• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.73-80
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• 1993

There and two important variables in machining process control, which are feed and cutting speed. It is possible to improve the machining accuracy and the productivity by maintaining the optimal feed and cutting speed. In this work, a controller is designed to achieve on-line cutting force control based on the modeling of cutting process dynamics established through step response test. Two schemes are proposed and implemented. The first is feed control under the constant spindle speed and the second is spindle speed control under the constant feed. Finally, both are proved to work properly through simulation and experimentation.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.5
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• pp.49-56
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• 1987

This paper is a study on the effect of the cutting speed on the tool wear in turning of the glass fiber reinforced plastics. The wear behavior of cutting tool is studied by means of turning, changing the cutting speed and feed in the wide range. Moreover, the theoretical model applicable to the cutting speed of wide range is analysed. The main results obtained are as follows: The relation between the tool wear and the cutting speed is divided into three range in case of the constant cutting distance. 1) At the low cutting speed, the tool wear is independent of the cutting speed, but dependent mainly on the contact length between tool and glass fiber(lst range). 2) At the high cutting speed, the tool wear is independent of the contact length, and dependent on the cutting speed only(2nd range). The tool wear increases in proportion to the cutting speed. 3) At the higher cutting speed than the speed in the 2nd range, the tool wear is independent both of the cutting speed and the contact length(3rd range). 4) In the 3rd range, tool flank wear is constant and is observed that only the wear of cutting edge increases.

• Journal of Biosystems Engineering
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• v.25 no.6
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• pp.445-456
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• 2000

A can type high-speed transplanting mechanism was developed. The mechanism consists of a cam and an epicycle gear train with one sun gear in the middle and four planet gears in a row but symmetric with respect to the sun gear. Two planting knives are pivoted on the two outer gears. When sun gear rotates with a constant velocity the planting knife rotates also with a constant velocity. This constant motion of the transplanting knife is accelerated partially by a cam fixed in the gear housing so that the locus of the planting knife becomes similar to that generated by a crank-type transplanting mechanism. This cam-type transplanting mechanism can solve the problems associated with the rotary-type transplanting mechanisms. The mechanism was designed with an aid of computer simulation and proved applicable to high speed transplanters by its mock-up model. The design process of the mechanism was presented and dynamic analysis was also carried out to show the advantages of the mechanism over the rotary type high-speed planting mechanism.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.48-57
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• 2003

A cylindrical constant volume combustion chamber was used to investigate the flow characteristics at spark plug and the combustion characteristics of homogeneous charge methane-air mixture under various initial pressure, excess air ratio and ignition times in quiescent mixture. The flow characteristics such as mean velocity and turbulence intensity was analyzed by hot wire anemometer. Combustion pressure development measured by piezoelectric pressure transducer and flame propagation acquired by ICCD camera were used to investigate the effect of initial pressure, excess air ratio and ignition times on pressure, combustion duration, flame speed and burning velocity. Mean velocity and turbulence intensity had the maximum value at 200 or 300ms and then decreased to near 0 value gradually after 3 seconds. Combustion duration, flame speed and burning velocity were observed to be promoted with excess air ratio of 1.1, lower initial pressure and ignition time of 300ms.

• Journal of Mechanical Science and Technology
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• v.14 no.2
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• pp.131-140
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• 2000

For a walking robot with high constant body speed, the dynamic effects of the legs on the transfer phase are dominant compared with other factors. This paper presents a new force distribution algorithm to maximize walkable terrain without slipping considering the dynamic effects of the legs on the transfer phase. Maximizing the walkable terrain means having the capability of walking on more slippery ground under the same constraint, namely constant body speed. A simple force distribution algorithm applied to the proposed walking model with a pantograph leg shows an improvement in the capability of preventing foot-slippage compared with one using a pseudo-inverse method.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.2027-2030
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• 2002

SFFS(Solid Freeform Fabrication System) is commercializing to rapid prototyping concept in world- wide some corporations including the U.S.A, have much technological problems yet and need new mode for agile solid freeform fabrication as well as prototyping. In this paper, we design an algorithm that the cutting path of laser beam, on the SFFS, is controlled with constant speed. The designed algorithm fer constant-speed path control is implemented and experimented in the CAFL$\^$VM/ (Computer Aided Fabrication of Lamination for Various Material) system, the new SffS which is developed in this paper. Finally, the ceramic, new material developed in this paper, cut and fabricated. The dimensional accuracy and mechanical stability of the 3D object is confirmed through the experiment, also.

• Elastomers and Composites
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• v.53 no.4
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• pp.195-201
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• 2018

Three kinds of rubber compounds were prepared, and their underwater acoustical properties were investigated for anechoic coating. Dynamic mechanical properties of the rubber compounds were measured using a dynamic mechanical analyzer and extended to 100 kHz using time-temperature superposition. The sound speed, reflection coefficient, and attenuation constant were calculated. Silicone rubber showed the lowest reflection coefficient, and nitrile rubber showed the highest attenuation constant. The acoustic properties of nitrile rubber compounds with various compositions were investigated. The sound speed, reflection coefficient, and transmission coefficient of the nitrile rubber in the frequency range of 200-1000 kHz were measured in a water-filled tank.

• 열병합발전
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• s.74
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• pp.12-17
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• 2010

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1473-1479
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• 2011

In this paper, speed control of IPMSM drives for the next generation domestic high speed railway system using multilevel inverter is presented. Multilevel inverter is suitable for the high-voltage high-capacity motor drive system because noise and switching frequency of power semiconductor devices is reduced. For the speed control of IPMSM using multilevel inverter, maximum torque control is applied in a constant torque region, and field weakening control is applied in a constant power region. Simulation programs based on Matlab/Simulink are developed. Finally the designed system is verified by simulation and their characteristics are analyzed by the simulation results.

• Journal of Power Electronics
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• v.10 no.1
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• pp.65-71
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• 2010

This paper presents the design and implementation of voltage source inverter type SVPWM based speed control of an induction motor using a fuzzy PI controller. This scheme enables us to adjust the speed of the motor by controlling the frequency and amplitude of the stator voltage; the ratio of the stator voltage to the frequency should be kept constant. A model of the fuzzy control system is implemented in real time with a Xilinx FPGA XC3S 400E. It is introduced to maintain a constant speed to when the load varies.