• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.7-14
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• 2018

In this study, a new check valve was studied to improve the load pressure of a brake system with a small piezoelectric-hydraulic pump. During the pressurization process, the steady-state pressure at the load is affected by the ratio of the cross-sectional area of the check valve the chamber pressure and load pressure. Since the flow path cover of the check valve is made wider than the cross-sectional area of the output flow to prevent backflow, a method of reducing the area ratio is proposed for a higher load pressure by mounting an additional mass to a thin plate spring type check valve. To identify the effect of mounting an additional mass to the existing check valve on the load pressure, a simple brake system with a small piezoelectric-hydraulic pump was modeled using a commercial code AMESim. The AMESim modeling was verified by comparing the simulation results with the experimental results of the pump the existing check valve. The additional mass was added to the verified AMESim modeling and higher load pressure was able to be obtained through simulation. The 35% performance improvement in load pressure identified by carrying out pressurization test of the brake system after adopting the new check valve the small piezoelectric-hydraulic pump.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.4
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• pp.21-27
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• 2007

A hydraulic breaker for construction machinery generally used for the destroying and disassembling of buildings, crashing road pavement, breaking rocks at quarry and so on. So the measurement of the impact energy of a hydraulic breaker is very important thing to prove its capability to manufacturers and customers. Therefore the prediction of impact energy in design process is very helpful to the most of breaker manufacturers. In this study, we carried on modeling and simulation of a hydraulic breaker to predict impact energy via commercial CAE software. The modeling and simulation of a hydraulic breaker was achieved with two parts. One is a hydraulic circuit analysis part via AMESim and the other is impact strain analysis part via ANSYS.

• Journal of Drive and Control
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• v.12 no.2
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• pp.1-6
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• 2015

Recently, the Electro-Hydrostatic Actuator(EHA) has been developed as a result of research on energy saving. EHA is usually composed of a direct driven pump from an electric motor and is available to control cylinder displacement or velocity with high efficiency. In addition, it has the advantage of compactness, minimum leakage and availability of decentralized control. In this study, an EHA system was designed to decrease the path tracking error and manufactured for test. The linearization method provided in AMESim software was used to derive the model of EHA system. The derived model was applied to design the PI-D controller to effectively overcome the disturbance. The effectiveness of this controller was verified by further testing.

• Tribology and Lubricants
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• v.29 no.3
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• pp.171-179
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• 2013

In this study, hydraulic systems of the rope brake system of an elevator are modeled to evaluate design parameters that consider friction characteristics such as cylinder pressure, piston displacement, and flow rate. Hydraulic systems of the rope brake system are analyzed using the commercial program AMESim. Analysis modeling data are compared with data obtained from experiments, and the analysis modeling results are found to be reliable. The analysis results will be used to design hydraulic systems of the rope brake system of elevators.

• Journal of Aerospace System Engineering
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• v.4 no.1
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• pp.1-9
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• 2010

As the rocket KSLV-1 called NARO was launched lately, development of domestic rocket technology has been accelerated elastically. Since the rocket technology needs a lot of empirical data, a variety of experiments should be done and lots of time have to be spent for accumulating the foundation of technology. However using a computer can be the solution to close a gap of technique because the simulation can be executed in short time against real experiments and calculate a multiplicity of cases easily. In this research, the transient analysis of turbopump-fed liquid rocket system was worked by the one dimensional modeling. The rocket system consists of the modulized components that are engine, turbopump and so on. For 70 ton class system, the rocket transient process of starting was studied and the performance analysis in steady condition was achieved. In addition, the estimation of nozzle internal flow was investigated by using a nozzle coefficient.

• Journal of Drive and Control
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• v.11 no.3
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• pp.1-6
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• 2014

In forklifts, the machine performance is largely depended on the transmission performance. The aim of this paper is to develop a complete model of transmission control valve (TMV) system of a typical forklift using AMESim simulation tool. By using the developed TMV model, it becomes easy to investigate the system concept, working principle, and performance. In addition, an optimization on the TMV structure can be achieved by using this model with tunable parameters. Simulations have been carried out in a comparison with the actual experiments to verify the model.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.167.2-167.2
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• 2011

Motions in nature, for example ocean wave, has been playing a significant role for generating electricity production in our modern life. This paper presents an innovative approach for electric power conversion of the vast ocean wave energy. Here, a floating-buoy wave energy converter (WEC) using hydrostatic transmission (HST), which is shortened as HSTWEC, is proposed and designed to enhance the wave energy harvesting task during all wave fluctuations. In this HSTWEC structure, the power take-off system (PTO) is a combination of the designed HST circuit and an electric generator to convert mechanical energy generated by ocean wave into electrical energy. Several design concepts of the HSTWEC have been considered in this study for an adequate investigation. Modeling and simulations using MATLAB/Simulink and AMESim are then carried out to evaluate these design concepts to find out the best solution. In addition, an adaptive controller is designed for improving the HSTWEC performance. The effectiveness of the proposed HSTWEC control system is finally proved by numerical simulations.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.57-65
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• 2011

In this paper, a hydropneumatic modeling and dynamic analysis of a heavy truck semi-active cabin air suspension system is presented. Semi-active cabin air suspension system improves driver's ride comfort by controlling the damping characteristics in accordance with driving situation. So it can reduce vibration between truck frame and cabin. Semi-active cabin air suspension system is consist of air spring, leveling valve and CDC shock absorber, and full cabin system are mathematically modelled using AMESim software. Simulation results of components and full cabin system are compared with experimental data of components and test results of a cabin using 6 axis simulation table. It is found that the simulation results are in good agreements with test results, and the hydropneumatic model can be used well to predict dynamic characterics of heavy truck semi-active cabin air suspension system.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.128-134
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• 2008

In this paper, a hydropneumatic modeling and analysis of a heavy truck cabin air suspension system is presented. Cabin air suspension system is a system which improves ride comfort of a heavy truck and it can reduce vibration between truck frame and cabin. The components of the system, air spring, shock absorber, leveling valve and full cabin system are mathematically modelled using AMESim software. Simulation results of components and full cabin system are compared with experimental data of components and test results of a cabin using 6 axis simulation table. It is found that the simulation results are in good agreements with test results, and the hydropneumatic model can be used well to predict dynamic characteric of heavy truck cabin air suspension system.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.2
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• pp.86-92
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• 2014

Combustion Chamber Test Facility (CCTF) to be constructed in Naro Space Center for re-burning the fuel-rich gas of gas generator have afterburner system. The afterburner system is supplied the Oxygon ($O_2$) gas and Methane ($CH_4$) gas to reduced the harmful exhaust gas. The detailed design for the planned CCTF afterburner system is simulated and analysed by AMESim program through the all of gas supply system components. Afterburner system is performed to verify the pipe size, orifice diameter, and gas supply conditions according to the total gas consumption from analysis of gas supply system.