• Journal of Power System Engineering
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• v.21 no.6
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• pp.101-109
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• 2017

The pneumatic driving system has advantages such as high output power per weight and low heat generation rate. However, it is difficult to control the position because of its strong non-linearity such as large friction forces compared to driving force, and heat transfer characteristics that change during operation. Therefore, in order to achieve the control objectives, a robust controller should be designed considering modeling error and model uncertainty. In this paper, a sliding mode controller is designed to improve the position control performance of pneumatic cylinder driving system. Experimental results show that the designed controller achieves the designed control objectives even if the model of the cylinder driving system, such as the initial pressure inside the cylinder and the initial position of the piston is changed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.268-275
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• 1999

The purpose of this study is to propose the method of determining the initial pneumatic membrane structures surface and stresses and displacements. Tension structure such as pneumatic membrane structures is stabilized by their initial prestress and air pressure. The process to find initial structural overall shape of tension structures produced by initial prestress called shape finding. One of the most important factor for the design of membrane structures is to search initial smooth surface, because unlike steel or concrete building elements which resist loads in bending, all tension structure forces are carried within the surface by membrane stress. The result for initial surface of pneumatic membrane element and maximum displacement in large deformation in analysis is compared with well-known nonlinear numerical method such as Newton-raphson method and dynamic relaxation method

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.6
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• pp.794-805
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• 1999

Pneumatic cushioning cylinders are commonly employed for vibration and shock control. A mathematical simulation model of a double acting pneumatic cushioning cylinder designed to absorb shock loads is presented which is based on the following assumptions; ideal equation of state isentropic flow through a port conservation of mass polytropic thermodynamics single degree of freedom piston dynamics and energy equivalent linear damping. These differential equation can be solved through numerical integration using the fourth order Runge-Kutta method. An experimental study was conducted to validate the results obtained by the numerical integra-tion technique. Simulated results show good agreement with experimental data. The computer simulation model presented here has been extremely useful not only in understanding the has been extremely useful not only in understanding the basic cushioning but also in evaluating different designs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1231-1234
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• 2003

Pneumatic servo valve which is widely applied in industrial world is advanced technology compounded with electric, electronic and machine. And It is consist of Linear Force Motor. Spool Commutation Mechanism and Microprocessor. In this study, we accomplished test method of Linear Force motor test, Static characteristic test, Dynamic characteristic test for KS(Koran industrial standard) of Pneumatic servo valve. we accomplished study about the main item of Static characteristic test which is related to unload flow characteristic test. And Dynamic characteristic test was step input test and frequency response test. Specially about frequency response test, There was a difficulty resulting from the time delay problem caused by the basic compressibility of air. In order to solve the problem in this study. we proposed two methods. First, displacement of the servo valve spool was directly measured by using a laser sensor. Second, method of calculating control flow by measuring pressure and temperature of chamber.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1303-1308
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• 2008

In this study, we researched how to estimate life-stress relationship and acceleration factor through performing accelerated life test and analyzing it. The purpose of this study is to predict life of pneumatic cylinder within short time which is widely used in automation manufacturing line. In design of accelerated life test, we selected operating pressure and load that have the most influence on main failure mode of pneumatic cylinder as accelerated factor. We used two-way factorial design for arranging of test condition to accelerated factor and accelerated level.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1387-1390
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• 2008

Pneumatic cylinder is widely used in the various industrial fields. Reliability Study of this field is very important part to the related companies. In this study, we want to predict the life of pneumatic cylinder using Cox (or proportional hazards) model. Used in biomedical applications, the Cox model can be used as an accelerated life testing model. We considered working pressure and temperature as stress factors. The statistical software is used to analyze and forecast the life data.

• Journal of Power System Engineering
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• v.4 no.1
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• pp.20-25
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• 2000

In this study, methods for the characteristics measurement of pneumatic elements using isothermal chamber, the methods for the flow rate and dynamic characteristic measurement of pneumatic control valve, are proposed. An isothermal chamber is a chamber in which the steel wool is stuffed and isothermal condition can almost be realized. Therefore, the instantaneous flow rate could be measured only from the pressure response using the state equation of gas. Effectiveness and simplicity of the proposed method are confirmed by comparing the measured results obtained by proposed methods with the methods defined JIS and the ISO standards.

• 한국기계연구소 소보
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• s.20
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• pp.41-48
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• 1990

Electro-pneumatic valves are an electro-mechanical device which convert electric signal into pneumatic flow rate or pressure signal. Recently, the development tendency of electro-pneumatic valve is to make the valve with more compact and less electric power consumption style. To make the valve such as a style, the role of solenoid part is very important. This paper is used in the finite-element method for the purpose of evaluating the magnetic property of solenoid and analyze flux distribution of solenoid theoretically. From flux contour line which is obtained by numerical analysis, it verified that the plunger shape and physical property of solenoid part have influence on saturation phenomenon and leakage of magnetic fluxs. This paper made an experiment on the measurement of dynamic response time and force in order to confirm the propety of analytic result, and confirmed a good agreement between analysis results and experiment results.

• Journal of the Korean Institute of Gas
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• v.13 no.5
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• pp.7-14
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• 2009

This study describes to analyze the pressure drop characteristics for the air-particle flow in pneumatic coal powder conveying system and to proper design of the orifice located in the system to enhance combustion efficiency in furnace of the coal-fired power plant. Usually the system consists of the straight type pipe, the curved type pipe and the elbow, which cause increase of the pressure drop. In this study, the pressure drop arised in the system with straight and curved type pipes is analyzed with interactions of motion of air flow and particles. It is realized that total pressure drop increases with increasing of the pipe length and the angle of curved type pipe due to friction loss of air and particles in the system. The program for analysis of the pressure drop and optimum design of the orifice size for air flow control in the system is developed. The result is also compared with the existing system.

• The Journal of Engineering Geology
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• v.14 no.2
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• pp.189-197
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• 2004

For a long time, groundwater has been used for a substitution for surface water but recently many problems have risen due to shortage of water resources and decrepitude of waterwells. Pneumatic fracturing technique is likely to be an efficient way to solve the problem of tile wells, in which pressure under the ground is applied to increase the amount of ground water. When applied pressure is given artificially to unstabilize the rock stress or to remove substances between fractures the groundwater can inflow. As the air pressure applied on the base rocks is stronger, permeability is getting higher, thus producing much groundwater than ever before. The result of this study show 15% increase of pumping rate in the P-5 well. After pneumatic fracturing pumping rate changed from 26m3/day to 30m3/day, drawdown rate increase from 51.12m to 56.58m, and specific yield also increased from 0.51m3/day to 0.53m3/day.