• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.444-448
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• 1994

광 fiber를 이용한 새로운 구조의 초고속 광디스크 드라이버를 제안하였다. 기존의 광 픽 업 모듈을 레리져 다이오드, 광검출기, 렌즈 및 각종 광학계등의 무거운 부분과 GRIN렌즈 및 초경량의 PD로만 구성되는 광 헤드의 가벼운 부분으로 분리하였다. 무거운 부분은 Fixed part로 고정시키고 가벼운 부분만을 Moving part로 함으로써 광 헤드의 tracking 속도를 증가 시켰다. 또한 컴퓨터의 하드디스크 드라이버에서와 같은 초고속의 Pivot-arm tracking방식 을 채용하기 위해 Fixed part와 Moving part를 광 fiber를 이용해 접속하였으며 이 새로운 구 조에서 데이타 신호, tracking 및 focusing 에러 신호를 검출하는 메커니즘에 대해 설명하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.67-68
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• 2006

In this paper, a new revolute cooperating robot arms with 12 d.o.f was developed for autonomous moving robots. The robot ann was designed to have the load capacity of 10 Kg. For this, a new joint actuator based on the fourbar link mechanism was employed. As a control system for the robot arm, a distributed control system was developed composed of the main controller and five motor controller for the ann joints. The main controller and the motor controller were developed using the ARM microprocessor and the TMS320c2407 processor, respectively. To validate the performance of the robot system, an experiment to support 10 Kg payload was performed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.847-850
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• 2005

In modern Automobile engineer, continuos development technology and improve on manufacture system are very important to the reinforcement of technology and improvement of productivity. In this study make a comparative welding methodology to make automotive trailing arm for change to welding system. A progress of test is durability test and banding fracture test for make collection of data about properties of welding system.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.1
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• pp.52-57
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• 1997

The paper deals with kinematic evaluation of performance of a hydraulic shovel arm for deburrinhg task. First, a new criteria for evaluation is derived to evaluate accuracy of an ene-effector at each position with- in the movable area of the hydraulic shovel arm. Secondly a graphic evaluation system that displays a map of the criteria for evaluation and a map of the manupulability measure is build. Thirdly, by using by using the sas- tem, a hydraulic shovel arm is kinematically evaluated. Finally, from the comparison of the result obtained from the computer simulation and an experimental result, it is indicated that the derived criteria for evalu- ation and the graphic system are useful.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.3 s.192
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• pp.84-90
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• 2007

As a result of vehicle maintenance of rocker arm shaft for 4-cylinder SOHC engine, failure stress analysis of rocker arm shaft is needed. Because more than 30% of vehicles investigated have been fractured. Failure stress analysis is classified into an naked eyes, microscope, striation and X-ray fractography etc. Failure stress analysis by using striation is already established technology as means for seeking cause of fracture. But, although it is well known that striation spacing corresponds to the crack growth rate da/dN, it is not possible to determine ${\sigma}_{max}\;and\;{\sigma}_{min}$ under service loading only from striation spacing. This is because the value of striation spacing is influenced not only by ${\Delta}K$ but also by the stress ratio R. In the present paper, we determine the stress ratio using orthogonal array and ANOVA, and propose a prediction method of failure stress which is combined with FEM and striation.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.2
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• pp.115-123
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• 2017

This paper presents the design and the control performance of a novel dynamic compliant-arm support with parallel elastic actuators that was developed to assist with the daily living activities of those whose arms are compromised by muscular disease or the aging process. The parallel elastic-arm support consists of a compliant mechanism with combined passive and active components for human interaction and to reach the user's desired positions. The achievement of these tasks requires impedance control, which can change the virtual stiffness, damping coefficients, and equilibrium points of the system; however, the desired-position tracking by the impedance control is limited when the end-effector weight varies according to the equipping of diverse objects. A prompt algorithm regarding weight calibration and friction compensation is adopted to overcome this problem. A result comparison shows that, by accurately assessing the desired workspace, the proposed algorithm is more effective for the accomplishment of the desired activities.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.133-138
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• 2017

Recently, CFRP composites are widely used as lightweight materials have with excellent mechanical properties and can beare widely used in various fields. In general, thermosetting resins are used for CFRP. However, in recent years, studies have been carried out using thermoplastic resins have been actively carried out to overcome the disadvantages of thermosetting resins. The LFT-D system is a molding method in which a fiber is directly cut to a the desired length while being impregnated with a thermoplastic resin to produce a compound and that is then press-molding molded to form the product. In this paper, before the production of the trailing arm, the compression molding analysis was carried out in order to grasp the problems that may occur during production. Through cCompression molding analysis was applied to calculate of the minimum press pressure and to compare and analysis analyze the molding conditions characteristic required to formfor forming the trailing arm.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.9
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• pp.707-714
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• 2016

This paper describes analysis results of vibration characteristics and modal test for a small-scale quad-rotor drone. The rotor arm has a slender body with a propeller and motor at its tip. Rotor system generates excitation for an unbalanced mass. Therefore, the drone platform is involved in the possibility of resonance. For advance identification of the possibility of resonance, confirmation of eigen-mode being closest to the propeller operation range is necessary. Material properties of CFRP tubes used for the rotor arm were acquired by finding the natural frequency based on Rayleigh method. A simplified quad-rotor FE model consisting of rotor arm assembly with tip mass was built to perform numerical analysis, and a free-free boundary condition was applied to provide flight status. Modal tests for the actual platform with impact hammer instrument were performed to verify analysis results. Separation margin from hazardous eigen-mode was checked on the propeller operation range.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8B
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• pp.1412-1420
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• 1999

In order to enhance multi-channel audio signals, Dolby Pro Logic is widely used especially for the Hi-Fi audio system, since it can provide highly stereophonic effects and a nice separation of multi-channel sound. This paper describes an implementation of Dolby Pro Logic decoder with ARM-7 core. The code is modified for the fixed point operation and optimized. For the verification of the code, the operation time and the precision are estimated thoroughly. As a result, it is verified that Dolby Pro Logic decoder can be implemented with ARM-7 core operating at 54 MHz.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.279-280
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• 2012