• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1152-1158
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• 2011

In this paper a configuration of the load evaluation device for the tilting actuator using hydraulic power is presented, which makes it possible to measure the force action on the tilting actuator. It is possible to measure only current using the conventional electro-mechanical actuator when the bogie is in the process of the tilting. This makes impossible to measure the force acting on the tilting actuator. In order to overcome this problem a kinetic mechanism test system using hydraulic cylinder is proposed. The system are consisted of hydraulic cylinder for the tilting actuation, control system to control hydraulic power, sensors to measure for force and displacement and monitoring system for the user interface.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.150-151
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• 2007

In hydraulic oil pump system, pressure has a linear relationship with output torque of motor. Torque control of pump drive can easily output stable pressure, and it can retain required pressure at minimum speed to save power consumption. Switched reluctance motor(SRM) has many advantages such as low cost and low inertia. It can generate high torque at low speed. But inherent high torque ripple of SRM influences performance of pressure control in hydraulic oil system. This paper presents direct instantaneous torque control(DITC) of hydraulic oil pump system. DITC method can reduce inherent torque ripple of SRM, and output smoothing torque to load. So the proposed hydraulic oil pump system can support smooth pressure and fast dynamic power supply to the hydraulic pump system. At last the proposed hydraulic oil pump system is verified by computer simulation and experimental results.

• Journal of Power Electronics
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• v.9 no.3
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• pp.491-498
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• 2009

The hydraulic-oil pump is widely used for building machinery, brake systems of vehicles and automatic control systems due to its high dynamic force and smooth linear force control performance. This paper presents a novel direct instantaneous pressure control of the hydraulic pump system with SRM drive. The proposed hydraulic pump system embeds the pressure controller and direct instantaneous torque controller. Due to the proportional relationship between pump pressure and torque, pressure can be controlled by the motor torque directly. The proposed direct torque controller can reduce inherent torque ripple of SRM, and develop a smooth torque, which can increase the stability of the hydraulic pump. The proposed hydraulic pump system has also fast step response and load response. The proposed hydraulic pump system is verified by computer simulation and experimental results.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.158-165
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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 agreement between simulation and experimental results shows the validity of the simulation model. The parameter sensitivity analysis such as valve opening area, torsional stiffness for system design are carried out by the analysis and experimental method.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.999-1006
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• 2020

This study was conducted to develop an efficiency prediction program of a hydraulic secondary energy converter for calculating annual power generation of a Wavestar type wave power generator. Using the period and wave height obtained from the frequency domain analysis, the behavior of the floating body was obtained by assuming the sin function. The piston displacement and speed of the hydraulic cylinder were calculated considering the behavior of the floating body and the shape of the mechanism. The numerical simulation of the hydraulic system was performed by physically modeling the hydraulic cylinders, check valves, hydraulic motors, which are the main devices. In the future, this analysis program will be used to develop a program for estimating annual power generation of a moveable body type wave power generation device.

• Journal of Drive and Control
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• v.18 no.2
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• pp.1-8
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• 2021

In this work, a circuit with a hydraulic power unit is formulated as a means of predicting the behavior of the prefill valve in the future. The behavior of the prefill valve can be examined by the measurements of the configured power unit, and the performance is determined by using hydraulic pumps, relief valves, and hydraulic hoses that make up the power unit. In particular, pressure/flow pulsation generated by hydraulic pumps can cause instability in the prefill valve and cause noise-induced degradation of the overall performance and reliability of the hydraulic system containing the prefill valve. Therefore, to study the behavior and performance of the prefill valve in a relatively accurate manner, the prediction of the characteristics of the hydraulic power unit driving the prefill valve is very important. In this study, the pulsation characteristics of the hydraulic pump were analyzed to theoretically demonstrate its relationship with different settings of the power unit, such as relief valve pressure settings and the presence/absence of the hose.

• Journal of Drive and Control
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• v.17 no.3
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• pp.15-25
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• 2020

The cycle time and power saving effect of a hydraulic hybrid injection molding machine using a servo motor are considered in this paper. In order to verify control characteristics, such as pressure and speed, experiments were performed with the hydraulic hybrid injection molding machine, clamping force of 110 ton. The power consumption and production cycle time of a conventional hydraulic injection molding machine were measured to compare its performances with the hydraulic hybrid injection molding machine. An injection molding machine with a clamping force of 1300 ton was used as the conventional machine, the hybrid machine was implemented by replacing its induction motors with servo motors. In the remodeled hybrid machine, experiments were performed to investigate how the displacement of the mold clamping pump affects the power consumption and production cycle time. The results showed that the production cycle time of the hybrid injection molding is similar to a conventional hydraulic injection molding machine but with a significant energy saving of about 40%.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.1
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• pp.65-76
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• 1999

Our status of off-shore stow-net fishery is in face with many difficult problems; the lack of fisherman by evading the 3-D occupation, the safety accident by unskilled crew and old type fishing system. In order to solve those problems, it is necessary to save the man power and ensure the safety of fishing work by the effective utilization of power and automatization of fishing gear system. This is consists of the side drum driven by main engine, the net hauler, the bow and stern capstan, jib crane etc. Therefore, we suggest the design on unification of power device of fishing gear system as follows; (1) fishing system by uni-hydraulic power and (2) fishing system by electric motor and electro-hydraulic power.

• Journal of Drive and Control
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• v.9 no.2
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• pp.8-14
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• 2012

Electro-hydraulic spring return actuator(ESRA) is utilized for air conditioning facilities in a nuclear power plant. It features self-contained, hydraulic power that is integrally coupled to a single acting hydraulic cylinder and provides efficient and precise linear control of valves as well as return of the actuator to the de-energized position upon loss of power. In this paper, the algebraic equations of ESRA at steady-state have been developed for the analysis of static characteristics that includes control pressure and valve displacement of pressure reducing valve, flow force on flapper as well as its displacement over the entire operating range. Also, the effect of external load on piston deviation is investigated in terms of linear system analysis. The results of static characteristics show the unique feature of force balance mechanism and can be applied to the stable self-controlled mechanical system design of ESAR.

• Transactions of The Korea Fluid Power Systems Society
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• v.7 no.2
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• pp.19-26
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• 2010

The typical trunk lid system for vehicle is composed of a hinge having 4-bar link and gas lifter. Here, the energy regenerative brake of hydraulic driven systems is applied to the tail gate system for vehicle and removed the gas lifter. The new tail gate system is composed of a hydraulic pump by electric motor, a hydraulic motor, four check valves, an accumulator, a relief valve and a directional control valve. The dynamic characteristics of the hydraulic motor system, such as the surge pressure and response time, are investigated in both brake action and acceleration action. The capacity selection method of accumulator by mathematical model is based upon trial and error approach and computer simulation by AMEsim software is carried out.