• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.498-502
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• 2004

In a link-motion mechanism, numerous links are interconnected and each link executes a constrained motion at a high speed. Due to the complicated constrained motions of the constituent links, dynamic unbalance forces and moments are generated and transmitted to the main frame. Therefore unwanted vibration is produced. This degrades productivity and precise work. Based on constrained multi-body dynamics, the kinematic analysis is carried out to enable design changes to be made. This will provide the fundamental information for significantly reducing dynamic unbalance forces and moments which are transmitted to the main frame. In this work, a link-motion punch press is selected as an example of a link-motion mechanism. To calculate the mass and inertia properties of every link comprising a link-motion punch press, 3-dimensional CAD software is utilized. The main issue in this work is to eliminate the first-order unbalance force and moment in a link-motion punch press. The mass, moment of inertia link length, location of the mass center in each link have a great impact on the degree of dynamic balancing which can be achieved maximally. Achieving good dynamic balancing in a link motion punch press is quite essential fur reliable operation at high speed.

• Advances in robotics research
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• 제1권1호
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• pp.61-79
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• 2014

This paper presents theoretical and experimental investigations into the dynamic modelling and characterisation of a two-link flexible manipulator incorporating payload. A planar two-link flexible manipulator that moves in a horizontal plane is considered. A dynamic model of the system is developed using a combined Euler-Lagrange and assumed mode methods, and simulated using Matlab. Experiments are performed on a lab-scaled two-link flexible manipulator for validation of the dynamic model and characterisation of the system. Two system responses namely hub angular position and deflection responses at both links are obtained and analysed in time and frequency domains. The effects of payload on the dynamic characteristics of the flexible manipulator are also studied and discussed. The results show that a close agreement between simulation and experiments is achieved demonstrating an acceptable accuracy of the developed model.

• 한국통신학회논문지
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• 제37C권11호
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• pp.1045-1053
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• 2012

Link-16은 가장 널리 사용 중인 전술데이터링크로써 TDMA(Time Division Multiple Access)를 기반으로 동작한다. Link-16은 안정적이지만 전송 속도가 매우 낮아 전술 메시지, 음성 등 작은 사이즈의 데이터 전송을 지원한다. 그러나 최근 효과중심작전(EBO: Effect-Based Operation)에 대한 관심이 증가하면서, Link-16을 통해 이미지와 같은 상황 인식 정보를 전송하려는 동향이 있다. 이미지는 기존 메시지에 비해 크기가 매우 크기 때문에 Link-16의 Static TDMA가 아닌 별도의 TDMA 스케줄링이 필요하다. 따라서 본 논문에서는 Link-16의 MAC을 진화시킨 Link-16K를 제안하였다. Link-16K는 Link-16과 호환성을 유지한다. 그리고 이미지 전송을 효과적으로 지원하기 위해 DTDMA(Dynamic TDMA), 새로운 재전송 방법, 새로운 패킹 방법을 포함한다. 제안하는 아이디어의 시뮬레이션 결과를 통해 이미지 전송 시간이 단축되었고, 채널 효율성이 높아졌음을 확인하였다.

• 한국통신학회논문지
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• 제35권11B호
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• pp.1640-1650
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• 2010

최근 전장의 환경이 네트워크 중심전으로 빠르게 변화함에 따라 다양한 전술정보를 신속하고 정확하게 전송할 수 있는 전술데이터링크가 요구되고 있다. 현재 한국군은 효율적인 합동전술 작전을 지원하기 위해 한국형 합동전술데이터링크(KJTDLS: Korea Joint Tactical Data Link System) 체계 개발을 기본형과 완성형 2단계로 나누어 추진하고 있다. 하지만 한국형 합동전술데이터링크 체계(기본형)는 미군의 대표적인 전술데이터링크인 Link-16과 비교하여 통신 대역폭의 제한과 낮은 전송효율 때문에 Link-16의 TDMA 프로토콜을 적용하기에는 많은 문제점이 있다. 본 논문에서는 한국군의 전술 작전환경을 고려하여 Dynamic TDMA 기술 기반의 프로토콜의 구조를 제안하였으며, 제안된 전술데이터링크 프로토콜을 검증하기 위해 시뮬레이션을 구현 및 성능을 분석하였다.

• 한국정밀공학회지
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• 제12권6호
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• pp.105-111
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• 1995

The inverse dynamic equations for 5 link robot including a closed chain have been derived. The closed chain is virtually cut open, and the kinematics and dynamics of the virtual open chain robot are analyzed. The constraints are applied to the virtually cut joints by the Jacobian matrix which represents the configuration of the closed chain. The topology of tree structrued open chain robot is described by a FATHER array. The FATHER array of a link indicates the link tha tis connected in the direction of base link. Based on the inverse dynamic equations, the torque sensitivity models of the 5 link robot have been developed. The sensitivity models characterize the sensitivity of the driving torque with respect to the link parameters. All the procedures are illustrated through the 2 link robot.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.18-23
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• 1990

In this paper, the dynamic modeling and a tip-position controller of a single-link flexible manipulator are developed. To design the controller of a flexible manipulator, at first, it is required to obtain the accurate dynamic model of manipulator describing both rigid motion and flexible vibration. For this purpose, FEM(Finite Element Method) and Lagrange approach are utilized to obtain the dynamic model. After obtaining the dynamic model of a single-link manipulator, a controller which computes the input torque to perform the desired trajectory is developed using neural network.

• 전기학회논문지
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• 제64권9호
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• pp.1297-1305
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• 2015

This paper proposes a power feedforward technique for the performance improvement of DC-link voltage control in the dynamic voltage restorer (DVR). The DC-link Voltage is able to be unstable for an instant owing to any change in the load and voltage sag. The distortion of the DC-link voltage leads to the negative influence on the performance of DVR. To mitigate the distortion of the DC-link voltage, the power feedforward component is calculated by the load power and the grid voltage, and then it is added to the reference current of the conventional DC-link voltage controller. By including output power feedforward component on the DC-link controller, the DC-link voltage can settle down more quickly than when the conventional DC-link voltage controller applied. The proposed technique was validated through the simulation and experimental results.

• Journal of the Optical Society of Korea
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• 제18권4호
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• pp.330-334
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• 2014

In this paper, we present an incoherent dual-parallel modulation linearized optical link employing two different optical wavelengths. Comparing with previous dual-parallel modulation, this linearization method prevents the recreation of distortion products and can be readily implemented. Furthermore, a dual-wavelength dual-parallel modulation linearized optical link constructed with the commercially available devices is experimentally demonstrated with a spurious-free dynamic range of $122.5dB.Hz^{4/5}$. More than 25 dB suppression of the intermodulation distortion, 15.6 dB improvement of spurious-free dynamic range and 1.5 dB improvement of compression dynamic range are achieved after linearization.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1846-1850
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• 2005

This paper presents a constrained-based routing (CBR) algorithm called, Dynamic Possible Path per Link (D-PPL) routing algorithm, for MultiProtocol Label Switching (MPLS) networks. In MPLS on-line routing, future traffics are unknown and network resource is limited. Therefore many routing algorithms such as Minimum Hop Algorithm (MHA), Widest Shortest Path (WSP), Dynamic Link Weight (DLW), Minimum Interference Routing Algorithm (MIRA), Profiled-Based Routing (PBR), Possible Path per Link (PPL) and Residual bandwidth integrated - Possible Path per Link (R-PPL) are proposed in order to improve network throughput and reduce rejection probability. MIRA is the first algorithm that introduces interference level avoidance between source-destination node pairs by integrating topology information or address of source-destination node pairs into the routing calculation. From its results, MIRA improves lower rejection probability performance. Nevertheless, MIRA suffer from its high routing complexity which could be considered as NP-Complete problem. In PBR, complexity of on-line routing is reduced comparing to those of MIRA, because link weights are off-line calculated by statistical profile of history traffics. However, because of dynamic of traffic nature, PBR maybe unsuitable for MPLS on-line routing. Also, both PPL and R-PPL routing algorithm we formerly proposed, are algorithms that achieve reduction of interference level among source-destination node pairs, rejection probability and routing complexity. Again, those previously proposed algorithms do not take into account the dynamic nature of traffic load. In fact, future traffics are unknown, but, amount of previous traffic over link can be measured. Therefore, this is the motivation of our proposed algorithm, the D-PPL. The D-PPL algorithm is improved based on the R-PPL routing algorithm by integrating traffic-per-link parameters. The parameters are periodically updated and are dynamically changed depended on current incoming traffic. The D-PPL tries to reserve residual bandwidth to service future request by avoid routing through those high traffic-per-link parameters. We have developed extensive MATLAB simulator to evaluate performance of the D-PPL. From simulation results, the D-PPL improves performance of MPLS on-line routing in terms of rejection probability and total throughput.

• 한국소음진동공학회논문집
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• 제17권5호
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• pp.415-426
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• 2007

링크모션 펀치프레스는 많은 링크들이 서로 연결되어 있으며 각각의 링크는 고속에서 구속 운동을 수행한다. 그 결과 동적 불평형 힘과 모멘트가 프레스의 메인프레임으로 전달되며 원하지 않는 진동을 수반한다. 이로 인하여 생산성과 정확한 스탬핑 작업의 저하를 초래한다. 이 논문은 기구학 및 동역학 분석에 기초하여 링크모션 펀치프레스의 다이나믹 언발란스를 저감하는 효과적인 방법을 제시한다. 그리고 디자인 변화가 필요할 때마다 메커니즘의 모델 구성을 자동화하기 위한 디자인 변수 방식을 소개한다. 질량, 질량관성모멘트, 질량중심 등의 링크들의 관성 성질을 얻기 위하여 3차원 캐드 소프트웨어를 활용하였다. 메커니즘의 기구학적, 동역학적 거동에 주요한 영향을 미치는 일부 링크들의 디자인을 변화시킬 때 얻을 수 있는 다양한 조합에 대하여 동역학 시뮬레이션을 수행하였다.