• Proceedings of the KSR Conference
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• 2002.05a
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• pp.392-398
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• 2002

In this paper, an engineering database management system(EDMS) has been developed to support the system engineering for design of the high speed titling train to be put into the conventional lines. The developed system can be operated on client-server or web circumstances. To accomplish the concurrent engineering in design of the rolling stocks, this system has been fully equipped with a powerful viewer and a postprocessor for 3D CAD data or FE results. The system was tested using the engineering data produced during carrying out the G7 project to design KHST(Korean High Speed Train) in a crashworthy viewpoint. Through this example, it is shown that the system should be powerfully applied to improving the performance of the system engineering.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.6
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• pp.132-141
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• 2013

Robotic Drilling Systems(RDSs) set the standard for the factory automation systems in aerospace manufacturing. With the benefits of cost effective drilling and predictive maintenance, RDSs can provide greater flexibility in the manufacturing process. The system can be easily adopted to manage very complex and time-consuming processes, such as automated fastening hole drilling processes of large aircraft sections, where it would be difficult accomplished by workers following teaching or conventional guided methods. However, in order to build an RDS based on a CAD model, the precise calibration of the Tool Center Point(TCP) must be performed in order to define the relationships between the fastening-hole target and the End Effector(EEF). Based on the kinematics principle, the robot manipulator requires a new method to correct the 3D errors between the CAD model of the reference coordinate system and the actual measurements. The system can be called as a successful system if following conditions can be met; a. seamless integration of the industrial robot controller and the IO Level communication, b. performing pre-defined drilling procedures automatically. This study focuses on implementing a new technology called iGPS into the fastening-hole-drilling process, which is a critical process in aircraft manufacturing. The proposed system exhibits better than 100-micron 3D accuracy under the predefined working space. Based on the proposed EEF fastening-hole machining process, the corresponding processes and programs are developed, and its feasibility is studied.

• Korean Journal of Computational Design and Engineering
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• v.11 no.6
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• pp.412-421
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• 2006

Recently, the needs for sharing and exchanging drawing information between 2D and 3D data in complex facilities are well recognized throughout the construction industries. The purpose of this study is to propose an information framework to represent 3D IFC (Industry Foundation Classes) -based drawing of building services in complex facilities as 2D drawing. In this study, 1) attributes of building service objects which are used in 3D CAD system are analyzed and present drawing standards are analyzed, 2) based on the analysis, an information framework is developed to represent 3D model in 2D representation, and 3) further more, to test a compatibility of the information sharing framework, number of standardized APIs and an IFC2Dbrowser are developed during the study.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1021-1029
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• 2001

Rapid prototyping(RP) is a novel technology to create 3D products directly from CAD system. This study proposes a new RP method which uses the PZT ceramic plate to make a Drop-On-Demand liquid jet from the nozzle. The characteristic of drop formation in the new system is investigated both numerically and experimentally. The optimal drop for 3-D Printing can be obtained by the proper amplitude and frequency of the applied voltage. Also the process of the drop formation is analyzed using the pressure wave theory and verified by numerical simulation. First, the pressure wave generated by the deformation of the Piezo-plate at the nozzle is analyzed by solving the 2D axisymmetric wave equation via Finite Element Method. Finally, the drop formation process is simulated using a commercial software, FLOW 3D considering the pressure at the nozzle obtained by solving the wave equation as the boundary condition.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.798-802
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• 2003

The robustness and reliability of vision algorithms is the key issue in robotic research and industrial applications. In this paper, the robust real time visual tracking in complex scene is considered. A common approach to increase robustness of a tracking system is to use different models (CAD model etc.) known a priori. Also fusion of multiple features facilitates robust detection and tracking of objects in scenes of realistic complexity. Because voting is a very simple or no model is needed for fusion, voting-based fusion of cues is applied. The approach for this algorithm is tested in a 3D Cartesian robot which tracks a toy vehicle moving along 3D rail, and the Kalman filter is used to estimate the motion parameters, namely the system state vector of moving object with unknown dynamics. Experimental results show that fusion of cues and motion estimation in a tracking system has a robust performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.327-330
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• 2004

Laser aided direct metal deposition (LADMD) process offers the ability to make a metal component directly from 3-D CAD dimensions. A 3-D object can be formed by repeating laser cladding layer by layer. The key of the build-up mechanism is the effective control of powder delivery and laser power to be irradiated into the melt-pool. A feedback control system using optical sensors is introduced to control laser power and powder mass flow rate. Using H13 tool steel and $CO_2$ laser system, comprehensive analysis are executed to test the efficiency of the system. In addition, the dimensional characteristics of directed deposited material are investigated with the parameters of deposition thickness, laser power, traverse speed and powder mass flow rate.

• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1680-1690
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• 2006

As a promising and novel manufacturing technology, laser aided direct metal deposition (DMD) process produces near-net-shape functional metal parts directly from 3-D CAD models by repeating laser cladding layer by layer. The key of the build-up mechanism is the effective control of powder delivery and laser power to be irradiated into the melt-pool. A feedback control system using two sets of optical height sensors is designed for monitoring the melt-pool and real-time control of deposition dimension. With the feedback height control system, the dimensions of part can be controlled within designed tolerance maintaining real time control of each layer thickness. Clad nugget shapes reveal that the feedback control can affect the nugget size and morphology of microstructure. The pore/void level can be controlled by utilizing pulsed-mode laser and proper design of deposition tool-path. With the present configuration of the control system, it is believed that more innovation of the DMD process is possible to the deposition of layers in 3-D slice.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2235-2245
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• 2000

The necessity of using rapid prototyping(RP) for short-run manufacturing is continuously driving a development of a cost-effective technique that will produce completely-finished quality parts in a very short time. To meet these demands, the improvements in production speed, accuracy, materials, aid cost are crucial. Thus, a new hybrid-RP system performing both deposition and machining in a station is proposed. For the new hybrid RP process to maintain the same degree of process automation as in currently available processes like SLA or FDNI, a sophisticated process planning system is developed. In the process planner, CAD models(STEP AP203) are partitioned into 3D manufacturable volumes called 'Ueposition feature segment"(DFS) after machining features called "machining feature segmenf'(MFS) are extracted from the initial CAD model. Once MFS and DFS are identified, the process planner arranges them into a chain of processes and automatically generates machining information for each DFS and MFS. The goal of this paper is to present a framework for a process planning system for hybrid RP processes and to outline the geometric algorithms involved in developing such an environment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.551-556
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• 2009

3-D CAD (Computer Aided Design) system is an indispensable tool for manufacturing. A lot of engineers have studied for the methods to generate a curved surface on an N-sided shape, which is the basic technology of 3-D CAD systems. This surface generation, however, has three problems on the case of long and narrow shapes: the resultant surface is distorted, the surface is not continuous to adjacent surfaces, or additional user inputs are required to generate the surface. Conventional methods have not yet solved these problems at the same time. In this paper, we propose the method to generate internal curves that divide a long and narrow shape into regular N-sided sections so as to divide the shape into an N-sided section and four-sided ones. Our method controls the shape of internal curves by dividing an N-sided long and narrow shape into an N-sided section and four-sided ones, and solves distortion of the generated curved surface. In addition, each of the generated sections is interpolated with G1-continuous surfaces. This process does not require any user's further input. Therefore, the three problems mentioned above will be solved at the same time.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.62-67
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• 2007

The research team for the virtual construction development was established with the support of Korea Ministry of Construction and Transportation, and KICTEP (Korea Institute of Construction and Transportation Technology Evaluation and Planning). Its aims are to develop system that is to improve productivity & quality, to create a higher value-added business, and to cultivate international competitiveness in the construction industry. The virtual construction system is a design, engineering, and construction management information system that allows the project participants to effectively share the information throughout the construction life cycle with the support of 3D and design information. To achieve this, the research team focuses on developing several systems. First, the team focuses on developing for the pre-planning, the structural engineering, MEP, and the 3D based estimation system. Second, they focus on developing a simulation system for the construction process planning and feasibility study with help of the virtual reality technologies. Third, they focus on developing the CPLM (Construction Project Life-cycle Management) system for managing construction project data, and the decision support system that makes the collaboration among the project participants based on 3D technologies and information. We also focus on developing the SDAI (Standard Data Access Interface), the localized guideline for 3D design, and a training program. In addition, we focus on developing the undeveloped area of the commercial system and building an environment that can support the communication and collaboration in the construction life-cycle rather than developing the existing and commercialized system.