• International Journal of Precision Engineering and Manufacturing
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• 제4권6호
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• pp.50-60
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• 2003

A web-based dynamic simulation system, called O-DYN, for multibody systems is developed. All the interfaces of the system are accessible via web browsers, such as Netscape or Explorer. The system uses a block-diagram type O-DYN/Modeler developed in JAVA Applet as a preprocessor. The O-DYN postprocessor composed of O-DYN/Plotter and O-DYN/Animator is developed in JAVA Applet. The O-DYN/Solver for predicting the dynamic behavior is run on the web server. Anyone who wants to simulate the dynamics of multibody systems or share results data can access the analysis system over the internet regardless of their OS, platform, or location.

• 한국자동차공학회논문집
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• 제5권1호
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• pp.101-109
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• 1997

A tool for the dynamic simulation and design technique of the excavator plays an important role in the prediction of dynamic behavior of the excavator in the initial design stage. In this paper, a flexible multibody dynamic analysis model including track of the crawler type excavator is developed using DADS and ANSYS. Through the driving simulation of the excavator travelling over rough road track, frequency characteristics of the upper frame and cabin are obtained, and the reaction forces acting on the track rollers are also presented for the fatigue life estimation. The effect of boom vibration modes on the joint reaction forces and accelerations is presented from the swing simulation.

• 대한기계학회논문집A
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• 제21권8호
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• pp.1311-1321
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• 1997

In multibody dynamics, differential and algebraic equations which can satisfy both equation of motion and kinematic constraint equation should be solved. To solve these equations, coordinate partitioning method and constraint stabilization method are commonly used. In the coordinate partitioning method, the coordinates are divided into independent and dependent and coordinates. The most typical coordinate partitioning method are LU decomposition, QR decomposition, and SVD (singular value decomposition). The objective of this research is to find an efficient coordinate partitioning method in the dynamic analysis of flexible multibody systems. Comparing two coordinate partitioning methods, i.e. LU and QR decomposition in the flexible multibody systems, a new hybrid coordinate partitioning method is suggested for the flexible multibody analysis.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1764-1771
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• 2002

The latch needle cam system of circular knitting machines is analysed using multibody dynamics. A formulation is made to obtain the vertical stiffness between the needle and the cam. By implementing this formulation into the data of the multibody dynamics program, the motion of the needle is described and the forces and impulses between the needle and the cam are obtained.

• 소음진동
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• 제8권1호
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• pp.203-211
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• 1998

In order to find out relationship between hit probability and gun firing of a moving tank, a turret and flexible gun system model has been developed using a recursive flexible multibody dynamics. For a firing simulation model, nodal coordinates for a finite element model of a flexible gun have been employed to include transverse loads to the gun tube due to moving bullet and ballistic pressure. Modal coordinates are also used to represent the motion induced gun vibration before a firing occurs. An efficient switching technique from modal equations to nodal equation has been introduced for an entire gun firing simulation with a rotating turret.

• 대한조선학회논문집
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• 제47권1호
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• pp.47-57
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• 2010

This study analyzes the dynamic response of a floating crane with a cargo considering an elastic boom to evaluate(or for evaluation of) its flexibility effect on their dynamic response. Flexible multibody system dynamics is applied in order to establish a dynamic equation of motion of the multibody system, which consists of flexible and rigid bodies. In addition, a floating reference frame and nodal coordinates are used to model the boom as a flexible body. The study also simulates the coupled surge, pitch, and heave motions of the floating crane carrying the cargo with three degrees of freedom by numerically solving the equation. Finally, the simulation results of the elastic and rigid booms are comparatively analyzed and the effects of the flexible boom are discussed.

• 동력기계공학회지
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• 제16권4호
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• pp.12-16
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• 2012

In this paper, the equations of motions for planar multibody dynamics are established for considering the parallel programming based on GPU. Cartesian coordinates are used to formulate the equations of motion and implicit integration method called HHT-alpha is employed. Open chain multibody system is considered for computer simulation. CUDA toolkit is employed for establishing the GPU parallel programming. The exactness of the analysis is verified from the comparison with ADAMS. The results from parallel computing based on GPU are compared with the results from the sequential programming based on CPU in terms of calculation time. The multiple pendulum with bodies and joints is employed for the computer simulation. In the pendulum system that has 290 bodies, the parallel program indicates an improved efficiency of about 25.5 second(15.5% improvement). It is noted that the larger the size of system is, the time efficiency is better.

• 한국정밀공학회지
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• 제17권9호
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• pp.133-144
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• 2000

The dynamic walking planning and the inverse dynamics of the biped robot is investigated in this paper. The biped robot is modeled with 14 degrees of freedom rigid bodies considering the walking pattern and kinematic construction of humanoid. The method of the computer aided multibody dynamics is applied to the dynamic analysis. The equations of motion of biped are initially represented as terms of the Cartesian corrdinates then they are converted to the minimum number of equations of motion in terms of the joint coordinates using the velocity transformation matrix. For the consideration of the relationships between the ground and foot the holonomic constraints are added or deleted on the equations of motion. the number of these constraints can be changed by types of walking patterns with three modes. In order for the dynamic walking to be stabilizable optimized trunk positions are iteratively determined by satisfying the system ZMP(Zero Moment Point) and ground conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.548-555
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• 2000

The dynamic walking and the inverse dynamics of the biped walking robot is investigated in this paper. The biped robot is modeled with 14 degrees of freedom rigid bodies considering the walking pattern and kinematic construction of humanoid. The method of the computer aided multibody dynamics is applied to the dynamic analysis. The equations of motion of biped are initially represented as terms of the Cartesian coordinates, then they are converted to the minimum number of equations of motion in terms of the joint coordinates using the velocity transformation matrix. For the consideration of the relationships between the ground and foot, the holonomic constraints are added or deleted on the equations of motion. The number of these constraints can be changed by types of walking pattern with three modes. In order for the dynamic walking to be stabilizable, optimized trunk positions are iteratively determined by satisfying the system ZMP(Zero Moment Point) and ground conditions.

• 대한기계학회논문집A
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• 제41권6호
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• pp.507-515
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• 2017

많은 절점 자유도로 표현이 되는 유연다물체 시스템의 효율적인 해석을 위해서는 병렬처리 기법이 적용될 수 있다. 이 분야에서의 병렬처리기법은 주로 선형대수방정식의 효율적인 해법에 초점이 맞추어 연구가 진행되었다. 본 논문에서는 기존의 방법과는 달리 병렬처리에 적합한 유연다물체 동역학 공식을 부분 시스템 합성방법을 이용하여 개발하고, OpenMP를 사용한 효율적인 병렬처리 방식을 제안하였다. 서로 다른 두 가지 병렬처리 방식을 3개의 동일한 유연체 회전 날개 시스템 시뮬레이션 통하여 비교하였다. 또한 실제의 CPU시간을 비교하여 제안한 병렬처리 방법의 효율성을 고찰하였다.