• 한국산학기술학회논문지
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• 제8권4호
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• pp.848-852
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• 2007

널말뚝의 관입속도 예측을 위한 해석수단 중 많은 경우에 얕은 근입깊이에 대해서 관입속도를 지나치게 크게 평가하기 때문에 해석법의 신뢰성을 떨어뜨리는 요인으로 작용한다. 본 연구에서는 이러한 해석상의 단점을 보완하고자 널말뚝의 휨진동모델을 정립하고 휨진동에 의해 발생하는 에너지 손실량을 평가하였다. 또한 휨진동에 의한 에너지손실에 따른 진동타입력의 감소를 하중감소계수를 써서 반영하고자 하였다.

• Journal of Mechanical Science and Technology
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• 제17권2호
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• pp.181-186
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• 2003

In order to assure the quality of the bent axis design axial piston pumps driven by tapered pistons, it is necessary to know the characteristics of force applied to tapered pistons and the mechanism for driving the tapered pistons. Since they are able to perform both reciprocating and spinning motions in cylinder block, it is difficult to understand the driving mechanismand-tomeasure the forces applied to tapered pistons experimentally In the present study, the theoretical mechanism for driving the tapered pistons is studied by use of the geometric method. The driving area of the tapered pistons is measured by measuring the strain of a cylinder forced against a tapered piston using an electric strain gauge and a slip ring. The forces applied to tapered pistons is also investigated with the change of discharge pressure and the rotational speed. As a results of this investigation, it is concluded that the cylinder block is driven by one tapered piston in a limited area and the driving area is changed due to space angle of the tapered pistons and the swivel angle of the cylinder block. It is also observed that the force applied to tapered pistons increases as the discharge pressure and the rotational speed increase.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.238-240
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• 1997

In two case, LPM driving by full step or microstep, we simulated the thrust force in LPM using finite element method and measured the force by experimental equipment. And We analyze the harmonics of trust force by Fast Fourier Transform. We proposed the method, which can reduced harmonic force by microstep driving.

• 한국ITS학회 논문지
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• 제7권6호
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• pp.133-139
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• 2008

본 논문에서는 플라스틱 광섬유 센서가 운전자의 졸음 방지용 센서로서 응용 가능한 지에 관하여 논의된다. 졸음방지용 플라스틱 광섬유 센서는 광섬유의 구부림이 잘 유도될 수 있도록 소프트한 물질로 덮개를 씌운 핸들에 플라스틱 광섬유가 감겨져 여는 구조로 되어져 있다. 운전자가 핸들을 잡을 때 운전자가 핸들에 힘을 가하게 되고 이 힘이 플라스틱 광섬유의 구부림을 유도하여 플라스틱 광섬유 내부를 진행하는 빛의 양을 감소시킨다. 실험 결과로부터 핸들에 가해지는 힘이 크면 클수록 검출되는 광량이 적어짐을 보여주어 졸음 방지용 센서로서의 사용할 수 있음을 검증해 보인다.

• 열처리공학회지
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• 제9권4호
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• pp.243-251
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• 1996

Dilatometric experiment and thermodynamic calculation have been performed to determine $M_s$, $A_s$ and driving forces for ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation of Fe-Mn alloys. The transformation temperatures($M_s$, $A_s$, $T_o) were decreased with increasing manganese content and were newly formulated as a function of manganese content. Driving force for ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation was increased from -75J/mole to -105J/mole with increasing manganese content from 15wt.% to 25wt.%. Transformation temperature hysteresis($A_s-M_s$) was also increased from 50K to 80K with increasing mangenese content from 15wt.% to 25wt.%. The small driving force(-75J/mole~-105J/mole) and small ${\Delta}T$(50K~80K) for ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation indicated that Fe-Mn alloys behave like thermoelastic martensitic alloys : We would like to call them semi-thermoelastic martensitic alloys.

• 대한전기학회논문지
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• 제40권3호
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• pp.250-257
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• 1991

In the analysis of the electric machine by finite element method, the primary current has been selected as a driving source. But the voltage is constant and the primary current varies according to the load condition in the pracdtical system. Therefore, in this paper, magnetic flux distribution, primary current, input effective power, power factor, efficiency and propulsion force of S.L.I.M. were calculated by the finite element method cnsidering the voltage as a driving source. Because the driving characteristics could not be measured in the S.L.I.M., voltage-current curve, 3-phase current curve, and propulsion force were measured at the starting and they were compared with theoretical values.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.224-231
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• 2006

A six-degree-of-freedom dynamic model with time-varying mesh stiffness/damping and friction has been developed for the dynamic analysis of a gear driving system. This model includes a spur gear pair, bearing, friction and prime mover. Using Newton???s method, equations of motion for the gear driving system were derived. Two computer programs are developed to calculate mesh stiffness, transmission error and friction force and analyze the dynamics of the modeled system using a time integration method. The influences of mesh stiffness/damping, bearing, and friction affecting the system were investigated by performing eigenvalue analysis and time response analysis. It is found that the reduction of the maximum peak magnitude by friction is decided according to designing the positions of pitch point and maximum peak in the responses.

• 전기학회논문지
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• 제61권12호
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• pp.1843-1847
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• 2012

Piezo devices have large power density and simple structure. They can generate larger force than the conventional actuators. It has also wide bandwidth with fast response in a compact size. Thus the piezo devices are expected to be used widely in the future for small actuators with fast response time and large actuating force. However, the piezo actuators need high voltage with high driving current due to their large capacitive property. In this paper, we propose a simple method to drive piezo devices using voltage inversion circuit with coil inductance. Experiments with real circuit demonstrates that the proposed scheme can improve the energy efficiency very much.

• 한국자동차공학회논문집
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• 제24권5호
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• pp.512-519
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• 2016

In this study, the tire road friction estimation(TRFE) algorithm for controlling the rear wheel driving force of a 4WD vehicle during acceleration is developed using a standard sensor in an ordinary 4WD passenger car and a speed sensor. The algorithm is constructed for the wheel shaft torque, longitudinal tire force, vertical tire force and maximum tire road friction estimation. The estimation results of shaft torque and tire force were validated using a torque sensor and wheel force transducer. In the algorithm, the current road friction is defined as the proportion calculated between longitudinal and vertical tire force. Slip slop methods using current road friction and slip ratio are applied to estimate the road friction coefficient. Based on this study's results, the traction performance, fuel consumption and drive shaft strength performance of a 4WD vehicle are improved by applying the tire road friction estimation algorithm.

• 한국산학기술학회논문지
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• 제12권4호
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• pp.1523-1531
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• 2011

본 다축 차량은 험지와 야전에서 높은 이동성 때문에 비포장도로를 주행해야 하는 군용차량으로 사용된다. 특히 군용차량은 군 요구 사항에 의거 기본적으로 60% 경사로에서 안정적인 등판 성능을 지녀야 한다. 따라서 본 논문은 최적 타이어 힘 분배 방법을 통한 6WD/6WS차량의 등판능력 향상을 다루었다. 경사로 등판 시 사용할 최적 타이어 힘 분배 방법을 위하여 운전자로부터, 목표로 하는 종 방향 힘과 횡 방향 힘, 요 모멘트를 계산하였고, 마찰 원이론과 목적함수에 따른 최적화 된 토크가 각 륜에 분배되었다. 알고리즘 성능을 확인하기 위해서, 트럭심 소프트웨어를 이용하여 시뮬레이션 하였고, 비교를 위하여 2대의 차량을 제안하였다. 한 대의 차량은 최적타이어 힘 분배 방법이 적용되었고, 나머지 한 대는 궤도 차량과 같은 균등 힘 분배 방법이 적용되었다. 경사로에서 등판능력은 최적 타이어 힘 분배 방법에 의해서 향상 되어졌다.