• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1138-1142
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• 2007

As a brush DC motor, the brushless DC motor is also operated by DC power supply but has no mechanical contacts occurred by a brush or a commutator. Though the performance of BLDC motor is almost similar with that of DC motor, the BLDC motor has the advantage of the high speed responsibility, the high controllability, and the high effectiveness. The control valve using the BLDC motor, which excludes the burnout effect provoked possibly by the vacuum condition during the flight, is employed for the upper stage of a launch vehicle. For the component level analysis, the dynamic response characteristics of BLDC and DC motors to the same design input sources have been studied in using AMEsim.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.2
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• pp.5-12
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• 2003

This study presents a solution to control a PMSM without sensors. The control method is the presented superposition principle. This method of sensorless theory is very simple to compute estimated angle. Therefore, computing time to estimate angle is shorter than other sensorless methods. The use of this system yields enhanced operations, fewer system components, lower system costs, efficient energy control system designs and increased efficiencies. A practical solution is described and its results are given in this study. The performance of a sensorless architecture allows an intelligent approach to reduce the complete system costs of digital motion control applications using the cheaper electrical sensorless motors. This paper deals with an overview of solutions in the sensorless PHSM control applications, whereby the focus will be the new sensorless controller and its applications.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.161-171
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• 2002

This paper presents a linear motor, which generates large thrust with a low operating rate. In industrial fields there is a need for actuators that work with a low duty cycle but generate large thrusts. An example of such a case is provided by the actuators for ejector mechanisms in electric injection molding machines. The ordinary LSM (linear synchronous motor) is unsuitable for this large-thrust and low-operating-rate usage, because of its large size and high cost. This paper contains experimental results on linear motors that can generate large thrusts for a short time, and which can be cheaply produced. The described linear motor could be contained space of $250mm \times250mm\times 250mm$ and generate a maximum thrust of about 20000 N at a current of 250 A.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.1
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• pp.73-81
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• 2005

A multi-purpose polariscope is developed by applying an electro-mechanical control system to a diffused transmission-type circular polariscope. A conventional polariscope is only good for manual control of optical elements. The new polariscope system is devised to be controlled through two stepping motors and two magnetic clutches. The developed system has both functions of a conventional linear- and circular-polariscope. The new polariscope can be used not only for the point-wise measurement using Tardy compensation technique but also for the full-field fringe analysis using conventional and/or phase measuring techniques, if applicable.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.10
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• pp.44-51
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• 2006

According to global trend of the expanding need of high-quality automobiles, the usage of small precise worm consisting of gearing part for motors to actuate convenience modules has increased rapidly. Precision of those worms has very sensitive characteristic to motor performance and noise. Forming process has been generally used to manufacture worms because of its mass productivity. However, it has problems such as deformation due to residual stress and wear of dies. Planetary milling and side milling are among alternatives using cutting tools. To overcome those problems the two machining methods have some contrast features in the sense of tool numbers and cutting mechanism. In this paper, machinability of both methods was compared in terms of cutting force, precision and cycle time.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.117-122
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• 2004

In order to improve the fuel economy by design change of automatic transmission, various technologies such as increased shift stages, slip control of lock-up clutch and compact and low-weight design have been developed. And also many OEMs have developed their own ATFs as a part of these automatic transmissions. In this study. to investigate the effects of ATF characteristics on fuel economy, we got the worldwide OEM ATFs and made some reference fluids. And physical properties, frictional characteristics and fuel economy using dynamometer test for these fluids were evaluated. From the investigation, it was found that viscosities of ATFs are correlated with fuel economy in dynamometer test and reducing the viscosities made it possible to obtain fuel economy.

• Transactions of Materials Processing
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• v.14 no.1 s.73
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• pp.57-64
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• 2005

This study deals with the cold forging process design for shaft in the main part of automobile motors with rectangular deep groove. In forging process, the accuracy and die lift is very important because it have influence on reduction of the production cost and the increase of the production rate. Therefore, it is necessary to develop the manufacturing process of shaft by cold forging., process variables are the cropped face angle of billet and the eccentric load of punch. The former is derived from cropping test, the latter is occurred by clearance between container and preform. Also, grooved preform select the process variable for decrease in punch deflection. We investigate that a deflection of punch and a deformation of preform to every process variables. Through this investigation, we suggest the optimal preform and process design, expect to be improved the tool life in forging process.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.1
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• pp.9-15
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• 2000

This paper presents a implementation of digital motion control system for induction motor vector drives using the 16bit DSP TMS320F240. The DSP controller enable enhanced real time algorithm and cost-effective design of intelligent controllers for motors which can be yield enhanced operation, fewer system components, lower system cost, increased efficiency and high performance. The system presented are speed and current sensing, sine look-up table and generated SVPWM by fully integrated control software. The developed system in a implementation are shown a good speed response and motion control characteristic results, and high performance features in general purposed 2.2[kW] machine. The system can be adapted variform motor drive system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.3
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• pp.68-73
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• 2017

In this study, we design a low-cost test equipment for real-time image observation and transmission/reception distance test using 1m by 1.5m bang-pai kite. The image observation is made by using two servo motors to enable the camera to control the two axis attitude. The image observation equipment is hung on the string of a kite and the test is performed to observe the real time image. The transmission and reception distance test of the wireless RF transceiver module is conducted on the ground and in the air.

• Journal of Engineering Education Research
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• v.15 no.5
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• pp.19-24
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• 2012

Robots have been attracting students' interest recently. Therefore, they are a good way to motivate to study related subjects. However, there are difficulties in teaching general students because a wide background is required to understand the fundamentals of robotics. In order to teach robotics fundamentals to beginners in a short period, an effective experimental class, including several phased experiments, is proposed in this paper. A portable two-DOF robot arm system with servo motors was developed for experiments, and the operation method based on kinematics was introduced for its operation. The effectiveness of the class was investigated by using a questionnaire after carrying it out in a university class for junior students.