• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.60-62
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• 2001

In this paper, a CAE system, $MotorPro^{(TM)}$, is presented for motor design. It is composed of equivalent magnetic circuit method and finite element method. It provides fully automated finite element method that takes only a few seconds to a few minutes. Using this system. 18kw brushless DC motor is dealt as design example.

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.2
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• pp.103-109
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• 2020

This paper finds solutions for using ZigBee in wireless networked control system (WNCS). The round trip time delay and packet loss rate of the WNCS are measured. On the basis of these measured data, a playback buffer is used to solve the variable time delay in WNCS, and a Smith predictor is introduced to compensate for the time delay. The WNCS was able to be actually constructed to perform DC motor position control with 40 Hz sampling frequency.

• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.79-79
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• 2007

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.282-284
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• 1997

The harmonics are injurious on the operation of the motor, electric instruments etc. In this paper, it is certified the capability of the electric measuring devices at the input/output of inverter. And it is measured the harmonics of the voltage and current waveforms. Also, this paper presents the efficiency of the inverter's power conversion by measuring the fundamental and total power at the input, DC bus and output.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.959-962
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• 2005

Servomotors are used as key components of automated system by performing accurate positioning, accurate speed regulation, and precise motion control in response to commands from computers and sensors. Especially linear brushless servomotors have numerous advantages over ball screws, timing belts, rack/pinion drives and friction drives compared with rotary servomotors. This paper proposes the estimation of unknown parameters from the linear brushless DC motor which is operated by sinusoidal commutation. The estimated parameters are used to tune the controller gain and disturbance observer. In order to agree with this purpose, Digital Signal Processor(TMS320F240), developed for implementation of a speed Field Oriented Control(FOC), adopted in this study. The processor playing an important role in controller has A/D converters, PWM generators, riched I/O port internally.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.920-922
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• 2002

This paper investigates the cogging torque reduction in a brushless DC(BLDC) motor having an inner-rotor with surface-mounted segment-type permanent magnets. The kind of magnets for the BLDC motor could have different waveforms of magnetization such as square, trapezoidal and sinusoidal form. This paper discusses the effect of the unsymmetrical magnetization distribution in the segment-type permanent magnet, which is able to obtain through a segment structure that the number of poles per segments is 2 ($N_p/N_s$), on the cogging torque and EMF waveform. Where the existing magnetizer fixture for the square-type magnetization is used to magnetize the magnets in two segment structures of $N_p/N_s$ = 1 and 2. The effectiveness of the proposed designs had been confirmed by comparing cogging torque, and EMF waveform between conventional and new models which are analyzed by Finite Element Method (FEM).

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.2
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• pp.193-199
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• 2014

In this paper, we present an overview of the structure of a lab-built powered knee prosthesis and the control of it. We build a powered prosthesis prototype on the basis of previous researches and aim at obtaining the essential technology related with its control. We adopt the slider-crank mechanism with a DC motor as an actuator to manipulate the knee joint. We also build an embedded control system for the prosthesis with a 32-bit DSP controller as a main computation unit. We divide the gait phase into five stages and use a FSM (Finite State Machine) to generate a torque reference needed for each stage. We also propose to use a position-based impedance controller for driving the powered knee prosthesis stably. We perform some walking experiments at fixed speeds on a tread mill in order to show the feature of the built powered prosthesis. The experimental results show that our prosthesis has the ability to provide a functional gait that is representative of normal gait biomechanics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.788-792
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• 2007

국내외의 자동차 메이커는 고효율, 저공해 자동차 개발에 집중하고 있으며, 그 방법으로 하이브리드 자동차가 최우선시 되고 있다. 하이브리드 자동차의 밧데리 팩을 구성하는 핵심 부품 중 하나인 고전압 직류 릴레이는 주행 중 엔진 구동력을 보조하는 구동모터에 전기 에너지를 공급하는 밧데리의 출력을 개폐하는 기기이다. 고전압 직류 릴레이의 개폐 동작시 발생하는 소음은 자동차 운전 중 실내로 유입되어 운전자의 승차감을 떨어뜨리는 요인이 되므로 릴레이의 개폐 동작시 발생하는 소음 저감을 위한 연구가 필요하다. 본 연구에서는 폐로(ON) 동작시 발생하는 소음 저감을 위해 소음원인 충격력을 감소시키기 위한 이중 접압스프링 구조를 제안하였으며, 소음 저감 성능평가를 수행하였다. 먼저 정확한 충격해석을 위해 고전압 직류 릴레이의 최소 동작 전압인 5.9V부터 상시 인가 전압인 12V까지 총 6개의 전압레벨에서 릴레이의 전자력을 측정하였으며, 기존 접압스프링 구조와 이중 접압스프링 구조에 관하여 외연적 탄소성 유한요소 프로그램인 LS-DYNA를 사용하여 충격해석을 수행하였다. 고전압 직류 릴레이의 소음원인 가동전극과 고정전극에서 발생하는 일차 충격력과 가동철심과 고정철심에서 발생하는 이차 충격력을 비교, 평가하였다.

• Journal of the Korean Society of Safety
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• v.21 no.4 s.76
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• pp.25-32
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• 2006

LonWorks over IP(LonWorks-IP) virtual device network(VDN) is an integrated form of LonWorks device network and IP data network. In especially real-time distributed servo applications on the factory floor, timely response is essential for predictive and preventive maintenance. The time delay in servo control on LonWorks-IP based VDN has highly stochastic nature. LonWorks-IP based VDN induced transmission delay deteriorates the performance and stability of the real-time distributed control system and can't give an effective preventive and predictive maintenance. In order to guarantee the stability and performance of the system, and give an effective preventive and predictive maintenance, LonWorks-IP based VDN induced time-varying uncertain time delay needs to be predicted and compensated. In this paper new Pill control scheme based on Smith predictor, disturbance observer and band pass filter is proposed and tested through computer simulation about position control of DC servo motor. It is shown that how can the proposed control scheme be designed to minimize the effects of uncertain varying time delay and model uncertainties. The validity of the proposed control scheme is compared and demonstrated with the comparison of internal model controllers(IMC) based on Smith predictor with and without disturbance observer.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.599-601
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• 2001

This paper investigates the permanent magnet (PM) overhang effect on the characteristics such as cogging torque and torque in brushless DC motor (BLDCM). The overhang effect has been used to enlarge the performance of the radial flux density in BLDCM and balance the force in the axial direction for the reduction of the vibration. 3D equivalent magnetic circuit network method (3D EMCNM) is used for the accurate and efficient analysis. The characteristics of BLDCM are analyzed according to the variation of overhang length and the optimal length and ratio of overhang is determined.