• Title/Summary/Keyword: Design stabilization

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Design and Development of Antenna with Stabilization of Radiation Pattern and Wide-Band Characteristics for MIMO/LAN/Broadcast Operations (안정된 복사패턴과 광대역 특성을 갖는 MIMO/LAN/방송용 안테나 설계 및 개발)

  • Jang, Yong-Woong
    • Journal of Broadcast Engineering
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    • v.16 no.3
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    • pp.483-489
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    • 2011
  • In this paper, we propose a new antenna, which has wide bandwidth, good radiation patterns, and high-gain characteristics. We analysis the antenna using FDTD(Finite Difference Time Domain) method. And the antenna parameters are optimized to get maximum bandwidth. From the measured results, the bandwidth of the antenna is 0.839 octave, for the S11${\leq}$-10 dB. And the measured cross polarization level of the proposed antenna is less than -25 dB at the center frequency. Experimental data of the return loss and the radiation pattern of the proposed antenna are also presented, and the experimental bandwidth characteristics are relatively in good agreement with the FDTD results. The proposed antenna can be applied to MIMO, LAN, biomedical instruments, broadcasting-network system.

A Study on the design of stabilization Optical Source for 16 Channel Loss measurement (16채널 손실측정을 위한 안정화 광원 설계에 관한 연구)

  • Yoon, Sung-Do;Park, Jong-Ran;Kim, Sa-Woong;Park, Soo-Bong;Kim, J.-Bin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.307-308
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    • 2005
  • 본 연구에서는 현재 주로 사용하고 있는 광파장인 980nm, 1310nm, 1480nm, 1550nm 에 대한 안정화된 광파워를 갖는 광원개발이다. 내부에 온도안정화와, 자체 광파워 피드벡에 의한 안정화 회로를 내장하고 있으며, 독립적 혹은 동시적으로 4 개의 광파장을 출력할 수 있도록 구성되어있다. 또한 0$\sim$ -7dBm 사이의 광파워를 0.5dB 단위로 가변시킬 수 있으며, +-0.05dB 이내의 안정성을 갖는다. 또한 RS-232 시리얼 통신으로 PC 와 인터페이스가 가능하며, 광출력 상태를 모니터링하거나 원격으로 광파워를 제어할 수 있도록 구성하였다. 온도범위는 +-0.5도 이내에서 제어가 가능하며, 이러한 부분으로 구성된 4 파장 광원은 +-0.05dB 이내에서 안정화된 광을 출력할 수 있게 되었다. 본 연구 개발을 수행한 결과 레이져 다이오드의 안정화에 대한 확실한 이론적 및 실험적인 결과를 얻게 되었으며, 현재 확산되고 있는 광통신 시장에서 광통신 부품, 광케이블, 통신망 등에서 각종 소자 및 선로의 광학적 특성을 측정하는데 필수적으로 이용될 것이다.

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Dynamic Simulation of Pump-Storage Power Plants with different variable speed configurations using the Simsen Tool

  • Kruger, Klaus;Koutnik, Jiri
    • International Journal of Fluid Machinery and Systems
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    • v.2 no.4
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    • pp.334-345
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    • 2009
  • Pumped storage power plants are playing a significant role in the contribution to the stabilization of an electrical grid, above all by stable operation and fast reaction to sudden load respectively frequency changes. Optimized efficiency and smooth running characteristics both in pump and turbine operation, improved stability for synchronization in turbine mode, load control in pump mode operation and also short reaction times may be achieved using adjustable speed power units. Such variable speed power plants are applicable for high variations of head (e.g. important for low head pump-turbine projects). Due to the rapid development of power semiconductors and frequency converter technology, feasible solutions can be provided even for large hydro power units. Suitable control strategies as well as clear design criteria contribute significantly to the optimal usage of the pump turbine and motor-generators. The SIMSEN tool for dynamic simulations has been used for comparative investigations of different configurations regarding the power converter topology, types of semiconductors and types of motor-generators including the coupling to the hydraulic system. A brief overview of the advantages & disadvantages of the different solutions can also be found in this paper. Using this approach, a customized solution minimizing cost and exploiting the maximum usage of the pump-turbine unit can be developed in the planning stage of new and modernization pump storage projects.

Anti-Sway Tracking Control of Container Cranes with Friction Compensation (마찰 보상을 갖는 컨테이너 크레인의 흔들림 억제 추종 제어)

  • Baek, Woon-Bo;Shin, Jin-Ho
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.6
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    • pp.878-884
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    • 2012
  • In this paper, we consider the sway suppression control problem for container cranes with the frictions between the trolley and the rail. If the friction effects in the system can be modelled, there is an improved potential to design controllers that can cancel the effects. The proposed control improves the trolley positioning and sway suppressing against various frictions. The proposed synthesis combines a variable structure control and the adaptive control to cope with various frictions including the unknown constants. First, the variable structure control with the simple switching action is designed, which is based on a class of feedback lineariztion methods for the fast stabilization of the under-actuated sway dynamics of container. Second, the adaptive control with a parameter estimation is designed, which is based on Lyapunov stability methods for suppressing the oscillation of the trolley travelling, especially due to Coulomb friction in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulation are shown under initial sway, external wind disturbances, and various frictions.

Vehicle Stabilization Using MPC Based on Nonlinear Tire Model (비선형 타이어모델 기반 MPC를 이용한 차량 안정화)

  • Song, Yuho;Kim, Hansu;Kim, Seungki;Kim, Youngwoo;Lee, Tae Hee;Huh, Kunsoo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.6
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    • pp.730-736
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    • 2016
  • Recent research suggests the various applications of Model Predictive Control on vehicle systems. In numerous cases, nonlinear tire models such as the Magic Formula, which are highly complex and are more detailed than necessary, are used. This paper presents a nonlinear tire model that excludes the region of negative slope but expresses the nonlinear properties of tire well enough for tracking the lane of a racing course. The proposed inverse tire model can also be used to calculate the slip angle from the tire force. Thus, the model can be utilized to design the Model Predictive Controller.

The effect of obstacle gait training on balance, gait and ADL of the stroke patient - pilot study (장애물 보행훈련이 뇌졸중 환자의 균형, 보행 및 일상생활활동에 미치는 영향 - 예비연구)

  • Kim, Soo Jin;Oh, Gku Bin;Lee, Hyo Jeong
    • Journal of Korean Physical Therapy Science
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    • v.27 no.2
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    • pp.1-12
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    • 2020
  • Background: The purpose of this study is intended to evaluate the effectiveness and analyse the change on balance, gait and ADL of the stroke patient by obstacle gait training. Design: Randomized controlled trial. Methods: Ten subjects with stroke patient are recruited from C rehablitation hospital located Chungbuck. The subjects which are divided to 2 group as experimental group (N=5) conducted the obstacle gait training and control group (N=5) conducted the general gait training. The gait (10mWT), balance (BBS) and ADL (FIM) were measured before and after intervention. Results: There were no significant differences (p>.05) in sex, age, height, weight and K-MMSE among subjects. There were significant differences (p<.05) in balance and gait between of the experimental group and control group. But there was no significant difference (p>.05) in the ADL between of the experimental group and control group. There were significant differences (p<.05) gait and balance in the experimental group. But there were no significant difference (p>.05) gait, balance and ADL in the control group. Conclusion: Obstacle gait training showed positive effects on the gait, balance of the stroke patient.

Nonlinear Control with Magnitude and Rate Constraints (크기 및 변화율 제한을 갖는 비선형 시스템의 제어)

  • Lee, Jung-Kook;Lee, Keum-Won;Lee, Jun-Mo
    • Journal of the Institute of Convergence Signal Processing
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    • v.8 no.2
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    • pp.130-135
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    • 2007
  • This paper deals with a controller design for a 2 dimensional aeroelatic model which has unknown parameters including polynomial type nonlinearity. Actually in case of state and acuator signal having magnitude, rate and bandwidth limitations, the controller can't be implemented and so in each case, a filter is used for implementation. First, error signals are defined upon the backstepping theory, and tracking error signals are also defined due to command signal and filter signals and then compensated tracking error signals are defined. Lastly, a Lyapunov function is defined for the stabilization and from this method, an adaptive law is derived. Simulations are done for the demonstrtion of the effectiveness of the algorithms.

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A Numerical Study for Design of a Fixed Type Fin Stabilizer Utilizing the Coanda Effect (콴다 효과를 적용한 고정식 핀 안정기 설계를 위한 수치적 연구)

  • Seo, Dae-Won;Lee, Seung-Hee
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.2
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    • pp.113-120
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    • 2011
  • Fins are widely used for roll stabilization of passenger ferries and high performance naval ships, among others. The Coanda effect is noticeable when a jet stream is applied tangentially to a curved wing surface since the jet can augment the lift by increasing the circulation. The Coanda effect has been found useful in various fields of aerodynamics and speculated to have practical applicability in marine hydrodynamics where various control surfaces are used to control motions of ships and the other offshore structures. In the present study, numerical computations have been performed to find proper jet momentum coefficients $C_j$ and trailing edge shapes suitable for the application of the Coanda effect to a stabilizer fin. The results show that the lift coefficient of the modified Coanda fin at the zero angle of attack ${\alpha}$ identically coincides with that of the original fin at ${\alpha}\;=\;25^{\circ}$ when Coanda jet is supplied at the rate of $C_j$ = 0.1. It is also shown that a fixed type fin stabilizer utilizing the Coanda effect can be implemented without changing the fin angle to actively control the motions of ships and the other offshore structures.

Study on the De-Q'ing System for the Output Voltage Stabilization of a 200MW Modulator (200MW MODULATOR의 출력안정화를 위한 DE-Q'ING SYSTEM에 관한 연구)

  • Son, Y.K.;Oh, J.S.;Cho, M.H.;Namkung, W.
    • Proceedings of the KIEE Conference
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    • 1994.07b
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    • pp.1612-1614
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    • 1994
  • Modulators Installed in PLS(Pohang Light Source) Linac are composed of a DC high voltage section, a charging section and a discharging section. PFN is charged by a resonant charging mechanism, and discharged by a switching device through the primary of the pulse transformer connected to a load. Charged PFN voltage must be well regulated to obtain stable output pulse voltage at the load. For this purpose, DCHV is controlled by a SCR controller with feedback signal, and PFN voltage is regulated by a De-Q'ing circuit. The full power operation test shows the pulse voltage regulation within ${\pm}0.13%$ with SCR feedback control alone, and within ${\pm}0.08%$ together with De-Q'ing. This paper describes the design concept and operational characteristics of the De-Q'ing circuit.

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An Adaptive Filtering Technique for Vibration Reduction of a Rotational LOS Control System and Frequency Noise Reduction of an Imaging System (적응형 필터링 기법을 이용한 회전형 시선제어시스템의 진동 저감 및 영상 주파수노이즈 저감 기법)

  • Kim, Byeong-Hak;Kim, Min-Young
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.10
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    • pp.1014-1022
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    • 2014
  • In mechatronic systems using electric signals to drive control systems, driving signals including the frequency band of the unwanted signals, such as resonant frequencies and noise frequencies, can affect the accuracy of the controlled system and can cause serious damage to the system due to the resonance phenomenon of the mechatronic system. An LOS (Line of Sight) control unit is used to automatically rotate the gimbal system with a video imaging system generally mounted on modern aerial vehicles. However, it still suffers from natural frequency variation problems due to variations of operational temperature. To prevent degradation in performance, this paper proposes an adaptive filtering technique based on real-time noise analysis and adaptive notch-filtering for LOS control systems, and verifies how our proposed method maintains the LOS stabilization performance. Additionally, this filtering technique can be applied to the image noise filtering of the video imaging system. It is designed to reduce image noises generated by switching circuits or power sources. The details of design procedures of the proposed filtering technique and the experiments for the performance verification are described in this paper.