• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2525-2528
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• 2003

본 논문은 제철소 원료공장에서 선박으로부터 철광석, 석탄 등의 원료를 언로다 내부의 벨트 컨베이어로 이송 시, 선박과 부두와의 공간이 발생하여 이 공간으로 원료가 낙광 하여 해양오염이 발생하고 원료의 유실 등의 문제점을 해결하기 위한 낙광방지 시스템 개발에 관한 연구이다. 초음파 센서를 이용한 선박과의 거리 인식 및 PLC 제어기를 이용한 자동 제어 방법을 제시한다. 언로다 본체에 낙광방지판과 이를 구동하는 에어 실린더형태의 구동기와 낙광방지판을 연결하는 링크부로 구성되는 시스템에 있어서, 거리 감지 센서 3대로부터 선박과의 최소 거리를 구하고 이를 PLC 제어기를 이용하여 목표 거리와의 오차를 구한 다음, 오차의 증감에 따라 구동기인 에어 실린더의 이동량을 구하여 낙광방지판을 선박과 최대한 밀착시켜 하역 작업을 하고, 떨어진 낙광을 자동으로 회수하는 시스템에 관한 논문이다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.280-281
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• 2010

컨테이너의 효율적인 이송은 작업 시간이 곧 비용으로 연결되는 항만에서 가장 중요한 요소이다. 따라서 1990년대 중반부터 세계항만은 RMGC(Rail-Mounted Gantry Crane), RTGC(Rubber-Tired Gantry Crane)등의 크레인이 개발되어 야드에서 컨테이너를 적재하는데 널리 이용되어 오고 있으며, 특히 최근에는 CCD카메라, 각종 센서 둥을 이용하여 트랜스퍼 크레인의 무인화를 위해 수많은 연구가 진행되었고 실용화 된 많은 기술들이 현장에서 사용되고 있으나, 여전히 많은 부분이 연구를 필요로 한다. 특히 RTGC의 경우 RMGC에 비해 무인 자동화 연구개발은 미비한 수준이다. 따라서 본 논문에서 RTGC의 무인자동화 작업을 위한 가장 기초라고 볼 수 있는 수학적 모델링을 기반으로한 고정밀도 주행제어기를 설계하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1480-1486
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• 2002

In this study, the cross-coupling control (CCC) with three new features is proposed to maintain contour precision in high-speed nonlinear contour machining. One is an improved contour error model that provides almost exact calculation of the errors. Another is the utilization of variable controller gains based on the instantaneous curvature of the contour and the variable command. For this scheme, a stability is analyzed. As a result, the stability region is obtained, and the variable gains are decided within that region. The other scheme in the proposed CCC is a real-time feedrate adaptation module to regulate cutting force fur better surface finish through regulation of material removal rate (MRR). The simulation results show that the proposed CCC system can provide better precision than the existing method particularly in high-speed machining of nonlinear contours.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.2
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• pp.63-72
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• 1996

In order to regulate the cutting force at a desired level during peripheral end milling processes a feedrate override Adaptive Control Constraint (ACC) system was developed. The feedrate override function was accomplished through a development of programmable machine controller (PMC) interface technique on the NC controller, Nonlinear model of the cutting process was linearized as an adaptive model with a time varying process parameter. An integral type estimator was introduced for on-line estimation of the cutting process parameter, Zero order hold digital control methodology which uses pole-assignment concept for tuning of PI controllers was applied for the ACC system. Performance of the ACC system wsa confirmed on the vertical machining center equipped with fanuc OMC through a large amount of experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.690-694
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• 1996

In order to regulate the cutting force at a desired level during peripheral end milling processes, a feedrate override Adaptive Control Constant system was developed. This paper presents an explicit pole-assignment PI-control law through spindle motor current monitoring and its application to cutting force regulation for feedrate optimization. An experimental set-up is constructed for the commercial CNC machining center without any major changes of the structure. A data transfer system is constructed with standard interface between an IBM compatible PC and a CNC of the machining center. Experimental results show the validity of the system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.225-229
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• 1996

This paper presents an active position control of a moving table utilizing ER(electro-rheological) brake and ER clutch. A transformer oil-based ER fluid is composed and its Bingham properties are evaluated with respect to electric fields. The dynamics of the actuators : ER brake and ER clutch, are identified through experiments, and subsequently the governing equation of motion of the moving table system is formulated from the governing equation, a sliding mode controller is designed to achieve an accurate position control. Both simulation and experimental results and presented in order to demonstrate the effectiveness of the proposed control methodology.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.1-7
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• 2005

This paper deals with the position control for a feed drive system in CNC milling machine. The study shows that reduction in tacking error does not necessarily increase contouring accuracy, and proposes that a proper control scheme is able to exhibit the optimal tracking and contouring accuracy. The proposed scheme is to fix the parameter of the contouring control, and to find the optimal value of the parameter of the tracking control, which is automatically tuned. The effectiveness of the proposed scheme is confirmed through simulations.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.131-134
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• 2013

디지털 홀로그램 기록 방식에 있어서 기록하고자 하는 영상을 디지털화하는 작업과 더불어 영상을 필름에 투영시키기 위한 공간 광 변조기, 기록 광원을 생성하기 위한 광학 시스템 및 필름 이송을 담당하는 스테이지의 정밀한 제어가 필요하다. 본 논문에서는 디지털 홀로그래픽 기록 시스템을 개발함에 있어서 전체 운용 기능에 해당하는 제어 구조를 제안하고 제안된 구조의 기능과 구현된 결과를 통해 향후 개선 사항을 소개하고자 한다.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.38-46
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• 1999

Spindle motor current is used to estimate the cutting force indirectly and control the feed rate for the cutting force regulation. The proposed algorithm is implemented to a DSP board based hardware for the industrial application. The software to make POP terminal communicate with the DSP board and POP server is coded under Windows 95 environment. Experiments under varying cutting conditions show that the DSP board recognizes the information of installed cutting tool and cutting conditions delivered from the POP server to use them for the proper control of the feed rate. The cutting force is regulated well during machining of tapered or stepped workpiece and circular shaped workpiece as well.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.2
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• pp.169-175
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• 2009

This paper presents motion control of the Inchworm composed of the piezoelectric actuators and mechanical elements. Piezoelectric actuator shows nonlinear response characteristics including hysteresis due to the ferroelectric characteristics. This paper proposes feedback control scheme to improve the ability of tracking response to complex input signal and suppress the phenomenon of hysteresis using the sliding mode control technique with the integrator. The sliding mode control system has the limit to minimize both the settle time and overshoot. For making up this limit, this paper also suggests input shaping technique suitable to the inchworm control system.