• 한국전자통신학회논문지
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• 제10권6호
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• pp.749-756
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• 2015

본 논문에서는 동기식 디지털 통신 프로토콜을 사용하여 노드 간 견고한 링크를 유지하고 초 저 전력 통신을 수행할 수 있는 고유의 시스톨릭(systolic) 구조 및 통신 알고리즘을 제안한다. 이 시스템은 CC2500 RF 트랜시버, CC2590 RF 프론트 엔드 및 C8051F330 저 전력 마이크로컨트롤러를 사용하여 설계 및 평가 되었고 구현된 링크 노드의 전력소모는 320bps의 데이터 전송 속도에서 $400{\mu}W$ 이하로 측정되었다. 구현된 시스템은 각각 센서 노드 8개를 연결할 수 있는 링크 노드 7개로 구성된 저 전력 무선 센서 네트워크를 구성하는 기본 장치의 기능을 가지고 있다. 실험을 통해 링크 노드는 4Ah의 배터리를 사용하는 경우 4초의 주기로 3년 이상의 배터리 무교체 동작을 구현할 수 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.921-922
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• 2011

• 대한수학회지
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• 제56권3호
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• pp.789-804
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• 2019

In this paper, we prove that a link which has an almost positive diagram with a certain condition is Lagrangian fillable.

• 한국전자통신학회논문지
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• 제4권3호
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• pp.236-242
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• 2009

2관절 유연한 로봇 팔는 관절 축을 회전할 때 진동이 발생한다. 본 논문에서는 유연한 로봇팔의 진동 동력학은 bernoulli-Euler의 beam이론과 라그란지 방정식을 이용하여 구하였고, $\dot{D}$-2C가 skew symmetric이다는 사실을 사용하여 계산량을 줄이는 단순한 구조의 새로운 제어기를 제안한다. Lyapunov 안정도 이론은 관절을 조절하기 위한 안정한 확정적인 비선형 제어기를 성취하기 위하여 적용된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.280-284
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• 1997

In this paper, Nonlinear VSS control based on bang-bang control concept is derived under the assumption that the control input is bounded. We try to derive control algorithm which has almost same performance as the time optimal control. We focus this control scheme on the real implementation of DC motor position controller of flexible link, i.e. we obtain the switching curves from the real data of DC motor system operating under the full maximum and minimum applied voltages. State space is separated into several regions and we set different switching surfaces in each region to reduce chattering problem. The efficiency of the proposed controller is compared with PID controller and it is shown that the controller converges fast than PID controller without chattering. The hybrid controller scheme is also proposed not only to control the position of hub but also to reduce the vibration of end tip of flexible link.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.19-22
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• 2005

In order to achieve high capacity and reliable link quality in user communication, this paper proposes a new concept of virtual cell: the Dual Virtual Cell(DVC), and DVC employment strategy based on DWCS. The proposed system uses two kinds of virtual cell. One is the AVC(Active Virtual Cell) which exists for actual traffic and the other is the CVC(Candidate Virtual Cell) which contains a set of candidate antennas to protect user's link quality from performance degradation or interruption. And also this system aims to reduce MT's overloads and acheive a prompt link change successfuly by introducing DVC structure which makes it possible for network to monitor real-time channel and to conrol communication links. The proposed system constructs DVC by using antenna selection method and improves frame error performance with employing Space-Time Trellis Code(STTC).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.995-998
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• 1992

A fully software-controlled pulse-width modulatioed (PWM) rectifier with current link is presented. Line power factor is controlled, while maintaining dc current. The input fitter of the PWM rectifier is analyzed and its analysis, shows that unity power factor is achieved with lagging of the input current of the PWM rectifier with respect to the source voltage. The PWM technique is developed using a space vector modulation and is implementation is carried out with a minimal control hardware structure based on one 16-bit single-chip microcomputer. It is shown via experimental results that the proposed sheme gives good performance for the PWM rectifier with current link.

• 전기학회논문지
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• 제59권6호
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• pp.1179-1185
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• 2010

This paper deals with a robust controller design problem for a small one-link robot arm system subject to input time delay and load variations. The uncertain parameters of the system are considered as a disturbance input. A disturbance observer(DOB) has been designed to alleviate disturbance effects and to compensate performance degradation owing to the time-delay. This paper employs a new DOB structure for non-minimum phase systems together with the Smith predictor. We propose a new controller for reducing the both effects of disturbance and time-delay. In order to test the performance of proposed controller, four different other control laws are compared with the proposed one by computer simulations. The simulation results show the effectiveness of the proposed control method.

• Journal of Mechanical Science and Technology
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• 제18권4호
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• pp.573-581
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• 2004

A self-contained wall climbing robot, called MRWALLSPECT (Multi-functional Robot for WALL inSPECTion) II, is developed. It is designed for scanning external surfaces of gas or oil tanks with small curvature in order to find defects. The robot contains all the components for navigation in itself without any external tether cable. Although it takes the basic structure of the sliding body mechanism, the robot has its original characteristic features in the kinematic design with closed link mechanism, which is enabled by adopting a simple and robust gait pattern mimicking a biological system. By employing the proposed link mechanism, the number of actuators is reduced and high force-to-weight ratio is achieved. This paper describes its mechanism design and the overall features including hardware and software components. Also, the preliminary results of experiments are given for evaluating its performances.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.265-268
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• 2006

Performed fatigue strength analysis for Hub to get the targeted service life of 20 years. ANSYS is used to analysis. The major structure of bearing which connect the hub and blades is modeled using the element of LINK10. To represent the stiffness of LINK10 element, initial strain and diameter of LINK10 element is applied. Prior to calculating the fatigue damages, the influence matrix is extracted from the unit loads. The target service life of 20 years is achieved from the Analysis results.