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MVC 상태에서의 무릎관절 모멘트 추정을 위한 모델 개발
남윤수,이우은,Nam, Yoon-Su,Lee, Woo-Eun 대한의용생체공학회 2008 의공학회지 Vol.29 No.3
This paper introduces a method of estimating the knee joint moment developed during MVC. By combining the Hill-type muscle model and analytic results on moment arm and musculotendon length change as a function of hip and knee joint angle, the knee joint moment at a specific knee joint angle during MVC is determined. Many differences between the estimated results and the experimental data are noted. It is believed that these differences originate from inaccurate information on the muscle-tendon parameters. The establishment of exact values for the subject's muscle parameters is almost impossible task. However, sensitivity analysis shows that the tendon slack length is the most critical parameter when applying the Hill-type muscle model. The effect of a change of this parameter on the muscle length force relationship is analyzed in detail.
스트레인 게이지 변위추정 센서를 사용한 유동공진 가진기 설계
남윤수,최재혁,강병하,Nam, Yun-Su,Choe, Jae-Hyeok,Gang, Byeong-Ha 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.9
Heat dissipation technology using the flow resonant phenomenon is a kind of a new concept in the heat transfer area. A vibration exciter is needed to enhance air flow mixing which has the natural shedding frequency of thermal system. A mechanical vibrating device for the air flow oscillation is introduced, which is driven by a moving coil actuator with a displacement estimator using strain gage. An analytical dynamic model for this mechanical vibration exciter is presented and its validity is checked by the comparison with experimental data. Values of some unknown system parameters in the analytic model are estimated through the system identification approach. Based on this mathematical model, the vibration exciter using strain displacement estimator is developed. During the experimental verification phase, it turns out the high modal resonant characteristics of a vibrating plate are a major barrier against obtaining a high bandwidth vibration exciter.
남윤수,Nam, Yun-Su 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.3
A dynamic load simulator(DLS) which can reproduce on-ground the aerodynamic hinge moment of control surface is an essential rig for the performance and stability test of aircraft actuation system. By setting up load actuator as counter acting with the control surface driving actuator and designing an appropriate force control system for load actuator, DLS can be mechanized. Obtaining an accurate mathematical model for the DLS is the first step to successfully design an aerodynamic load replicati on system. Two theoretical models are presented and tested for their validities with the experimental results, which turns out to be not successful. An alternative way of using system identification approaches in investigated to develop a good nominal model for DLS dynamics, and suitable uncertainty bounds for this nominal model are proposed with the consideration of experimental results.
작동 조건 변화에 따른 풍력발전 시스템의 동적 특성 해석
남윤수(Yoonsu Nam),윤태준(Tai Jun Yoon),유능수(Neung Soo Yoo) 대한기계학회 2009 大韓機械學會論文集A Vol.33 No.1
A design methodology for control strategy and control structure gives a direct impact on wind turbine's performance and life cycle. A baseline control law which is a variable rotor speed and variable pitch control strategy is introduced, and a mathematic performance model of a wind turbine dynamics is derived. By using a numeric optimization algorithm, the steady state operating conditions of wind turbines are identified. Because aerodynamic interaction of winds with rotor blades is basically nonlinear, a linearization procedure is applied to analyze wind turbine dynamic variations for whole operating conditions. It turns out the wind turbine dynamics vary much depending on its operating condition.
남윤수(Yoonsu Nam),임창희(Chang Hee Im) 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.11
풍력 터빈의 용량이 대형화될수록, 난류성분에 의한 풍력 터빈 구조물의 하중을 최소화시키는 하중완화 제어가 점차 중요해진다. 한번 설치되면 20 년 이상 작동되어야 하는 풍력 터빈 구조물은 끊임없이 바람에 의한 하중에 노출되는데, 이것이 적절하게 제어되지 않으면 풍력 터빈의 회전 반복운동에 의하여 피로파괴에 이르게 될 가능성이 커진다. 본 논문은 NREL 5MW 풍력 터빈을 대상으로 타워의 하중을 저감시키는 제어시스템을 설계하고, 이의 성능을 평가하는 내용을 담고 있다. 타워의 하중 완화제어시스템을 설계하려면 5MW 풍력 터빈의 동적 특성이 먼저 파악이 되어야 하며, 파워 커브를 추종하는 기본 제어시스템의 설계가 선행되어야 한다. As the size of a wind turbine increases, the mechanical structure has to have an increasing mechanical stiffness that is sufficient to withstand mechanical fatigue loads over a lifespan of more than 20 years. However, this leads to a heavier mechanical design, which means a high material cost during wind turbine manufacturing. Therefore, lightweight design of a wind turbine is an important design constraint. Usually, a lightweight mechanical structure has low damping. Therefore, if it is subjected to a disturbance, it will oscillate continuously. This study deals with the active damping control of a wind turbine tower. An algorithm that mitigates the mechanical loads of a wind turbine tower is introduced. The effectiveness of this algorithm is verified through a numerical simulation using GH Bladed, which is a commercial aero-elastic code for wind turbines.
남윤수(Yoonsu Nam),홍성경(Sungkyung Hong),유창선(Changsun Yoo) 한국항공우주학회 2004 韓國航空宇宙學會誌 Vol.32 No.10
본 논문은 2중으로 다중화된 무인 비행체의 다중화 관리 설계 방법에 대하여 논의한다. CCM(Cross Channel Monitor) 기법의 두 주요 인자, 즉 두 채널간의 편차 허용한도인 문턱값(threshold) 및 지속시간(persistence count)을 어떻게 설계하여야 하는 가에 관한 문제를 통계학적인 해석을 사용하여 그 해결법을 제시하였다. 또한, 무인 비행체의 생존확률을 증대시킬 수 있는 해석적 다중화 기법에 대한 문제를 칼만 필터링(Kalman filtering)을 적용하여 접근하였다. 여기서 제시된 방법으로 설계된 CCM 및 칼만 필터링을 이용한 해석적 다중화의 설계 결과들은 XV-15 틸트 로터 비행체에 적용되어, 그 설계의 타당성이 시뮬레이션을 통하여 검증되었다. A design methodology of the redundancy management for a duplex FBW flight control system is introduced. A statistical analysis is applied to determine two design parameters in CCM(Cross Channel Monitor), threshold and persistence count. An analytic redundancy, which is implemented using a Kalman filtering algorithm is considered. The application of an analytic redundancy to the FCS design of the smart UAV has several advantages of increasing the aircraft's survivability and breaking the tie-condition for a duplex FCS. All the redundancy management algorithms are verified through the numeric simulation for the flight dynamics of the XV-15 tilt rotor.