• 유공압시스템학회:학술대회논문집
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• 유공압시스템학회 2010년도 춘계학술대회
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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.

• 한국생산제조학회지
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• 제8권6호
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• pp.35-42
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• 1999

This paper concentrates on the position control of a pneumatic cylinder under parameter variation. A closed-loop control is proposed to design the different controllers(P, PI, PID, PD controller) in order to choose the best con-troller based on the fast and accurate control of the system. It is shown that the control algorithm, is robust and effective in attaining the fast and accurate position control of system under time-dependent parameter variation. Experimental results showed that PD controller law is effective to obtain the fast response and to increase that sta-blity of the system The method is a useful control algorithm which always automatically adjusts the position con-trol in accordance with the error using carrier wave of triangle type regardless of changes on the operating condi-tion and physical differences between components.

• 한국자동차공학회논문집
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• 제20권1호
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• pp.46-52
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• 2012

A PAEM(Pneumatic Active Engine Mount) system has been developed to improve NVH performance of a SUV in idle state. Control objective to attenuate the vibration of a vehicle should be determined prior to the design of control algorithm. This study presents the correlation analysis of output variables of PAEM system by means of TPA(Transfer Path Analysis) using experimental data obtained by vehicle test. The analysis results show that the vibration of vertical direction is more serious than those of longitudinal and lateral direction of the vehicle, and that the correlation between the vibration of front seat rail and that of steer wheel is highest. In conclusion, the vibrations of front seat rail and steer wheel in vertical direction should be considered as the control objectives of the PAEM.

• 한국정보통신학회논문지
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• 제26권11호
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• pp.1697-1705
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• 2022

대규모 해양 건설에 따른 해양 건설 작업자의 안전 및 해양 오염 문제가 발생하고 있다. 특히, 해양의 수중 건설 작업은 다른 작업에 비해 위험도가 높아 작업자의 안전을 고려한 무인 대체 시스템의 적용이 필요하다. 본 논문에서는 수중 무인 작업을 위해 해양 건설용 ROV 시스템을 개발 완료하였다. 수중 추진체의 제어를 통한 위치제어, 공압 gripper 그리고 수중 작업 모니터링을 위한 모니터링 시스템을 개발하였다. 성능평가 결과 ROV의 수중 이동속도는 최대 0.89m/s로 평가되었으며, 공압 gripper의 최대 하중은 80kg의 하중 허용 가능함을 확인하였다. 또한, 수중 ROV의 제어와 수중 영상 스트리밍에 필요한 네트워크 대역폭이 300Mbps 이상으로 평가되었으며, 유선 통신은 205m에서 92.7 ~ 95.0Mbit/s, 무선 통신은 78.3 ~ 84.8Mbit/s의 속도로 평가되었다.

• 동력기계공학회지
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• 제4권1호
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• pp.20-25
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• 2000

In this study, methods for the characteristics measurement of pneumatic elements using isothermal chamber, the methods for the flow rate and dynamic characteristic measurement of pneumatic control valve, are proposed. An isothermal chamber is a chamber in which the steel wool is stuffed and isothermal condition can almost be realized. Therefore, the instantaneous flow rate could be measured only from the pressure response using the state equation of gas. Effectiveness and simplicity of the proposed method are confirmed by comparing the measured results obtained by proposed methods with the methods defined JIS and the ISO standards.

• 드라이브 ㆍ 컨트롤
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• 제12권4호
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• pp.54-59
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• 2015

Due to the tendency to use high speed pneumatic cylinders to improve productivity, cushioning devices are adopted to decelerate the piston motion of pneumatic cylinders to reduce noise, vibration, and impact. This paper presents a comparison of the cushion characteristics of a high speed pneumatic cylinder with a relief valve type cushioning device. The system parameters selected are the damping coefficient, Coulomb friction, heat transfer coefficient, and cracking pressure of the relief valve in the air cushioning device. The integral of the time multiplied square error (ITSE) is used to quantitative measure the cushioning performance to assess the effect of varying these. The cushioning performance achieved good results when the ITSE is a minimum value. In a comparison of the piston displacement and velocity with the variations in system parameters, the heat transfer coefficients are not as significantly affected as the other. Also, the cracking pressure of the relief valve is mainly affected by the pressure and temperature in the cushion chamber.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.51-52
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• 2006

Gabion can be used for the purpose of preventing overflow of river and side loss of road. However the manufacturing process of the gabion is manually controlled especially to the joining process at the terminal part of gabion with small diameter wire. In this paper automatic feeding guide system was designed and fabricated to make automation. The fabricated system was tested in the factory level. Pneumatic system was considered as the main idea of the feeding system. 3/2-way and 5/2-way manual control valve, eight double-acting cylinders were used. Based on the theoretical simulation and actual test the fabricated system was well controlled. The system was applied to the patent.

• 대한기계학회논문집A
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• 제40권6호
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• pp.613-619
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• 2016

공기구동 제어밸브는 여러 유형의 발전소에서 유체계통의 유량을 제어하거나 탱크의 수위를 조절하는 중요한 기능을 수행하며 발전소 수명기간 동안 성능이 보장되어야 한다. 공기구동 제어밸브는 공기구동기에 공기를 공급하거나 배기하여 작동시키며, 다양한 기능을 하는 부속기기로 구성된 제어설비를 이용하여 공기량을 조절함으로서 밸브 위치를 제어한다. 본 논문에서는 2인치 공기구동기에 I/P 변환기, 포지셔너 등이 장착된 제어밸브 동작모사 실험 장치를 이용하여 공기공급배관에서의 공기누설, 밸브 패킹마찰력 변화, 포지셔너 설정 불량 등을 모사하고, 약 67% 개도에서 ${\pm}2%$ 이하 제어구간에서의 밸브-구동기 거동을 측정하여 비교하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.33-34
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• 2006

The most bottleneck of development of automation excavator system is the making mathematical linear model. Because of non-linear of control circuit, cylinder, join in hydraulic circuit, and heavy loading so on. Therefore, whatever robust controller is designed, real experimentation is necessary. But, a real experimentation has many risks. The excavator is expensive and large size. Therefore a development of experimentation system is difficult and not safe. Specially, there have a difficulty, because of big noise. So, on experimentation is difficult in school. Manufacturing pneumatic excavator modeland using system identification, design a system transfer function in this paper. Also, planning m-PID Controller using CDM, and examining usefulness applied to actuality model.

• 한국자동차공학회논문집
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• 제11권4호
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• pp.135-143
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• 2003

In this study, a real-time simulation model was developed for tracked vehicles with in-arm type semi-active hydro-pneumatic suspension unit using MATLAB S-functions. Since the vehicle model uses relative coordinates and massless link elements, the developed model has an enhanced analytic time performance. Through the comparison of simulation results with multi-body software(DADS), the vehicle model is verified. A controller using on-off skyhook control algorithm is designed with the pilot-centre]led proportional valve based on conventional damper characteristics. Exploiting the developed tracked vehicle model with other subsystem model such as a controller model, a suspension unit model, and a test road model, computer simulations are carried out. Control simulation results with the developed tracked vehicle model show that the semi-active suspension control system has a better performance than the conventional suspension system.