• 한국ITS학회 논문지
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• 제16권4호
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• pp.25-35
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• 2017

본 연구는 야간 시간대의 농기계 주행시 등화장치 장착여부에 따른 운전자의 야간시인성분석을 목표로 하였다. 야간시인성 분석을 위해 등화장치에 대한 휘도측정실험과 안구운동측정기기를 활용한 주시시간측정실험을 수행하였다. 휘도측정실험결과, 농기계와의 상대거리가 가까워지며 등화장치의 상태가 양호해질수록 휘도 값이 증가하는 것으로 나타났다. 또한, 주시시간측정실험에서는 주행속도에 상관없이 등화장치의 상태가 양호해질수록 농기계에 대한 총 주시시간이 증가하는 것으로 나타났다. 연구결과, 농기계에 등화장치를 장착할 경우 농기계에 대한 운전자의 야간 시인성이 향상되어 농기계사고의 예방에 큰 도움을 줄 수 있을 것으로 기대된다.

• 정보저장시스템학회논문집
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• 제8권2호
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• pp.67-71
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• 2012

Page-oriented holographic data storage (HDS) is very sensitive to the tilt error. Therefore, tilt error should be measured and compensated. Especially, mechanical tilt measurement method cannot cope with tilt error measurement because photopolymer medium has shrinkage problem. Therefore, the method to solve this problem is using the reconstructed image which can represent both tilt and shrinkage effect. In this paper, we suggest disc tilt measurement algorithm using image pattern of retrieval data.

• 제어로봇시스템학회논문지
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• 제12권4호
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• pp.395-399
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• 2006

A method to recognize unpaved road region using a 3D depth measurement system is proposed for mobile robots. For autonomous maneuvering of mobile robots, recognition of obstacles or recognition of road region is the essential task. In this paper, the 3D depth measurement system which is composed of a rotating mirror, a line laser and mono-camera is employed to detect depth, where the laser light is reflected by the mirror and projected to the scene objects whose locations are to be determined. The obtained depth information is converted into an image. Such depth images of the road region represent even and plane while that of off-road region is irregular or textured. Therefore, the problem falls into a texture identification problem. Road region is detected employing a simple spatial differentiation technique to detect the plain textured area. Identification results of the diverse situation of unpaved trail are included in this paper.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.471-475
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• 2003

This paper proposes a sensor-fusion technique where the data sets for the previous moments are properly transformed and fused into the current data sets to enable accurate measurement, such as, distance to an obstacle and location of the service robot itself. In the conventional fusion schemes, the measurement is dependent on the current data sets. As the results, more of sensors are required to measure a certain physical parameter or to improve the accuracy of the measurement. However, in this approach, instead of adding more sensors to the system, the temporal sequence of the data sets are stored and utilized for the measurement improvement. Theoretical basis is illustrated by examples and the effectiveness is proved through the simulations. Finally, the new space and time sensor fusion (STSF) scheme is applied to the control of a mobile robot in an unstructured environment as well as structured environment.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권1호
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• pp.23-28
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• 2004

This paper proposes a sensor-fusion technique where the data sets for the previous moments are properly transformed and fused into the current data sets to enable accurate measurement, such as, distance to an obstacle and location of the service robot itself. In the conventional fusion schemes, the measurement is dependent on the current data sets. As the results, more of sensors are required to measure a certain physical parameter or to improve the accuracy of the measurement. However, in this approach, instead of adding more sensors to the system, the temporal sequence of the data sets are stored and utilized for the measurement improvement. Theoretical basis is illustrated by examples and the effectiveness is proved through the simulations. Finally, the new space and time sensor fusion(STSF) scheme is applied to the control of a mobile robot in an unstructured environment as well as structured environment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.836-841
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• 2002

This paper is concerned with the development of remote control and measurement systems system using the internet. Recently, various techniques are developed based on the advance of the internet environment. In this study, we developed the remote control and measurement system using the internet server programming technique, stepper motor control and the data acquistion programming techniques. Hence, we can perform measurement and control remotely. The feasibility of the system is validated using the experimental setup. A personal computer is equipped with the stepping motor controller which control the weight and the A/D board which measures the strain of the beam, server program was then installed on the PC and can be accessed through internet.

• Journal of Biosystems Engineering
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• 제15권2호
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• pp.79-87
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• 1990

An automatic guidance system based upon two position-measurement systems was designed to record where the tractor traveled and to guide the tractor along the predetermined path. An algorithm, using the kinematic behavior of tractor movement, was developed to determine the steering angle to reduce lateral position error. The algorithm was based upon constant travel speed, constant steering rate, and zero slip angles of the tractor wheels. The algorithm was evaluated through use of computer simulation and verified in field experiments. Results showed that the distance interval between position measurements was an important factor in guidance system performance. The position-measurement error of the guidance system must be less than 5 cm to be acceptably precise for field operations. An algorithm based upon a variable steering rate might improve the stability of the guidance system. More accurate measurement of tractor position and yaw angle, and faster error processing are required to improve the field performance of the guidance system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1853-1857
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• 2005

In most of motor-driven motion control systems, an encoder is used to measure a position of the motor and the velocity information is obtained by measuring the position increment over a sampling period. The quantization effect due to limited resolution of the encoder induces some measurement errors, and consequently causes deterioration of the motion performance especially in low velocity. In this paper, we propose a gain-scheduled acceleration estimator which works in wider velocity range than the original acceleration estimator. We investigate and analyze characteristics of the velocity measurement mechanism which takes into account the quantization effect of the encoder. Next, we introduce the acceleration estimator and propose a gain-scheduled acceleration estimator. The bandwidth of the gain-scheduled acceleration estimator is automatically adjusted by the velocity command. Finally, its performance is evaluated by simulation and experiment, and the results are compared with those of a conventional method and the original acceleration estimator.

• 제어로봇시스템학회논문지
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• 제13권5호
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• pp.507-512
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• 2007

This paper presents a tracking filter with ship's motion compensation for a ship-borne radar tracking system. The ship's maneuver is described by displacement and rotational motions in the ship-centered east-north frame. The first order Taylor series approximation of the measurement error covariance of the converted measurement is derived in the ship-centered east-north frame. The ship's maneuver is compensated by incorporating the measurement error covariance of the converted measurement and displacement of the position state in the tracking filter. The simulation results via 500 Monte-Carlo runs show that the proposed method follows the target successfully and provides consistent tracking performance during ship's maneuvers while the conventional tracking filter without ship motion compensation fails to track during such periods.

• 제어로봇시스템학회논문지
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• 제16권12호
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• pp.1176-1181
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• 2010

This paper proposes three positioning algorithms using TOA measurements: 1) The well-known linearization method using Taylor series, 2) a modified Savarese method considering measurement noise, which does not need linearization, and 3) a modified Bancroft method where TOA measurements instead of pseudorange measurements are considered. Furthermore, through an error analysis, for Savarese method, divergence of altitude is anticipated if the transmitters are located at the same height. To prevent height divergence, the Savarese method is modified again for receivers which assumed moving on the even plane. Error analysis also shows the relationship between Bancroft and Savarese method. From the analysis it is expected that the performance of Savarese method is worse than Bancroft method because of error amplification during difference operation. Experiments using real TOA measurement from the time difference of ultra sound and RF validate the proposed methods and show that analysis is correct.