• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1339-1342
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• 2005

The development of an accurate and energy saving pneumatic regulator that may be applied to a variety of practical pressure control applications is described in this paper. A novel modified pulse width modulation(MPWM) valve pulsing algorithm allows the pneumatic regulator to become energy saving system. A comparison between the system response of conventional PWM algorithm and that of the modified PWM(MPWM) algorithm shows that the control performance is almost the same, but energy saving is greatly improved by adopting this new MPWM algorithm. The effectiveness of the proposed control algorithm is demonstrated through experiments with various reference trajectories.

• 한국정밀공학회지
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• 제22권8호
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• pp.64-70
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• 2005

The development of an accurate and energy saving pneumatic regulator that may be applied to a variety of practical pressure control applications is described in this paper. A novel modified pulse width modulation(MPWM) valve pulsing algorithm allows the pneumatic regulator to become energy saying system. A comparison between the system response of conventional PWM algorithm and that of the modified PWM(MPWM) algorithm shows that control performance is almost the same, but energy saving is greatly improved by adopting this new MPWM algorithm. The effectiveness of the proposed control algorithm are demonstrated through experiments with various reference trajectories.

• 대한기계학회논문집A
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• 제21권10호
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• pp.1619-1625
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• 1997

This paper concerns a 2-axis PR type pneumatic manipulator system translating in vertical and rotating in horizontal directions. A simplified linear model is mathematically formulated similar to the pneumatic acturators in dynamic responses in order to devise an appropriate position control scheme. A PD controller preceding the on/off solenoid valve turns out not only economical but also effective in reducing rise time and amplitude of limit cycles, if its control gains are determined on the basis of frequency response. And, additional implementation of symmetric or asymmetric deadband at the PD controller output greatly helps minimize valve opening numbers, positional error, and undesirable direction-dependent property due to the gravitational load. Such a control concept is synthesized through numerical simulations and next applied to the experimental set-up, featuring enhanced positional servo characteristics.

• 한국지열·수열에너지학회논문집
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• 제17권3호
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• pp.1-12
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• 2021

In this study, the effects of various operational conditions for floor radiant heating system were researched by experiments. Hot water supply set temperature, indoor air set temperature and supply water flowrate were considered as operational conditions. The control method for this system is On-Off control of automatic thermostatic valve. The purpose of this study is to evaluate indoor thermal control characteristics and energy performance, respectively. As a result, if lower supply water temperature is applied, the supply and return temperature difference is reduced and energy consumption of heat supply is also reduced.

• 설비공학논문집
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• 제29권1호
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• pp.38-42
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• 2017

This study proposes an idea for energy saving in apartment machine rooms. A conventional district heating system is equipped with constant-flow pumps and bypass valves to regulate pump differential pressure. Each family unit is equipped with a constant-flow on/off valve. This leads to excessive hot water circulation and a high return temperature. To reduce energy loss, this study assumes that each family unit is renovated with a heating valve which regulates the return temperature at $35^{\circ}C$. The hot water supply pump is also replaced with a pump with an inverter to vary flow rate. Expected energy savings is then estimated from field test data. According to the results, pump electricity consumption was reduced by 6,100 kWh for a family unit building over about half a year. The supply temperature can also be lowered by $5^{\circ}C$, which can contribute to a production of electricity of 10.3 kWh/ton of hot water.

• 드라이브 ㆍ 컨트롤
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• 제19권1호
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• pp.69-75
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• 2022

This study aimed to develop solutions for the intermittent performance deterioration of self-propelled spinach harvesters through analysis model. The study was conducted in the following manner. First, changes in performance deterioration and surplus flow, which result from oil temperature changes, were analyzed by simulating actual sequential harvesting movements, which involve driving with actuators operated simultaneously, by analysis model developed in a previous study. Second, fundamental solutions for surplus flow problems were presented. Third, the solutions were applied to a virtual environment to present their practicality and quantitative effects. The two solutions based on the study results were as follows. First, a closed center-type directional control valve was applied to the hydraulic circuit. Second, an unloading system was set up through an on-off solenoid valve.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.364-369
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• 1987

It has recently shown that a solenoid valve can be utilized in a hydraulic position-control system by discontinuous control methods. The objective of this study is to investigate the effects of solenoid valves on the response characteristics of a hydraulic position-control system by applying two kinds of discontinued control methods i.e., Simple On-Off (SOF) and Pusating On-Off(POF) controls. Three types of solenoid valves i.e. low-frequency, closed-center type (LF/C), high-frequency, closed-center type (HF/C), low-frequency, tandem-center type(LF/T) were used in this study. Effects of loading conditions and control parameters on the response characteristics were experimentally examined and compared each other. Pressure transients within the actuator were also studied.

• 대한기계학회논문집
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• 제12권6호
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• pp.1282-1289
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• 1988

본 연구에서는 형태와 특성이 다른 솔레노이드 밸브를 사용한 위치제어 시스 템에 위에서 언급한 두가지 단속적 제어 방법을 적용하여 이들 밸브의 형태와 특성이 시스템의 응답특성에 미치는 영향을 실험적으로 규명하고 실린더 내의 압력 변화에 미 치는 영향도 조사하였다.

• 한국가스학회지
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• 제22권3호
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• pp.84-90
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• 2018

정수장에서 염소 누출 사고 시 피해를 최소화하는 방안을 연구하였다. 장외영향평가의 위험도는 영향범위내 주민수와 사고 발생 빈도의 조합으로, 취급시설 운전온도, 긴급차단밸브 설치 위치 및 시설의 밀폐정도에 따른 피해범위 변화를 분석하여 피해범위 내 주민 수를 줄일 수 있는 최적의 조건을 제시하였다. 피해범위 산정은 KORA(Korea Off-site Risk Assessment Supporting Tool) 프로그램을 이용하였고, 운전온도가 낮아질수록, 용기의 브렌치 배관마다 긴급차단밸브가 설치될수록, 시설의 밀폐수준이 높을수록 피해범위가 감소하였다. 최악의 사고시나리오에서 감소율은 각각 17.6%, 71%, 34.5% 이며, 대안의 사고시나리오에는 각각 31.6%, 69.0%, 34.8% 이다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제4B권2호
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• pp.39-46
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• 2004

Modern users demand that the on and off type solenoid actuator should be smaller, lighter in weight, lower in consumption power, and higher in response time. The complete design satisfying such requirements can be achieved when electromagnetic theories and empirical knowledge are combined. This paper presents various types of empirical coefficients essentially needed for optimal design of a solenoid actuator. The values of these empirical coefficients are obtained through extensive experiments over a great length of time for various kinds of solenoid actuators. We have developed a design program that is composed by combination of governing equations and empirical coefficients, and have also manufactured a prototype solenoid actuator based on the final results of the design program. The propriety of the design program and empirical coefficients have been proven by experiments.