• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.174-177
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• 2007

본 연구에서는 액체로켓엔진의 제어기구로서 많이 사용되는 유압식 레귤레이터에서의 제어 프로세스와 제어 변수의 조절에 관한 정적 및 동적 특성을 연구하였다. 본 연구의 대상으로는 8K14 "SCUD"의 9D21 엔진에 사용되는 유압식 레귤레이터를 선택하였으며, 본 유압식 레귤레이터의 수학적 모델링을 거쳐, 액체로켓엔진 내부에서의 유압식 레귤레이터의 응답속도와 자동제어시스템의 정밀도 분석을 수행함으로써, 유압식 레귤레이터의 유압조절기구인 니들밸브 유로면적의 설계값을 도출하였다.

• 조명전기설비학회논문지
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• 제28권8호
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• pp.54-61
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• 2014

This paper proposes a boost/flux-weakening controller (BFWC) for wide speed operation range having engine and interior permanent magnet synchronous generator (IPMSG) for special equipment vehicle. The proposed BFWC exploits direct torque/flux control (DTFC) scheme based on space vector modulation method to control the constant DC voltage output within the entire speed operation range of engine. And, to improve the response characteristics of maximum torque per ampere (MTPA) operation and flux-weakening operation, the MTPA and flux-weakening feed-forward controllers are applied. To estimate feasibility and usefulness of the proposed controller, the simulation and experimental results are compared.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.383-388
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• 2003

As an effective way of response evaluation in structural vibration analysis, the phase vector sum(PVS) method used in shaft torsional vibration analysis is introduced. Basic relation of PVS applicable to structural problem is derived and applied to Diesel engine structures. Concepts of forced phase vector sum (FPVS) and significance level (SL) are proposed to visualize the correlation between excitation orders and vibration modes in the SL map. The maximum responses and SL are compared and reviewed to confirm the validity of the method. It is regarded FPVS is adequate to newly evaluate the structural vibration based on excitation information.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권2호
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• pp.90-96
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• 2005

This paper presents hardware scheme of fuzzy inference engine, based on α-level set decomposition of fuzzy sets for fuzzy control of DC servo system. We propose a method which is directly converted to PWM actuating signal by a one body of fuzzy inference and defuzzification. The influence of quantity α-levels on input/output characteristics of fuzzy controller and output response of DC servo system is investigated. It is concluded that quantity α-cut 4 give a sufficient result for fuzzy control performance of DC servo system. The experimental results shows that the proposed hardware method is effective for practical applications of DC servo system.

• 한국산업정보학회논문지
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• 제4권1호
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• pp.58-62
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• 1999

본 논문은 엔진마운트에서 주기적인 미지의 외란에서 나타나는 시스템의 입출력으로부터의 시스템 동특성을 인식할 수 있는 응용가능성을 보여 주고자 한다. 일반적으로 외란 진동과 파장형태는 확실히 알려져 있지 않고 임의적으로 발생되고 있다. 단지 제어량인 입력과 외란이 섞여 있는 출력측정량만이 시스템인식을 위하여 사용될 뿐이다. 보다 일반화되어 개발된 시스템인식기술 알고리즘은 승용차 능동엔진마운트의 진동제어를 위하여 능동제어에 앞선 미지의 주기적외란을 포함한 동특성시스템에서의 수학적 모의시험을 통하여 시스템인식기술의 완벽성을 나타내고 있다.

• 한국항공우주학회지
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• 제30권5호
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• pp.79-87
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• 2002

로켓엔진에서 발생하는 음향 불안정성의 정성적 경향성을 파악하기 위해 축대칭 연소실에서의 음향파 응답 특성을 수치해석적으로 조사하였다. 주로 작동조건의 변화와 외부교란의 가진 주파수 변화에 따른 응답 특성을 계산하였다. 외부교란으로 연소실 입구부분의 전압이 정현파 형태로 섭동하도록 인위적으로 부여하였다. 음향 응답의 정성적 경향성이 유지되는 범위내에서, 분무 연소과정에 수반되는 여러 가지 물리 화학적인 과정들을 단순화하였다. 먼저, 주어진 작동조건에서 정상상태의 연소장을 구하고, 다음 단계로 압력섭동에 대한 연소장의 거동을 시간의 경과에 따라 구하였다. 작동조건의 변화에 따른 음향파 응답의 계산 결과, 반응 지역에서 약한 강도의 화염이 형성되는 경우 민감한 응답이 나타나 불안정안 압력분포를 나타냈다. 또한, 가진되는 압력 섭동의 주파수에 따라 응답 특성이 변하였고, 특히 높은 가진 주파수의 압력 섭동에 대해서 불안정한 응답이 나타났다. 해석 결과로 나타난 거시적 현상의 이해를 돕기위해, 기존의 화염소 모델을 채택한 음향파 응답 연구 결과와의 상관성을 찾아 본 해석 결과를 분석하였다.

• 한국산학기술학회논문지
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• 제14권7호
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• pp.3127-3134
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• 2013

본 연구는 DME 연료를 사용할 수 있도록 변경된 엔진의 제어 알고리즘, 로직구성 및 차량상태에서 검증결과를 나타낸 것으로써, 제어구조 및 자동코드 생성기법에 의한 제어로직 설계과정과 제어 맵을 소개하고 최종적으로 제어의 신뢰성 및 성능을 검증한 것이다. 제어구조는 운전자 요구를 엔진발생토크로 구현하기위한 분사제어부와 배기가스 및 동력특성을 만족시키기 위한 공기제어 시스템부로 크게 구성되며, 제어로직은 제어응답성을 향상시키기 위하여 각 제어 기능별로 앞먹임 및 뒤먹임 제어부로 설계되었고, 앞먹임 제어부의 제어 맵은 엔진모델을 이용하여 생성한 뒤, 이를 엔진 및 차량 시험과정에서 보정하였다. 개발된 제어기를 장착하여 차량 시험모드를 완주하였으며, EGR, VGT 및 분사시기 보정에 의하여 배출가스 저감효과를 확인하였다.

• 대한치과보철학회지
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• 제14권1호
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• pp.47-54
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• 1976

Pulpal temperature is changed in response for various conditions which were mechanical, thermal, chemical and biological stimuli. This study was performed to determine the pulpal temperature changes which were using air turbine with air-water coolant, water coolant, and conventional dental engine with water coolant and no coolant on 28 canine of dogs. In order to record pulpal temperature, pulp chamber was opened on the labiocervical area of canine. Thermocouple was inserted into pulp chamber and was fixed with filling material(dycal). Changes of pulpal temperature were recorded on the physiograph, which had been standardized temperature degree, through thermocouple to thermistor bridge and carrier preamplifier. The amount of experimental temperature change to that of control was interpreted in the pulpal cavity. The obtained results were as followings: 1. The mean normal temperature was 33.07 centigrade. 2. The temperature was decreased than normal pulpal temperature. It was 12.04 centigrade in reduction by air turbine with air-water coolant, 7.17 centigrade in reduction by air turbine with air coolant, 5.54 centigrade in reduction by conventional engine with water coolant, and 1.26 centigrade in reduction by conventional engine with no coolant. 3. The time for maximal temperature change was 53.3 seconds in reduction by air turbine with air-water coolant, 73.4 seconds in reduction by air turbine with air coolant, 50.9 seconds in reduction by conventional engine with water coolant, and 27.1 seconds in reduction by conventional engine with no coolant. 4.. After reduction was ceased, the recovery time to normal pulp temperature was 287.1 seconds in air turbine with air-water coolant, 189.0 seconds in air turbine with air coolant, 86.9 seconds in conventional engine with water coolant, and 52.9 seconds in conventional engine with no coolant respectively.

• 한국자동차공학회논문집
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• 제19권5호
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• pp.14-21
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• 2011

In diesel engines, accurate EGR control is important due to its effect on nitrogen oxide and particulate matter emissions. Conventional EGR control system comprises a PI feedback controller for tracking target air mass flow and a feedforward controller for fast response. Physically, the EGR flow is affected by EGR valve lift and thermodynamic properties of the EGR path, such as pressures and temperatures. However, the conventional feedforward control output is indirectly derived from engine operating conditions, such as engine rotational speed and fuel injection quantity. Accordingly, the conventional feedforward control action counteracts the feedback controller in certain operating conditions. In order to improve this disadvantage, in this study, we proposed feedforward EGR control algorithm based on a physical model of the EGR system. The proposed EGR control strategy was validated with a 3.0 liter common rail direct injection diesel engine equipped with a DC motor type EGR valve.

• 수산해양기술연구
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• 제59권4호
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• pp.344-353
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• 2023

In the actual sea, the additional resistance due to external force such as wind, current and wave is accompanied, and the required power is added in response to these resistance. Especially when the ship is sailing at low speed, the effects of wind and current have a great impact on the safe control of the ship. Likewise, it is thought that the effects of wind and current have a great impact on the trawl ship control since the towing speed of a bottom trawl ship is a low speed of 3 to 4 knots. If the reduce of ship speed and the increase of engine power due to the influence of wind and current can be identified, the safe towing power can be calculated based on a given engine output. Thus, the appropriate size of a fishing gear can be determined. In this study, a total of 20 trawl operations were conducted for seasonal maritime research in the same research area according to the operation mode of propeller. Based on navigation data, trawl fishing data, and engine performance data acquired during the towing fishing gear, and data of ship speed, hull resistance, fishing gear resistance, wind force and current force according to an incidence angle were estimated. The overall power for these loads was calculated and compared with the measured engine power, and the effects of wind force and current force on the engine power were investigated.