• 한국항공우주학회지
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• 제34권9호
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• pp.76-81
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• 2006

본 논문에서는 공기흡입식 추진기관용 연료공급 시스템의 연료조절 밸브 시스템을 제안하였으며, 제안된 시스템은 서보밸브에 의해 구동되는 차압유지 밸브와 미터링 밸브로 구성되어 있다. 시스템 성능 및 안정성에 영향을 미치는 인자를 찾기 위해 비선형 및 선형 해석을 수행하였다. 이를 통해 미터링 밸브 오리피스 양단의 차압 유지량 ${\Delta}P$가 시스템 안정성에 영향을 미침을 예측하였고 실험 및 비선형 전산모사를 통하여 입증하였다. 해석 및 실험 결과차압 유지량 ${\Delta}P$를 줄이고 동시에 이등변 삼각형 형상의 오리피스를 차압유지 밸브에 적용함으로써 요구 유량에 따라 유량이득이 조절되도록 하여 시스템의 안정성을 높일 수 있었다.

• 한국군사과학기술학회지
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• 제8권4호
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• pp.152-158
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• 2005

In this paper, we have proposed a fuel metering unit of ai breathing engine. The proposed valve system consists of a constant pressure drop valve and a metering valve, which are controlled by servovalve. We carried out nonlinear and linear analysis, computer simulation and experimentation to find effects of some factors on system performance. Analysis and experimental results show a good agreement. It is also shown that the system stability is affected by pressure drop of metering valve and inlet pressure of injectors.

• 드라이브 ㆍ 컨트롤
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• 제18권2호
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• pp.9-19
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• 2021

The spool displacement signal of a directional control valve, including the servo valve, can be considered as the standard signal to measure dynamic characteristics. When the spool displacement signal is not available, the velocity signal of a metering cylinder piston can be used. In this study, the frequency response characteristics of the metering cylinder are investigated for the spool displacement input. The transfer functions of the servo valve-metering system are derived taking into consideration the oil inertia effect in the transmission lines. The theoretical results of the transfer functions are verified through computer simulations and experiments. The oil inertia effect in the transmission lines was found to have a very significant effect on the bandwidth frequency of the servo valve-metering cylinder system. In order to more precisely measure the dynamic characteristics of a servo valve, the metering cylinder should be set up to minimize the oil inertia effect by increasing the inner diameters of the transmission lines or shortening their lengths.

• 드라이브 ㆍ 컨트롤
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• 제15권1호
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• pp.1-9
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• 2018

The spool displacement of directional control valve can be considered as the standard signal to measure the bandwidth frequency of a directional control valve. When the spool displacement is not available, the metering-orifice system is implemented in this research as an alternative way of measuring the 90 degrees phase bandwidth frequency of the hydraulic directional control valve. The inertia effect on the transmission line oil induces the phase lead of the valve load pressure when compared with the phase of spool displacement. The capacitance effect of the oil induces the phase lag of the valve load pressure. The phase of the load pressure can be adjusted to be the same as that of the spool displacement by controlling the opening area of the metering orifice. A series of experiments were conducted to verify the effectiveness of the metering orifice. The 90 degrees phase bandwidth frequency measured from the valve load pressure was significantly deviated in some cases from the frequency of the spool displacement. The metering orifice was hard to be applied to measure the -90 degrees phase bandwidth frequency of the high precision.

• 드라이브 ㆍ 컨트롤
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• 제14권2호
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• pp.1-8
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• 2017

The spool displacement of a directional control valve can be considered as the standard signal for the measurement of its bandwidth frequency. When the spool displacement is not available, the metering-orifice system is suggested in this study as an alternative way to measure the - 3 dB amplitude-ratio bandwidth frequency of the hydraulic directional-control valve. The amplitude ratio of the metering-orifice pressure can be adjusted to equal that of the spool displacement through the controlling of the metering-orifice opening area. A series of experiments were conducted to verify the effectiveness of the metering-orifice system. The metering orifice was confirmed as adequate for the measurement of the - 3 dB amplitude-ratio bandwidth frequency.

• 드라이브 ㆍ 컨트롤
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• 제15권4호
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• pp.119-124
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• 2018

• 드라이브 ㆍ 컨트롤
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• 제15권4호
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• pp.102-107
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• 2018

• 드라이브 ㆍ 컨트롤
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• 제15권4호
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• pp.108-112
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• 2018

• 드라이브 ㆍ 컨트롤
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• 제18권1호
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• pp.17-23
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• 2021

The flow signal or spool position signal is used to determine the dynamic characteristics of directional control valves. Alternatively, the signal of spool position or flow can be replaced with the velocity of a low friction, low inertia actuator. In this study, the frequency response of the servo valve equipped with a spool position transducer is measured with a metering cylinder. The input signal, spool displacement, load pressure, and velocity of the metering cylinder are measured, and the theoretical results from the transfer function analysis are verified. The superposition rule for magnitude ratio and phase angle was found to be always applicable among any signal type, and it was found that the load pressure signal is not appropriate for use as the signal for measuring the frequency response of a servo valve. It was confirmed that the frequency response of a servo valve using metering cylinder was similar to the results from a spool displacement signal. The metering cylinder used for measuring the frequency response of a servo valve should be designed to have sufficiently greater bandwidth frequency than the bandwidth frequency of the servo valve.

• 항공우주기술
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• 제2권2호
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• pp.11-17
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• 2003

항공기 전기체 구조시험에 과하중 방지 밸브로 사용되는 미터-아웃방식의 유량제어 방법을 본 보고서로 소개하고자 한다. 전기체 구조시험에서는 여러 요인에 의해 비상시험 중지상태(덤프상태)가 발생하며, 이 상태가 되면 서보밸브의 전원이 차단되어 하중을 가하던 실린더의 양단에 외부조건에 따른 급격한 압력변화가 발생되고, 이 변화는 시험체에 과하중으로 가해진다. 본 연구에서는 덤프로 기인한 하중으로부터 시험체를 보호하기 위해 사용되는 오리피스 면적조절 기술에 대해 소개하였고 실제 시험에서 유압작동기의 덤프특성이 효과적으로 감소되고 있음을 확인하였다.