• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.962-964
• /
• 2004

The plunger speed of solenoid actuator is affected by mass of plunger, magnetic motive force, inductance, and return spring. These factors are not independent but related with each other according to design characteristics of solenoid actuator. So, it is impossible to change the designed value for the purpose of increasing plunger speed. In this study, we have analyzed the characteristics of high-speed solenoid actuator having a non-magnetic ring which plays a role to concentrate the effective magnetic flux into plunger. For more detailed analysis, we have induced characteristic equations and performed FEM analysis and simulation for dynamic characteristics of plunger, and proved the propriety of these by experiments.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1309-1311
• /
• 2005

The operating speed of PWM controlled high speed magnet is affected by mass of plunger magnetic motive force inductance and return spring It is impossible to change the value of them for the purpose of increasing the speed because these factors are related with each other This paper introduces a speed increasing method using a non magnetic ring which is welded in the middle of magnetic guide tube and also presents the characteristic equations results of FEM analysis for magnetic flux distribution and computer simulation results for the dynamic characteristics of plunger motion And we proved the effect of non magnetic ring by experiments using a prototype

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.1
• /
• pp.133-142
• /
• 2002

To improve the hydraulic control performance of ABS, it is necessary to establish an efficient control algorithm. And also it is necessary to ova]Hate a hydraulic modulator with solenoid valve quantitatively. In this paper, FEM and permeance method are used to analyze dynamic characteristics of outlet valve. In return, mathmatical modeling of a hydraulic modulator and operating pressure is presented, and the model parameters of an outlet valve are moving plunger, spring constant and orifice diameter. This study shows the way to improve the dynamic characteristic of an ABS outlet valve heavily depending on operating pressure. It is recommended that operating pressure should be justified at the first step toward the design to get the optimal design of an outlet valve.

• Proceedings of the KIEE Conference
• /
• 2005.04a
• /
• pp.6-8
• /
• 2005

The plunger speed of solenoid actuator is affected by mass of plunger, magnetic motive force, inductance, and return spring. These factors are not independent but related with each other according to design characteristics of solenoid actuator. So, it is impossible to change the designed value for the purpose of increasing plunger speed. In this study, we have analyzed the characteristics of high-speed solenoid actuator having a non-magnetic ring which plays a role to concentrate the effective magnetic flux into plunger. For more detailed analysis, we have performed FEM analysis and decided the optimal attaching position and length on the guide tube based on these results. And, we proved the propriety of the non-magnetic ring effect by experiments.

• Transactions of The Korea Fluid Power Systems Society
• /
• v.8 no.1
• /
• pp.1-9
• /
• 2011

The main design factors which effect on operating speed of linear actuator for valve operation are mass of plunger, electromagnetic motive force, inductance, and return spring, and these factors are not independent but related with each other in view point of design and electromagnetic theory. It is impossible to increase the operating speed by only change the value of any one design factor. The change of any one value results in change of any value related it in various design factors. This paper presents a speed increasing method of linear actuator using a solenoid design method by some governing equations which are composed of electromagnetic theory and empirical knowledge and permanent magnets as assistant material, and proved the propriety by experiments.

• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.816-818
• /
• 2003

Solenoid actuator's operating speed is affected by magnetic motive force, plunger mass, inductance, return spring constant, and eddy current. Recently, non-magnetic ring is generally used for improving the operational speed, because it is impossible that changing of any specified design factor and stacking of plunger steel. This paper represents the dynamic equations of solenoid actuator, simulations for the response characteristics, analysis of eddy current effect by using the induced time constant. And, we experiment for the operating characteristics in case of non-magnetic ring is exists and not exists in the plunger.

• Korean journal of aerospace and environmental medicine
• /
• v.30 no.1
• /
• pp.25-29
• /
• 2020

Space exploration is one of the dreams of humankind. However, the intriguing environment was a challenge for the human body, where we must counter with many extreme conditions such as thermal support, radiation, microgravity. Life, as well as the human body, developed and evolved in the continuous presence of gravity, especially when living creatures transfer from the ocean to the land. Once this gravitational force doesn't impact on the body, the drastic changes occur. Some of these changes were observed immediately, while others progress only slowly. Since the first orbital flight was performed, several hazards for the organs of the human body were identified [1]. These changes in human physiology can reverse when astronauts return to Earth. This article will review the published findings of the effects of microgravity exposure on the human body.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.985-990
• /
• 2007

This paper presents a novel control algorithm for position control of pneumatic cylinder. Generally, it is difficult to control the pneumatic servo system, due to nonlinearities such as air compressibility, the opening area of the valve, and frictional force between the cylinder and the piston. Especially, it is of significant importance for the control consisten-cy to return the cylinder pressures at equilibrium point to the initial states, still with guaranteeing the continuity of the pressures. For this purpose, the proposed control algorithm makes pressures of both cylinder chambers identical in magnitude but different in direction. The effectiveness and practicability of the control algorithm for the precise position control of the pneumatic cylinder are verified through the simulation study.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.06a
• /
• pp.251-254
• /
• 2009

Thermal performance of a thermosiphon for medium-temperature solar thermal application was investigated. The working fluid was Dowtherm A and the container was made of STS 316L. The thermosiphon had a outer diameter of 12.7 mm and a total length of 2 m, where the evaporator and the condenser had the same length of 0.3 m and the adiabatic section was 1.4 m. Both the evaporator and the condenser were aligned horizontal with an elevation difference of 0.18 m to utilize the gravitational force for the working-fluid return. The optimum fill charge ratio of the working fluid was investigated to obtain the maximum heat transport with the lowest thermal resistance. The maximun input thermal load was 500 W and thermal resistance was $0.60^{\circ}C/W$.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.5
• /
• pp.164-170
• /
• 2008

A typical clutch system for automotive manual transmissions transfers hydraulic pressure generated by driver's pedal manipulation to the clutch diaphragm spring. The foot effort history during the period of push is different than the period of the clutch pedal's return. The effort or load difference is called clutch foot effort hysteresis. It is known that the hysteresis is caused by friction. The frictional force and moment are produced between various component contact points such as between the rubber seal and the inner wall inside the hydraulic cylinder and between the diaphragm spring and the pressure plate, etc. Understanding the clutch pedal foot effort hysteresis is essential for a clutch release system design and analysis. The dynamic model for a clutch release system is developed for the foot effort hysteresis prediction and a simulation analysis is performed to propose a tool for analysing a clutch system.