• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.649-652
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• 2003

In this paper, we presents a vector control method for the parallel-connected motor drive system. The new estimation scheme of rotor flux position is presented to reduce sensitivity due to load difference between the motors. To confirm the validity of the proposed control method. we compare a simulation result of the proposed control method with that of the conventional indirect vector control method. The simulation results show that the proposed control method is more effective for change in load torque and motor parameters.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2161-2163
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• 2003

This Paper presents a vector control method for the parallel-connected motor drive system. The new estimation scheme of rotor flux position is presented to reduce sensitivity due to load difference between the motors. To confirm the validity of the proposed control method, we compare a simulation result of the proposed control method with that of the conventional indirect vector control method. The simulation results show that the proposed control method is more effective step change in load torque.

• 한국컴퓨터산업학회논문지
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• 제9권2호
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• pp.63-68
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• 2008

병렬 스케줄링의 목적은 다중프로세서 병렬시스템 환경에서 병렬성을 가진 응용 프로그램에 대하여 최소 동기화 오버헤드(Synchronization overhead) 및 병목현상(Bottleneck) 그리고 부하균등(Load balance)을 달성하도록 스케줄링을 수행하는데 있다. 본 논문에서는 기존의 대표적인 병렬수행 스케줄링 알고리즘들을 분석하고 각 방법들로부터 문제점들을 도출한다. 이는 향후 효율적인 알고리즘을 설계하는데 도움이 필 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2281-2283
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• 2004

In this paper, we show the vector control performances for the parallel-connected motor drive system using the indirect vector control and the proposed vector control. The suggested estimation scheme of the rotor flux position is presented to reduce the sensitivity due to the load difference between the motors. To confirm the validity of the proposed control method, we compare the simulation results of the proposed control method with those of the conventional indirect vector control method. The simulation results show that the proposed control method is more effective for a change in the load torque.

• 연구논문집
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• 통권33호
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• pp.89-97
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• 2003

A barrel cam is used as a very important part of an index drive unit. The index drive unit must have an intermittent-rotational motion. The barrel typed cam and roller gear mechanism has the advantages of high reliability to perform a prescribed motion of a follower. This paper proposes a new method for the shape design of the barrel cam and also a CAD program is developed by using the proposed method. As defined in this paper, the relative velocity method for the shape design calculates the relative velocity of the follower versus cam at a center of roller, and then detemines a contact point by using the geometric relationships and the kinematic constraints, where the direction of the relative velocity must be parallel to a common tangential line at the contact point of two independent bodies, i.e. the cam and the follower. Then, the shape of the cam is defined by the coordinate transformation of the trace of the contact points. This paper presents shape design of the barrel cam in order to prove the accuracy of the proposed methods

• 로봇학회논문지
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• 제5권4호
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• pp.359-366
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• 2010

This study proposes the design method for the robot rotation arm which the end effector that is connected in end of the arm keeps parallel motion even though the robot arm rotates. So far, most robot arm rotates together the end effector when the arm rotates. For this, this study proposes the mechanism that the arm is linked to each 4 parallel link so that rotation is possible by 4 pins, and the rotation arm connects 2 joints of diagonal line direction to a link in each 4 joint for rotation, and designs so that can change length of the link. For verification of design, this study targeted that develop the rotation arm for medical examination that use in ophthalmology. It is important that a medical robot offers comport to patient and design compactly so that medical examination and treatment space may can be defined enough. It is designed so that all drive elements may be positioned on interior of the arm and optimization of design for main parts was carried out in this study for this. The robot arm which is developed in this study manufactured to use by medical phoropter arm, and got good result by an experiment. The robot rotation arm which is proposed in this study is judged to contribute very effectively in case use of a medical robot arm for medical examination and treatment, also the robot arm which the end effector that is connected in the end of the arm needs to keep parallel motion. And, the robot arm which is developed in this study made an application as license.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.115-120
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• 2003

In a motor driving, the current rate is directly related to the rate of a switching device and in cost reduction, the parallel switching operation is the alternatives because it has the smaller current rate through current division. There are many investigations for the parallel switching operations to equaling the current division. However it remains many problems for practical usage. The reason is that the switching characteristics are mainly relied on the different saturation voltage of each device etc. and these factors are not altered by circuit designer. In order to compensate this problem, a proper resistance is experimently inserted to the switching device. But this method can not be the optimal solution. Therefore this paper proposes a new parallel operation which uses a parallel phase winding to remove the traditional effect of switching device such as saturation voltage according to the division of current. Also the reliable and stable driving is improved through experiments and the detailed principles.

• 대한기계학회논문집
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• 제18권2호
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• pp.260-270
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• 1994

With the prevalent use of robot, the interests in moving speed of robot have been increasing for the purpose of upgrading performance of production. But the faster robot manipulator moves, the worse working accuracies are. And mechanical vibration is more and more serious with the increment of the moving speed of robot. So, the study on the cause and control method of robot vibration is one of the points of issue in robotics. This paper focuses on the vibration of 3 DOF parallel link drive mechanism robot. We assume that links of robot manipulator are `rigid' and joints are `flexible elements'. Governing equations of robot system including controller, servo amplifier, D.C servo motor, transmission with elasticity, and manipulator dynamics are derived. On the basis of modelling, we define `controller stiffness' by the proportional gain of controller and `stiffness of transmission'. Numerical and experimental research is performed to study vibration phenomena of robot induced from the variation of these two defined stiffnesses, and its results are shown.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권1호
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• pp.40-47
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• 2002

This paper describes a re-adhesion control method for the Korean High-Speed Train (KHST) with parallel induction motor drive. To keep a traction efficiency and to improve vehicle maintenance, the adhesion characteristics between wheel and rail are analyzed. Also the re-adhesion controller is designed as the subsystem of induction motor vector control. In order to verify performance of the proposed control techniques, the simulation is executed by train model and a downscaled re-adhesion control simulator is utilized. Both simulation and running test results show that good re-adhesion characteristics are obtained.

• 한국조명전기설비학회지:조명전기설비
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• 제9권5호
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• pp.51-56
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• 1995

The transistors of single phase 3 level PWM Inverter compose output power transistors and neutral point clamping transistors, which are NPN transistors. Waveforms of driving signals for this are PWM waves for power transistors and period operating waves for neutral point clamping transistors, which signals made W-type modulation from rectangular and sine wave. The output power transistors operate at ON-time complementary and neutral point clamping transistors operate at OFF-time complementary respectively. Therefore, each transistors operate in half period at parallel. Characteristics of this inverter circuit is parallel switching method about series switching method of general inverter. As modulation of 3 level drive signals made from full-wave rectifier of sine wave and rectangular wave, which are level wave about 3 level of complementary transistor inverter. So, this circuit composed complementary operation inverter of NPN transistors only compare with PNP-NPN complementary inverter, which have high power 3 level inverter of complementary operation.