• Title/Summary/Keyword: Ground Alignment

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LQG/LTR controller design for ground alignment of intertial platform

  • Kim, Jong-Kwon;Shin, Yong-Jin;Cho, Kyeum-Rae
    • 제어로봇시스템학회:학술대회논문집
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    • 1995.10a
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    • pp.372-375
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    • 1995
  • The LQG/LTR controller design procedure for ground alignment of inertial platform is accomplished. Due to the alignment system dynamics, LQG/LTR controller is proposed to overcome both singular problem and nonsquare problem. To show the effectiveness of this control system, computer simulation was performed under the assumption of random sway motion.

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The Thrust Axis Alignment of Kick Motor for Ground Firing Test (지상 연소 시험을 위한 킥 모터의 추력 축 정렬)

  • Jung, Dong-Ho;Kim, Ji-Hoon;Lee, Han-Ju;Oh, Seung-Hyub
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.389-392
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    • 2008
  • The thrust axis alignment of the launch vehicle is very important because of the misalignment causes the unstable attitude control and results in mission failure. Generally, optical methods such as digital theodolite and laser tracker and mechanical method such as turn table method are used to thrust axis alignment. This article deals with the simple method of thrust axis alignment of Kick Motor.

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A Study on Spacecraft Alignment Measurement with Theodolite (데오도라이트를 이용한 위성체 얼라인먼트 측정에 관한 연구)

  • 윤용식;이동주
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.6
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    • pp.64-70
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    • 2003
  • A measurement of spacecraft alignment is an important process of spacecraft assembly, integration and test because it is necessary that a ground station controls the precise positions of on-orbit spacecraft by using the alignment data of attitude orbit control sensors(AOCS) on spacecraft. In addition, accuracy of spacecraft alignment requirement is about $0.1^{\circ}$~$0.7^{\circ}$. The spacecraft alignment is measured by autocollimation of theodolite. This paper describes the measurement principle and method of spacecraft alignment. The result shows that all of the AOCS on the spacecraft are aligned within the tolerance required through the alignment measurement.

A Method of Tunnel Information Modeling Reflecting Curved Alignment and Model-based Information Management using IFC Data Schema (곡선 선형을 반영한 터널 정보모델링 및 IFC 데이터 스키마를 활용한 모델기반의 정보관리 방안)

  • Jang, Seong Geun;Kwon, Tae Ho;Park, Sang I.;Lee, Sang-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.6
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    • pp.549-557
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    • 2017
  • In order to improve the productivity in the civil engineering field, efforts to apply BIM have been continuing, however, research on information modeling of tunnel structures considering alignment is insufficient. In this study, we proposed the method of building tunnel models reflecting curved alignment by transferring point data to BIM Authoring Tools(BAT) through discretization of alignment in Alignment-centered Modeling Tools(AMT). IFC data schema was derived to consider the physical and spatial elements of tunnel structures and alignment and IFC-based information management for tunnel alignment, tunnel structures and ground conditions was possible by referring to the extended data schema and including meanings in IFC property sets. The ratings for ground condition in Rock Mass Rating(RMR) and Q-system was automatically derived by using generated information model according to the proposed method.

Transformation of Forest Road Fill-slope Alignment by Elapsed Years and Physical Properties (임도시공경과년수 및 물리적 인자에 따른 성토사면 선형의 변화)

  • Choi, Yeon Ho;Lee, Joon Woo;Kim, Myeong Jun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.3 no.2
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    • pp.47-52
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    • 2000
  • This study was carried out to analyze the effects of elapsed years and physical properties on fill-slope alignment of forest road. For the study, 21 forest roads in Puy$\check{o}$-gun and Asan-shi of Chungchungnam-do were selected and fifteen factors that might influence on fill-slope alignment were analyzed. The major forms of alignment of the fill-slope in the time of construction were concave and compound. But, with the elapsed years, the concave and compound forms have decreased and linear and convex forms have increased. And fill-slope alignment was strongly related with fill-slope distance, fill-slope gradient and ground gradient among the physical properties.

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Mathematical Modeling for the Physical Relationship between the Coordinate Systems of IMU/GPS and Camera (IMU/GPS와 카메라 좌표계간의 물리적 관계를 위한 수학적 모델링)

  • Chon, Jae-Choon;Shibasaki, R.
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.6
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    • pp.611-616
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    • 2008
  • When extracting geo-referenced 3D data from cameras mounted on Mobile Mapping Systems, one of important properties for accuracy of extracted data is the alignment of the relative translation(lever-arm) and rotation(bore-sight) between the coordinate systems of Inertial Measurement Unit(IMU)/Ground Positioning System(GPS) and cameras. Since the conventional method calculates absolute camera orientation using ground control points (GCP), the alignment is determined in one Coordinated System (GPS Coordinated System). It basically require GCP. We proposed a mathematical model for the alignment using the initially uncoupled data of cameras and IMU/GPS without GCPs.

A Study of Spacecraft Alignment Measurement with Theodolite (데오도라이트를 이용한 위성체 얼라인먼트 측정에 관한 연구)

  • Yun,Yong-Sik;Park,Hong-Cheol;Son,Yeong-Seon;Choe,Jong-Yeon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.10
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    • pp.105-111
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    • 2003
  • A measurement of spacecraft alignment is an important process of spacecraft assembly, integration and test. Because, it is necessary that a operator of a ground station controls the precise positions of on-orbit spacecraft by using the alignment data of attitude orbit control sensors(AOCS) on spacecraft. And, an accuracy of spacecraft alignment requirement is about $0.1^{\circ}{\sim}0.7^{\circ}$. A spacecraft alignment is measured by autocollimation of theodolite. This paper describes the measurement principle and method of spacecraft alignment. The result shows that all the AOCS on the spacecraft are aligned within the tolerance required through the alignment measurement.

A Study on Satellite Alignment Measurements Accuracy Improvement (인공위성 정렬 측정 정확도 향상을 위한 연구)

  • Choi, Jung Su;Kim, In-Gul
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.12
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    • pp.987-995
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    • 2020
  • Accurate alignment between high-performance payloads and attitude control sensors is essential factor to guarantee accurate attitude orientation and high pointing stability of the satellite. Space craft developers often use theodolite measurement system for satellite alignment during ground AIT(Assembly Integration and Test) phase. When measuring theodolite, errors may occur due to line of sight error, tilting axis error, vertical index error, and vertical axis error. In addition, errors that can occur during alignment measurements with multiple theodolites are analyzed through the alignment cube measurements test. Based on the alignment cube measurements test, a technical method that can improve the alignment measurement accuracy was suggested and it's measurements results satisfied the satellite design requirements.

The Effect of Genu Valgum on the Body Mass Index, Moment of Lower Limb Joints, Ground Reaction Force (신체질량지수, 하지관절의 모멘트, 지면반발력이 무릎외반슬에 미치는 영향)

  • Lee, Yong-Seon
    • Korean Journal of Applied Biomechanics
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    • v.25 no.3
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    • pp.257-263
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    • 2015
  • Objective : The purpose of this study was to investigate the effect of genu valgum on the body mass index, movement of lower limb joints, and ground reaction force. Methods : Gait patterns of 30 college students with genu valgum were analyzed and the static Q angle of the femur was measured for selecting genu valgum of the subjects. To analyze the kinetic changes during walking, the six-camera Vicon MX motion analysis system was used. The subjects were asked to walk 12 meters using the more comfortable walking method for walking. After they walked 12 meters more than 10 times, their most natural walking patterns were chosen three times and analyzed. Results : As a result of measuring a relationship between genu valgum and Q-angle, as the Q-angle increases, it showed a genu valgum also increased. Body Mass Index showed a significant difference between the groups was higher in the genu valgum group.(p<.001). The analysis result showed that genu valgum had a significant effect on the internal rotation moment in the hip joint(p<.05). Also, genu valgum had a significant effect on the internal rotation moment of the knee joint(p<.05). The comparative analysis of the Medial-Lateral ground reaction force in the genu valgum group showed a tendency to increase the medial ground reaction force(p<.05). The vertical ground reaction forces of the middle of the stance phase(Fz0) showed a significant increase in genu valgum group(p<.05), in particular the results showed a decrease in the early stance phase(p<.001). Conclusion : In conclusion, the change in body mass is considered to be made by proactive regular exercise for improvement of the genu valgum. In addition, the prevention of the deformation caused by secondary of the genu valgum in this study may be used as an indicator of the position alignment rehabilitation for structural and functional improvements. Applying a therapeutic exercise program for the next lap will require changes in posture alignment.

Applications of high resolution satellite image in road alignment design (도로의 최적노선 선정시 고해상도 위성영상의 활용 방안)

  • 박병욱;최윤수;안기원;강의성
    • Spatial Information Research
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    • v.10 no.3
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    • pp.469-480
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    • 2002
  • Nowadays, digital maps of 1:5,000 scale are used to plan and review far road alignment design. However, the updating and modifying period of digital maps is not so harmonious as topographical changes caused by rapid developments can be reflected in digital maps, the different areas between real surface and digital map can be found easily. This research is aimed to suggest that the use of high resolution satellite image is effective way to get latest topographical information for road alignment design about wide region. IKONOS satellite images were geometrically corrected, and the road alignment data previously designed by traditional procedure were overlapped on the satellite images. As a result, the satellite image maps clearly described wrong road alignment, and modification of road alignment could be accomplished adequately By these procedures, road alignment design was Improved in quality, and could be reasonable and economic design to prevent modification that would be happened in the next step of practical plan. For the geometric correction method of IKONOS images, Thin Plate Spline(TPS) transformation with large number of ground control points, as well as ortho rectification, was effective.

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