• 동력기계공학회지
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• 제7권1호
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• pp.68-73
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• 2003

The purpose of this study is to develop a new proportional pressure reducing valve and to verify the validity of a new mechanism with pressure control pin. The dynamic characteristics of the object pressure reducing valve was studied by numerical analysis of the mathematical model. Also, static and dynamic characteristics of the new pressure control valve were tested with a testing system based on the test standard.

• 동력기계공학회지
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• 제12권2호
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• pp.62-70
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• 2008

The paper made a description of the method for numerical analysis and modeling of a proportional pressure control valve by bondgraph. The valve is a three port pressure regulator valve, consists of two subsystems; a proportional solenoid and a spool assembly. A purpose of this study is to analysis the dynamic characteristics of the valve using bondgraph method and to verified results that each of parameters has an effect on modeling. It considered the effect which the presence of solenoid, flow coefficient and non-linearity of resistance causes in the valve modeling. In particular, it is analyzed the effect that the solenoid interacted with modeling results and characteristics of the nonlinear resistance through orifice on the supply and discharge side of valve. Thus this paper described method to present nonlinear characteristics by bondgraph modeling method, so that we could know easily result that each parameters has an effect on the modeling.

• 한국자동차공학회논문집
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• 제2권3호
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• pp.75-84
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• 1994

In general direct-operated pressure reducing valves have been gardly applied to a dynamic control system such as active suspension control because of their poor control stability. But they are more robust than pilot-operated type and do not need pilot control flow. In this paper development of a new direct-operated proportional pressure reducing valve for low-band type active suspension control is reported. By means of a special damper directly linked to the valve spool, the control stability could be effectively improved without drawback in response time. The linearity error was less than $\pm$3.5%. Applied to an experimental active suspension system the new valve showed the $-90^{\circ}$ phase delay at 4Hz with 20% sinusoidal signal input and could control the suspension system with almost same performance as that with a pilot-operated type valve.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1109-1110
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• 2010

• 드라이브 ㆍ 컨트롤
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• 제13권2호
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• pp.34-41
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• 2016

Unlike the commonly used On/Off solenoid, constant attraction force which is independent of plunger displacement is a considerably important characteristic to proportional solenoid of the EPPR Valve. Attraction force uniformity is mainly affected by the internal shape design parameters. Due to a number of shape design parameters, the optimal parameter values are very complex and time consuming to find by trial and error method. Much research has been conducted or are still in progress to find the optimal parameter values by applying various optimization techniques like Genetic Algorithm, Evolution Strategy, Simulated Annealing, or the Taguchi method. In this paper, the design parameters which have primary effects on the attraction force uniformity and the average attraction force are decided by main effects analysis of Design of Experiments. Optimal parameter values are derived using finite-element analysis and a neural network model.

• 대한전자공학회논문지
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• 제21권5호
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• pp.41-45
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• 1984

양질의 에피택셜 층을 성장시키기 위해서는, 에피택셜 층을 성장시키기 직전에 HCl 가스를 사용하여 실리콘 기판을 에칭하는 과정이 거의 언제나 포함된다. 본 논문에서는, 대기압[1 기압]과 감압[0.1기압]에서 HCl 가스 농도와 에칭 온도의 변화에 따른 에칭속도 및 에치-피트 생성에 관하여 조사하였다. 그 결과, 대기압 공정과 감압 공정 모두 에칭 속도는 HCI 가스 농도의 2승[X ]에 비례하였으며, 명목상 활성화 에너지는 0∼11 Kcal/mole인 것으로 나타났다. 이러한 결과로부터, 감압 공정에서 HCl 가스에 의해 실리콘이 에칭되는 것은 대기압 공정에서와 같이 다음과 같은 반응에 의해 일어난다고 예측된다; Si + 2HCl ↔SiCl2 + H2.

• 동력기계공학회지
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• 제6권3호
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• pp.71-77
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• 2002

In this study, a dynamic model of proportional pressure control valve using the bond graph and a predictive controller are presented in the form of dynamic matrix control which is concerned with a design method of digital controller for the electro hydraulic servo system. The bond graph can be utilized for all types of systems which involve power and energy, and it is applied to a propotional pressure control valve in this study. Recently, many researchers suggested that better control performance could be obtained by means of the predictive controls with future reference input, future control output and future control error. The Predictive controller is very practical because the controller can be easily applicable to a personal computer or a microprocessor. This study investigates through numerical simulations that hydraulic system with the predictive controller shows very good control performances.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.20-26
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• 1997

A System for reducing vehicle body roll by active control is developed. The stabilizer bar with hydraulic rotary actuator produces anti-roll moment which suppresses roll tendency. This reduction of roll improves the driving safety as well as the ride comfort. Vehicle test data shows considerable reduction of roll angle during steady-state turning. Also improvement of ride comfort is achieved by making the actuator freely rotatable, i.e. by connecting all chambers of actuator in normal driving conditions. A control algorithm using steering wheel angle and vehicle speed signal as input valve is applied. It is compared with signal of the G-sensor.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.463-467
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• 2003

The traveling system of wheel type excavator, that is applied to drive method by friction of transmission, has many problems about transmisson. It need to settle the problem which is occurred at wheel type excavator and to study continuously variable transmisson which is used with only travel motor. This paper base on mathmetical modeling for travel motor and travel motor of wheel type excavator is designed continuously variable transmisson system without transmisson by direct control method.

• 유공압시스템학회논문집
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• 제5권4호
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• pp.32-37
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• 2008

For the bucket tip position control of the excavator, a traditional hydraulic excavator system was exchanged into an electro-hydraulic one. EPPR valves are attached to the traditional MCV and hydraulic joysticks are replaced by electronic ones to develop the electro-hydraulic system. To control the electronic pump with a good performance, the control logic for the pump is deduced from the AMESim simulation and the experimental method on the test bench. To get a good position control performance of the excavator bucket tip, PI+AntiWindup controller is selected as a position controller. The experimental results showed the good controllability for the electro-hydraulic excavator system on the test bench.