Nonlinear Estimation for Spacecraft Attitude using Decentralized Unscented Information Filter

Jonghee Bae,Youdan Kim 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

This paper presents a spacecraft attitude estimation algorithm using the unscented information filter. The objective of the proposed algorithm is to make the spacecraft attitude accurately estimate with low computational load. The main contribution of this study is to derive the unscented information filter for nonlinear spacecraft attitude dynamics and multiple sensor systems. For the multiple sensor estimation, the decentralized unscented information filter is used in this study. This filter provides accurate attitude estimation from the unscented filtering and less computational time from the information filtering. To verify the effectiveness of the proposed decentralized unscented information filter algorithm, numerical simulations are performed for a spacecraft system with three gyroscopes.

Design of Optimal Controllers for Spacecraft Formation Flying based on the Decentralized Approach

Jonghee Bae,Youdan Kim 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

Formation controller for multiple spacecrafts is designed based on a decentralized approach. The objective of the proposed controller is to make each spacecraft fly to the desired waypoints, while keeping the formation shape of multiple spacecrafts. To design the decentralized formation controller, the output feedback linearization technique using error functions for goal convergence and formation keeping is utilized for spacecraft dynamics. The primary contribution of this paper is to propose optimal controller for formation flying based on the decentralized approach. To design the optimal controller, eigenvalue assignment technique is used. To verify the effectiveness of the proposed controller, numerical simulations are performed for three-dimensional waypoint-passing missions of multiple spacecrafts.

Design of Optimal Controllers for Spacecraft Formation Flying Based on the Decentralized Approach

Jonghee Bae,Youdan Kim 한국항공우주학회 2009 International Journal of Aeronautical and Space Sc Vol.10 No.1

Formation controller for multiple spacecrafts is designed based on a decentralized approach. The objective of the proposed controller is to make each spacecraft fly to the desired waypoints, while keeping the formation shape of multiple spacecrafts. To design the decentralized formation controller, the output feedback linearization technique using error functions for goal convergence and formation keeping is utilized for spacecraft dynamics. The primary contribution of this paper is to proposed optimal controller for formation flying based on the decentralized approach. To design the optimal controller, eigenvalue assignment technique is used. To verify the effectiveness of the proposed controller, numerical simulations are performed for three-dimensional waypoint-passing missions of multiple spacecrafts.

Attitude Estimation for Satellite Fault Tolerant System Using Federated Unscented Kalman Filter

Jonghee Bae,Youdan Kim 한국항공우주학회 2010 International Journal of Aeronautical and Space Sc Vol.11 No.2

We propose a spacecraft attitude estimation algorithm using a federated unscented Kalman filter. For nonlinear spacecraft systems, the unscented Kalman filter provides better performance than the extended Kalman filter. Also, the decentralized scheme in the federated configuration makes a robust system because a sensor fault can be easily detected and isolated by the fault detection and isolation algorithm through a sensitivity factor. Using the proposed algorithm, the spacecraft can continuously perform a given mission despite navigation sensor faults. Numerical simulation is performed to verify the performance of the proposed attitude estimation algorithm.

Adaptive controller design for spacecraft formation flying using sliding mode controller and neural networks

Bae, Jonghee,Kim, Youdan Elsevier 2012 Journal of the Franklin Institute Vol.349 No.2

<P><B>Abstract</B></P><P>A spacecraft formation flying controller is designed using a sliding mode control scheme with the adaptive gain and neural networks. Six-degree-of-freedom spacecraft nonlinear dynamic model is considered, and a leader–follower approach is adopted for efficient spacecraft formation flying. Uncertainties and external disturbances have effects on controlling the relative position and attitude of the spacecrafts in the formation. The main benefit of the sliding mode control is the robust stability of the closed-loop system. To improve the performance of the sliding mode control, an adaptive controller based on neural networks is used to compensate for the effects of the modeling error, external disturbance, and nonlinearities. The stability analysis of the closed-loop system is performed using the Lyapunov stability theorem. A spacecraft model with 12 thrusts as actuators is considered for controlling the relative position and attitude of the follower spacecraft. Numerical simulation results are presented to show the effectiveness of the proposed controller.</P>

Initial Error Dispersion and Midcourse Correction Maneuver Analysis of the Lunar Orbiter

Jonghee Bae,송영주,Young-Rok Kim,Bang-Yeop Kim 한국항공우주학회 2018 International Journal of Aeronautical and Space Sc Vol.19 No.4

The preliminary error analysis is performed to design the midcourse correction (MCC) maneuver of the lunar orbiter. During the trans-lunar trajectory, the lunar orbiter will perform several MCC maneuvers using the on-board propulsion system. The objectives of these maneuvers are to remove the deviation from the nominal trajectory by the injection error of the launch vehicle and to achieve the high accuracy for the lunar orbit insertion (LOI). To design the MCC maneuver, it is required to analyze the dispersion of the trans-lunar injection (TLI) error from the launch vehicle. In addition, the MCC maneuver epoch is also considered to design the MCC maneuver, which is an essential factor to analyze the MCC maneuver. To investigate the effects of the TLI uncertainty and the MCC maneuver epoch on the MCC maneuver, the Monte Carlo simulation is performed for the statistical analysis. The numerical simulation results and analysis provide a guideline to design the trans-lunar trajectory using the MCC maneuver in the presence of various error sources in the preliminary design phase.

Spacecraft Formation Reconfiguration using Impulsive Control Input

Jonghee Bae,Youdan Kim 한국항공우주학회 2013 International Journal of Aeronautical and Space Sc Vol.14 No.2

This paper presents formation reconfiguration using impulsive control input for spacecraft formation flying. Spacecraft in a formation should change the formation size and/or geometry according to the mission requirements and space environment. To modify the formation radius and geometry with respect to the leader spacecraft, the follower spacecraft generates additional control inputs; the two impulsive control inputs are general control type of the spacecraft system. For the impulsive control input, Lambert’s problem is modified to construct the transfer orbit in relative motion, given two position vectors at the initial and final time. Moreover, the numerical simulation results show the transfer trajectories to resize the formation radius in the radial/along-track plane formation and in the along-track/cross-track plane formation. In addition, the maneuver characteristics are described by comparing the differential orbital elements between the reference orbit and transfer orbit in the radial/along-track plane formation and along-track/cross-track plane formation.

Spacecraft Formation Reconfiguration using Impulsive Control Input

Bae, Jonghee,Kim, Youdan The Korean Society for Aeronautical and Space Scie 2013 International Journal of Aeronautical and Space Sc Vol.14 No.2

This paper presents formation reconfiguration using impulsive control input for spacecraft formation flying. Spacecraft in a formation should change the formation size and/or geometry according to the mission requirements and space environment. To modify the formation radius and geometry with respect to the leader spacecraft, the follower spacecraft generates additional control inputs; the two impulsive control inputs are general control type of the spacecraft system. For the impulsive control input, Lambert's problem is modified to construct the transfer orbit in relative motion, given two position vectors at the initial and final time. Moreover, the numerical simulation results show the transfer trajectories to resize the formation radius in the radial/along-track plane formation and in the along-track/cross-track plane formation. In addition, the maneuver characteristics are described by comparing the differential orbital elements between the reference orbit and transfer orbit in the radial/along-track plane formation and along-track/cross-track plane formation.

시험용 달 궤도선의 WOL에 따른 달 임무궤도 고도 유지를 위한 궤도조정 기동 분석

배종희(Jonghee Bae),송영주(Young-Joo Song),김영록(Young-Rok Kim),김방엽(Bangyeop Kim) 한국항공우주학회 2017 한국항공우주학회 학술발표회 논문집 Vol.2017 No.11

예비교사의 눈으로 작은 학교 체육수업 바라보기

배종희(Bae, JongHee) 학습자중심교과교육학회 2014 학습자중심교과교육연구 Vol.14 No.12

이 연구는 예비교사가 작은 학교의 체육수업에서 보는 것, 생각하는 것, 느끼는것을 알아보는데 목적을 두고 있다. 이 목적을 위해 D교육대학교의 농어촌 실습에참여한 3학년 학생 5명을 연구참여자로 하였다. 실습에 참여한 3학년 학생 60여명의 수업일지를 문서자료로 수집하였으며 이를 바탕으로 5명의 연구참여자와 개별 및 전자우편을 활용한 심층면담을 하였다. 수집된 문서 및 면담자료는 텍스트 파일로변환된 후 NVivo 10.0 프로그램을 활용한 귀납적 과정을 거쳐 분석되었다. 연구결 과, 체육수업 환경, 체육수업의 실제, 체육 수업자, 작은 학교를 위한 배려 등 4가지의 주제로 나타났다. 체육수업 환경에서는 수업이 이루어지는 장소, 체육자료실, 학교체육복에 관한 내용이 주를 이루었고 체육수업의 실제는 규칙변형과 교사참여, 학 년성 없는 경쟁활동, 합동체육에 관한 것이었다. 체육 수업자는 체육전담교사, 다른교과에 보직교사를 겸하는 체육전담교사, 무용 및 스포츠 강사에 관한 것이며, 작은학교를 위한 배려로 업무의 경감과 교원의 확충, 다양한 체육자료 및 작은 학교 학 생들이 모일 수 있는 환경을 들었다. 이러한 결과를 바탕으로 작은 학교를 위한 교과서나 교사용 지도서의 개발이 필요하며, 학생들이 체육 수업을 위해서 모일 수 있는 정책적 지원이 절실함을 알 수 있다. The purposes of this study was to investigate the thimg which pre-service teachers saw, thought, and felt through physical education in small elementary school. For this purpose, participants consisted of five pre-service teachers (3 male, 2 female) who has participated educational practice in rural elementary school. Teaching practice diaries of 60 pre-teachers were collected by documentation. Based on this, Data were collected through in-depth interviews with participants. The collected data were analyzed by process of transcription, coding, and theme formation with NVivo 10.0 program. Results indicated the four theme including physicl education environment , actual physical education , PE teahers , caring for a small school . Physicl education environment were divided into physical education places , physical resources , uniforms for PE . Actual physical education included rule changes and teacher participation’, ‘competitive activity without grade , joint PE . PE teacher were specialist teacher of PE , PE and director teacher , dance and sports instructor . Caring for a small school were relief work and teachers expansion , a variety of physical education resources , environment where students can gather . Based on these findings, we need to develop PE textbook or teacher instuctions for small Elementary school and to propose a policy that many students in other small school can meet in physical education.