• Journal of Drive and Control
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• v.14 no.1
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• pp.29-34
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• 2017

This study analyzed a life test method for a power take-off (PTO) gearbox. An engine transfers mechanical power (rotation and torque) to a hydraulic pump through a PTO Gearbox with one input shaft and three output shafts. PTO gear box durability under high loads over long time periods was tested using dynamometers. In order to reflect the rated operating conditions, power must be distributed to each output shaft, and experiments were conducted under various conditions to verify the characteristics of the distributed power. An accelerated life test was designed using speed and torque as acceleration factors. Also, efficiency tests were conducted under various load conditions. Also, a lubrication oil composition analysis was performed to analyze gearbox wear status.

• Journal of the Korean Society for Railway
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• v.8 no.1
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• pp.87-92
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• 2005

Numerous advance studies usually have focused on preventing human error through mechanization and automation; however, this study. by connecting with accidents caused by careless handling on the basis of the present aptitude test, aims at investigating an improving plan for the railroad safety management system. To attain this purpose, present situation and point at issue of the aptitude test were surveyed through the questionnaire. Through this research, the aptitude test on railroad safety might be systematically improved by reforming some institutional issues.

• Journal of Power Electronics
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• v.13 no.1
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• pp.77-85
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• 2013

This paper proposes a new dead time compensation method of independent six-phase permanent magnet synchronous motors (IS-PMSM). The current of the independent phase machines contains odd-numbered harmonics because of the dead time and the nonlinear characteristics of the switching devices. By using the d-q-n three-dimensional vector analysis, these harmonics can be extracted at the n-axis current. Thus, the current distortion can be compensated by controlling the n-axis current of the IS-PMSM to zero. The proposed method is simple and can be easily implemented without additional hardware setup. The validity of the proposed compensation method is verified with simulations and several experiments.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.233-234
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• 2015

전기추진선박의 엔진발전기를 부하에 따라 가변속 운전하면 일정속도로 운전하는 것보다 연료를 절약할 수 있다. 내연 기관 엔진은 저속 운전 시 속도 리플로 인하여 운전이 불안정해지므로 저속 운전에 한계가 있다. 또 발전기 조속기의 느린 응답으로 속도 리플이 발생하기도 한다. 본 논문에서는 배터리 에너지 저장 장치를 이용하여, 과도 상태에서의 속도 리플을 감소시키는 제어 방식을 제안하여 가변속 엔진의 운전 범위를 넓히고자 한다.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.3
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• pp.132-140
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• 1996

This paper developes a torsional vibration model of heavy duty truck drive line for simulation of a driving rattle, which causes very annoying noise to driver at the full load driving condition. Test results show a peak in the fit plots at the frequency of the 2nd harmonics of propeller shaft revolution. A 10 d.o.f. lumped parameter nonlinear torsional vibration model is constructed and engine torque variation is calculated from P- .theta. diagram. Time responses are simulated and compared with the test results, which show fairly good agreement. The effects of paramenter change are investigated, and the optimum configuration is proposed.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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• pp.74-83
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• 1997

The non-periodic angular accelerations of engine are the major cause of gear rattle. This gear rattle is based on the existence of a backlash between the drive gear of input shaft and the free gear of output shaft in the gearbox. Especially, the neutral gear rattle have a very bad effect on the ride quality. Test-rig was constructed in order to evaluate the parameter influence upon the neutral gear rattle. Also, each different 4 type torsional characteristic of clutch was manufactured. Experimental conditions are the use of each different 4 type torsional characteristic of clutch and oil temperature variation in gearbox. In case of the same stiffiness of pre-damper type clutch at idling, the clutch of large hysteresis showed dam- ping effects at the 2nd input gear and the 2nd output gear. Also, the main-damper type clutch was shown to large resonance phenomenon at the 2nd input gear. Accordingly, main-damper type clutch was unapp- roriate at idling.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.4
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• pp.263-270
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• 2021

Active AC/DC converters with PWM operation are utilized to regulate rectified DC bus voltage of a permanent magnet synchronous generator in the maritime DC power system. A DC bus voltage regulation strategy that exploits the six-step operation is proposed in this study. Compared with that of the PWM operation, switching loss of the converter can be significantly reduced under the six-step operation. Moreover, conduction loss can also be reduced due to the high modulation index and reduced flux-weakening current of the six-step operation. A controller is used for the proposed DC bus voltage regulation strategy to verify its validity with the simulation and experimental setup. The simulation and the experimental test results showed that the converter loss reduces to a maximum of 70% and 19%, respectively.

• The Journal of Korea Robotics Society
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• v.17 no.4
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• pp.477-483
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• 2022

In this paper, we propose waste collection vehicle system with a safety device for worker safety and an autonomous driving function. The steering system is applied as MDPS (Motor Drive Power Steering) system to control the waste collection vehicle of the internal combustion engine. Safety-related errors is prevented through redundancy brake of the integrated system and the control braking system. In order to ensure safety between workers and waste collection vehicles, work guidelines and safety devices for emergency stop in case of danger are applied to vehicles. In addition, this research is conducted on improving the working efficiency through vehicle condition monitoring system and a short-range control system for field test. This research is aimed to secure stability through demonstration and contribute to the industrialization of unmanned waste collection vehicles.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.139-148
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• 1995

In this paper an electro-hydraulic servo system is designed by using a fuzzy control algorithm. In order to drive an optimal fuzzy control system, a simulation program for the control system has been developed. By this program the fuzzifier and defuzzifier, a fuzzy inference method, a fuzzy relational matrix, and a fuzzy inference method are investigated. As a result, Larsen inference method, 9*9 fuzzy relational matrix, and center of area defuzzifier are turned out the best as parameters. Finally this method is compared with the conventional PID algotithm, and showed that the fuzzy control performs better than PID algorithm. The fuzzy control performs very well adap- tation against uncertain disturbances.

• Journal of the Korea Society for Simulation
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• v.32 no.4
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• pp.77-84
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• 2023

In the agricultural sector, power sources are being developed that use alternative energy sources such as electric tractors and hydrogen tractors, away from internal combustion engine tractors. As parts such as engines and transmissions used in conventional internal combustion engine tractors are replaced with motors and batteries, the center of gravity changes, and thus the risk of rollover should be considered. The purpose of this study is to analyze the overturn angle of the main parts of the electric tractor through dynamic simulation to minimize the overturn accident and to derive the optimal arrangement of parts to improve stability. A total of nine dynamics simulations were conducted by designing three components of the PTO motor, drive motor and the battery pack, and three factors of the arrangement method. As a result of the experiment, it was confirmed that Type3 Level3, in which the drive motor and the PTO motor are located at the front and rear of the tractor, and two battery packs are located in the middle of the tractor, has a high rollover angle. As a result of this study, the stability increased as the center of gravity was placed backward and located below. Future research needs to be done to find the optimal location of parts considering their performance and placement efficiency.