• 전기학회논문지
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• 제63권11호
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• pp.1551-1558
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• 2014

We propose a multi-rate sensor fusion of vision and radar using Kalman filter to solve problems of asynchronized and multi-rate sampling periods in object vehicle tracking. A model based prediction of object vehicles is performed with a decentralized multi-rate Kalman filter for each sensor (vision and radar sensors.) To obtain the improvement in the performance of position prediction, different weighting is applied to each sensor's predicted object position from the multi-rate Kalman filter. The proposed method can provide estimated position of the object vehicles at every sampling time of ECU. The Mahalanobis distance is used to make correspondence among the measured and predicted objects. Through the experimental results, we validate that the post-processed fusion data give us improved tracking performance. The proposed method obtained two times improvement in the object tracking performance compared to single sensor method (camera or radar sensor) in the view point of roots mean square error.

• International Journal of Aeronautical and Space Sciences
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• 제6권1호
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• pp.17-26
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• 2005

An optical phase tracking technique for an extrinsic Fabry-Perot interferometer (EFPI) is proposed in order to overcome interferometric non-linearity. Basic idea is utilizing strain-rate information, which cannot be easily obtained from an EFPI sensor itself. The proposed phase tracking system consists of a patch-type EFPI sensor and a simple on-line phase tracking logic. The patch-type EFPI sensor comprises an EFPI and a piezoelectric patch. An EFPI sensor itself has non-linear behavior due to the interferometric characteristics, and a piezoelectric material has hysteresis. However, the composed patch-type EFPI sensor system overcomes the problems that can arise when they are used individually. The dynamic characteristics of the proposed phase tracking system were investigated, and then the patch-type EFPI sensor system was applied to the active suppression of flutter, dynamic aeroelastic instability, of a swept-back composite plate structure. The proposed system has effectively reduced the amplitude of the flutter mode, and increased flutter speed.

• 한국태양에너지학회 논문집
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• 제32권6호
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• pp.29-36
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• 2012

The existing solar tracking sensor for 2 axial control system to trace latitude and longitude is made of four phototransistor. The phototransistor-making is difficult and it's manufacturing is more high-priced than a wide use phototransistor because they have to the same characteristics of each phototransistor output signal. This paper described the algorithm for supplement these weakness. The algorithm applied to signal normalizing method and vector decomposition law. The deviations of each a wide use phototransistor output signal are resolved by signal normalizing method and it is able to make a solar tracking sensor using three phototransistor by vector decomposition law. Therefore, in this paper, it is reduced the number of phototransistor that is composed of solar tracking sensor and possible to use a wide use phototransistor by the proposed algorithm.

• 한국지능시스템학회논문지
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• 제16권6호
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• pp.710-715
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• 2006

최근 반도체 제조기술의 발달로 저가의 센서 노드의 개발이 가능해 짐에 따라 실제 시스템에 대한 모니터링 및 제어 시스템의 개발이 가능하게 되고 있다. 이에 본 연구에서는 센서 네트워크 어플리케이션 중 하나인 움직이는 물체의 추적을 위한 새로운 형태의 알고리즘을 제안하고자 한다. 제안된 알고리즘은 물체의 이동을 감지한 센서 노드들간의 협업을 통해 이동 물체의 움직임을 지속적으로 감지하는 것을 가능케 한다. 이로 인해 제안된 알고리즘은 타켓의 순간적인 놓침을 초래할 수 있는 예측 실패 등에 대해 강인한 특성을 갖는다. 또한 시뮬레이션 고찰을 통해 제안된 알고리즘이 랜덤한 움직임을 갖는 타켓에 대한 정확한 추적이 가능함을 확인하였다.

• 한국정밀공학회지
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• 제31권11호
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• pp.1007-1013
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• 2014

In this study to improve the productivity, advantage Tandem circumferential weld process of seam tracking system was applied for the laser vision sensor. Weld geometry scanning laser vision sensor and PLC control unit are used to scan correct positioning of welding torch when the program is implemented so that it can correctly track the welding line. The welding experiment was conducted to evaluate the performance of laser vision seam tracking sensor in tandem welding process. The seam tracking several experiments was to determine the reliability of the system, welding experiments relatively good quality welding bead was confirmed. Furthermore, the PLC program for seam tracking was used to confirm the validity of the application of tandem welding process according to the benefits of increased productivity, which is expected to contribute to national competitiveness.

• Journal of Welding and Joining
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• 제16권3호
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• pp.55-63
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• 1998

Among the position sensing methods available, the arc sensor which utilizes the electrical signal obtained from the welding arc itself is one of the most prevalently used methods, because it has an advantage that no particular sensing device is necessary and real-time sensing of a groove position is possible directly under the arc. The authors have already developed a seam tracking system that contains a new arc sensor algorithm, which uses the relative welding current variation according to the tip-to-workpiece distance in GMA welding. In this study a torch height control algorithm for automatic weld seam tracking was proposed for completing the previous system, which uses an on-off control technique. To implement the torch height control algorithm during weld seam tracking the system parameters which include 2nd averaging range, weighting factor for 2nd moving averaging, and Z-directional basic compensation distance were determined by experimental analysis. Finally the two different height control methods, one is simple on-off control and the other on-off control using a reference current value , were compared in their tracking abilities.

• Journal of Power Electronics
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• 제10권4호
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• pp.405-411
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• 2010

This paper proposes a novel tracking algorithm considering radiation to improve the power of a photovoltaic (PV) tracking system. The sensor method used in a conventional PV plant is unable to track the sun's exact position when the intensity of solar radiation is low. It also has the problem of malfunctions in the tracking system due to rapid changes in the climate. The program method generates power loss due to unnecessary operation of the tracking system because it is not adapted to various weather conditions. This tracking system does not increase the power above that of a power of tracking system fixed at a specific position due to these problems. To reduce the power loss, this paper proposes a novel control algorithm for a tracking system and proves the validity of the proposed control algorithm through a comparison with the conventional PV tracking method.

• 한국정보통신학회논문지
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• 제13권9호
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• pp.1913-1920
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• 2009

본 논문에서는 오류센서 보정 기능을 갖춘 태양광 조명용 정밀 태양 추적제어기 개발에 대하여 기술하였다. 태양 위치에 대한 광역범위 추적과 미소범위에서의 정밀추적 제어를 위하여 대범위 센서군과 소범위 센서군으로 나뉜 센서모듈을 개발하였다. 태양위치의 정밀 추적을 위하여 소범위 센서군의 응답특성을 분석하여 퍼지 제어엔진을 개발하였으며, 주축성분 분석법(Principal Component Analysis)을 적용하여 오류센서의 감별 및 복원을 하였다. 개발된 시스템의 실외 태양추적 실험을 통하여 본 연구의 유용성을 입증하였다.

• 제어로봇시스템학회논문지
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• 제16권3호
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• pp.239-244
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• 2010

This paper is to present map building of mobile robot using RFID (Radio Frequency Identification) technology and ultrasonic sensor. For mobile robot to perform map building, the mobile robot needs its localization and accurate driving in space. In this reason, firstly, kinematic modeling of mobile robot under non-holonomic constrains is introduced. Secondly, based on this modeling, a tracking controller is designed for tracking a given path based on backstepping method using Lyapunov function. The Lyapunov function is also introduced for proving the stability of the designed tracking controller. Thirdly, 2D map building is performed by RFID system, mobile robot system and ultrasonic sensors. The RFID mobile robot system is composed of DC motor, encoder, ultra sonic sensor, digital compass, RFID receiver and RFID antenna. Finally, the path tracking simulation results and map building experimental results are presented to show the effectiveness of the designed controller.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.452-456
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• 2002

자연환경에 노출된 센서기반의 제어장치는 센서오류가 발생하게 된다. 본 논문에서는 센서의 오류 보정기능을 갖는 고정밀 태양추적장치를 개발하였다. 다항식회귀분석 (Polynomial Regression)과 주성분 분석(Principal Component Analysis)을 응용하였으며 태양추적장치의 센서를 모델링하고 자체 진단하고 복구하는 방법을 연구하였다. 시스템의 정상동작시의 센서간의 상호관계를 이용한 모델링과 센서 표본값의 주분포 모델인 PCA 모델이 이루어지면 이를 기준으로 센서의 여러 가지 오류를 점검하고 오류센서 신호를 재건을 한다.