• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.4
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• pp.15-21
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• 2004

High speed on-off electro-magnetic valves have been used for pressure control or flow control in automotive or construction machine servomechanisms. These systems require quicker valve switching speed to improve control preciseness. The authors designed and manufactured an electric valve driver with quick response characteristics by using 3 power source type valve driver concept. In experiments by using a hydraulic system incorporating the new valve driver, the new driver shortened the switching lag time from 5 ms to 1.3 ms. And also the new driver showed excellent position tracking control performances.

• Journal of Electrical Engineering and Technology
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• v.7 no.1
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• pp.34-45
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• 2012

In the present paper, the mover speed control of a linear induction motor (LIM) using a sliding mode control design is proposed, considering the end effects. First, the indirect field-oriented control LIM is derived, considering the end effects. The sliding mode control design is then investigated to achieve speed- and flux-tracking under load thrust force disturbance. The numerical simulation results of the proposed scheme present good performances in comparison to that of the classical sliding mode control.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.328-330
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• 2016

내시경을 이용한 진단 및 시술은 빈번하게 이루어지고 있으며, 대장암의 증가와 정부의 암 조기검진사업의 영향으로 시행건수가 많아지면서 천공 및 출혈 등의 의료사고도 늘어나고 있다. 내시경 장비를 이용한 시술은 시술자의 경험이나 감각, 숙련도에 의존하여 시행된다. 내시경 시술시 내시경 선단부의 수평 및 수직, 압력에 대한 실시간 정보를 제공하면 의료사고를 줄일 수 있다. 본 논문에서는 가속도와 자이로센서를 융합하여 각도 및 자세정보를 얻고 압력센서를 이용하여 선단부가 받는 압력을 시술자에게 제공하여 내시경 시술시 천공 및 출혈 등의 의료사고를 줄일 수 있는 방안을 제시한다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.3
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• pp.182-188
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• 2006

Contactless power system is base on power transmission by magnetic force. The transformer loss is large because it separated with the gap. Also the system has unstable factor, since the parameters in the secondary can vary with the system movement. This paper proposes light train power transmission system using contactless transformer with multiple primary winding. To increase the system efficiency and to obtain the stable power transmission to the dynamic load, a resonant inverter is adopted. The proposed system was verified by the simulation using Spice and Maxwell. The designed contactless power transmission system is implemented for 5[kW] class and experimental results are discussed.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.3
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• pp.25-34
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• 1992

This paper proposes a Self-Tuning control algorithm for tracking the reference trajectory by measuring the end-point of robot manipulator whose links are light and flexible, and the performance of it is tested through the computer simulation. As an object of system, a flexible robot manipulator with two-links is considered and an assumed mode shape method including gravity force is adopted to analyze the vibration modes for each links and dynamics equation is derived. The controller is designed as a combined form which consists of dynamic feedforward compensator and self-tuning feedback controller. The one supplies nominal torque and the other supplies variational torque to manipulator. Apart from the, K-incremental predictor is also proposed in order to eliminate the offset error. and it shows that the result of simulation adapted well to load change and rapid velocity.

• Multiscale and Multiphysics Mechanics
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• v.1 no.3
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• pp.261-270
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• 2016

The longitudinal velocity (forward speed) having significant importance in proper running of railway wheelset on track, depends greatly upon the adhesion ratio and creep analysis by implementation of suitable dynamic system on contamination. The wet track condition causes slip and slide of vehicle on railway tracking, whereas high speed may also increase slip and skidding to severe wear and deterioration of mechanical parts. The basic aim of this research is to design appropriate model aimed estimator that can be used to control railway vehicle forward velocity to avoid slip. For the filtration of disturbance procured during running of vehicle, the kalman filter is applied to estimate the actual signal on preferered samples of creep co-efficient for observing the applied attitude of noise. Thus error level is detected on higher and lower co-efficient of creep to analyze adhesion to avoid slip and sliding. The skidding is usually occurred due to higher forward speed owing to procured disturbance. This paper guides to minimize the noise and error based upon creep coefficient.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1050-1052
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• 1996

This paper presents a neuro-control algorithm for the speed control of a direct drive motor without the knowledge of the dynamics of the motor and the characteristics of a nonlinear load. In the field of motor control, it is not possible to directly use the back-propagation method in order to train a network since the desired output of the network is not known. Hence, we propose an extended back-propagation algorithm to force the closed loop system to give desired results. Experimental results shown that the proposed neuro-controller can reduce the unknown load effects and have the good velocity tracking capabilities.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.571-578
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• 2006

Research using multiple shake tables present new and unique challenges in controls. Typical single shake table tests with large specimens must cope with significant specimen force feedback that can increase tracking error due to specimen gain, damping, and non-linearity. Multiple shaking tables with distributed specimens can produce cross-coupling forces due to inertial and response effects and forces due to static differential displacements. Although many various control architectures exist, basic simplified techniques can yield excellent results without risk to control stability. Off-line simulation techniques can also prove invaluable for studying system response before the real system is operated.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_1
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• pp.397-409
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• 2021

This study proposes a new approach to implimentation of robust control and torque control response analysis based on monitoring simulator for smart factory. According to the physical properties of a flexible manipulator, a two time-scale approach, namely, singular perturbation ap proach, is further utilized for thorough analysis and general controller design. It is shown that asymptotic motional tracking can be effectively achieved, whereas the force regulation errors can be made arbitrarily small. For demonstration of the proposed technology performance, experiments of a eight joint flexible manipulator are performed for the proposed control method, and the reliability of proposed control results are illustrated based on monitoring simulator.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.10
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• pp.955-962
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• 2016

In this paper, we propose a design method for speed controller, current control of a Brushless Direct Current(: BLDC) motor using disturbance rejection techniques. Disturbance assumes a back electromotive force occurring in the electrical system and the variation of the load acting on the rotary shaft from the outside of the motor. And it assumed to be constant during the time interval and the Luenberger's observer design. So that the error of the observer about the system status can converge to zero show how to set the appropriate gain. Further, to stabilize the whole system, and proposes a method for setting the appropriate PI gain control to improve the tracking performance. By applying the proposed controller to 120W BLDC motors were tested for the ability to follow the velocity and current reference. Since the simulation results of the steady state error is within 0.1%, we were able to show the usefulness of the tracking performance of the proposed controller.