• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.305-310
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• 1998

This research conducted concerning measures for the influence reduction to an investigation in the structure of offshore breakwater maintenance, an evaluation, a reexamination of the forecast, and a peripheral sediment transport environment. Furthermore, it aimed at the establishment of the beach transformation forecast method based on a hydraulic model study and a numeric simulation. A good result was obtained from a hydraulic model experiment and a numeric simulation as part of the basic research. And a qualitative evaluation of the flow field around the structure became possible since a numeric simulation examined flow field characteristics.

• 물과 미래
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• 제15권4호
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• pp.31-37
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• 1982

본 연구는 매빈 지형변동에 관한 이동상 수리모형실험에 있어서의 난점인 매상저질축척 및 시간축척을 결정하는 방법을 제안하고 이 상사율에 의해 현지와 재현성이 좋은 실험결과를 얻었다.

• 한국유체기계학회 논문집
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• 제3권3호
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• pp.25-30
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• 2000

Thermodynamic method of pump performance measurement calculates pump efficiency and flowrate by measuring fluid temperature increase and pressure rise through the pump. The theory of this method is investigated and precise comparison experiment with classical hydraulic method was conducted to verify the accuracy. Classical hydraulic pump performance measurement results and Yatesmeter results based on the thermodynamic method showed good agreement in measured performance.

• 한국농공학회지
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• 제42권
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• pp.31-37
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• 2000

Regulated Deficit Irrigation (RDI) is one of the most important measures for the water-saving and high yield of crops. RDI is based on the crop and water relations. The theories of RDI were analyzed using the experiment data in Shaanxi and Gansu Province. There are several problems of RDI in practical use, which include; the uncertainty of crop-water relations, the proper growth stages and water deficit degree of RDI applied, and the requirements of RDI to irrigation system and irrigation techniques.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.253-257
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• 2007

In case of the hydraulic turbine dynamo room at Dam, due to its big volume and reflexible finishing material, since the noise of electricity-generation is amplifying, it influences the difficulty of mutual communication among the workers, also it is causing both mental and physical damages to those workers in the neighboring office. Accordingly, after presentation of the optimized renovation model of the hydraulic turbine dynamo room using the acoustic simulation, this Research has compared and evaluated them using the auralizational technique between the present condition of "before improvement" and the acoustic condition of "after improvement". As the result of psycho-acoustics experiment, as the acoustic conditions at both "before & after Improvement" were apparently compared, it appeared that there is a considerable amount of noise-reduction effect at psycho-acoustics. It is considered that such material could be utilized as the valuable data hereafter for the time when any construction and renovation of the hydraulic turbine dynamo room and other similar workshop.

• 한국정밀공학회지
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• 제21권1호
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• pp.101-108
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• 2004

An electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to obtain stable control performance. In this report, we applied disturbance estimation and compensation type robust control to all axes in a 3-link electro-hydraulic manipulator. From the results of experiment, it was confirmed that the performance of trajectory tracking and attitude regulating is greatly improved by the disturbance observer, which model is the same for each axis. On the other hand, for the autonomous assembly tasks, it is said that compliance control is one of the most available methods. Therefore we proposed compliance control which is based on the position control by disturbance observer for our manipulator system. To realize more stable contact work, the states in the compliance loop are feedback, where not only displacement but also velocity and acceleration are considered. And we applied this compliance control to Peg-in-Hole insertion task and analyzed mechanical relation between peg and hole. Also we proposed new method of shifting the position of end-effector periodically for the purpose of smooth insertion. As a result of using this method, it is experimentally confirmed that Peg-in-Hole insertion task with a clearance of 0.05［mm］can be achieved.

• 드라이브 ㆍ 컨트롤
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• 제12권4호
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• pp.28-34
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• 2015

Because heavy-duty construction vehicles such as excavators are required for good engine-room cooling capacity, a hydraulic gear motor is adopted in the cooling fan drive mechanism to actively control the output speed, instead of adopting the conventional ON/OFF type belt drive. While gear motors are normally limited to 140bars of operating pressure, those for the cooling fan are capable of operating at continuous pressures of up to 220bars. After assembly, all gear motors for high pressure must pass an aging test which is a kind of the wearing process between the gear teeth and motor housing. During the aging process with gradual pressure increments, gear sticking sometimes occurs due to abnormal wear, resulting in defects. This paper focuses on a gear-sticking free aging test controller that is designed together with the knowledge of an experienced operator and the analysis results of experimental data of the gear jamming phenomenon. From the aging experiment, it is demonstrated that the developed controller that can alter the setting pressure of the load pump is effective for stabilizing the abrupt increase in the motor input pressure, thus preventing the hydraulic motor from stopping. This is expected to be helpful for the reduction of defects and increase in productivity.

• 한국방재학회 논문집
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• 제9권2호
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• pp.87-93
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• 2009

래버린스 위어는 마루부의 형상이 직선이 아닌 위어로 월류 폭을 증가시켜 월류량을 증대시키는 수공구조물이다. 최근 강우량 증가에 의한 댐 여수로의 개선 및 관개시설 및 운하관련 수공구조물 등 래버린스 위어의 활용범위는 다양하고 이에 관한 연구가 필요한 실정이다. 본 연구의 목적은 수리모형실험을 통해 삼각형 래버린스 위어 형상에 따른 수리특성 및 유량특성을 분석하여, 삼각형 래버린스 위어의 유량계수식을 제시하는데 있다. 본 연구에서 제시된 유량계수식은 상관계수, 잔차의 합, 평균절대오차율을 분석한 결과 적용성이 있는 것으로 나타나 댐의 여수로 및 관개시설 등 수공구조물 설계에 적용이 가능할 것이다.

• 상하수도학회지
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• 제11권3호
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• pp.67-78
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• 1997

The objective of study was to examine to transient response of hydraulic shock loading in activated sludge process for treatment of municipal sewage. The general experiment approach was to operate the system under steady-state(pre-shock), then to apply step changes during 24hours in fourfold hydraulic shock loading at the same organic loading. Performance was assessed in both the transient state and the new steady-state(post-shock). Three bench scale activated sludge reactors were operated to investigate the effect of fourfold hydraulic shock loading on TSS and COD removal efficiency. In activated sludge reactors operated with 13hours and 7hours of HRT, effluent quality of all reactors was not changed for few effects, and also showed no foaming and no sludge bulking. Those results are the same as sludge withdrawn reactors. The effect of fourfold hydraulic shock loading on the activated sludge reactors operated with 3hours of HRT was most severe. The effluent quality was deteriorated significantly and generate foaming in reactors. Less than 24hours after the fourfold shock loading applied, the activated sludge system seemed to attain a new steady-state condition as show by effluent.

• 드라이브 ㆍ 컨트롤
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• 제16권1호
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• pp.7-13
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• 2019

The objective of this study was to present a damped pneumatic suspension, a bike fork suspension, which can adapt itself to incoming road excitations is presented in this paper. It consists of a hydraulic damper and a pneumatic spring in parallel with a linear spring. The study also proposed a variable and switchable orifice, in the hydraulic damper, to select appropriate damping property. Hydraulic-pneumatic circuit model for the bike fork suspension was established based on AMESim, in order to predict its performance. In addition, elastic-damping characteristics of the fork such as spring constant and viscous damping coefficient were computed and compared, for validation, with those evaluated by experiment using the universal test machine. Through simulation analysis and test, it was established that the hydraulic-pneumatic circuit model is effective and practical for development of future MTB suspensions.