• 한국환경과학회지
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• 제24권7호
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• pp.939-946
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• 2015

Hydraulic conductivity is an important parameter in the analytical model of groundwater. This study analyzed the groundwater movement characteristics by estimating optimal parameters according to hydraulic conductivity input methods with the MODFLOW model which is widely used. It first estimated the optimal parameters by dividing hydraulic conductivity zones by attitude. Next, it estimated optimal parameters by geological characteristic. It analyzed the groundwater movement characteristics by applying the recharge quantity and amount of evapotranspiration of drought periods and flood years with the estimated parameters. As the result was analyzed that there are differences of observation water level values according to hydraulic conductivity input methods but there is no big differences of overall groundwater movement characteristics by hydraulic conductivity input method, the two methods have found to be applicability in analyses of groundwater. So, it is judged that studies on more exact application of hydraulic conductivity and the application methods are needed.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.201-211
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• 2002

In this research, we are trying to research about hydraulic system design and vehicle dynamic modeling far the development of the tire roller. The reason why we would like develop it is that tire roller is one of the most useful machine for the road construction site and application other construction equipments. Here, we conceptualize the new hydraulic system and derive the equations of motion fur dynamic analysis and also investigate system modeling by using a DAQ board. We design the hydraulic circuit of steering and traction mechanism system. This design can be used to create virtual prototypes of construction equipment. So, we studied tire roller to integrate development technology. In system analysis, we formulate hydraulic traction system model and hydraulic steering system model. Also, we integrate DAQ system to acquire experimental results in real tire roller equipment.

• 대한기계학회논문집A
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• 제32권3호
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• pp.280-289
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• 2008

This paper presents design of the quantitative feedback control system of the three axes hydraulic road simulator with respect to the dummy wheel for uncertain multiple input-output(MIMO) feedback systems. This simulator has the uncertain parameters such as fluid compressibility, fluid leakage, electrical servo components and nonlinear mechanical connections. This works have reproduced the random input signal to implement the real road vibration's data in the lab. The replaced $m^2$ MISO equivalent control systems satisfied the design specifications of the original $m^*m$ MIMO control system and developed the mathematical method using quantitative feedback theory based on schauder's fixed point theorem. This control system illustrates a tracking performance of the closed-loop controller with low order transfer function G(s) and pre-filter F(s) having the minimum bandwidth for parameters of uncertain plant. The efficacy of the designed controller is verified through the dynamic simulation with combined hydraulic model and Adams simulator model. The Matlab simulation results to connect with Adams simulator model show that the proposed control technique works well under uncertain hydraulic plant system. The designed control system has satisfied robust performance with stability bounds, tracking bounds and disturbance. The Hydraulic road simulator consists of the specimen, hydraulic pump, servo valve, hydraulic actuator and its control equipments

• 한국습지학회지
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• 제13권2호
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• pp.319-327
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• 2011

수리계수는 하천의 수리학적 특성을 대표하는 인자라고 할 수 있다. 따라서 우리는 하천정비기본계획에 의하여 하천을 측량하고 그 측량성과를 바탕으로 수리계수를 산정하여 왔다. 이러한 수리계수는 하천의 홍수위, 유사량, 수질 산정을 위하여 중요한 매개변수로 활용할 수 있다. 하지만, 하천 측량성과가 없는 미계측 유역의 경우 수리계수를 산정할 수 없는 한계가 있는 것이 사실이다. 이러한 문제점을 극복하고자 SWAT 모형의 방법론을 검토하고 미계측 유역에서 수리계수를 산정하는 방안을 제시하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.651-652
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• 2005

• 한국터널지하공간학회 논문집
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• 제17권4호
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• pp.429-440
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• 2015

본 연구에서는 배수형 쉴드터널 적용시 작용수압의 저감을 평가하기 위해 모형실험장치를 개발하여 배수 및 비배수 조건에서 작용수압 차이를 실험하였다. 모형실험 결과 배수 조건에서 간극수압 증가율이 감소하는 경향을 보였고, 비배수 조건에 비해 전응력이 더 작게 나타나 모형터널 내 지하수 유입에 의해 작용수압이 저감되는 것으로 나타났다. 현장계측 결과 쉴드터널 배면 지반 내 작용수압은 지하수위로 계산되는 수압($r_w{\cdot}H$)보다 약 11~22%정도 적게 나타났다. 모형실험 및 현장계측 결과에서 배수 및 비배수 조건의 이론적인 설계수압과 작용수압의 차이가 나타났는데, 배수형 쉴드터널 적용시 기존 설계수압보다 감소된 수압을 적용하는 것이 가능할 것으로 판단되며, 수압 감소를 통해 세그먼트 단면 축소도 가능할 것으로 판단된다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 춘계학술발표회요약집
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• pp.158-158
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• 1999

• 한국자동차공학회논문집
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• 제14권4호
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• pp.32-38
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• 2006

A clutch hydraulic system for automotive manual transmissions transfers hydraulic pressure generated by driver's pedal manipulation to the clutch mechanism. The foot effort when the clutch pedal is pushed is different than that when the clutch is returned. The effort or load difference, called hysteresis, is caused by the friction produced between rubber seal and inner wall inside the hydraulic cylinder. This clutch pedal travel foot effort hysteresis is essential for a clutch hydraulic system design and analysis. The dynamic model for a clutch hydraulic system is developed and a simulation analysis is performed to estimate the fiction coefficient as a function of the cylinder pressure. The simulation result is then compared to the measurements obtained from a clutch hydraulic system tester to ensure the reliability of the dynamic model and the coefficients estimated. Also the estimated friction coefficients at various pressure values are compared to those reported by an independent study.

• 한국정밀공학회지
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• 제25권4호
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• pp.93-99
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• 2008

The clutch is a subcomponent of the transmission that is designed to engage and disengage power flow between the engine and the transmission. Recently, the engine power of automobile has been continuously increased because of customer's demand for the bigger one. As the engine power is increased, the vibration transmitted to the hydraulic clutch operating system has been increased. Therefore the demand for the reduction of clutch pedal vibration during the operation of the clutch system has been increased. This paper describes the pressure pulsation reduction characteristics of the damper cylinder which is applied to the hydraulic clutch operating system. And the purpose of this study is to confirm the availability of a simulation model and investigating the test results of hydraulic clutch operating system. The test results are compared with the simulation results. Therefore it may be concluded that the simulation model and test results will be very useful f3r the design of hydraulic clutch damper cylinder.

• 한국정밀공학회지
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• 제13권7호
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• pp.78-89
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• 1996

This paper discusses automation of a small-scale hydraulic shovel and its trajectory control. To move an end-effect (grinder) along a desired trajectory, the controller uses PID(proportional-integral- defferential) control and internal pressure of hydraulic cylinder. To apply PID control in the present hydraulic system, the system model is derived physically and its system parameters are obtained by actual measurement. To show the effectiveness of the PID controller and propriety of system model, the computer simulations and experiments are performed. These results of the simulations and experiments indicate that the PID trajectory control of robotic deburring by hydraulic shovel is very effective.