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An Implementation of a Teleoperation System for Robotic Beam Assembly in Construction
홍대희,정경모,주백석,박신석 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
Recently, a robot-based construction automation (RCA) project was finished in Korea, whose purpose was to employ a robotic system instead of human labor in steel beam assembly tasks. In that research, a robotic beam assembly (RBA) system was developed to execute a beam assembly task. A field application using the RBA system at an actual construction site was completed. Because a human operator had to board the cabin and manipulate the system in the air, causing possible safety problems, a teleoperation system was developed and is the subject of this paper. To evaluate the performance of the teleoperation system, a pointing task experiment based on Fitts’ law was conducted to determine whether it obeyed speed-accuracy tradeoff rules. Results are discussed and an overview of the actual bolting test using the teleoperation system is presented here. Finally, conclusions are drawn about the feasibility of implementing an RBA system with teleoperation in actual building construction applications.
$Al_2O_3/Cu$ 나노복합분말의 제조 및 소결 특성
홍대희,오승탁,김지순,김영도,문인형 한국분말야금학회 1999 한국분말재료학회지 (KPMI) Vol.6 No.4
Mechanical properties of oxide based materials could be improved by nanocomposite processing. To investigate optimum route for fabrication of nanocomposite enabling mass production, high energy ball milling and Pulse Electric Current Sintering (PECS) were adopted. By high energy ball milling, the $Al_2O_3$-based composite powder with dispersed Cu grains below 20 nm in diameter was successfully synthesized. The PECS method as a new process for powder densification has merits of improved sinterability and short sintering time at lower temperature than conventional sintering process. The relative densities of the $Al_2O_3$-5vol%Cu composites sintered at $1250^{\circ}C$ and $1300^{\circ}C$ with holding temperature of $900^{\circ}C$ were 95.4% and 95.7% respectively. Microstructures revealed that the composite consisted of the homogeneous and very fine grains of $Al_2O_3$ and Cu with diameters less than 40 nm and 20 nm respectively The composite exhibited enhanced toughness compared with monolithic $Al_2O_3$. The influence of the Cu content upon fracture toughness was discussed in terms of microstructural characteristics.
홍대희,김우동,김태형,민원,Hong, Daehie,Kim, Woo-Dong,Kim, Tae-Hyung,Min, Won 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.1
The tunnels built in recent years are equipped with traffic counters and pollution sensors (mostly, CO and Vl sensors). Utilizing these built-in sensors, it is possible to develop an algorithm to estimate the amount of pollutants exhausted from the each class of cars passing through the tunnel. These estimated data can be effectively utilized not only for ventilation control but also for designing ventilation facilities. The diffusion of pollutants in a tunnel can be described with one-dimensional diffusion-convection equation. This equation is approximated with interpolation functions and weighted residual method converting to adequate form for standard state estimate algorithms. With this converted equations, a least square optimization based algorithm is developed, whose outputs are the estimated amounts of pollutants emitted from each class of cars. In order to verify the feasibility of the developed algorithms, simulations are performed with the real data acquisitioned from the Tunnae tunnel located in Young-Dong highway in Korea.