• 한국터널지하공간학회 논문집
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• 제22권3호
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• pp.219-237
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• 2020

급속한 경제 발전과 도시 인구 증가는 기존의 인프라의 개선과 확대를 위한 지하 공간 활용의 필요성을 증가 시킨다. 쉴드 TBM (Tunnel Boring Machine)은 높은 굴진율과 최소한의 지반 교란이 필요한 지하 구조물 설계에 널리 이용되어 왔다. 허용 추력과 커터헤드 토크는 적절한 TBM 타입을 선택에 있어서, 중요한 설계 인자 이므로 TBM 공사 시에 적절히 산정되어야 한다. 하지만, 기존의 추력과 토크의 추정 모델은 오직 경험적인 인자와 TBM 직경에만 의존하고 있는 실정이다. 이는 최적의 추력 유압 시스템과 적절한 유압부품의 선택을 어렵게 한다. 본 연구에서는 4개의 추력 및 토크 계산 모델을 설명하고 정리하였으며, 각각의 모델들을 비교 및 논의하였다.

• 한국정밀공학회지
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• 제12권5호
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• pp.77-87
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• 1995

In-process detection of drill wear is one of the most important technoligies for automatic, unmaned machining systems. In this study, an on-line drill wear estimation model based on spindle/Z-axis motor currents generated during the drilling process is proposed. The theoretical model is obtained by integrating the drilling process model and the servomechanism model. The drilling process model describes the relationship of drill wear and drilling torque/ thrust force, whereas the servomechanism model describes the relationship of drilling torque/ thrust force applied to motor and spindle/Z-axis motor current. Evaluation tests have shown that the proposed model is a good real-time estimator for drill wear.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.526-529
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• 2009

본 연구에서는 Lab-Scale의 하이브리드 연소기를 이용하여 하이브리드 로켓의 추력제어 범위와 연소 시간에 따른 추진제의 후퇴거리를 분석하기 위하여 산화제 유량에 따른 추진제별 연소 특성을 파악하였다. 산화제 유량을 제어하기 위해서 니들 밸브와 스텝모터를 결합하여 스텝모터의 구동에 의해 니들밸브의 개폐량을 조절할 수 있도록 배관 시스템을 설계하였다. 산화제 유량 변화를 통해 추진제에 따른 질유량과 후퇴율 관계식을 유도하였다. 추력제어를 하면서 명령 추력 값에 따른 산화제 유량을 통해 후퇴거리를 예측하였으며 실제 추력제어 연소 실험을 통해 신뢰성을 확인하였다.

• 대한기계학회논문집A
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• 제29권9호
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• pp.1270-1275
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• 2005

Rolling process to fabricate a strip with even thickness is significant to enhance the quality of the strip. The thickness of a strip can be effectively controlled by pair-cross mills. However, pair-cross mill generates thrust in the axial direction of roller and causes skewness, deflection, twist and even accidental roll chock failure. Therefore, accurate estimation of the thrust of the pair-cross mill during rolling process is necessary to monitor the failure of roll and the quality of products. An empirical equation given by Mitsubishi Heavy Industry (MHI) is hitherto employed, where the thrust is expressed in terms of rolling force, reduction ratio and crossed angle. However it turns out that the MHI empirical equation provides somehow inaccurate and unsuitable thrust in practical rolling processes. Moreover, we learn that three parameters involved in MHI equation are coupled each other. In this paper, axiomatic design principle is employed to select appropriate parameters involved in approximate equation in order to make parameters uncoupled. A quadratic equation using response surface method with new parameters is suggested. The accuracy of the approximate model is examined by comparing with real experimental data.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권1호
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• pp.24-33
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• 2010

Design of a Pump Jet Propulsor (PJP) was undertaken for an underwater body with axisymmetric configuration using axial/low compressor design techniques supported by Computational Fluid Dynamics (CFD) analysis for performance prediction. Experimental evaluation of the PJP was earned out through experiments in a Wind Tunnel Facility (WTF) using momentum defect principle for propulsive performance prior to proceeding with extensive experimental evaluation in towing tank and cavitation tunnel. Experiments were particularly conducted with respect to Self Propulsion Point (SPP), residual torque and thrust characteristics over a range of vehicle advance ratio in order to ascertain whether sufficient thrust is developed at the design condition with least possible imbalance torque left out due to residual swirl in the slip stream. Pumpjet and body models were developed for the propulsion tests using Aluminum alloy forged material. Tests were conducted from 0 m/s to 30 m/s at four rotational speeds of the PJP. SPP was determined confirming the thrust development capability of PJP. Estimation of residual torque was carried out at SPP corresponding to speeds of 15, 20 and 25 m/s to examine the effectiveness of the stator. Estimation of thrust and residual torque was also carried out at wind speeds 0 and 6 m/s for PJP RPMs corresponding to self propulsion tests to study the propulsion characteristics during the launch of the vehicle m water where advance ratios are close to Zero. These results are essential to assess the thrust performance at very low advance ratios to accelerate the body and to control the body during initial stages. This technique has turned out to be very useful and economical method for quick assessment of overall performance of the propulsor and generation of exhaustive fluid dynamic data to validate CFD techniques employed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.129-131
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• 2005

This paper deals with an electromagnetic analysis and control parameter estimation of a moving-coil linear oscillatory actuator (MCLOA). Analytical solutions for electromagnetic characteristics of the MCLOA are obtained from transfer relations derived in terms of a magnetic vector potential and two-dimensional (2-d) rectangular coordinate systems. And then, on the basis of 2-d analytical solutions, control parameters such as the thrust constant, the back-emf constant and winding inductances are estimated. Finally, analytical results for both electromagnetic characteristics and control parameters of the MCLOA are validated extensively by finite element (FE) analyses. In particular, test results such as static thrust, resistance and inductance measurements are given to confirm the analyses.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3203-3208
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• 2007

The performance study shows the result using two different methods which are used to control missile or aircraft. One is the Thrust Vector Control(TVC) method for the aviation of next generation and the other is the present effective Shroud Jet-vane System(SJVS) method for the satellite effector development. The research was done through the performance estimation using the numerical simulation analysis, the modelling, the performance measuring using the model, the investigation of the flow visualization and aerodynamic performance with the enforced power to the vane and the result comparison.

• 한국군사과학기술학회지
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• 제23권1호
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• pp.18-27
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• 2020

In order to estimate the launch point of a high-speed vehicle, predicting the various characteristics of the vehicle's movement, such as drag and thrust, must be preceded by the estimation. To predict the various parameters regarding the vehicle's characteristics, we build the IMM filter specialized in predicting the parameters of the post-launch phase based on flight dynamics. Then we estimate the launch point of the high-speed vehicle using Inverse Dynamics. In addition, we assume the arbitrary error level of the radar for accuracy of the prediction. We organize multiple-dimensioned IMM structures, and figure out the optimal value of parameters by comparing the various IMM structures. After deriving the optimal value of parameters, we verify the launch point estimation error under certain error level.

• 한국추진공학회지
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• 제16권2호
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• pp.34-41
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• 2012

추력편향장치는 일반적으로 노즐 뒤에 장착되어 추진기관에서 분사되는 초음속 제트의 유동방향 자체를 편향시킴으로 단일 추진체의 노즐에서 종축, 횡축, 회전축 방향의 제어를 할 수 있다. 노즐 유동장내에 노출되어 있는 편향장치인 제트 베인의 경우 그 형상과 편향각도에 따라서 상호 유동 간섭에 의한 추력손실이 발생되게 된다. 본 연구에서는 실험에 사용된 노즐의 수치해석과 더불어 제트 베인 각도 변화에 따른 공기역학적 유동가시화를 수행하였으며 베인에 미치는 유동간섭의 특징을 분석하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 추계학술대회 논문집
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• pp.69-71
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• 2007

Need correct analysis of thrust for control performance improvement of HB-LPM (Hybrid type Linear Pulse Motor). It is difficult to analyze HB-LPM's thrust. In this paper, HB-LPM's thrust is expressed to mathematical expression. And it is proved validity of this numerical formula by thrust measurement system. Two phase driver is composed. It is verified validity of numerical formula that measure waveform of electric current and voltage that is supplied in each phase. In this study, composed two phase drive driver, advantage of this IGBT element 6 by accumulated IPM module 1 Driver composition possible. That is, can economize 1 moule. In other words, Driver composition is available by IGBT or metal oxide semiconductor field effect transistor element 4. This is economical big gain.