• Title/Summary/Keyword: Pointing

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Gyroless Yaw Angle Compassing of Earth-Pointing Spacecraft Using Magnetic Sensor

  • Lee, Seon-Ho;Ahn, Hyo-Sung;Rhee, Seung-Wu
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.2055-2058
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    • 2004
  • This paper formulates a yaw angle determination algorithm for earth-point satellite. The algorithm based on vector observation, is implemented with the limited vector measurements. The proposed algorithm doesn't require gyro measurement data but magnetic sensor measurement data. In order to confirm the usefulness of the proposed method, we investigate the simulated telemetry data of the KOMPSAT-2, a satellite that is scheduled to be launched into a 685km altitude sun synchronous circular orbit in 2005.

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A Development of Numerical Method for Bifurcational Bucklingof the Spatial Structures (공간구조물의 분기좌굴해석이론의 개발)

  • Lee, Kyung-Soo;Han, Sang-Eul;Lee, Jae-Young;Kim, Man-Jung
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2009.04a
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    • pp.496-499
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    • 2009
  • 본 논문은 기하학적 비선형성을 가진 보존적 단일 하중 매개변수의 탄성 상태 공간구조의 분기이론에 관한 수치 해석적 기본 방법 및 경로 추적, pin-pointing, 경로 전환을 기술하고 있다. 비선형 탄성 불안정 상태는 극한점과 분기점으로 분류될 수 있으며, 평형경로상의 평형점의 계산 및 평형경로상의 특이점을 찾기 위한 pin-pointing 반복계산을 수행하는 일반적인 비선형 수치해석법으로 극한점을 계산할 수 있다. 그러나 분기좌굴 해석을 위해서는 좌굴 후 분기경로의 추적을 위한 분기경로 전환 알고리즘이 추가적으로 필요하다. 본문에서는 에너지이론에 기초한 일반 탄성안정이론을 소개하고, 평형경로 추적, 분기 좌굴점을 찾기 위한 직접법과 분기경로 전환에 관한 이론을 전개한다. 분기좌굴 해석예제로 트러스로 이루어진 스타돔, 핀지지의 평면아치, 평면프레임, 3차원 공간프레임의 분기좌굴 해석을 수행하여 본문에서 제시한 수치해석법의 정확성 및 실용성을 검증한다.

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Infrared Sensitive Camera Based Finger-Friendly Interactive Display System

  • Ghimire, Deepak;Kim, Joon-Cheol;Lee, Kwang-Jae;Lee, Joon-Whoan
    • International Journal of Contents
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    • v.6 no.4
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    • pp.49-56
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    • 2010
  • In this paper we present a system that enables the user to interact with large display system even without touching the screen. With two infrared sensitive cameras mounted on the bottom left and bottom right of the display system pointing upwards, the user fingertip position on the selected region of interest of each camera view is found using vertical intensity profile of the background subtracted image. The position of the finger in two images of left and right camera is mapped to the display screen coordinate by using pre-determined matrices, which are calculated by interpolating samples of user finger position on the images taken by pointing finger over some known coordinate position of the display system. The screen is then manipulated according to the calculated position and depth of the fingertip with respect to the display system. Experimental results demonstrate an efficient, robust and stable human computer interaction.

PC Based Drawing Using Wii Remote (Wii Remote를 이용한 PC 기반 드로잉)

  • Oh, eun-byeol;Ryoo, seung-taek
    • Proceedings of the Korea Contents Association Conference
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    • 2009.05a
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    • pp.70-73
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    • 2009
  • Wii Remote is the primary controller for Nintendo's Wii console. A main feature of the Wii Remote is its motion sensing capability, which allows the user to interact with and manipulate items on screen via movement and pointing through the use of accelerometer and optical sensor technology. Another feature is its expandability through the use of Bluetooth. In this Study, use of motion sensors and Bluetooth capabilities. The user holding the remote on the screen, pointing to receive information about the values of the coordinates on the screen indicating the drawing of the implementation.

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APDE(Antenna Positioning Drive Electronics) Design for MSC (Multi-Spectral Camera)

  • Kong Jong-Pil;Heo Haeng-Pal;Kim YoungSun;Park Jong-Euk;Youn Heong-Sik
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.440-443
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    • 2004
  • As a main management unit of MSC, PMU controls the MSC payload operation by issuing commands to other subunit and PMU internal modules. One of these main control functions is to drive the APS(Antenna Pointing System) when APS motion is required. For this purpose, SBC(Single Board Computer) for calculating motor commands and APDE for driving APM(Antenna Pointing Mechanism) by PWM signal operate inside PUM. In this paper, details on APDE design shall be described such as electronic board architecture, primary and redundant design concept, Cross-Strap, FPGA contents and latch-up immune concept, etc., which shall show good practices of electronic board design for space program.

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Fuzzy Controller Design for Fuel Saving in Sun Point Mode for KOMPSAT-2

  • Choi, Hong-Taek;Oh, Shi-Hwan;Rhee, Seung-Wu
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2108-2111
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    • 2005
  • The mission life of a satellite determines the amount of fuel required on-board, while the total mass requirement limits the fuel to be loaded. Hence, for the design of thruster control loop, not only the satellite pointing accuracy but the saving of fuel is to be considered. In this paper, a two-step fuzzy controller is proposed for the thruster control loop to save fuel consumption. This approach combines requirements for pointing control accuracy with minimum fuel consumption into a fuzzy controller design. To demonstrate this approach, we have designed a fuzzy controller for the Sun point Mode of KOMPSAT-2. The performance of this fuzzy controller design is compared with that of PD controller used for KOMPSAT-2.

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Performance Evaluation of Hybrid Vibration Isolator using FxLMS algorithm (FxLMS 알고리즘을 적용한 하이브리드 미소진동 절연장치의 절연성능 평가)

  • Lee, Dae-Oen;Park, Geeyong;Han, Jae-Hung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.173-174
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    • 2014
  • Vibration disturbances generated by reaction wheels may cause serious problems in high precision pointing spacecraft missions. Implementation of vibration isolator is a practical solution to meet the high pointing stability requirement placed on precision payloads. In this paper, development of hybrid vibration isolator that combines passive and active component is described. Vibration isolation performance of the developed isolator is evaluated using reaction wheel disturbance model. Hybrid isolation results obtained using FxLMS algorithm show clear improvement compared to the results obtained using only passive means.

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Kalman Filtering for Spacecraft Attitude Estimation by Low-Cost Sensors

  • Lee, Henzeh;Choi, Yoon-Hyuk;Bang, Hyo-Choong;Park, Jong-Oh
    • International Journal of Aeronautical and Space Sciences
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    • v.9 no.1
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    • pp.147-161
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    • 2008
  • In this paper, fine attitude estimation using low-cost sensors for attitude pointing missions of spacecraft is addressed. Attitude kinematics and gyro models including bias models are in general utilized to estimate spacecraft attitude and angular rate. However, a linearized model and a transition matrix are derived in this paper from nonlinear spacecraft dynamics with external disturbances. A Kalman filtering technique is applied and offers relatively high estimation accuracy under dynamic uncertainties. The proposed approach is demonstrated using numerical simulations.