• 한국생산제조학회지
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• 제6권1호
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• pp.7-17
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• 1997

During the past decade, there were many well-established theories for the adaptive control of linear systems, but there exists relatively little general theory for the adaptive control of nonlinear systems. Adaptive control technique is essential for providing a stable and robust performance for application of industrial robot control. Neural network computing methods provide one approach to the development of adaptive and learning behavior in robotic system for manufacturing. Computational neural networks have been demonstrated which exhibit capabilities for supervised learning, matching, and generalization for problems on an experimental scale. Supervised learning could improve the efficiency of training and development of robotic systems. In this paper, a new scheme of adaptive-neuro control system to implement real-time control of robot manipulator using digital signal processors is proposed. Digital signal processors, DSPs, are micro-processors that are developed particularly for fast numerical computations involving sums and products of variables. The proposed neuro control algorithm is one of learning a model based error back-propagation scheme using Lyapunov stability analysis method. The proposed adaptive-neuro control scheme is illustrated to be an efficient control scheme for implementation of real-time control for SCARA robot with four-axes by experiment.

• 한국콘텐츠학회논문지
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• 제16권8호
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• pp.671-680
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• 2016

본 연구에서는 통행시간과 점유율의 융합 정보를 이용하는 새로운 실시간 신호제어 알고리즘을 제시하였다. 교통정보시스템의 통행시간 정보를 신호운영에 적용하였으며, 통행시간으로 부터 산정한 포화도를 신호제어에 이용하기 위한 프로세스를 개발하였다. 결정적 지체모형을 이용해 통행시간으로부터 대기행렬 길이를 생성하고, 대기행렬 길이를 다시 포화도로 변환하는 과정이 적용되었다. 또한 통행시간 기반 포화도와 루프검지기 포화도를 융합해 신호시간이 산정되도록 하였다. 신호제어 알고리즘의 효과평가를 위해 미시적 시뮬레이션 분석을 시행하였으며, 과포화 상태에서 기존 루프검지기 기반 실시간 신호제어 대비 최대 27%의 지체 감소 효과를 확인하였다. 또한 과포화 및 검지기 고장상황에 대한 효과적이고, 유용한 대응이 가능함을 확인하였다. 본 연구에서는 교통신호제어시스템과 교통정보시스템의 교통정보 통합이용 방안을 제시하였다는데 의의가 있겠다.

• 전자공학회논문지SC
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• 제45권1호
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• pp.31-40
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• 2008

본 논문에서는 자기변형재료를 이용한 미세 구동기의 개발과 실시간 제어 알고리즘에 관한 내용을 다룬다. 자기변형재료는 빠른 응답속도, 미세변위동작, 높은 에너지 효율 등의 장점을 가지고 있어 미세 구동기의 재료로 적합하지만 히스테리시스 특성도 함께 갖고 있어 제어에 많은 어려움이 따른다. 본 논문에서는 자기변형재료의 히스테리시스를 제어하기위해 Preisach model을 바탕으로 구동기를 모델링 하였다. 기존의 Preisach 모델은 실험적 데이터를 바탕으로 하기 때문에 정밀한 제어를 하기 위해서는 많은 양의 데이터가 필요하고 결과적으로는 처리해야할 데이터의 양이 많아져 연산하는데 많은 시간이 걸리는 문제가 있다. 본 논문에서는 이러한 문제를 해결하기 위하여 기존의 Preisach 모델의 데이터를 선행 처리하여 일정구간 구동기의 움직임을 저장해 놓은 확장된 Preisach 모델을 제안하였다. 본 논문에서는 Tefenol-D라는 자기변형재료를 사용하여 미세구동기를 제작하고 제어 실험을 통하여 제안된 모델의 우수성을 증명하였다.

• 전자공학회논문지SC
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• 제48권3호
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• pp.6-12
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• 2011

다중 구동기로 이루어진 실시간 분산제어시스템으로 전기자동차, 다중 로봇시스템 등을 들 수 있다. 이러한 시스템들에는 여러 개의 프로세서가 필수적으로 요구된다. 시스템 구성요소별로 프로세서를 내장한 제어 기기에는 모듈화, 소형화, 저전력화 및 상호운용가능성과 내고장성이 요구되며, 이를 위해서 제어시스템이 네트워크기반 실시간 분산제어시스템의 형태로 구현될 필요가 있다. 네트워크기반 실시간 분산제어시스템 구현 시 각 구동부간 동기화 문제에 의해 고속, 고정밀 및 고신뢰성을 갖는 것이 어렵다. 동기화 문제의 원인으로는 부하변동, 구동부간 동특성 불일치 및 구동부 제어기기간의 통신에 따른 시간지연을 들 수 있다. 본 연구에서는 연결 부하가 서로 다른 경우와 연결부하 뿐만 아니라 구동 모터의 동역학적 특성도 다른 경우의 단일 링크 머니퓰레이터에 대하여 외란관측기와 칼만 필터를 이용한 동기화 제어법과 목표치와 실측치 및 실측치들 사이의 에러 벡터의 노름에 대한 스칼라 함수를 정의하고 이 함수의 기울기 벡터를 최소화시키는 목표궤적을 이용한 동기화제어법을 제시하고 실험을 통하여 그 유용성을 확인한다.

• International Journal of Precision Engineering and Manufacturing
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• 제9권1호
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• pp.3-6
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• 2008

Electrical discharge machining (EDM) is one of the most widespread nonconventional machining processes. Recently, a low-power micro-EDM process was introduced using a cylindrical electrode. Since its development, micro-EDM has been applied effectively to micromachining, and because the device setup for this process is simple, it is suitable for a microfactory that minimizes machines to fabricate small products economically in one system. In the EDM process, however, the electrode is also removed along with the workpiece. Therefore, the electrode shape and length vary as machining progresses. In this paper, a control method using a high speed realtime voltage measurement is proposed to regulate the rate and amount of material removed. The proposed method is based on the assumption that the volume of the workpiece removed in a single discharge pulses is nearly constant. The discharge pulses are monitored and controlled to regulate the amount of material removed. For this purpose, we developed an algorithm and apparatus for counting the number of discharge pulses. Electrode wear compensation using pulse number information was applied to EDM milling in a microfactory, in which a slight tilt of the workpiece may occur. The proposed control method improves the machining quality and efficiency by eliminating the inaccuracies caused by electrode wear and workpiece tilt.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1179-1181
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• 1992

A discrete Pl controller is implemented easily using a micro-processor, and it can be confirmed to a adaption of a system and real time processing. In this paper, a speed controller by discrete Pl control using a IBM PC/AT(12MHz) as a micro-processor is implemented and applied to a DC servo motor. In designing the discrite Pl controller, a sampling time and a speed is accepted from key-board, and is processed the control coefficient automatically, and than calculate the gain. Therefore the speed of a DC servo motor is obtained and controlled regulaly. The designed and manufactured discrete Pl control system is experimented. The result shows the good response at the 60 RPM to 250 RPM on the load using the load-spring. The speed error is under 1% on the steady load, but nearly 2-3% on the transient load.

• 산업경영시스템학회지
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• 제37권1호
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• pp.33-40
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• 2014

Air compressor is an important facility with electric power in the industry. However, because of the noise and vibration of air compressor and is installed outside the building management difficulty. In this study, MCP (Micro Control Processor) to remote monitoring of the air compressor via the compressed air through improved quality and allows stable maintenance were designed. So, increase the productivity improvement of energy-saving effect can be obtained. Remote real-time information stored on your PC to manage air compressor equipment was higher reliability. Monitoring system is developed in this study was applied to embedded systems. It is easy to install air compressor, and low maintenance costs was to raise the economic impact.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1995년도 특별강연 및 추계학술발표 개요집
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• pp.3-20
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• 1995

Development of Real-Time Quality Evaluation of Friction Welding by Acousitc Emission : Report 1 ABSTRACT : According as the friction welding has been increasingly applied in manufacturing various machine components because of its significant economic and technical advantages, one of the important concerns is the reliable quality monitoring method for a good weld quality with both joint strength and toughness in the process of its production. However no reliable nondestructive test method is available at present to determine the weld quality particularly in process of production. So this paper presents an experimental examination and quantitative analysis for the real-time evaluation of friction weld quality by acoustic emission, as a new approach which attempts finally to develop an on-line quality monitoring system design for friction welds using AE techniques. As one of the important results, it was confirmed, through this study, that AE techniques can be reliably applied to evaluating the friction weld qualify with 100% joint strength, as the cumulative AE counts occurring during welding period were quantitatively correlated with reliability at 95% confidence level to the joint strength of welds. Real-Time Evaluation of Automatic Production Quality Control for Friction Welding Machine : Report 2 Abstract : Both in-process quality control and high reliability of the weld is one of the major concerns in applying friction welding to the economical and qualified mass-production. No reliable nondestructive monitoring method is available at present to determine the real-time evaluation of automatic production quality control for friction welding machine. This paper, so that, presents the experimental examinations and statistical quantitative analysis of the correlation between the initial cumulative counts of acoustic emission(AE) occurring during plastic deformation period of the welding and the tensile strength of the welded joints as well as the various welding variables, as a new approach which attempts finally to develop an on-line (or real-time) quality monitoring system and a program for the process of real-time friction welding quality evaluation by initial AE cumulative counts. As one of the important results, it was well confirmed that the initial AE cumulative counts were quantitatively and cubically correlated with reliability of 95% confidence level to the joint strength of the welds, bar-to-bar (SCM4 to SUM31, SCM4 to SUM24L) and that an AE technique using initial AE counts can be reliably applied to real-time strength evaluation of the welded joints, and that such a program of the system was well developed resulting in practical possibility of real-time quality control more than 100% joint efficiency showing good weld with no micro-structural defects.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.499-500
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• 2006

The electrode wear in micro-EDM significantly deteriorates the machining accuracy. In this regard, electrode wear needs to be compensated in-process to improve the product quality. Therefore, there are substantial amount of research about electrode wear. In this study a control method for micro-EDM using discharge pulse counting is proposed. The method is based on the assumption that the removed workpiece volume is proportional to the number of discharge pulses, which is verified from experimental results analyzing geometrically machined volume according to various number of discharges. Especially, the method has an advantage that electrode wear does not need to be concerned. The proposed method is implemented to an actual micro-EDM system using high speed data acquisition board, simple counting algorithm with 3 axis motion system. As a result, it is demonstrated that the volume of hole machined by EDM drilling can be accurately estimated using the number of discharge pulses. In EDM milling process a micro groove without depth variation caused by electrode wear could be machined using the developed control method. Consequently, it is shown that machining accuracy in drilling and milling processes can be improved by using process control based on the number of discharge pulses.

• 로봇학회논문지
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• 제9권3호
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• pp.154-159
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• 2014

The Global Positioning System (GPS) is widely used to aid the navigation of aerial vehicles. However, the GPS cannot be used indoors, so alternative navigation methods are needed to be developed for micro aerial vehicles (MAVs) flying in GPS-denied environments. In this paper, a real-time three-dimensional (3-D) indoor navigation system and closed-loop control of a quad-rotor aerial vehicle equipped with an inertial measurement unit (IMU) and a low-cost light detection and ranging (LIDAR) is presented. In order to estimate the pose of the vehicle equipped with the two-dimensional LIDAR, an octree-based grid map and Monte-Carlo Localization (MCL) are adopted. The navigation results using the MCL are then evaluated by making a comparison with a motion capture system. Finally, the results are used for closed-loop control in order to validate its positioning accuracy during procedures for stable hovering and waypoint-following.