposed controller prevent compressor surge and reduce the acceleration time of the fuel flow control system for turbo-jet engine. Turbo-jet engine controller is designed by applying fuzzy PI+D control algorithm and make an inference by applying Mamdani's inference method and the defuzzification using the center of gravity method. Fuzzy inference results are used as the fuel flow control inputs to prevent compressor surge and flame-out for turbo-jet engine and the controller is designed to converge to the desired speed quickly and safely. Using MATLAB to perform computer simulations verified the performance of the proposed controller.

• Journal of the Korean Society for information Management
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• v.22 no.1 s.55
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• pp.229-248
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• 2005

This study proposes a national cooperative model of access point control, that enables local systems to utilize national access point control record, without creating their own authority records. In order to applying this model, a client/server system is developed using SRU (Search and Retrieve URL Service) protocol. The suggested access point control system will be a cost-effective and time-saving model for the local system, and will be more flexible and extensible with concept of access point control, XML record format and SRU protocol.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.541-542
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• 2015

초고압 차단기는 개방 또는 투입 기능을 수행시 과도현상에 의한 개폐서지(Switching Surge)가 발생하여 차단기 구성품들에 부담이 가해진다. 초고압 차단기용 개폐제어 장치는 이러한 차단기의 개폐 동작시 차단기 접점의 분리 또는 접촉 순간을 제어하여 개폐서지를 최소화함으로써 접점의 마모와 구성품에 가해지는 스트레스를 감소시키는 장치이다. 즉, 차단기에 인가되는 전압의 위상을 기준으로 원하는 개폐시점에서 개방 및 투입이 일어나도록 제어하는 기기이다. 국외에서는 해외 선진사들이 이미 초고압 차단기용 개폐제어 장치를 상용화하여 현장에 적용하고 있으며, 국내에서는 기술의 검토 단계를 지나서 장치를 개발하고 시험하여 상용화하는 단계로 진입하고 있다. 본 논문에서는 상용화를 위하여 개발된 초고압 차단기용 개폐제어 장치에 대하여 하드웨어 구성을 소개하고, 운영 소프트웨어를 설명하며, 개폐제어 장치의 개폐제어 동작 성능을 자체 모의시험과 GIS(Gas Insulated Switchgear) 차단부와의 연계 시험을 통하여 평가한다.

• Journal of the Korean Society for information Management
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• v.26 no.1
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• pp.279-303
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• 2009

This study aims to clearly understand 'Functional Requisite of Authority Data(FRAD)' being studied by IFLA focused on aspect of change from FRAR. In addition, it has established relationship between FRAD and concerned rules by analyzing effect of FRAD on RDA and MARC21 and reviewed cataloguing rules, format and situations of major authority DB implementations concerned about domestic authority controls in reflection of IFLA's activities for authority control. Based on the analysis, it has looked into considerations for domestic authority controls standards such as access control methods, expansion of application scope, introduction of new approaches such as entity-relationship model, reinforcement of roles for national bibliographic agency. These study results would be utilized as basic data for authority control.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.4
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• pp.1-7
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• 2009

The surge control system in unmanned turbojet engine must be capable of accounting uncertainties from engine transient conditions, random fluctuations of key parameters such as air pressure and fuel flow and engine modeling errors. In this paper, taking into consideration of its effectiveness as well as system stability, a fuzzy PI controller is proposed. The role of the fuzzy PI controller is to stabilize the unmanned aircraft upon occurring unexpected engine surge. The proposed control scheme is proved by computer simulation using a linear engine model. The simulation results on the state space model of a small turbojet engine illustrate the proposed control system achieves the desired performance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.5
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• pp.297-304
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• 2016

When a control algorithm is developed to protect automotive compressor surges, the simulation model typically selects an empirically determined look-up table. However, it is difficult for a control oriented empirical model to show surge characteristics of the super charger. In this study, a dynamic supercharger model is developed to predict the performance of a centrifugal compressor under dynamic load follow-up. The model is developed using Simulink$^{(R)}$ environment, and is composed of a compressor, throttle body, valves, and chamber. Greitzer's compressor model is used, and the geometric parameters are achieved by the actual supercharger. The simulation model is validated with experimental data. It is shown that compressor surge is effectively predicted by this dynamic compressor model under various operating conditions.

• Journal of Advanced Navigation Technology
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• v.20 no.3
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• pp.190-195
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• 2016

In this paper, Propose to prevent compressor surge and improve the transient response of the fuel flow control system of turbojet engine. Turbojet engine controller is designed by applying Fuzzy-PID control algorithm. To prevent any surge or a flame out event during the engine acceleration or deceleration, the Fuzzy-PID controller effectively controls the fuel flow input of the control system. Fuzzy-PID results are used as the fuel flow control inputs to prevent compressor surge and flame-out for turbo-jet engine and the controller is designed to converge to the desired speed quickly and safely. Using LabVIEW to perform computer simulations verified the performance of the proposed controller. Response characteristics pursuant to the gain were analyzed by simulation.