• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.3
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• pp.394-399
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• 2010

This paper presents to study the velocity control method of AGV for heavy material transport. Generally, in the industries, fork-type AGV using path tracking requires high stop-precision with performing operations for 20 hours. To obtain the high stop-precision of AGV for heavy material transport, AGV requires driving technic during low speed. Hence, we use encoder with keeping the speed of AGV and study the velocity control method to improve for the stop-precision of AGV. To experiment the proposed the velocity control method, we performed the experiments engaging the pallet located 4m in front of the AGV. In the experimental result, the maximum error of stop-precision was less than 18.64mm, and we verified that the proposed method is able to control stable.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.131-146
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• 2017

Unlike in the past based on autonomous vehicle development sensor, In recent years, research has been conducted using external data such as LDM to compensate for the disadvantages of sensors. So, this study suggested the construction method of static map that provides road information for autonomous driving of vehicles as LDM - based information. In other to suggest, after review LDM's ISO 14296 and data specification and map of precise roda map of NGII, we had confirmed the correspondence wiht the international standard of NGII specification. As a result of the review, it is relatively good in terms of provided data and information, but the road structure expression is partially incompatible with the international standard. AS it is necessary to supplement about currently specification and method and suggest, this study had suggested ways to supplement the insuficient and to express the road structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.1955-1960
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• 2010

A performance of CNC 3-axis pipe profile-cutting machine we developed was evaluated by measuring and verifying a positioning accuracy of its feeding unit and a cutting shape accuracy of pipe workpiece. The positioning accuracy was verified by comparing moving distance actuated by PLC motion controller with actual one measured by a laser interferometer. The cutting shape accuracy was also verified by comparing a cutting shape obtained through scanning and 3D modeling the pipe workpiece with that through CL data.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.5
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• pp.315-321
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• 2009

Remote water meter monitoring is essential in U-city applications, whoγe digital water meter is a key component. While there are several kinds of water meters, the way to use has sensors has the merit of better preciseness, but the drawback of more power consumption. In this paper, we suggest an advanced sensing algorithm to diminish the power consumption while keeping the quality of preciseness. Our approach is to use less precise hall sensor for detecting the start of water impeller rotation with lower power consumption. During the rotation, a high precision hall sensor is used to meter the amount of water consumption. Our algorithm is analyzed to get 2 times lower power consumption than the previous algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2B
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• pp.107-116
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• 2006

In this paper, we propose a Sensing Resolution-based Grouping(SRG) protocol for wireless sensor networks. SRG is intended for meeting the application's sensing objectives, where sensor nodes are densely deployed and have the determinate accuracy requirement. The primary contribution of this paper is active group header node selection and round-robin procedure, which increase the sensing accuracy and evenly distribute the node energy consumption. The second contribution is use of energy efficient intermediate node selection by considering group size and energy consumption. We present the design principle of SRG and provide simulation results.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.5
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• pp.186-201
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• 2021

As autonomous driving technology advances, the accuracy of the vehicle position is important for recognizing the environments around driving. Map-matching localization techniques based on high definition (HD) maps have been studied to improve localization accuracy. Because conventional map-matching techniques estimate the vehicle position based on an HD map reference dataset representing the center of the lane, the estimated position does not reflect the deviation of the lateral distance within the lane. Therefore, this paper proposes a localization system based on the reference lateral position dataset extracted using image processing and HD maps. Image processing extracts the driving lane number using inverse perspective mapping, multi-lane detection, and yellow central lane detection. The lane departure method estimates the lateral distance within the lane. To collect the lateral position reference dataset, this approach involves two processes: (i) the link and lane node is extracted based on the lane number obtained from image processing and position from GNSS/INS, and (ii) the lateral position is matched with the extracted link and lane node. Finally, the vehicle position is estimated by matching the GNSS/INS local trajectory and the reference lateral position dataset. The performance of the proposed method was evaluated by experiments carried out on a highway environment. It was confirmed that the proposed method improves accuracy by about 1.0m compared to GNSS / INS, and improves accuracy by about 0.04m~0.21m (7~30%) for each section when compared with the existing lane-level map matching method.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.2
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• pp.78-90
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• 2021

In order to construct a precision geoid, it has been diversified into land, sea, aviation, and satellite gravity measurement methods, and measurement technology has developed, making it possible to secure high-resolution, high-precision gravity data. The construction of precision geoids can be fast and conveniently decided through GNSS surveys without separate leveling, and since 2014, the National Geographic Information Institute has been developing a hybrid geoid model to improve the accuracy of height surveying based on GNSS. In this study, the results of the GNSS height measurement were compared and analyzed choosing existing public reference points to verify the GNSS height measurement of public surveys. Experiments are conducted with GNSS height measurements and analyzed precision for public reference points on coastal, border, and mountainous terrain presented as low-precision areas or expected-to-be low-precision in research reports. To verify the GNSS height measurement, the GNSS ellipsoid height of the surrounding integrated datum to be used as a base point for the GNSS height measurement at the public datum. Based on the checked integrated datum, the GNSS ellipsoid of the public datum was calculated, and the elevation was calculated using the KNGeoid18 model and compared with the results of the direct level measurement elevation. The analysis showed that the results of GNSS height measurement at public reference points in the coastal, border, and mountainous areas were satisfied with the accuracy of public level measurement in grades 3 and 4. Through this study, GNSS level measurement can be used more efficiently than existing direct level measurements depending on the height accuracy required by users, and KNGeoids 18 can also be used in various fields such as autonomous vehicles and unmanned aerial vehicles.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.5
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• pp.652-658
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• 2021

When acquiring a point cloud using a 3D scanner, a registration process of making the acquired data based on each local coordinate into one data with a unified world coordinate system is required. Its process is difficult to obtain a satisfactory result with only one execution, and it is repeated several times to increase the registration precision. The criterion for determining the registration accuracy is an important factor. The previous methods for determining the accuracy of registration have a limitation in that the judgment may be ambiguous in some cases, and different results may be produced each time depending on the characteristics of the point cloud. Therefore, to calculate the accuracy of registration more precisely, I propose a method using the average distance value of the point group for the entire points rather than the corresponding points used in the registration. When this method is used, it is possible to determine the registration accuracy more reliably than the conventional methods.

• Transportation Technology and Policy
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• v.13 no.4
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• pp.42-50
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• 2016

• The Journal of the Korea Contents Association
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• v.15 no.10
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• pp.587-596
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• 2015

3D scanners are applied to many industries, such as manufacturing, construction, and shipbuilding. Recently, 3D scanner is used in 3D imaging of worksite in order to control and guide earthmoving heavy equipments, which provides basic information for intelligent excavation. This study compares the accuracy and productivity between total stations and high-resolution 3D scanners. The analysis results show that 3D scanner has high accurate rate of greater than 99 percent and has low error rate of less than 2.0mm compared to total stations. In terms of productivity, 3D scanner saves 71 percent of measuring time compared to the total station. This study confirms that 3D scanner can measure the earthwork sites with high accuracy and better productivity.