• Structural Engineering and Mechanics
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• v.28 no.2
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• pp.259-262
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• 2008

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.100-102
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• 2003

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.368-371
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• 2006

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.393-394
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• 2006

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.315-317
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• 2006

• Journal of Mechanical Science and Technology
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• v.19 no.3
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• pp.756-767
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• 2005

This paper presents a decentralized motion control method of welding mobile manipulators which use for welding in many industrial fields. Major requirements of welding robots are accuracy, robust, and reliability so that they can substitute for the welders in hazardous and worse environment. To do this, the manipulator has to take the torch tracking along a welding trajectory with a constant velocity and a constant heading angle, and the mobile-platform has to move to avoid the singularities of the manipulator. In this paper, we develop a kinematic model of the mobile-platform and the manipulator as two separate subsystems. With the idea that the manipulator can avoid the singularities by keeping its initial configuration in the welding process, the redundancy problem of system is solved by introducing the platform mobility to realize this idea. Two controllers for the mobile-platform and the manipulator were designed, respectively, and the relationships between two controllers are the velocities of two subsystems. Control laws are obtained based on the Lyapunov function to ensure the asymptotical stability of the system. The simulation and experimental results show the effectiveness of the proposed controllers.

• Journal of Engineering Education Research
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• v.15 no.2
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• pp.46-51
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• 2012

This work investigated experiment education in mechanical engineering of universities in USA. Through the investigation, characteristics of each university were analyzed. Finally, the study suggested new contents of experiment education, full-time professors and staffs for experiment, cooperation with design and experiment education, and incentive for the development of experiment education.

• 한국전산유체공학회:학술대회논문집
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• 2008.08a
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• pp.67.3-67.3
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• 2008

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.2
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• pp.11-17
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• 2008

Critical erosion kinetic energy models for radial/median cracks and lateral cracks in a workpiece are established in this study. We used experimental results to demonstrate that the fracture erosion resistance and erosion machining number could be used to evaluate the brittle fracture resistance and machinability of a workpiece. Erosion kinetic energy models were developed to predict brittle fracture and ductile shear, and a critical erosion kinetic energy model was developed to predict the transition from brittle fracture to ductile shear. These models were verified experimentally.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.134-140
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• 2002

Chemical mechanical polishing of aluminum and photoresist using colloidal silica-based slurry was experimented. The effects of slurry pH, silica concentration, and oxidizer ($H_2O_2$) concentration on surface roughness and removal rate were studied. The optimum slurry conditions for reduction of micro-scratch were investigated. The optimum chemical mechanical polishing with the colloidal silica-based slurry was compared with conventional chemical mechanical polishing with alumina-based slurry. Chemical mechanical polishing of the aluminum with the colloidal silica-based slurry showed improved result but chemical mechanical polishing of the photoresist did not. The improved result was comparative with that of chemical mechanical polishing with filtered alumina-based slurry which one of desirable methods to reduce the micro-scratch.