• Journal of Power Electronics
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• 제7권2호
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• pp.159-173
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• 2007

In this paper, an intelligent sliding-mode position controller (ISMC) for achieving favorable decoupling control and high precision position tracking performance of permanent-magnet synchronous motor (PMSM) servo drives is proposed. The intelligent position controller consists of a sliding-mode position controller (SMC) in the position feed-back loop in addition to an on-line trained fuzzy-neural-network model-following controller (FNNMFC) in the feedforward loop. The intelligent position controller combines the merits of the SMC with robust characteristics and the FNNMFC with on-line learning ability for periodic command tracking of a PMSM servo drive. The theoretical analyses of the sliding-mode position controller are described with a second order switching surface (PID) which is insensitive to parameter uncertainties and external load disturbances. To realize high dynamic performance in disturbance rejection and tracking characteristics, an on-line trained FNNMFC is proposed. The connective weights and membership functions of the FNNMFC are trained on-line according to the model-following error between the outputs of the reference model and the PMSM servo drive system. The FNNMFC generates an adaptive control signal which is added to the SMC output to attain robust model-following characteristics under different operating conditions regardless of parameter uncertainties and load disturbances. A computer simulation is developed to demonstrate the effectiveness of the proposed intelligent sliding mode position controller. The results confirm that the proposed ISMC grants robust performance and precise response to the reference model regardless of load disturbances and PMSM parameter uncertainties.

• 방송공학회논문지
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• 제23권2호
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• pp.186-196
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• 2018

본 논문에서는 객체를 추적하기 위해 합성곱 신경망 모델을 이용한 온라인 추적 기법을 제안한다. 오프라인에 모델을 학습시키기 위해서는 많은 수의 훈련 샘플이 필요하다. 이러한 문제를 해결하기 위해, 학습되지 않은 모델을 사용하고, 실험 영상으로부터 직접 훈련 샘플을 수집하여 모델을 갱신한다. 기존의 방법들은 많은 훈련 샘플을 획득하여 모델의 학습에 사용하였지만, 본 논문에서는 적은 수의 훈련 샘플만으로도 객체의 추적이 가능함을 증명한다. 또한 컬러 정보를 활용하여 새로운 손실 함수를 정의하였고 이로부터 잘못 수집된 훈련 샘플로 인해 모델이 잘못된 방향으로 학습되는 문제를 방지한다. 실험을 통해 4가지 비교 방법과 동등하거나 개선된 추적 성능을 보임을 증명하였다.

• Journal of Welding and Joining
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• 제16권6호
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• pp.68-76
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• 1998

A CCD camera with a laser stripe was applied to realized the automatic weld seam tracking. The 3-dimensional information obtained from the vision system made it possible to generate the weld torch path. The adaptive Hough transformation was used to extract laser stripes an to obtain specific weld points. It takes relatively long time to process image on-line control using the basic control using the basic Hough transformation, but it has a tendency of robustness over the noises such as spatter. For this reason, it was complemented with adaptive Hough transformation to have an on-line processing ability for scanning specific weld points. The dead zone, where the sensing of weld line is impossible, was eliminated by rotating the camera with its rotating axis centered at the weld torch. When weld lines were detected, the camera angle was controlled in order to get the minimum image data for sensing of weld lines. Consequently, the image processing time was reduced.

• 한국정밀공학회지
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• 제17권1호
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• pp.76-82
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• 2000

An arc sensor system to compensate positional errors was developed on the foundation of sensor interface system to make use of the on-line shift function of industrial welding robot. Investigating the on-line shift function, we examine the quantitative relationship between the deviation from programmed path and the correction data transferred from personal computer to robot controller. The number of input parameters for weld seam tracking can be reduced by making the relationship between the deviation and the correction data during half weaving be the function of only cross time. With the results of weld seam tracking for the butt joint with V-groove and fillet joint of sheet metal, good performance was implemented. By developing the sensor interface system to compensate the positional errors, industrial welding robot can be expected to contribute to the promotion of welding automation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.145-148
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• 1996

In moving object tracking based on the visual sensory feedback, a prerequisite is to determine which feature or which object is to be tracked and then the feature or the object identification precedes the tracking. In this paper, we focus on the object identification not image feature identification. The target identification is realized by finding out corresponding line segments to the hypothesized model segments of the target. The key idea is the combination of the Mahalanobis distance with the geometrica relationship between model segments and extracted line segments. We demonstrate the robustness and feasibility of the proposed target identification algorithm by a moving vehicle identification and tracking in the video traffic surveillance system over images of a road scene.

• Journal of Welding and Joining
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• 제22권6호
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• pp.43-49
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• 2004

In this study, a visual sensor system which can detect I-butt weld joint with height variation and includes a seam tracking algorithm was investigated. Three-dimensional position of an object can be acquired by using the method of distance measurement, i.e., an optical trigonometry which results from the spatial relations between the camera, the object and the structured light by a visible laser. Effects of laser intensity and iris number for the image quality as well as object material were investigated for the optical system design. For the image processing, a region of interest is defined from the whole image and a line image of laser is drew by using the gray level difference in the image. From the drew laser line, the weld joint can be recognized in searching the biggest point position calculated from the central difference method. Through a series of welding experiments, a good tracking performance was confirmed under GMA welding.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권1호
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• pp.17-25
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• 2014

This paper presents the formulation of an impedance controller for regulating the contact force with the environment. To achieve an accurate force tracking control, uncertainties in both robot dynamics and the environment require to be addressed. As part of the framework of the proposed force tracking formulation, a neural network is introduced at the desired trajectory to compensate for all uncertainties in an on-line manner. Compensation at the input trajectory leads to a remarkable structural advantage in that no modifications of the internal force controllers are required. Minimizing the objective function of the training signal for a neural network satisfies the desired force tracking performance. A neural network actually compensates for uncertainties at the input trajectory level in an on-line fashion. Simulation results confirm the position and force tracking abilities of a robot manipulator.

• 한국의류산업학회지
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• 제19권2호
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• pp.230-239
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• 2017

In the clothes industry, there are lack of experts including technical designers who can analyze the fit of clothes. This study is to provide practical data available for fit analysis education by distinguishing the differences in standards and aspects of garment fit between experts and novices, through the eye-tracking technology to quantify the sense of fit. For this study, two groups were organized; one composed of 7 experts with over 15 year-experience including technical designers and patternmakers, and the other composed of 7 novices who are students majoring in clothing. Wearing the goggle type eye-tracker Tobii Pro Glasses 2, the participants in the experiments were required to conduct fit analyses for a pair of pants on a live model. After those experiments, they were required to check the items for fit analysis and assess the importance level of them on a questionnaire. The differences between the two groups in the ratios of total visit count and total visit duration by each AIO(Area of Interest) of clothes were analyzed through non-parametric statistical test. The results of eye tracking experiments showed that experts focused on center front and back line, crotch area, and side seam, while novice's fixation points were dispersed around the pants. The survey results showed that the experts put importance on the center line position and its verticality, front-back proportion of side seam line, and front-back proportion of waist line, 71.4~100% of whom checked them, while 14.3% of the novices checked them.

• 정보처리학회논문지C
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• 제14C권1호
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• pp.105-114
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• 2007

센서네트워크 환경에서 이동객체의 위치추적방법은 추적방법론에 따라 데이터의 수신과 위치추적의 정확성에 문제가 있었으며, 이러한 위치데이터는 오로지 위치 추적만을 위한 데이터이었기에 주변의 환경 데이터를 활용하여 상황에 맞는 정보판단 또는 모니터링에 한계가 있었다. 이러한 한계를 극복하기 위한 방법으로 상황인식(context aware)을 종종 활용하는데, 본 문은 자기센서를 기반으로 측정된 자성체(magnetic line tracer)의 자성데이터 위치 추적 및 제어에 관한 데이터처리에 상창인식을 활용한 방법을 제안하였다. 제안된 방법은 센서네트워크 노드의 자기센서의 자성데이터 측정과 주변 환경정보 데이터를 이용하였고, 이러한 데이터를 상황인식 데이터베이스의 엔트리로 구성함으로써 추후 행동정보 추론 및 제어할 수 있다. 아울러 제안된 방법의 타당성을 검증하기 위하여 센서네트워크 환경을 만족하는 테스트베드를 구축하였으며, 이를 이용한 라인트레이서의 위치 추적과 경로탐색의 결과를 도출하였으며, 도출된 데이터를 근거로 하여 주변 환경정보 데이터베이스 엔트리 및 상황인식에 따른 라인트레이서의 방향제어에 미치는 영향을 분석하였다.

• 한국소음진동공학회논문집
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• 제14권8호
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• pp.726-733
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• 2004

On-line phase tracking of an extrinsic Fabry-Perot interferometer (EFPI) and experimental vibration control of a composite beam with a sensing-patch are investigated. We propose a sensing-patch for the compensation of the interferometric non-linearity. In this paper. a sensing-patch that comprises an EFPI and a piezo ceramic(PZT) is fabricated and the characteristics of the sensing-patch are experimentally investigated. A simple and practical logic is applied for the real-time tracking of optical phase of an interferometer Experimental results show that the proposed sensing-patch does not have the non-linear behavior of conventional EFPI and hysteresis of piezoelectric material. Moreover, it has good strain resolution and wide dynamic sensing range. Finally, the vibration control with the developed sensing-patch has been performed using Fuzzy logic controller, and the possibility of sensing-patch as a sensoriactuator is considered.