• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.5
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• pp.66-73
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• 2019

In this paper, we design a new automatic workpiece loading system for the loading and unloading of a workpiece for a CNC lathe. Conventional workpiece loading systems are bulky and require a large area when installed around a shelf. Therefore, an automatic loading system with small horizontal and vertical dimensions and a large loading capacity was designed. Structural analysis of the system was then carried out to assess the displacement and safety of the main components. Following this, the automatic loading system was manufactured according to the structural analysis results and conceptual design, and experiments characterizing the performance of the system were conducted. As a result, the automatic loading system was found to operate accurately and safely, meaning it can be used to load and unload workpieces for a CNC lathe.

• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.547-553
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• 2005

The purpose of this paper is to evaluate the quay crane productivity in automated container terminal with perpendicular yard layout. In particular, four quay crane (single trolley/dual trolley/double trolley/supertainer) are considered to evaluate the productivity on the terminal performance. Each quay crane load or unload containers by a different process. For each quay crane, two productivities are considered and compared: mechanical productivity, net productivity. As the net productivity of quay crane is significant, in this paper, an application of simulation model to simulate automated container terminal is developed and a wide variety of computational experiments were conducted.

• Journal of Navigation and Port Research
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• v.34 no.4
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• pp.271-279
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• 2010

The Mobile Harbor(MH) is a new transportation platform that can load and unload containers to and from very large container ships in the sea. This loading and unloading by crane can be performed with only very small movements of the MH in waves because MH is operated outside of the harbor. For this reason, an anti-rolling tank(ART) and an active mass driving system(AMD) were designed to reduce MH's roll motion, especially at the natural frequency of MH. In the conceptual design stage, it is difficult to confirm the design result of theses anti-rolling devices without modeling and simulation tools. Therefore, the coupled MH and anti-rolling devices' dynamic equations in waves were derived and a simulation program that can analyze the roll reduction performance in various conditions, such as sea state, wave direction, and so on, was developed. The coupled equations are constructed as an eight degrees of freedom (DOF) motion that consists of MH's six DOF dynamics and the ART's and AMD's control variables. In order to conveniently include the ART's and AMD's control dynamics in the time domain, MH's radiated wave force was described by an impulse response function derived by the damping coefficient obtained in the frequency domain, and wave exciting forces such as Froude-Krylov force and diffraction force and nonlinear buoyancy were calculated at every simulation time interval. Finally, the roll reduction performances of the designed anti-rolling devices were successfully assessed in the various loading and wave conditions by using a developed simulation program.