• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2001년도 가을 학술발표논문집 Vol.28 No.2 (2)
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• pp.523-525
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• 2001

본 논문은 많은 수의 rigid body 물체들을 물리학에 기반하여 실시간으로 애니메이션하는 방법을 제안한다 rigid body 물체들의 움직임을 생성해내는 과정은 상당한 시간이 소요되며 또한 물체의 수가 증가함에 따라 계산시간이 급증한다. 본 논문에서는 Timewarp rigid body 시뮬레이션 알고리즘을 실시간 애니메이션에 적용하기 위해 시간당 생성되는 프레임 수에 따른 다단계 롤백 범위 적용을 하는 방법을 제안하고 실험을 통하여 시뮬레이tus 시스템의 효율성을 보인다.

• 한국산업융합학회 논문집
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• 제20권5호
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• pp.405-410
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• 2017

This paper deals with 3D simulation of industrial robot for automated manufacturing system. In order to evaluate the operational characteristics of the industrial robot system in the worst case motion scenario, flexible - rigid multibody analysis was performed. Then, the rigid body dynamics analysis was performed and the results were compared with the flexible - rigid multibody analysis. Modal analysis was also performed to confirm the dynamic characteristics of the robot system. In the case of the flexible-rigid multibody simulation, only the structural members of interest were modeled as elastic bodies to confirm the stress state. The remaining structural members were modeled as rigid bodies to reduce computer resources.

• 소음진동
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• 제3권1호
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• pp.65-75
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• 1993

In this study, we identify the structural dynamic characteristics of the rigid body suspension system of waching machine containing rotating system, and consider the methods for the reduction of noise and vibration due to the structural problems. The structural dynamic characteristics of the suspension system have been studied by the computer simulation, in which the commercial software package, "DYMES(Dynamics of Mechanical System)" is used. The behaviour of the supporter by the rotating system has been parametrically studied by computer simulation, and the force and torque which are transferred to the fixed body through the suspension bar also has been calculated. The possibility to decide the position and the stability of the rigid body suspension system for waching machine is demonstrated based on various simulation results.n results.

• 한국철도학회논문집
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• 제13권1호
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• pp.16-22
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• 2010

다양한 철도차량 동역학 해석 프로그램들은 장단점을 가지고 있다. 이러한 프로그램들은 가선계를 표현할 수 있는 대변형체를 나타낼 수 없는 한계를 가지고 있다. 본 연구에서는 철도차량의 동역학 해석을 할 수 있는 프로그램을 개발하였다. 이 프로그램은 강체, 유연체, 대변형체에 대한 해석을 수행하고 상용프로그램과의 비교를 통하여 신뢰성을 확보하였다. 또한 가선계를 대변형체로 고려하였고, 강체와 대변형체를 연결하는 미끄럼 조인트를 추가하였다. 여기에 휠-레일 접촉모듈을 추가하여 철도차량의 동역학 해석이 가능한 프로그램을 개발하였다.

• Ocean Systems Engineering
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• 제1권3호
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• pp.207-222
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• 2011

A stabilized incompressible smoothed particles hydrodynamics (ISPH) method is utilized to simulate free falling rigid body into water domain. Both of rigid body and fluid domain are modeled by SPH formulation. The proposed source term in the pressure Poisson equation contains two terms; divergence of velocity and density invariance. The density invariance term is multiplied by a relaxed parameter for stabilization. In addition, large eddy simulation with Smagorinsky model has been introduced to include the eddy viscosity effect. The improved method is applied to simulate both of free falling vessels with different materials and water entry-exit of horizontal circular cylinder. The applicability and efficiency of improved method is tested by the comparisons with reference experimental results.

• 한국멀티미디어학회논문지
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• 제12권2호
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• pp.323-328
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• 2009

게임이나 가상현실 등에서 사용자들에게 사실성과 몰입 감을 주기 위해서 자연 현상들을 시뮬레이션하고 있다. 게임이나 가상현실에서 물이나 바다와 같은 유체를 3차원으로 시뮬레이션 하는데 있어서 중요한 요소는 실시간 처리와 사실성이다. 유체 모델은 특정 상황에 따른 다양한 방정식과 많은 파라미터 값에 의해 제어되기 때문에 시뮬레이션 하는데 많은 어려움이 따른다. 또한 복잡한 물리 수식을 기반으로 하기 때문에 유체 모델을 시뮬레이션하기 위해서는 많은 수행 시간이 소요된다. 본 논문에서는 실시간 유체와 강체(rigid body) 사이의 상호작용을 표현하기 위해 간략화 된 유체 표면 모델(Fluid-Surface Model)을 제안하고, 개선된 계산과정을 통해 보다 빠르게 시뮬레이션 하도록 한다. 또한 본 논문에서는 유체의 표면과 강체의 상호작용을 표현하는데 있어서 유체의 항력에 의해서 강체와 충돌 시 발생하는 유체 표면의 움직임을 나타낸다. 본 논문에서 제안하는 자연스러운 유체 표면 모델은 유체역학적 방법을 사용하여 실시간에 사실적으로 표현된다. 그리고 이러한 유체 표면 모델을 PC 환경에서 사용자와 상호작용 가능하도록 재현하여, 게임이나 애니메이션에서의 유체 모델들에도 적용할 수 있다.

• 소음진동
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• 제3권3호
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• pp.231-243
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• 1993

The dynamic characteristics of two types of mathematical models for a rigid body suspension system are analyzed and compared in this paper. One is a linearized model which is commonly used in the engine mount system analysis, the other is a nonlinear model which usually applied to the pendulum type system. The typical 3 d.o.f's mathematical model, for convenience, is chosen as a simulation model, because it has fundamental dynamic characteristics of suspension system. Time responses and unbalance responses of the rigid body, transmitted forces and torques are simulated by using the mathematical model. From the results of computer simulation, it is approved that he nonlinear model is valid and the linearized model gives erroneous results in the case of the pendulum type suspension system. In addition, in this study the effects of design change on the dynamic characteristics of the suspension system are investigated. Mount locations, mount angles, lengths, stiffness and damping coefficients of suspension bars are chosen as design parameters.

• 대한기계학회논문집
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• 제18권4호
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• pp.866-875
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• 1994

The problem of a rigid rod sliding on a rough horizontal surface in the plane is analyzed, which is commonly cited as an example of the inconsistency of rigid body frictional mechanics. The inconsistency is demonstrated by analyzing the normal reaction force at the contact point with the surface, and the concept of tangential collision is derived to resolve the inconsistency. Using the Poisson's hypothesis for the coefficient of restitution and Coulomb's law for the friction, the general methodology for solving the tangential collision is presented. The problem of the inconsistency generated in the sliding rod is completely resolved, building the concept of the tangential collision and adopting the theory of frictional impact. The result presented in this paper will obviate a generic obstacle to the development of simulation packages for planar rigid body mechanical systems with temporary contacts, and planning efficient motion strategies for robot manipulators.

• 융복합기술연구소 논문집
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• 제6권2호
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• pp.15-20
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• 2016

This paper presents the effects of a virtual mass on the stability boundary of a virtual spring in the haptic system. A haptic system consists of a haptic device, a sampler, a virtual rigid body and zero-order-hold. The virtual rigid body is modeled as a virtual spring and a virtual mass. According to the virtual mass and the sampling time, the stability boundary of the virtual spring is analyzed through the simulation. As the virtual mass increases, the value of the virtual spring to guarantee the stability gradually increases and then decreases after reaching the maximum value. These simulation results show that the addition of the virtual mass enables to expand the stability boundary of the virtual spring.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.142-145
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• 1989

The electromagnetic suspension system, which is a kind of magnetic levitation, can be categorized into two groups; separate lift & guidance system and combined lift & guidance system. This paper deals with the latter system, in which lift and guidance forces are generated by a pair of staggered magnets with the inverted U- shaped rail. In this work, a rigid body bogie-truck and a twist response type of bogie-truck, which are constructed by two magnetic wheels consist of two staggered magnet pairs, are modeled, and curvature running characteristics of both types obtained by simulation are presented. Simulation result showed that curvature running characteristics of twist response type of bogie-truck is better than that of rigid body bogie-truck.