• 한국분무공학회지
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• 제18권2호
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• pp.87-93
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• 2013

In this paper, high-pressure injection characteristic of servo hydraulic injector as the key component of diesel CRDi system, which is driven by solenoid and piezo-actuator were examined by experimental analysis. High-pressure injection characteristic of standard diesel fuel injected at high pressure up to 160 MPa was investigated at high-pressure chamber by using a high-speed camera for spray visualization and quantitative analysis. By this study, we found that the piezo-driven injector has better performances in controlling the fuel injection with the high pressure, including fuel quantity, spray penetration length and spray velocity, than that of a solenoid-driven injector. In particular, the needle response time for start of injection in piezo-driven injector was faster of about $125{\mu}s$ than that of solenoid-driven injector. Consequently, it is known that the piezo-driven injector has more degrees of freedom in controlling the fuel injection with the high pressure than solenoid-driven injector.

• 한국분무공학회지
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• 제19권1호
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• pp.9-14
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• 2014

Performance of DI diesel engine with high-pressure fuel injection equipment is directly related to its emission characteristics and fuel consumption. So, the electro-hydraulic injector for the common-rail injection system should be designed to meet the precise high fuel delivery control capability. Currently, most high pressure injector in use has a needle driven by the solenoid coil energy or the piezo actuator controlled by charge-discharge of output pulse current. In this study, macroscopic spray approaching method was applied under constant volume chamber to research the performance of three different injectors : solenoid, indirect-acting piezo and direct-acting piezo type for CR direct-injection. LED back illumination for Mie scattering was applied on the liquid spray visible of direct-acting piezo injector, including hydraulic-servo type solenoid and piezo-driven injectors. As main results, we found that a direct-acting piezo injector had better a spray tip penetration than hydraulic-servo injectors in spray visualization.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.775-776
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• 2012

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.745-746
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• 2010

• 대한기계학회논문집A
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• 제25권9호
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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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.248-253
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• 2013

The maximum speed is one of the most important performance in high speed railway vehicle. The higher the train speed is, the worse the ride comfort is, In order to solve this problem, a semi-active or active suspension can be applied to high speed railway vehicle. The variable damper with hydraulic solenoid valve is used in the semi-active suspension. But the variable damper with hydraulic solenoid valve requires tank for supplying fluid. The MR(Magneto Rheological) damper can be considered instead of hydraulic variable damper which needs additional device, i.e. reserver tank for fluid. In the case of active suspension, hydraulic actuator or electro-mechanical one is used to suppress the carbody vibration in railway vehicle. In this study the MR damper and electro-mechanical actuator was considered in secondary suspension system of high speed railway vehicle. The dynamic analysis was performed by using 10-DOF dynamic equations of railway vehicle. The performance of the semi-active suspension and active suspension system were reviewed by using MATLAB/Simulink S/W. The vibration suppression effect of semi-active and active suspension system were investigated experimentally by using 1/5-scaled railway vehicle model.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.751-753
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• 2001

The characteristic of magnetostrictive is to change shape in a magnetic field, TERFENOL-D is said to produce magnetostriction. A magneto strictive actuator need to the magnetic circuit. The most important design consideration is the magnetic circuit. The magnetic circuit consists of the solenoid coil, permanets for bias and shaping of the other parts through which the magnetic field passes. A good magnetic circuit ensures the proper magnetic field in th TERFENOL-D and very uniform magnetic field in all phases of the actuator operating cycle. This paper presents magnetic circuit design and analysis uesing FEM.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.996-998
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• 2005

전기철도나 지하철 분야에 사용되고 있는 고속 DC 차단기의 조작부는 solenoid actuator 방식이나 motor charging 방식을 주로 채택하고 있으나 구조가 복잡하고 부품수가 많아 부피가 크다는 단점이 있다. 이에 반해 magnetic actuator 방식은 동작시간과 제어가 용이하고 부품수가 감소하여 신뢰성과 반복성이 뛰어나다. 본 논문에서는 고속 DC 차단기 조작부를 영구자석 엑추에이터(PMA)방식으로 적용하고자 영구자석(PM)의 개략적 설계 및 이를 이용한 PMA 설계를 하였고, 유한요소 해석을 통해 이들의 동작특성을 해석하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.474-478
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• 2006

It is becoming more significant to develop a rotary voice coil motor(VCM) type's actuator for small form factor (SFF) optical disk drive(ODD), as portables are getting more and more popularized nowadays. The actuator which is applicable to small-sized ODD with a compact flash(CF) II card size was developed and fabricated. The experimental results showed that the finite element(FE) model is different from the fabricated model. And so flexible mode frequencies did not satisfy specifications of small-sized ODD, and tuning. Tuning procedures were required to improve dynamic characteristics of the fabricated actuator through finite difference method(FDM). At first, design variables were extracted through parameter study and the tuned FE model was improved by design of experiment(DOE). Consequently, It was confirmed that the improved model was applicable to SFF ODD.

• 대한기계학회논문집A
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• 제26권7호
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• pp.1438-1445
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• 2002

For robotic endoscope, some researchers suggest pneumatic actuators based on inchworm motion. But, the existing endoscopes have not been replaced completely because human intestine is very sensitive and susceptible to damage. We design and test a new locomotion of robotic endoscope that allows safe maneuverability in the human intestine. The actuating mechanism is composed of two solenoids at each side and a single permanent magnet. When the current direction is reversed, repulsive force and attractive at the opposition side propels permanent magnet. Impact force against robotic endoscope transfers momentum from moving magnet to endoscope capsule. The direction and moving speed of the actuator can be controlled by adjustment of impact force. Modeling and simulation experiments are carried out to predict the performance of the actuator. Simulations show that force profile of permanent magnet is the dominant factor for the characteristic of the actuator. The results of simulations are verified by comparing with the experimental results.