• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.486-494
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• 2001

This paper presents a real-time multibody vehicle dynamic analysis method using recursive Kanes formulation and suspension composite joints. To shorten the computation time of simulation, relative coordinate system is used and the equations of motion are derived using recursive Kanes formulation. Typical suspension systems of vehicles such as MacPherson strut suspension system is modeled by suspension composite joints. The joints are derived and utilized to reduce the computation time of simulation without any degradation of kinematical accuracy of the suspension systems. Using the develop program, a multibody vehicle dynamic model is formed and simulations are performed. Accuracy of the simulation results is compared to the real vehicle field test results. It is found that the simulation results using the proposed method are very accurate and real-time simulation is achieved on a computer with single PowerPC 604 processor.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.157-163
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• 2004

Scoliosis is a complex musculoskeletal dieses requiring 3-D treatment with surgical instrumentation. To investigate the effects of correction surgery, a finite element model of personalized model of the scoliotic spine that will allow the design of clinical test providing optimal estimation of the post-operation results was developed. Three dimensional skeletal parts, such as vertebrae, clavicle and scapular were modeled as rigid bodies with keeping their morphologies. Kinematical joints and spring elements were adapted to represent the inter-vertebral disc and ligaments respectively. With this model, two types of surgery procedure, distraction procedure with Harrington device and rod derotation procedure with pedicle screw and rod system had been carried out. The obtained simulation results were comparatively corresponding to the post operational outcomes and successfully demonstrated qualitative analysis of surgical effectiveness. From this analysis, it has been found that the preparing of appropriate rod curvature and its insertion was more important than just performing the excessive derotation for scoliosis correction.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.58.1-58.1
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• 2011

We present our N-body simulation study on the disk galaxy warp formation via close encounters. Using a publicly available code Gadget2, we investigate morphological and kinematical structures of disk galaxies while the galaxies are undergoing fly-by encounters with adjacent dark matter halos. In this study, we find that warps can be excited by impulsive encounters and sustained for a few billion years. Most of the warps from the simulation show inclination angles that are comparable to the observations. The creation of warps, their inclination and their lifetimes are governed primarily by the following three parameters: the impact parameter (the minimum distance between two halos), the mass ratio between two galaxies, and the incoming angle of the intruder. We discuss pros and cons about our alternative scenario in comparison with existing explanations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.963-967
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• 2008

There are many factors to affect polishing performance normally in chemical mechanical polishing (CMP) process. One of the factors is a pad profile. A pad profile has not been considered as a significant factor. However, a pad profile is easily changed by conditioning process in CMP, and then changed pad profile affects polishing performance. Therefore, understanding how the pad profile is changed by conditioning process is very important. In this paper, through the simulation based on kinematic analysis, the variation of the pad profile was described in accordance with difference condition of conditioning process. A swing-arm type conditioner was applied in this simulation. A swing-arm type conditioner plays a role of generating asperities on pad surface. The conditions of conditioing process to get uniform removal were also investigated by comparing the simulation with the experiment.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.4
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• pp.307-314
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• 2006

In this paper, we present a comprehensive study for the development of quadruped walking robot. To understand the walking posture of a tetrapod animal, we begin with a careful observation on the skeletal system of tertapod animals. From taking a side view of their skeletal system, it is noted that their fore limbs and hind limbs perform characteristic roles during walking. Moreover, the widths of footprints and energy efficiency in walking have a close relationship through taking a front view of their walking posture. According to these observations, we present a control method where the kinematical solutions are not necessary because we develop a new rhythmic gait pattern for the quadruped walking robot. Though the proposed control method and rhythmic pattern are simple, they can provide the suitable motion planning for the robot since the resultant movement is based on the animal's movements. The validity of the proposed idea is demonstrated through dynamic simulations.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.374-378
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• 2007

As people's living standard is being improved, human works are being replaced by robots. However, because roost robots are used in process industry, fixed on the ground, we need to develop human robots that have wide applications. Currently many researches are being conducted on human robots with the object of replacing human works, but because of lack of relevant hardware, such robots are being applied limitedly to very simple tasks. To overcome the limitation, the present study developed a kinematical mechanism and a controller. Based on human kinematics, the shoulders and the arms were composed of master arms with 3 degree of freedom, and we reproduced motions similar to human ones through the characteristics of joint variables and experiment on the trajectory of the end effector.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.7
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• pp.1-6
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• 2008

In industrial fields, human works are being replaced by robots. However, as the use of robots is limited in the process industry where they are operated fixedly, humanoid robots with wide applications need to be developed. Currently a great deal of research is being conducted on humanoid robots with the object of replacing humans in the workplace. However, because of the lack of relevant hardware and difficulty in mechanical parts, only very simple and limited progress is being made. In an effort to overcome these limitations, the purpose of the present study is to develop a kinematical mechanism and a controller. To this end, master arms with 3 degrees-of-freedom for the shoulders and the arms were composed which were able to reproduce human-like motions by simulating the characteristics of joint variables and the trajectory of the end-effector.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.320-327
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• 2005

A new mechanism for hyper redundant manipulator (HRM) is presented, which comprises of serially assembled compound three-bar linkages (CTL). The CTL mechanism has some unique properties. This paper presents the forward and inverse kinematics of this mechanism and shows the simulation of the HRM havig 9 CTL units. The recursive algorithm of the inverse kinematics that the author originally developed is employed. It is fast and stable ; moreover, it enables us to obtain a solution in which the end-point of the HRM is controlled by a portion of joints. It also presents the method of the dynamical analysis. There exist kinematical constraints in the proposed closed linkage mechanism. In the dynamic analysis constraints are sufficiently sustained by the constraint stabilization method that the author developed. The mechanical structure of the HRM having some CTL units that is under construction is shown.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.13-22
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• 2008

For the accuracy correction of the micro-positioning industrial robot, micro-manipulator has been devised. The compliant mechanisms using piezoelectric actuators is necessary geometrically and structurally to be developed by the optimization approaches. The overall geometric advantage as the mechanical efficiencies of the mechanism are considered as objective functions, which respectively art the ratio of output displacement to input force, and their constraints are the vertical notion of supporting leg and the structural strength of manipulation. In optimizing the compliant mechanical amplifier, the sequential linear programming and an optimality criteria method are used for the geometrical dimensions of compliant bridges and flexure hinges. This paper presents the integrated design process which not only can maximize the mechanism feasibilities but also can ensure the positioning accuracy and sufficient workspace. Experiment and simulation are presented for validating the design process through the comparisons of the kinematical and structural performances.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.189-196
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• 1996

Vibration of a beam translating over supports in vertical motion is investigated in this paper. Equations of motion are formulated using the virtual work principle by regarding the supports as kinematical constraints imposed on an unrestrained beam and by discretizing the beam via the assumed mode method. Differential-algebraic equations of motion are derived and reduced to differential equations in independent generalized coordinates by the generalized coordinate partitioning method. Geometric stiffness of the beam due to translating motion is considered and how the geometric stiffness of beam affects dynamic stability is also investigated. Instability of the beam. in various conditions is also investigated using Floquet theory and then the results are verified through the dynamic response analysis. Results of numerical simulation are presented for various prescribed motions of the beam.