• 한국생산제조학회지
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• 제22권5호
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• pp.886-893
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• 2013

A vibrating screen with multiple decks is widely employed for the process separation of many valuable export commodities. In this study, the inclination angle of the deck of the vibrating screen and the direction angle of the screen's vibration under single particle kinematics were predicted. A finite element model of the vibrating screen was established by parameterization modeling. Through modal analysis and static analysis of the model, the natural frequency, natural vibration mode, and stress distribution of the structure were determined, based on which the dynamics and design optimization of the vibrating screen could be achieved. Future plans also reflect this by conducting detailed design of vibrating screens for the manufacturing plans of vibrating screen machine.

• 한국공작기계학회논문집
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• 제10권3호
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• pp.19-25
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• 2001

In this paper, we developed a Windows 98 version Off-Line Programming System which can simulate a Robot model in 3D Graphics space. 4 axes SCARA Robot (especially FARA SM5) was adopted as an objective model. Forward kinemat-ics, inverse kinematics and robot dynamics modeling were included in the developed program. The interface between users and the OLP system in the Windows 98s GUI environment was also studied. The developing is Microsoft Visual C++. Graphic libraries, OpernGL, by silicon Graphics, Inc. were utilized for 3D Graphics.

• 제어로봇시스템학회논문지
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• 제14권8호
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• pp.842-847
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• 2008

This paper proposes a new sliding-surface-based tracking control system for nonholonomic mobile robots with disturbance. To design a robust controller, we consider the kinematic model and the dynamic model of mobile robots with disturbance. We also propose a new sliding surface to solve the problem of previous study. That is, since the new sliding surface is composed of differentiable functions unlike the previous study, we can obtain the control law for arbitrary trajectories without any constraints. From the Lyapunov stability theory, we prove that the position tracking errors and the heading direction error converge to zero. Finally, we perform the computer simulations to demonstrate the performance of the proposed control system.

• 한국정밀공학회지
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• 제26권6호
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• pp.106-113
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• 2009

A 6-DOF precision stage was developed based on parallel kinematics structure with flexure hinges to eliminate backlash, stick-slip and friction and to minimize parasitic motion coupled with motions in the other-axis directions. For the stage, lever linkage mechanism was devised to reduce the height of system for the enhancement of horizontal stiffness. Frequency response comparison between experimental results and mathematical model extracted from dynamics of the stage was performed to identify the system parameters such as spring constants and damping coefficients of actuation modules, which cannot be calculated accurately by analytic methods owing to their complicated structures. This newly developed precision stage and its identified model will be very useful for precision positioning and control because of its high accuracy and non-coupled movement.

• Journal of Mechanical Science and Technology
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• 제15권4호
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• pp.448-458
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• 2001

The primary goal of virtual prototyping is to eliminate the need for fabricating physical prototypes, and to reduce cost and time for developing new products. A virtual prototyping seeks to create a virtual environment where the development of a new model can be flexible as well as rapid, and experiments can be carried out effectively concerning kinematics, dynamics, and control aspects of the model. This paper addresses the virtual environment used for virtual prototyping of a passenger vehicle. It has been developed using the dVISE environment that provides such useful features as actions, events, sounds, and light features. A vehicle model including features, and behaviors is constructed by employing an object-oriented paradigm and contains detailed information about a real-size vehicle. The human model is also implemented not only for visual and reach evaluations of the developed vehicle model, but also for behavioral visualization during a crash test. For the real time driving simulation, a neural network model is incorporated into the virtual environment. The cases of passing bumps with a vehicle are discussed in order to demonstrate the applicability of a set of developed models.

• 천문학회지
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• 제43권4호
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• pp.105-113
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• 2010

We study the dynamical evolution of the M87 globular cluster (GC) system using the most advanced and realistic Fokker-Planck (FP) model.By comparing our FP models with both mass function (MF) and radial distribution (RD) of the observed GC system, we find the best-fit initial (at M87's age of 2-3 Gyr) MF and RD for three GC groups: all GCs, blue GCs, and red GCs. We estimate the initial total mass in GCs to be $1.8^{+0.3}_{-0.2}{\times}10^{10}M_{\bigodot}$, which is about 100 times larger than that of the Milky Way GC system. We also find that the fraction of the total mass currently in GCs is 34\%. When blue and red GCs are fitted separately, blue GCs initially have a larger total mass and a shallower radial distribution than red GCs. If one assumes that most of the significant major merger events of M87 have ended by the age of 2-3 Gyr, our finding that blue (metal-poor) GCs initially had a shallower radial distribution supports the major merger scenario for the origin of metallicity bimodality.

• 수산해양기술연구
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• 제56권1호
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• pp.61-70
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• 2020

In this study, system modeling and dynamic analysis of crane are conducted. Especially, among many different kinds of a crane system, the issues on crane operating problems installed on the vessel are considered. As well known, marine systems including cranes are exposed to various disturbances such as vessel motions, hydrodynamic forces, wave and wind attack, etc. In order to analysis the system dynamic with environmental conditions, the authors derived the nonlinear dynamic model of offshore crane and derived a linear model which is used for designing the control system. Using the obtained nonlinear and linear models, simulations were conducted to evaluate the usefulness of the obtained models. By simulation and result evaluation, the usefulness of the linear model, which presents the dynamics, is effectively verified.

• 전자공학회논문지
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• 제51권9호
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• pp.208-214
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• 2014

차선유지 제어시스템, 적응식순항 제어시스템과 같은 첨단운전 지원시스템은 기본적으로 차량의 거동 정보를 기반으로 구동되지만, 최근 도로의 기하학적 정보를 추가적으로 활용하는 연구가 활발히 진행되고 있다. 특히, 도로의 종단경사는 차량의 가감속 제어 및 항법알고리즘 구현에 있어 필수적인 정보로서 DGPS-RTK와 같은 고가의 장비로 직접 측정하는 방법과 디지털 맵에 저장된 속성정보를 활용하는 방식이 제안되고 있으나, 상용화 관점에서는 아직 많은 문제점이 존재한다. 따라서, 본 논문에서는 추가 센서의 장착없이 연속형 확장칼만필터를 활용하여 차량의 동특성과 도로종단경사를 효율적으로 추정하는 알고리즘을 제안한다. 도로종단경사를 포함하는 3자유도 차량동역학 모델과 차량의 내부 네트워크롤 통해 수집할 수 있는 차량의 상태정보를 기반으로 확장칼만필터를 설계하여 차량의 동특성과 도로종단경사를 추정한다. 제안된 알고리즘은 시뮬레이션과 실차실험을 통해 그 성능을 검증하였다.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.54-63
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• 2016

A novel attitude tacking control method using Time Delay Control (TDC) scheme is developed to provide robust controllability of a rigid hexacopter in case of single or multiple rotor faults. When the TDC scheme is developed, the rotor faults such as the abrupt and/or incipient rotor faults are considered as model uncertainties. The kinematics, modeling of rigid dynamics of hexacopter, and design of stability and controllability augmentation system (SCAS) are addressed rigorously in this paper. In order to compare the developed control scheme to a conventional control method, a nonlinear numerical simulation has been performed and the attitude tracking performance has been compared between the two methods considering the single and multiple rotor faults cases. The developed control scheme shows superior stability and robust controllability of a hexacopter that is subjected to one or multiple rotor faults and external disturbance, i.e., wind shear, gust, and turbulence.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1262-1269
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• 2004

This study predicts muscle forces acting on the lower extremity when the knee joint is in deep flexion. The whole body was approximated as a link model, and then the moment equilibrium equations at the lower extremity joints were derived far given reaction farces against the ground. Measurement of deep flexion was carried out by placing ten markers on the body. This study calculated the moment acting at each Joint from the equations of force and moment, classified the complicated muscles around the knee joint, and then predicted the muscle forces to balance the joint moment. Two models were proposed in this study: the simpler one that consists of three groups of muscle and the more detailed one of nine groups of muscle.