• Journal of the Korean Society for Precision Engineering
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• v.19 no.3
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• pp.73-79
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• 2002

This paper presents the experimental results to verify the environmental consciousness with economic balances due to cutting fluid behaviors, effectiveness in machining process. Even though cutting fluid improves the Productivity through the cooling, lubricating effects, its environmental impact is also increased according to the cutting fluid usage. The primary mechanism considered in this study is the spin-off motion of fluids away from rotating workpiece. In this study some parameters arc adopted to analyze the productivity(tool wear), environmental impact(mist diffusion rate). The results present talc criteria for the resonable cutting fluid usage quantitative1y to develop the environmentally conscious machining process.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.50-57
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• 2003

This paper presents the experimental results to verify the atomization characteristics and environmental impact of cutting fluid. Even though cutting fluid improves the productivity through the cooling, Lubricating effects, environmental impact due to cutting fluid usage is also increased on factory shop floor Cutting fluid's aerosol via atomization process can be affected human health risk such as lung cancer and skin diseases. Experimental results show that the generated fine aerosol which particle size less than 10 micron appears near working tone under typical operational conditions. The aerosol concentration also exceeds NIOSH regulations. This research can be provided a basis of environmental impact analysis fur environmental consciousness.

• Journal of Korea Game Society
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• v.10 no.6
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• pp.57-65
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• 2010

In this paper, mobility performance indices are proposed which may be used to estimate characteristics of output velocity space in six-degree-of-freedom parallel mechanism. In order for manipulability and condition number to not suffer from lack of the physical meaning due to dimensional inhomogeneity, output space is partitioned into translational velocity space and rotational velocity space, respectively. In each space, mobility ellipsoids corresponding to unit input space are defined and two types of mobility performance in translational velocity spaces indices are derived. Two types of mobility performance in rotational velocity spaces indices are derived.

• Korean Journal of Food Science and Technology
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• v.9 no.1
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• pp.61-67
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• 1977

Seed separation from half-cut red pepper were investigated with free falling, up-and-down shaking and rotating collision methods. The separation rates were related with impact appiied and the rotating case was distinguished from the other two methods. Beside the impact effect, velocity of the pod and tumbling factors were involved. Momentum effectiveness of seed separation were calculated as $2.50{\times}10^{-6}$, $2.09{\times}10^{-6}$, and $3.94{\times}10^{-8}$ for free falling, shaking and rotating method on the same velocity basis, respectively. The tendency of separation rate was similar to that of red pepper drying rate against time.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.10
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• pp.1173-1182
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• 1988

The stability, energetic efficiency and walking volume are affected by the geometric structure of legs of a walking robot. A quadruped walking robot is considered to have large stability margin among the walking robots and pantograph leg permits large walk stroke and mutually independent vertical and horizontal movements, but the kinematic characteristics are difficult to analyze. Graphical method may be useful to characterize three dimensional legged motion of the pantograph mechanism. We present the modelling method for three different quadruped robots with pantograph legs that have different joints mechanism. The modeled robots are animated by a path that is planned with respect to the center of body. In particular, graphical animation incorporates leg control to rotation and side walking and uses the window of Sun-3 system for displaying joint information.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.19-27
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• 2015

As the recent regulation of Internaional Maritime Organization (IMO) is enforced, the advanced technology of Ballast water treatment system (BWTS) is needed to meet its requirements. Until now, there are two kinds of the BWTS technologies such as physical methods (Membrane and UV) and chemical methods (Chlorin and Ozone). However, these conventional methods have some limitations of auxiliary power, low productivity, residual treatment and etc. In order to overcome these problems, this paper introduces the new kind of BWTS based on mechanical principle and investigates the effect of rotating disc shapes on flow characteristics between rotating and stationary discs by computational fluid dynamics (CFD). Planar and Step types can make the local cavitation generated along radius, and Circular type can increase the intensity of shear stress.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.98-104
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• 2002

We present a new self-calibration method to remove the systematic error of a 2-axis lateral shearing interferometer that has been specially designed for optical testing of aspheric optics. The method takes multiple measurements by rotating the test optics and extracts the systematic error by fitting the measured wavefronts into the Zernike polynomials. The method works with arbitrary azimuthal angles for test optics rotation, which offers an advantage of correcting the error induced by the non-orthogonality of the two axes of wavefront shearing as well as the error caused by the optical components of the interferometer system itself.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.8
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• pp.814-823
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• 2011

Nowadays many neurological diseases such as stroke and Parkinson diseases are continually increasing. Orthotic devices as well as exoskeletons have been widely developed for supporting movement assistance and therapy of patients. Robotic knee orthosis can compensate stiff-knee gait of the paralyzed limb and can provide patients consistent assistance at wearable environments. With keeping a robotic orthosis wearable, however, it is not easy to develop a compact and safe actuator with fast rotation and high torque for consistent supports of patients during walking. In this paper, we propose a novel kinematic model for a robotic knee orthosis to drive a knee joint with independent actuation during swing and stance phases, which can allow an actuator with fast rotation to control swing motions and an actuator with high torque to control stance motions, respectively. The suggested kinematic model is composed of a hamstring device with a slide-crank mechanism, a quadriceps device with five-bar/six-bar links, and a patella device for knee covering. The quadriceps device operates in five-bar links with 2-dof motions during swing phase and is changed to six-bar links during stance phase by the contact motion to the patella device. The hamstring device operates in a slider-crank mechanism for entire gait cycle. The kinematics and velocity/force relations are analyzed for the quadriceps and hamstring devices. Finally, the adequate actuators for the suggested kinematic model are designed based on normal gait requirements. The suggested kinematic model will allow a robotic knee orthosis to use compact and light actuators with full support during walking.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.9
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• pp.717-722
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• 2001

This paper presents a methodology on the backward path tracking control of a trailer type robot which consists of two parts: a tractor and a trailer. It is difficult to control the motion of a trailer vehicle since its dynamics is non-holonomic. Therefore, in this paper, the modeling and parameter estimation of the system using a real-coded genetic algorithm(RCGA) is proposed and a backward path tracking control algorithm is then obtained based on the linearized model. Experimental results verify the effectiveness of the proposed method.