• Journal of the Institute of Convergence Signal Processing
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• v.3 no.2
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• pp.83-88
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• 2002

In this paper, a POS interfacing and temperature compensable LPG dispensing control system(LDCS) has been developed. A LDCS includes a 16-bit 80C196 microprocessor, RAM, ROM, video driver, and programmable peripheral devices. Based on gas flow encoding pulse, temperature-voltage conversion values and apparatus calibration values, the LDCS controls the LPG dispensing quantity with switching on or off the solenoid valves. The temperature compensation is performed with a 10-bit A/D conversion and its range is from +7$0^{\circ}C$ to -3$0^{\circ}C$ with a 0.5$^{\circ}C$ resolution.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1341-1349
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• 2001

In this paper, 3 D.O.F. actuator, which has three degrees of freedom in one joint, is proposed. The proposed 3 D.O.F. spherical actuator is composed of the rotor and atator. The upper plate of the stator supports the rotor and five electromagnets are located at the base of the stator. The rotor has two permanent magnets, and each rotational axis of the rotor gimbal system is supported by the bearing. To find out the governing equations for the torque generation, Coulombs law and Lorentz force with respect to magnetism is applied. As the experimental results, if the distance between electromagnet and permanent maget is far enough, the force between these magnets can be expressed from current of coils and z-axial distance. For the purpose of control 3 D.O.F. actuator, PID control law is applied. The experimental results are presented to show the validity of the proposed 3 D.O.F. actuator.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.1 s.41
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• pp.51-59
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• 2005

Magnetorheological(MR) dampers are one of the most promising semi active control devices, because they have advantages such as small power requirement, reliability, and low price to manufacture. To reduce the responses of structures with MR dampers, a control system including power supply, controller, and sensors is required. However, when a mount of MR dampers are used to a large?scale civil structure such as cable stayed bridges, the control system becomes complex. Therefore, it is not easy to install and maintain the MR damper based control system. To resolve above difficulties, This paper proposes a smart passive system that consists of a MR damper and an electromagnetic induction(EMI) system. According to the Faraday’s law of induction, EMI system that is attached to the MR damper produces electric energy. The produced energy is supplied to the MR damper. Thus, the MR damper with EMI system does not require any power at all. Furthermore, the induced electric energy is proportional to external loads like earthquakes, which means the MR damper with EMI system is adaptable to external loads without any controller and corresponding sensors. Therefore, it is easy to build up and maintain the proposed smart passive system.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.185-190
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• 2019

This study aims to apply the mathematical method of fractional order derivatives to the controller that controls the system response. In general, the Laplace transform of the PID controller has an exponent of the integer order of s. The derivative of the fractional order has a fractional exponent of s when it is transformed by Laplace transform. Therefore, this controller proposes a design method with the result of discrete time conversion. Because controllers with fractional exponents of s are not easy to design. This controller is applied to a standard secondary system and its performance is examined. Then, it applies to solenoid valve which is widely used in industrial field. A Luenberger's observer was designed to estimate the disturbance state and the observed state was applied to the fractional order controller. As a result, uniform and precise control performance was obtained. It was confirmed that the position error of the steady state is within 0.1 [%] and the rising time is within about 0.03 [s].

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.233-233
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• 2011

ECR 이온원을 가볍고 작게 하면서 운전을 단순화함으로써 유지보수를 최소화하는 것은 특히 의료용 중입자 가속기에서 매우 중요한 조건 중 하나가 된다. 탄소 다가 이온을 만들어내기 위한 의료용 중입자가속기의 이온원으로 영구자석형 ECR 이온원을 개념 설계하였다. 영구자석은 이온원 입출구에서 강력한 축방향 자장을 만들기 위한 솔레노이드 자석 두 개와 반경방향 자장을 만들어 주기 6극 자석으로 구성된다. 또한 축방향 자장 흐름을 효과적으로 만들어주기 위한 두 개의 링 형 자석을 추가하여 자장의 강도를 높였다. 그러나 영구자석으로만 만들어진 자장 구조는 제작과 동시에 고정이 되어 수정이 불가능하기 때문에 제작 후 매우 제한적인 운전영역을 가질 뿐 만 아니라 최악의 경우에는 운전조건을 찾지 못하는 경우도 발생할 수 있다. 따라서 본 설계에서는 그림과 같이 두 개의 작은 보조 솔레노이드 전자석을 추가하여, 최소한의 운전조건으로 ECR 이온원의 공명영역을 결정하는 최소 자장의 구조뿐만 아니라 축방향 자장의 세기도 각각 능동적으로 제어할 수 있도록 하였다. 또한 마이크로파원으로는 TWT (Traveling Wave Tube)를 사용하여 10 GHz에서 14 GHz 까지 다양한 주파수에서 운전이 가능할 수 있도록 설계하였다. 이러한 설계를 통하여 다양한 운전조건을 가질 수 있는 안정된 ECR 이온원을 부피가 작으면서도 유지보수를 최소화하는 구조로 만들 수 있으며, 본 이온원은 탄소 다가 이온을 만들어내기 위한 목적뿐 만 아니라 다양한 중이온을 작은 규모로 만들어내기 위한 장치에서도 사용될 수 있다.

• Journal of the Korean Institute of Gas
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• v.15 no.3
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• pp.47-52
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• 2011

The purpose of this paper analyzes and studies to seek the failure examples of electronic control actuators for engine in liquified petroleum gas vehicle. The first, it was verified phenomenon for intial starting damage and no-acceleration of engine because of occasionally fuel feeding interception by clogged of emergency cutting solenoid valve filter. The second, the contact resistance produced in the connecting part of engine control relay because of no fully surface contacting by processes and assembly badness. It was displayed phenomenon of re-starting badness. The actuator that idle speed control system was sticked inside because of intake-air decreasing by carbon deposit. As a result, it was verified the phenomenon of disharmony that repeated up and down the engine revolution.

• Journal of Drive and Control
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• v.13 no.2
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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.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.200-203
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• 1997

This paper describes an study electric injection system for diesel engines. It is needed effective fuel injection which controls the solenoid valve of fuel pump. To solve this, this paper proposes DCC-PWM method which can realize fast reply and low holding current for solenoid valve on/off. For the proposed design method, simulation tools of ACSL are used to analyze the system. And the single-chip microcomputer is used to reduce the size of controller and to improve flexibility. And the system's validity can be verified through the experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.2
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• pp.83-89
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• 2009

An air-fuel ratio control is essential in reducing hazardous exhaust emissions from a compressed natural gas(CNG) engine, and can be accomplished by accurate control of gas injection flow. In this study, theoretical research was conducted on injection characteristics of a solenoid gas injector, and injection experiments for calibration and analysis were performed. Various factors for gas injection flow such as injection pressure, gas temperature, and supply voltage are studied. A dynamic flow equation of the natural gas was proposed on the basis of flow dynamics theories and results of the injection experiment. The verification of the dynamic flow equation of the solenoid injector was carried out with a large CNG-engine applied to an urban bus. Air-fuel ratio control experiments were conducted in both steady and transient state. Results of injection experiments for the solenoid injector and the CNG-engine was proved the control method proposed herein to be effective.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.113-115
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• 2006

Consulting Stout & Snell's paper[1], design approaches for the pressurization system for a launch vehicle are introduced. We have outlined the typical system requirements and a dynamic model of the pressurization system. A brief summary on the control loop design for multiple on-off valve control systems has been also presented.