• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2001년도 정기학술대회
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• pp.99-104
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• 2001

In this study, selecting methods of the hydraulic valve and evaluation item for development of reliability testing standard are c]early defined. And, we developed reliability testing standard of the hydraulic valves which are as follows, - Hydraulic directional control valve, - Hydraulic on-off solenoid valve - Hydraulic PWM valve, - Hydraulic check valve, - Hydraulic relief valve, - Hydraulic reducing valve, - Hydraulic flow control valve

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.167-174
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• 1997

In this paper, the mathematical model of the hydraulic control valve is formulated, that is, this dynamic modeling which includes the motion equations and continuity equations can analyze the dynamic characteristics of the hydraulic control valve. The control valve for the transmission has the Over Speed Protection to protect a hydraulic travel motor. Therefore, this simulation shows the over speed protection and researches the main design parameters. The results of the computer simulation were assured through the experiment. From the comparison between both results, it is shown that this simulation program is useful and effective.

• 한국자동차공학회논문집
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• 제9권4호
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• pp.121-130
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• 2001

For the purpose of optimal control of anti-lock brake systems, precise dynamic characteristics analysis of hydraulic modulator, especially solenoid valve is necessary. However, most of researches so far have dealt with dynamic characteristic analysis of valve itself, and the results have been restrictively applied to the actual ABS modulator, where hydraulic pressure is acting. In this study, mathmatical modeling and experimental analysis were peformed in order to evaluate the valve dynamic characteristics when the hydraulic pressure is applied. High pressure on the master cylinder that affects on the valve dynamic characteristics have been analyzed quantitatively, and performance improvement methods have been suggested through parameter study. Consequently, results of solenoid valve dynamic characteristics analysis derived in the study can be utilized as criteria for the optimal control of anti-lock brake systems.

• 한국산학기술학회논문지
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• 제13권5호
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• pp.1963-1968
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• 2012

본 논문은 현장에서 사용하고 있는 밸브 수압측정기를 3차원 자동설계 프로그램인 CATiA를 활용하여 설계하였다. 또한 유한요소 해석코드인 ANSYS를 활용하여 설계된 밸브 수압측정기에 대하여 유동해석을 수행하여 내부압력에 따른 유체의 흐름을 구하였다. 이러한 해석결과는 새로운 밸브 수압측정기를 개발하는데 기초자료로 활용될 계획이며 개발예정인 밸브 수압측정기는 밸브 점검 시 시간을 단축하고, 사고를 방지하여 안전성을 향상시킨다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1459-1464
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• 1996

The most important parameter for hydraulic active suspension system is to sustain desirable vehicle maneuvering stability and ride comfort without increasing consumption power. The performance of hydraulic active suspension system depends on damping force of body damping valve and piston damping valve. Hydraulic actuator design and damping valve parameter selection are essential and basic procedure to design hydraulic active suspension system. This paper is on computer simulation with use of mathematical model that was delivered from dynamic characteristic of hydraulic actuator, as know basic damping characteristics of hydraulic active suspension system. The aim of this paper is to select the system parameter that affect mainly hydraulic active suspension, and identify the validity on the system parameter selection.

• 대한기계학회논문집A
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• 제26권4호
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• pp.683-692
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• 2002

The most important parameter for hydraulic active suspension system is to sustain desirable vehicle maneuvering stability and ride comfort without increasing power consumption. The performance of hydraulic active suspension system depends on damping force of body damping valve and piston damping valve. Hydraulic actuator design and damping valve parameter selection are essential and basic procedure to design hydraulic system. This paper is on computer simulation with use of mathematical model that was delivered from dynamic characteristic of hydraulic actuator, as know basic damping characteristics of hydraulic active suspension system. The aim of this paper is to select the system parameter that affect mainly hydraulic active suspension, and identify the validity on the system parameter selection.

• 드라이브 ㆍ 컨트롤
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• 제16권2호
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• pp.72-79
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• 2019

Despite the development of electronic components and microprocessors, hydraulic actuators are still being applied in various applications. In some applications, there is a desire to apply a hydraulic actuator with a relatively small position error to the system. Various studies have been conducted to reduce the position error of hydraulic actuators. In this paper, the position error of the hydraulic actuator when the hydraulic oil pressure is supplied is defined as the offset generated by the servo valve, and the method for correcting the servo valve offset has been studied. A method for compensating the servo valve offset was proposed and it was verified through experiments that the position error of the hydraulic actuator was reduced. We also compared the servo valve offset correction method and controller using the PID control and disturbance observer used to reduce the position error of the hydraulic actuator. No-load test and load test were performed to confirm the performance of the servo valve offset correction method. The results of the study were compared with those obtained by using the disturbance observer and PID control.

• 한국산학기술학회논문지
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• 제13권4호
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• pp.1447-1452
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• 2012

산업현장에서 사용되고 있는 기존의 밸브 수압측정기는 압력조절을 수동으로 제어함으로서 정확한 압력측정을 할 수 없는 불편함이 있었다. 이를 개선하기 위하여 기존의 밸브 수압측정기에 대하여 자동설계 프로그램인 CATIA를 활용하여 설계하고 3차원 유한요소 해석코드인 ANSYS를 활용하여 설계된 밸브 수압측정기에 대하여 구조해석을 수행하고 내부압력에 따른 내부누수, 응력, 변형률, 총변형량 등을 구하였다. 이러한 결과는 새로운 밸브 수압측정기를 개발하기 위한 기초자료로 활용할 계획이다.

• 드라이브 ㆍ 컨트롤
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• 제18권3호
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• pp.8-15
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• 2021

A rear axle steering (RAS) system is attached to the rear of medium and large commercial vehicles that transport large cargo. The existing RAS systems are driven by electro-hydraulic actuator (EHA), and most commercialized EHAs consist of electric motors, hydraulic pumps, relief valves, prefill valves and cylinders. The prefill valve required for such EHAs is a type of check valve with extremely low cracking pressure that should not allow RAS to have noise or vibration, and the prefill valve prevents system negative pressure as well as unstable operation. Most papers on this topic rely on experiments to predict valve performance, and theoretically detailed modeling of valves or pipelines is performed, but it is very rare to evaluate hydraulic vibration characteristics by analysing everything from hydraulic pumps to valves comprehensively. In this study, we proposed an experimental circuit that can predict the performance of the prefill valve. The study also analysed the pressure-flow pulsation that is transmitted to the valve through the pipeline, and how the transmitted pressure-flow pulsation affects the valve vibration.

• 제어로봇시스템학회논문지
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• 제9권2호
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• pp.124-130
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• 2003

The electro-hydraulic servo system with a servo valve is applied widely in force control. However, the composition of control system using a servo valve is difficult due to nonlinearities in the servo valve, such as square-root terms in flow equation. The electro-hydraulic servo system using a DDV(Direct Drive Valve) instead of a servo valve was proposed and it's characteristics was estimated. The DDV and whole system are modelled by parameter identification using the input-and-output data, then the models are verified by the comparison of simulation with experiment. Also, the state feedback controller has been designed based on this model, then the performance of the electro-hydraulic force servo system using a DDV is evaluated by simulation and experimental results.