• Journal of Drive and Control
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• v.13 no.4
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• pp.7-13
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• 2016

This paper presents the meter-out and meter-in speed control characteristics of a pneumatic cylinder with relief valve type cushion device. The piston displacement and velocity are measured to investigate high speed driving performance with variation of the pressure setting in relief valve, air supply pressure, load mass, the supply and exhaust flow rate from the cylinder. Also, the internal pressures and temperatures driving pressure and cushion chamber are measured. The piston displacements and velocities of meter-out and meter-in control are compared experimentally determined data. A comparison experimental data meter-out and meter-in control show that a relief valve type cushion device is suitable for high speed pneumatic cylinders. The desired response characteristics of piston displacement and velocity are satisfactory adjust the pressure setting of a relief valve with varying system parameters such as air supply pressure, load mass and controlled flow rate.

• Journal of Drive and Control
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• v.9 no.2
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• pp.15-20
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• 2012

Pneumatic cylinder meter-out driving apparatus is used widely because it is clean, lightweight, and can be easily serviced. In this study an estimation method of energy consumption for pneumatic cylinder meter-out driving apparatus is proposed. The proposed method is derived from state equation and energy equation of air, and, the equation of motion of a moving part of a pneumatic cylinder reflecting the characteristics of the meter-out driving. The effectiveness of the proposed method is proved by simulation study and it demonstrates that the proposed method can evaluate the energy consumption quickly and easily when the parameters of the driving apparatus are changed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.1-7
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• 2013

Pneumatic cylinders are widely used to actuators in automatic equipments because they are relatively inexpensive, simple to install and maintain, offer robust design and operation, are available in a wide range of standard sizes and design alternatives. This paper presents a comparative study among the dynamic characteristics of meter-out and meter-in speed control of pneumatic cushion cylinders with a relief valve type cushion mechanism. Because of the nonlinear differential equations and a requirement for simultaneous iterative solution in a mathematical model of a double acting pneumatic cushion cylinder, a computer simulation is carried out to investigate pressure, temperature, mass flow rate in cushion chamber and displacement and velocity time histories of piston under various operating conditions. It is found that the piston velocity and pressure response in meter-in speed control are more oscillatory than with meter-out those when pneumatic cushion cylinders are driven at a high-speed. In meter-out speed control, the effective area of the flow control valve is larger than that of meter-in, and the supply pressure has to be much higher than the pressure required to move the load because it has also to overcome the back pressure in cushion chamber.

• Journal of Power System Engineering
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• v.15 no.6
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• pp.95-100
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• 2011

In this study, an evaluation equation of energy efficiency of pneumatic driving apparatus is proposed. The evaluation equation is derived from state equation and energy equation of air in a control volume, and, the equation of motion of a moving part of a pneumatic cylinder. As a result, distribution of consumption energy and energy efficiency of pneumatic driving apparatus can be analyzed quantitatively. The effectiveness of the proposed method is proved by a pneumatic cylinder driving apparatus using a meter-out driving method.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.24-30
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• 2013

This paper studies the comparative analysis on two different internal cushion devices (the types of needle and relief valve) used to absorb the energy which is generated when the pneumatic cylinder moves with the load at meter-out speed control system. The effect at varying the piston velocity under same driving condition is mainly investigated. The simulation results on pressure in the cushion chamber and the dynamic behavior of the relief valve type cushion device are compared with the needle valve type. Design and performance are improved with the cushion configuration of better quality at high-speed pneumatic cylinder. Based on the relation between absorbed energy and impact energy at cushion process, cushion performance at pneumatic cylinder is evaluated.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2139-2141
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• 1998

This study was carried out about the manufacture of test equipment for traction Motor Driving. The power converter is driven by two converter serially and keep a high power factor of power source. This system is haven all the characteristic of voltage source converter by having a processing ability of regenerating power. The traction motor is controlled by IGBT inverter. The test equipment is composed of traction motor, torque-meter, clutch, and inertia body of tubular type.

• Journal of Sensor Science and Technology
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• v.16 no.4
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• pp.286-293
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• 2007

For safe walking of the people who are blind, walking assistance robot which can detecting and avoiding the obstacle was investigated. The implemented prototype walking assistance robot consists of a obstacle detecting module, a user interface using acoustic signal and a driving module. The obstacle detecting module uses 6 ultrasonic sensors those located at the front part of the robot can perceive the obstacle which is in 3 meter distances and $180^{\circ}$ degrees. It calculates the distance and degree from the obstacle using TOF (time of flight) method and decides the 3-dimensional location of the obstacle. The obstacle information is delivered to the user using acoustic alarm and guide sound. The robot is designed to avoid by itself when the obstacle is detecting and the user only follows it to safe walking. After the designed robot was implemented, driving and obstacle detecting experiments were carried out. The result showed that the designed walking assistance robot will help the people who are blind to walk around safe.

• Journal of ILASS-Korea
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• v.23 no.3
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• pp.122-127
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• 2018

Recently, registrated passenger cars have increased and were close about seventy million at the end 2017 year in Korea. Among the passenger car using gasoline fuel make up forty six percentage of total registrated vehicles. In this study, investigation on real driving emission characteristics in the passenger car using gasoline fuel with various engine displacements were carried out. The real driving emission characteristics were measured and analyzed by using PEMS (Portable Emission Measurement System). PEMS was composed of gas analyzer, emission flow meter and sample conditioning system et al. Also, test six vehicles were selected to the gasoline passenger car with engine displacement from 1.6L to 3.7L. Two test routes with engine start of cold and hot conditions were applied to analyze the emission characteristics of RDE, respectively. The results show that the $CO_2$ emission have a increasing trend as the engine displacement and vehicle weight. Also, it is guessed that the $CO_2$ emission and vehicle weight were more correlated than the engine displacements. On the other hand, NOx emissions of RDE have not increasing or decreasing tendency according engine displacements or vehicle weight because the activation of three-way catalyst in the gasoline vehicles.

• Journal of The Korean Astronomical Society
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• v.36 no.1
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• pp.43-48
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• 2003

We introduce and describe performance of the 6-meter telescope of Seoul Radio Astronomy Observatory (SRAO). All the softwares and instruments except the antenna structure and its driving system are developed for ourselves. The SIS mixer type receiver resulted in the receiver noise temperature less than 50 K (DSB) over the whole 3-mm radio window. An autocorrelation spectrometer, developed first in Korea, provides maximum 50 MHz band width over 1024 channels. Antenna surface is measured and adjusted using template method and radio holography which resulted in a superb surface accuracy bet-ter than 30${\mu}m$. Accordingly, the aperture and beam efficiences amount to $70\%$ and $75\%$, respectively, largely independent of frequency in the 85 - 115 GHz range. It is also found that telescope pointing errors are less than 10" in both azimuth and elevation and that antenna gain is almost constant against elevation greater than $20^{\circ}$, without adjusting sub-reflector position. The SRAO 6-meter telescope is now fully operational and all these characteristics verify that observations are carried out with high precision and fidelity.

• 연구논문집
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• s.27
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• pp.153-166
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• 1997

In industry pneumatic control system has become a important means to obtain automation because of its simplicity, fast speed and low cost. However Due to of the compressibility of air and damping friction between moving parts, it is difficult to achieve high speed driving, accurate positioning and stopping without overshoot in one pneumatic control system. This paper describes the dynamic behaviors of pneumatic linear actuator. The results will be very useful in the prediction of actuated dynamics and for the manufacturers to improve the techniques in their redesign and get better performance. Also, the experimental data is very important for the dynamic simulation and theoretical analysis.