• Journal of Power Electronics
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• 제7권1호
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• pp.21-27
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• 2007

This paper investigates a PID fuzzy controller for output voltage regulation of a current-doubler-rectified asymmetric half-bridge (CDRAHB) DC/DC converter. The controller is a PD-type fuzzy controller in parallel with a linear integral controller. The PD type fuzzy controller is for providing the varying gain at the different operating conditions to regulate the output voltage. The linear integral controller is for removing the steady-state error of the output voltage. In order to show the outstanding dynamic characteristics of the proposed controller, PSIM simulation studies are carried out and compared to the results for which the conventional loop gain design method is used.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1843-1845
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• 1998

Gyroscope is a very important core sensor as a rotation sensor in inertial space, in inertial guidance and navigation system on aeronautics. Plane, vessel and so on for civilian and millitary applications. Research and development of fiber optic gyroscope began in 1976 and focused on improving the gyroscope's sensitivity to rotation. bias performance and reducing noise. We have developed a Interferometric Fiber Optic' Gyroscope using a integrated-optic-circuit (IOC), which is operating with closed-loop electronic circuit. This paper describes the scheme of optical part and electronic part and also test results of this fiber optic gyroscope using a integrated-optic-circuit (IOC). The performance have been achieved as long-term bias drift of $1.73^{\circ}/h$.

• 전자공학회논문지B
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• 제31B권8호
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• pp.64-73
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• 1994

In this paper we present an algorithmic technique for determining a feedback compensator which will stabilize the interval dynamic system specifically the robust regulator design for interval plants. The approach taken here is to allow the system parameters to live within prescribed intervals then design a dynamic feedback compensator which guarantees closed-loop system stable. The main contribution of this paper is the idea of introducting a "simplified Kharitonov`s results" for low order polynomials to search for suitable compensator parameters in the compensator parammeter space to make the uncertain system robust. We also design the robust regulator which will $D_{\phi}$ -stabilize (have the closed-loop poles in the left sector only) the dynamic interval system while having good performance. the numerical examples are given to show the substantially improved robustness which results from our approach.

• 한국컴퓨터정보학회논문지
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• 제3권4호
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• pp.132-138
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• 1998

ATM망에서 CVR, VBR, UBR, ABR과 같은 트랙이 존재하는데 특히 ABR 트래픽 관리에 대해서 많은 연구가 진행되고 있다. ABR은 CBR/VBR이 쓰고 남은 대역폭을 쓰게 되는데 이 남은 대역폭을 효율적으로 사용하고자 많은 방식이 나오고 있다 ATM Forum의 트래픽 관리 WG(Working Group)에서는 ABR서비스의 흐름제어 loop을 구현하기위한 방식으로 Rate-based와 Credit-base. 그리고 이 두 가지 방식을 혼합한 방식에 대해서연구를 진행하고 있다. 본 논문에서는 Rate-based 방식에서 EFCI. ER과 VS / VD(Virtual Source/Virtual Destination)등을 이용한 스위치에 대해서 알아보고 VS/VD 방식과 기존의EPRCA알고리듬을 응용하여 효율적으로 ABR트래픽을 관리할 수 있는 새로운 메커니즘을제안한다.

• 전기학회논문지
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• 제61권1호
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• pp.110-116
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• 2012

This paper proposes a new diversity antenna which is the base of MIMO, tunable and reconfigurable antennas. The antenna has a small size and high inter-antenna isolation resulting from the compact radiating element comprising a meandered line and an open-loop combined in one limited uniplanar space and a modified T-shaped decoupling structure, respectively. In a WiMAX band, the radiating element and the entire antenna are $0.092{\lambda}$ and $0.2216{\lambda}$ in size, which shows effective size-reduction and the gain and efficiency of the proposed antenna attached to the ground of a handheld device are 3.7dBi and 56% acceptable to the industrial standard.

• 한국정밀공학회지
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• 제17권1호
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• pp.34-44
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• 2000

In this paper, a modified skyhook control for the semi-active Macpherson suspension system is investigated. A new model for the semi-active type suspension, which incorporates the rotational motion of the unsprung mass, is introduced and an output feedback control law using the skyhook control method is derived. The gains in the skyhook controller are adaptively adjusted by estimating the road conditions. Because two vertical acceleration sensors, one for the sprung mass and another for the unsprung mass, are used rather than using the angle sensor for the rotational motion of the control arm, the relative velocity of the rattle space is filtered using the acceleration signals. For testing the control performance, the actual damping force has been incorporated via the hardware-in-the-loop simulations. The performances of a passive damper and a semi-active damper are compared. Simulation results are provided.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.758-771
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• 2021

This paper presents a novel control scheme for the three-dimensional (3D) path following of underactuated Autonomous Underwater Vehicle (AUVs) subject to unknown internal and external disturbances, in term of the time scale decomposition method. As illustration, two-time scale motions are first artificially forced into the closed-loop control system, by appropriately selecting the control gain of the integrator. Using the singular perturbation theory, the integrator is considered as a fast dynamical control law that designed to shape the space configuration of fast variable. And then the stabilizing controller is designed in the reduced model independently, based on the time scale decomposition method, leading to a relatively simple control law. The stability of the resultant closed-loop system is demonstrated by constructing a composite Lyapunov function. Finally, simulation results are provided to prove the efficacy of the proposed controller for path following of underactuated AUVs under internal and external disturbances.

• 천문학회보
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• 제46권1호
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• pp.43.2-43.2
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• 2021

In this study, we report oscillations of the total intensity of white light loops in the off-limb solar flare observed in 2017-Sep-10 with the SDO/HMI. The total intensity oscillations are correlated with the area of the flaring loop in the plane of the sky. The oscillatory pattern is well fitted by two consecutive damped oscillations. The period and damping time of the first oscillation are 12.9 minutes and 9.9 minutes, respectively. Those of the second oscillation are 11.7 minutes and 15.4 minutes. The excitation of the oscillations coincides with two consecutive type III radio bursts observed in meter range. Assuming the oscillations are magnetoacoustic waves in the flaring loops with the loop lengths ranging from 30 to 90 Mm, the temperature of the white light emitting loops could be in the range from 0.3 MK to 2.6 MK.

• International Journal of Aeronautical and Space Sciences
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• 제11권3호
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• pp.184-192
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• 2010

In this paper, an initial fine alignment algorithm, which is developed for the strap-down inertial navigation systems of satellite launch vehicles, is considered. For fast and accurate alignment, a simple closed-loop estimation algorithm using a proportional-integral controller is introduced. Through computer simulation for the sway condition in the launch pad, it is shown that a simple filter structure can guarantee fast computational speed that is adequate for real-time implementation as well as the required alignment accuracy and robustness. In addition, its implementation results are presented for the Naro-1 flight test.

• 제어로봇시스템학회논문지
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• 제13권4호
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• pp.365-370
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• 2007

This paper studies an automation problem of a heating, a ventilating, and an air conditioning (HVAC) for the development of smart space. The HVAC system is described by the fuzzy system for the stability analysis and the controller design. The linear matrix inequalities (LMIs) conditions are derived for the stabilization problem of the closed-loop system under the analog control. Also, it is required to digitally redesign the pre-designed the analog HVAC control system in order to accomplish the remote control via web. It is shown the this digital redesign problem can be converted to the convex optimization problem with the LMI constraints. An example is provided to show the effectiveness of the proposed method.