• Title/Summary/Keyword: 추종공기 효과

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A Study on the Analysis of Underwater Behaviors of Two Bodies Having Different Weight Characteristics (중량 특성이 다른 2종류 운동체의 수중거동 해석 연구)

  • Ahn, Jin-Hyeong;Jung, Chan-Hee
    • Journal of the Korea Society for Simulation
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    • v.21 no.1
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    • pp.35-43
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    • 2012
  • In this study, underwater behaviors of negative buoyant body and positive buoyant body, which are ejected from a platform, are compared through eject test and simulation. CFD(Computational Fluid Dynamics) method is used to calculate the hydrodynamic derivatives of negative buoyant body with varied hull. Hydrodynamic derivatives that cannot be calculated with CFD are used with the same values of base shape. The pitch angles of test data are much bigger than those of simulated data, and the reason is supposed to be the trailing air effect. A more accurate simulation is possible via modified force modeling which reflects this phenomenon. The underwater behaviors of positive buoyant body and negative buoyant body are somewhat different with each other at the same eject condition, but it may not be a problem in the view of operation.

MPC based path-following control of a quadcopter drone considering flight path and external disturbances in MATLAB/Simulink (MATLAB/Simulink 기반 주행 경로와 외란을 고려한 쿼드콥터 드론의 모델 예측 제어 기반 경로 주행 제어)

  • Soon-Jae Gwon;Gu-Min Jeong
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.16 no.6
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    • pp.472-477
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    • 2023
  • In this paper, we proposes the use of Model Predictive Control (MPC) techniques to enable quadcopter drones to effectively follow paths and maintain flight safety even under dynamic external environments and disturbances. Through simulations conducted in MATLAB/Simulink, the performance of two controllers, PID and MPC, is compared in flight scenarios with disturbances. The proposed design method shows that the MPC controller, when compared to the PID controller, exhibits a difference in the Mean Squared Error between the intended flight path and the actual path of the quadcopter drone. This difference is 0.2 in performance under no disturbance, and it increases to 0.8 under disturbance, demonstrating the improved path following accuracy of the MPC controller.

Development of Low-Cost, Double-Speed, High-Precision Operation Control System for Range Extender Engine (레인지 익스텐더 전기자동차 엔진용 저가형 2단속도 고정밀 운전제어시스템 개발)

  • Ham, Yun-Young;Lee, Jeong-Jun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.11
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    • pp.529-535
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    • 2018
  • The range extender vehicle runs on a mechanism that allows the small power generation engine to start in the most efficient specific operating range to charge the battery and extend the mileage. In this study, we developed a step motor type intake air supply system that replaces existing throttle body system to develop a simple low cost control logic system. The system was applied to the existing base engine, and in order to improve the performance by increasing the amount of intake air, the effect of changing the length of the intake and exhaust manifold was experimentally examined. As a result, the Type B intake air control actuator operated by one step motor showed higher performance than the Type A in all the operation region, but the performance was lower than that of the base engine due to the increase of flow resistance. To improve this, it was confirmed that the engine performance was improved at both speeds of 2200rpm and 4300rpm when the 140mm adapter was installed in the intake manifold and when the newly designed 70mm exhaust manifold was applied. Through this process, high - precision operation control was realized by connecting the generator load to the optimized engine for the range extender electric vehicle. Experimental results showed that the speed change rate was within ${\pm}2.5%$ at 2200rpm in 1st stage and 4300rpm in 2nd stage and the speed follow-up result of 610 rpm/s was obtained when the speed was increased from 2200rpm to 4300rpm.