• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.743-750
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• 2000

This paper presents an equivalent linearization method and application to the equations of motion of a 6 degree-of-freedom PRRS HexaSlide type parallel manipulators which are characterized as the architecture with constant link lengths that are attached to moving sliders on the ground and to a mobile platform. Since dynamic equations of parallel manipulators are complicated and highly nonlinear, control bandwidth, adjustable control gain as well as vibration characteristics cannot be easily found. The proposed equivalent linearization method can be applied over specified workspace as well as on a path of mobile platform. Through an equivalent linearization method, one can easily get a simple linear dynamic model. This linearized dynamic model may be utilized in a simplified computed torque control strategy.

• 한국소음진동공학회논문집
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• 제18권11호
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• pp.1170-1176
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• 2008

In this study, we propose a new method to control both the beat clarity and beat period in a ring structure. An equivalent ring which satisfies the measured mode condition is determined by using the equivalent ring theory. Theoretical analysis and finite element analysis on the equivalent ring are performed to investigate the effect of the local structural modification on the beat clarity and beat period. Beat clarity and period are improved by attaching asymmetric mass or decreasing local thickness. Through the analysis on the equivalent ring, the proper position and the amount of the local variation are determined to satisfy the required clarity and period condition. All the analysis results are compared and verified by the experiment.

• 한국자동차공학회논문집
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• 제20권6호
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• pp.46-51
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• 2012

Fuel Cell Hybrid Vehicles (FCHVs) have become a major topic of interest in the automotive industry owing to recent energy supply and environmental problems. Several types of power management strategies have been developed to improve the fuel economy of FCHVs including optimal control strategy based on optimal control theory, rule-based strategy, and equivalent consumption minimization strategy (ECMS). The ECMS is applied in this study. This strategy is based on the heuristic concept that the usage of the electric energy can be exchanged to equivalent fuel consumption. This strategy is known as one of the promising solutions for real-time control of hybrid vehicles. The ECMS for an FCHV is introduced in this paper as well as the equivalent fuel consumption parameter. The relationship between the battery final state of charge (SOC) and the fuel consumption while changing the equivalent fuel consumption parameter is obtained for three different driving cycles. The function of the equivalent fuel consumption parameter is also discussed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.427-430
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• 2002

The present parer outlines the system identification and vibration control performance of air traffic control tower of Yangyang international airport with tuned mass damper(TMD). From the free vibration test, natural frequency, damping ratio and mode shape of tower are obtained and these values are compared with the values from numerical analysis. In the vibration control test to evaluate the vibration control performance, equivalent damping ratio increased by tuned mass damper are obtained in case the TMD is operated as passive mode. Damping ratio of tower evaluated from free vibration test is about $1.0{\%}$. It is very low value than damping ratio recommended in general code. Damping ratio of passive mode is about $5{\%}$. These equivalent damping ratio increased by TMD is enough to enhance the serviceability of tower structure under wind load.

• 한국음향학회지
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• 제27권7호
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• pp.365-371
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• 2008

본 연구에서는 미소 비대칭 링을 대상으로, 맥놀이의 주기를 조절하는 실용적 기법을 제시한다 미세한 비대칭성은 하나의 링 모드를 근접한 주파수를 갖는 모드 쌍으로 분리시키는데, 이 모드 쌍이 동시에 가진되면 근접한 주파수 성분이 간섭함으로써 진동과 음향의 맥놀이가 발생한다. 단순화된 종형상의 링 시편을 대상으로 모드 쌍 데이터를 정밀 측정하고, 측정된 모드 쌍 조건을 만족하는 등가 링 모델을 만든다. 등가 링에 대한 유한요소해석을 통하여, 질량을 부착시키거나 두께를 감소시킬 때, 모드 쌍의 조건 변화를 예측하고 맥놀이 주기를 조절하는 방법을 제시한다. 구조변경에 따른 맥놀이 주기 변화의 예측치와 측정치를 비교하여 제시된 맥놀이 조절기법의 타당성을 검증한다.

• 대한기계학회논문집A
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• 제38권6호
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• pp.619-627
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• 2014

본 논문은 등가정하중을 이용하여 제어시스템을 포함한 구조물의 설계를 위한 최적화 방법을 제안한다. 지난 연구는 구조물과 제어시스템 최적설계를 독립적으로 분리하여 수행하였고, 구조물과 제어시스템을 동시에 최적화하여도 제어시스템의 제어변수는 정상상태에서만 최적화하여 성능을 향상시켰다. 하지만 제어변수는 모든 시간영역에서 최적화해야 한다. 즉, 제어시스템의 해석은 과도상태에서 수행해야 한다. 본 연구에서는 새로운 등가정하중을 이용하여 제어변수를 포함하는 제어시스템 구조물의 최적설계를 위한 방법을 제시하였다. 등가정하중은 동적하중이 구조물에 작용할 때 발생하는 임의 시간에서의 변위장과 동일한 변위장을 만들어내는 정하중을 의미한다. 이렇게 계산된 등가정하중을 이용하여 설계영역에서 선형정적응답 최적설계를 진행한다. 몇 가지 예제를 통해 새로운 등가정하중을 적용한 동적응답 최적설계방법의 유용성을 확인하였다.

• International Journal of Control, Automation, and Systems
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• 제1권4호
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• pp.401-411
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• 2003

Important results about two-degree-of-freedom PID controllers are surveyed for the tutorial purpose, including equivalent transformations, various explanations about the effect of the two-degree-of-freedom structure, relation to the preceded-derivative PID and the I-PD controllers, and an optimal tuning method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.273-277
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• 1995

Many hudraulic components have nonlinearities to some extent. These nonlinearities often cause the time delay, thus degrading the performance of the hydraulic control systems and making it difficult to modelthem. In this paper, a new vibration isolation control algorithm that eliminates the necessity of a sophiscated modeling of hydraulic system was proposed. The algotithm is a hybrid type control shecheme consisting of a linear controller and a hetero-synaptic neural network controller. Using this control scheme, simulations and experiments were performed for 1 DOF(Degree of freedom) and 2 DOF vibration isolation. The hybrid type control algorithm can isolate the base vibration signifcantly rather than linear control algorithm. And from the weights in hetero-synaptic neural network, we can get the 2nd equivalent differentialmodel of the hydraulic control system with on-line control operation. This equivalent model provides us with much information, such as stability and the characteristics of the control system.

• 대한전기학회논문지
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• 제34권11호
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• pp.440-444
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• 1985

Voltage equations of a synchronous machine are derived from the electromagnetic field theory in order to develop a new equivalent circuit model considering core loss. The result from the new equivalent circuit model is superior to that of the conventional one in the analysis of machine performance and characteristics on optimal efficiency control of a synchronous motor.

• 조명전기설비학회논문지
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• 제12권3호
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• pp.59-66
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• 1998

In this paper, the thrust control of PWM Inverter-Fed SLIM(Single-sided Linear Induction Motor) is achieved with Space Vector control and PI control. The trembling of air gap length which is occurred between the primary winding core and the secondary structure of the SLIM must be minimized in order to get quick response characteristics. First, the equivalent circuits and voltage equations of SLIM are shown on th suitable d-q axis which analyze characteristics of the thrust and the normal force. Also, modeling and analysis of the equivalent circuits transferred d-q axis are able to make robust transient torque from the current regulation in the equivalent circuit. These results exemplified the direct drive of SLIM with the reference speed and torque were verified by experiments.