• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.533-541
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• 2011

This paper presents a frequency-response test performed on an antagonistic actuation system consisting of two Mckibben pneumatic artificial muscles and a pneumatic circuit with pressure valves. Varying switching frequency to pressure valves from 0.1 Hz to 5 Hz, parameters of a linear model were estimated optimally to predict dynamic characteristics of the antagonistic actuation. A model-base control scheme with estimated parameters was built for the precise trajectory tracking of the antagonistic structure and realized on a reconfigurable embedded control system, CompactRIO. Experimental results showed that the proposed model-based control scheme gave good performance in trajectory tracking comparing with a PD control scheme when square wave and sinusoidal wave were given as references to follow.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.731-736
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• 2011

A pneumatic driving solenoid valve operates pneumatic control devices by opening/closing operating flow passage when the command is given by control system for the liquid-propellant feeding system of space launch vehicle. The simulation model of pneumatic driving solenoid valve is designed with AMESim to verify the designs and evaluate the dynamic characteristics and pneumatic behaviors of valve. To validate a valve simulation model, the simulation results of their operating durations of valve by AMESim analysis are compared with the results of experiments. In addition, the results of internal flow simulation with FLUENT are utilized to improve the accuracy of valve-modeling. Using the model, we analyze performance of valve; opening/closing pressure, operating time on various design factors; shape of control valve seat, drainage seat, rate of sealing diameter, volume of control cavity. This study will serve as one of reference guides to enhance the developmental efficiency of ventilation-relief valves with the various operating conditions, which shall be used in Korea Space Launch Vehicle-II.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.93-97
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• 2010

Wheel skids may occur during train operations due to low adhesion at the wheel-rail contact point abnormally, and the skids, in turn, result in flats appearing on the wheels, which affect safety and ride comfort significantly. Thus, anti-skid control has a crucial role for safe braking and prevention from flats that could cause a disastrous train accident. This paper presents simulation studies on an anti-skid control unit (ASCU) with a brake system of a rolling stock including a pneumatic model for brake power supply and dump valve operation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.440-445
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• 2002

공압쿠션실린더(${\psi}80{\times}500^{st}$)의 쿠션장치인 쿠션슬리브(${\psi}20{\times}28^{st}$) 4종(Model #a, Model #b, Model #c, Model #d) 모델을 제작하여 수직하강하는 실린더에 각각 장착한 후, 각 모델에 따라 압력과 부하 특성을 비교하였다. 동일한 실험조건인 공급압력($5kg_{f}/$\textrm{cm}^2$)과 부하하중($70kg_{f}$)에서 각 모델별 실험을 실행하였다. 각 모델별 실험에서, Model #c의 쿠션슬리브인 경우가 가장 적합한 형상임을 알 수 있었다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.113-114
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• 2022

가상의 공간에 실제의 설비를 구현하는 시뮬레이션 기술은 스마트팩토리를 구성하는 필수 요소 중의 하나이다. 다만, 현업의 제조 설비 도면을 시뮬레이션 소프트웨어에 적용하는데 있어 자유 곡선을 가지는 공압 배관 등의 모델 데이터는 작업의 난해함 등의 이유로 기 설계 도면에 누락되어 있는 경우가 빈번하다. 본 연구에서는 시뮬레이션 툴 중에 하나인 유니티를 이용하여 내부에서 직접 스윕 곡선을 생성하는 과정을 구현하였다. 이를 통해 기 설계 데이터에 누락된 다양한 자유 곡선 모델을 신속하게 시뮬레이션에 적용하는데 효과가 있을 것으로 기대된다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.89-93
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• 2008

The effect of pintle shapes and position to the thrust performance of Solid Rocket Motor was studied by experimental-aided Computational Fluid Dynamic(CFD). Among the turbulent models for RANS in Fluent, Spalart-Allmaras model was better agreement with the nozzle wall pressure distribution attained by cold-flow test than other models. When nozzle throat area was decreased, magnitude of thrust was increased. The bigger pintle size was, the more thrust of pintle tip pressure was obtained. Meanwhile the more thrust of nozzle and chamber pressure decreased. Hence, total thrust of big pintle was less than a small pintle under same throat area condition.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.57-64
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• 2015

In this paper, a model reference adaptive control (MRAC) scheme is applied for the precise and robust motion control of a pneumatic system with load variation. The reference model for MRAC is designed systematically using linear quadratic Gaussian control with loop transfer recovery (LQG/LTR). The sigmoid function of inverse velocity is used to compensate for the nonlinear friction force between the sliding parts. The experimental results show that MRAC effectively overcame the limit of the PID controller when there was unknown disturbance, including abrupt load variation and model uncertainty in the pneumatic control system.

• Proceedings of the KTCVS Conference
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• 1998.10a
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• pp.3-3
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• 1998

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2320-2322
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• 2004

전자제어식 미끄럼방지 제동장치 (ABS, Antilock Brake System)는 차량의 급제동시 발생할 수 있는 바퀴의 슬립을 방지하여 차량의 제동거리를 단축시키고 주행 성능을 향상시키는 차량 내 안전장치이다. 지난 몇 년 동안 공압식 제동시스템을 사용하는 대형차량에 적합한 미끄럼방지 제동 제어기를 연구해 왔다. 이 제어기는 바퀴의 슬립율과 그 변화량을 이용한 제어 법칙을 유도하여, 제어 파라미터로 사용하고 있다. 이러한 제어 파라미터의 튜닝에는 맡은 반복적인 실험이 요구된다. 이러한 요구에 부응하기 위하여 차량의 제동을 실시간으로 모사 할 수 있는 HILS (Hardware In-the Loop Simulation) 시스템을 개발, 구축하였다. 개발 HILS는 공압식 브레이크 시스템 및 14 자유도를 가지는 차량 동역학 모델 및 타이어-바퀴 동역학을 소프트웨어 모델로 사용하고, 개발 중인 전자제어식 미끄럼 방지 제동 제어기를 하드웨어로 사용하여, 바퀴속도 센서 신호 모의 장치 및 공압 엑추에이터 모의 신호등의 인터페이스 장치를 사용하여 제동중인 차량의 상태를 실시간으로 시뮬레이션 및 감시할 수 있다. 이 개발 HILS를 이용하여 제동 제어기의 제어 파라미터의 튜닝을 짧은 시간에 성공적으로 끝낼 수 있었을 뿐만 아니라, HILS 실험을 마친 제어기는 미끄럼 방지 제동 시험장에서 실차 주행 시험을 무사히 마침으로써, 개발 기간과 비용을 절감할 수 있는 하드웨어를 이용하는 시뮬레이션의 효용성을 간접적으로 증명하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.2
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• pp.193-200
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• 2009

This paper investigated the drop characteristics of oleo pneumatic type landing gear for small aircraft and the effects of cavitations in modeling the landing gear system. The landing gear system employed a simple oleo pneumatic type damper without a metering pin. In general, oleo-pneumatic type landing gears are light-weighted because of it's simplicity, yet they offer excellent impact absorption characteristics. In this study, the landing gear system was modeled using MSC ADAMS, which offers a drop simulation module. After modeling the system, a series of testing was conducted, using a prototype landing gear system, to validate the analysis model and simulation results. The effect of cavitation was considered in the simulation model to obtain a better correlation between the test and simulation results. The results show that adding the cavitation effect in the simulation model significantly improved the simulation model and better captured the dynamic behaviors of the landing system. Using the 'cavitation' model, dynamics characteristics of the landing gear were further evaluated for other landing conditions, such as landing in various angles of slopes.