• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.1172-1177
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• 1993

Dynamic characteristics of a hydraulic power supply are studied theoretically and computationally. The transfer function between the supply pressure and the load flow is derived considering relief valve dynamics, accumulator dynamics, and flow line dynamics. Frequency responses and time responses are obtained in many conditions using the transfer function and nonlinear mathematical model respectively.

• 전력전자학회논문지
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• 제11권1호
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• pp.1-6
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• 2006

본 논문에서는 유압펌프 시스템의 효율적 구동을 위한 SRM 구동시스템이 제안된다. 유압 펌프 시스템이 요구하는 최대 사용 유압 및 사용유량으로부터 적정한 용량의 SRM을 설계 및 제작하고, 시험을 위해 SRM과 제어기를 포함한 전체 유압시스템을 구성한다. 제시한 SRM 구동시스템은 효율적 구동을 위해 속도제어 뿐만 아니라 유압계통의 압력검출로부터 압력제어도 같이 행하며, 이로부터 SRM이 적정한 운전영역에서 구동되도록 한다. 2.2[KW] 12/8극 SRM과 DSP를 사용한 제어기가 설계되고, 이 시스템을 실제 유압시스템에 적용하여 운전 특성을 확인하였다. 그 결과 제안한 시스템이 고효율과 빠른 응답특성을 가짐을 알 수 있다.

• 드라이브 ㆍ 컨트롤
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• 제1권2호
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• pp.9-11
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• 2004

• Journal of Advanced Marine Engineering and Technology
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• 제33권7호
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• pp.1052-1059
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• 2009

The effects of varying the inlet flow angle on the output power of a Francis hydraulic turbine were studied numerically and the result was compared to the experimental results conducted at Korea Institute of Energy Research to determine the brake power of the turbine for each set of operating conditions. The loss of mechanical power of the model turbine was determined by comparing the numerical and experimental results, and thus the turbine efficiency or energy conversion efficiency of the model turbine could be estimated. From the result, it was found that the maximum brake efficiency of the turbine is approximately 46% at an induced angle of 35 degrees. The maximum indicated mechanical efficiency of the turbine is approximately 93% at an induced angle of 25~30 degrees.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.165.2-165.2
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• 2011

Flow with suction to water turbine must be in stable state at small hydraulic power plant. But because of water level fluctuation and water gate effect according to irregular supply of cooling water, it would happen to produce bubble and vortex and finally lead to problems in power-plant system. With utilizing the concept design of double size gate, surface water overflowed the overhead of gate for stable flow at suction. We developed the overflow condition and analyzed the design factor with existed one such as water level(overflow amount) and overhead of water gate(overflow figure). Flow test and CFD simulation say that flow have stable state around suction and 20% of wave reduction effect at surface layer after surface water overflow.

• 한국자동차공학회논문집
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• 제17권1호
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• pp.58-63
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• 2009

Flow rate of the power steering oil pump is affected by oil temperature, engine rpm and pressure of pump. In this paper, considering those conditions, approximate model expressed by flow rate characteristics between hydraulic power steering oil pump and steering gear is proposed. Oil pump displacement is considered to be 9.6cc/rev. which is adapted to mid size car. Flow rate of the oil pump is predicted from the proposed model and compared with experimental data. And catch-up is also predicted in each steering wheel speed and is compared with experimental results.

• 드라이브 ㆍ 컨트롤
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• 제14권3호
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• pp.1-7
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• 2017

Energy consumption of conventional hydraulic excavators controlled by MCV is considerable when negative load is applied because the meter orifice and meter-out orifice are machined in one spool. Therefore, IMV is introduced to save energy use of hydraulic excavators, but existing hydraulic excavators have various advantages so it is difficult to make a clear comparison. In this study, we compare the use of an existing MCV excavator that has many advantages such as negative control, and IMV for boom up and down operation, and if IMV is used to save energy, we will examine the cause. If possible, for comparability under the same conditions, both systems use pressure balance valves to minimize power consumption when not using power in the actuator. The orifice area at each notch of each valve is calculated, and energy saving is verified by comparing the two systems through simulation.

• 유공압시스템학회논문집
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• 제5권3호
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• pp.1-8
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• 2008

The optimal design of a large-size fully hydraulic breaker is studied in this paper. Mathematical modeling of the breaker is established and verified by experiments. Through sensitivity analysis, the key design parameters of the breaker are selected, which mostly affect the performance of the breaker. Taguchi method is used to optimize the key design parameters in order to maximize the output power through simulation using AMESim. As a result, the impact energy is increased by 18.9% and the output power is increased by 12.4% compared with the current design. The pressure pulsation in the supply line is also reduced by the optimization.

• International Journal of Automotive Technology
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• 제6권1호
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• pp.65-70
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• 2005

Pressure ripples, which are inevitably generated by a fluctuation of flow rate caused by a pump mechanism, include noises and vibrations in hydraulic pipeline. These noises and vibration deteriorate the stability and accuracy of hydraulic systems. The accumulator and hydraulic attenuator are normally used to reduce the pressure ripples. In this study, a parallel line is introduced to the hydraulic pipeline for the hydraulic system with a bent-axis piston pump as a method to reduce the pressure ripples. The dynamic characteristics of the hydraulic pipeline with a parallel line are analyzed by a transfer matrix in the frequency domain. The usefulness of the hydraulic pipeline with a parallel line was ascertained by experiment and simulation. The results from the experiment and simulation show that the hydraulic pipeline with a parallel line were effective in reducing the pressure ripples.

• 한국자동차공학회논문집
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• 제16권4호
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• pp.135-142
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• 2008

Hydraulic power steering system has been adopted in seniority passenger and commercial vehicle system for an easy maneuverability and a smoother ride. In this study, hydraulic power steering system analysis model which includes hydraulics and mechanical sub-systems was developed using commercial software, AMESim in order to predict characteristics for various steering components. Each component which constructs system was modeled and verified by experimentally obtained characteristics curves of each components. The parameter sensitivity analysis such as valve opening area, torsional stiffness of torsion bar for system design are carried out by the analysis and experimental method. The predicted results by the development model were a good agreement with experimentally obtained results. The sensitivity investigation results rotary torque when changing an input shaft edge width, was most sensitive, to change in angle and slot width and supply flow of input shaft edge is not a lot sensitively.