• Journal of Drive and Control
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• v.17 no.4
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• pp.31-37
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• 2020

We are concerned with the dual-arm manipulation for disaster-responding special-purpose machinery. This paper presents a control strategy for performing complex work in an irregular environment, the control algorithm, the hydraulic circuit, and the master devices. The occurrence of collapse accidents at disaster sites such as natural disasters and building collapses is increasing, which is emerging as a social problem. In particular, for the initial response, various tasks must be performed in an irregular environment. The Marionette algorithm for intuitive control of 'as if the operator's arm is moving' was presented as a control strategy for dual-arm manipulators with attachments and the prototype. Next, the hydraulic circuit, control system, and wearable-type master device presented to implement the Marionette algorithm were explained and verified through an experiment in which rebar-cutting, drum-lifting, and lifting a bottle with one arm and pouring the water into the bucket with the other arm were tested.

• Journal of Drive and Control
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• v.19 no.3
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• pp.32-38
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• 2022

The in-wheel drive gearbox for military special vehicles converts the high-speed & low-torque output generated by the electric servomotor, into low-speed & high-torque mechanical power. As the vehicle is remotely maneuvered in mountainous terrain, wet fields, rough terrain, etc., the gearbox must generate a maximum input speed exceeding 5,000 rpm, a maximum torque of 245 Nm, and MTBF of 9,600 km. The purpose of this study was to analyze the failure mode of the gearbox, to ensure the durability of the in-wheel drive gearbox. Also, the field load test data of the vehicle was analyzed, the acceleration durability test standards were established, the acceleration durability test was conducted, and the durability test results were analyzed as well.

• Journal of Drive and Control
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• v.17 no.4
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• pp.165-169
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• 2020

• Transactions of the KSME C: Technology and Education
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• v.5 no.2
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• pp.115-126
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• 2017

This paper proposes an accelerated life evaluation of drive shaft for the power train parts of special purpose vehicle. It is necessary the real load data of usage level driving load condition for life evaluation of power train parts, but we can't get the load spectrum data for evaluation in many case of special purpose vehicle. So, in this paper, the road load spectrum data for evaluation is created by modeling and simulation based on vehicle data and special road condition. The inverse power model is used for accelerated life test. The equivalent torque of load spectrum is achieved using the Miner's Rule. This paper also proposes the calibrated acceleration life test method for drive shaft. The fatigue test is performed through three stress levels. The lifetime at normal stress level is predicted by extrapolation, and is verified through comparison of experimental results and load spectrum data.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.666-674
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• 2017

Today, the term of fusion, such as technology convergence and industrial convergence, is emerging as one of the most important trends in our society. The purpose of this study is to analyze the convergence coefficient of each industry using patent data and to analyze the convergence phenomenon in industry based on convergence coefficient. To do this, 2011-2015 Korean patent data were utilized. The research findings revealed that the ICC by industry was the highest in order of man-made fibres, paints/varnishes, petroleum products/nuclear fuel and other chemicals. Also, according to the inter-industry convergence matrix, the number of convergence patents was the greatest in order of office machinery and computers, special purpose machinery industries and Measuring instruments. Added same analysis was conducted through Industry with high number of patents. As a result, the convergence has been actively carried out in the fields of optical instruments, Basic chemical, Fabricated metal products, Measuring instruments and special purpose machine manufacturing industries.

• Journal of Drive and Control
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• v.13 no.4
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• pp.95-101
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• 2016

• The KSFM Journal of Fluid Machinery
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• v.15 no.5
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• pp.20-26
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• 2012

An APU(Auxiliary Power Unit) for helicopters has been developed in Korea and tested at the AETF(altitude engine test facility) in KARI(Korea Aerospace Research Institute) for the purpose of the military qualification. A cell correlation test was performed before the official test, and the results are within the tolerance. The APU has the capability of supplying electric power as well as compressed air to the helicopters. It was tested at bleed extraction conditions, electric power extraction conditions, and maximum continuous concurrent power conditions within the entire helicopter flight envelop. Some special test equipments were implemented for the measurement of air flowrate, electric power and so on. The tests were successfully performed and their results satisfy the requirements of the helicopters.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.961-968
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• 2022

Hydrogen embrittlement leads to the damages in bolts, nut, especially, high pressure valves, in the semiconductor facilities, hydrogen vehicles, hydrogen stations and so on. Monel material has higher strength than SUS material. Therefore, even though Monel material with special alloy is usually used to prevent the hydrogen embrittlement, it needs powerful drawing system to manufacture the rectangular or hexagonal bar using circular bar. The purpose of this study is to investigate the characteristics of plastic deformation of Monel material and 2 rollers of rolling unit in plastic limit through numerical analysis. As the results, it was predicted that, based on mean stress, as the rolling step was increased, the rolling force of rolling unit was decreased. In addition, the heat treatment for Monel material was needed because of residual stress due to plastic deformation. As for rollers, the roller was safe about 1.86 times compared with that of ultimate strength. In this study, as the roller 2 showed larger stress than roller 1, thus, roller 2 should be designed carefully to guarantee the safety. Further it was confirmed that the reaction force of roller could be helpful in bearing design.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.3
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• pp.46-51
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• 2002

Recently, High capacity alternator are used fur some special equipments in industry. But, several serious problem are occured, especially, broken coil of rotor, caused by crash with stator on rotating the rotor. Although added coil cover thor protect coil of rotor, coil cover is broken. In this study purpose 2 step for corrected that problems. First, three dimensional finite element method far investigate what is most important point. For that purpose, performed stress analysis of coil and coil cover that modeling and finite analysis by ANSYS software. Second, Apply prestress when winding the coil on stator to modify direction of net force. Vector analysis is used for determine corrected prestress. Result of the analysis and prestress are reviewed.

• The KSFM Journal of Fluid Machinery
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• v.18 no.1
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• pp.51-58
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• 2015

This paper presents a study on Vane Tidal Turbine (VTT) focusing on analysis of two types of blade arrangement originated from the previous studies where the original design was examined and performance-tested for different numbers of blades (six, eight and twelve). Compared to conventional tidal turbines, VTT has several special features and potential advantages which have been being thoroughly developed. The purpose of this study is to analyze VTT's capability of extracting and converting the hydrokinetic energy of tidal currents into electricity at given arrangement of blades (single and double rows, six and twelve blades) using CFD. From the calculation results, the six-blade single row turbine shows the best performance, in which the highest power and torque coefficients reach up to about 34 % and 36 %, respectively, at TSR=0.94. However, despite of lower power coefficient, by adding more blades, the torque's extraction of twelve-blade turbine, especially the double row type, is less fluctuate than that of the six-blade setups.