Department News
Control and Experiment of Tethered Formation Flying Satellites for the NASA Dist
Seminar Date
2005-01-24
Author
지국현
Date
2005-01-24
Views
2009
1. 제 목 : Control and Experiment of Tethered Formation Flying Satellites for the NASA Distributed Aperture Systems.
2. 연 사 : 정순조 (Research Assistant, Space Systems Laboratory, MIT)
3. 일 시 : 2005년 1월 28일 (금) 16:00 - 17:00
4. 장 소 : 서울대학교 신공학관(301동) 117호
5. 내 용 :
This talk elaborates on theory and experiment of completely decentralized estimator and controller for the future space-borne tethered interferometers. The nonlinear equations of multi-vehicle tethered spacecraft system are derived by Lagrange equations and decoupling method. The preliminary analysis predicts unstable dynamics depending on the direction of the tether motor. The controllability analysis indicates that both array resizing and spin-up are fully controllable only by the reaction wheels and the tether motor, thereby eliminating the need for thrusters. Linear and nonlinear decentralized control techniques have been implemented into the tethered SPHERES testbed, and tested at the NASA Marshall Space Flight Center (MSFC)'s flat floor facility using two and three SPHERES configurations. The performance of the LQR controller gain-scheduled over the operating angular rate using only reaction wheels was somewhat unsatisfactory resulting in a large pendulum mode angle.
The nonlinear control using feedback linearization technique performed well in both two SPHERES in-line configuration and three triangular configuration with varying the tether length. The relative metrology system, using the pseudo-GPS system and the inertial sensor as well as the decentralized nonlinear estimator, is developed to provide necessary state information. The other formation flying testbed platforms at the MIT Space Systems Laboratories (MIT-SSL) are also briefly introduced: ARGOS- a ground-based satellite testbed with three aperture inteferometric array on the spherical air-bearing; EMFF- an electromagnetically controlled array of formation flying satellites using superconducting magnets.
6. 약 력
1998, KAIST, B.S.
2002, MIT, S.M.
2002.9-2003.1, Research Engineer, NOAO, Tucson AZ
2004.6-2004.9, Fulltime Consultant, Mide Tech. Corp., Medford MA
2003.2-present, Ph.D. Student, MIT Aero/Astro Dept.
7. 문 의 : 기계항공공학부 신상준 교수 (☏ 880-1642)
2. 연 사 : 정순조 (Research Assistant, Space Systems Laboratory, MIT)
3. 일 시 : 2005년 1월 28일 (금) 16:00 - 17:00
4. 장 소 : 서울대학교 신공학관(301동) 117호
5. 내 용 :
This talk elaborates on theory and experiment of completely decentralized estimator and controller for the future space-borne tethered interferometers. The nonlinear equations of multi-vehicle tethered spacecraft system are derived by Lagrange equations and decoupling method. The preliminary analysis predicts unstable dynamics depending on the direction of the tether motor. The controllability analysis indicates that both array resizing and spin-up are fully controllable only by the reaction wheels and the tether motor, thereby eliminating the need for thrusters. Linear and nonlinear decentralized control techniques have been implemented into the tethered SPHERES testbed, and tested at the NASA Marshall Space Flight Center (MSFC)'s flat floor facility using two and three SPHERES configurations. The performance of the LQR controller gain-scheduled over the operating angular rate using only reaction wheels was somewhat unsatisfactory resulting in a large pendulum mode angle.
The nonlinear control using feedback linearization technique performed well in both two SPHERES in-line configuration and three triangular configuration with varying the tether length. The relative metrology system, using the pseudo-GPS system and the inertial sensor as well as the decentralized nonlinear estimator, is developed to provide necessary state information. The other formation flying testbed platforms at the MIT Space Systems Laboratories (MIT-SSL) are also briefly introduced: ARGOS- a ground-based satellite testbed with three aperture inteferometric array on the spherical air-bearing; EMFF- an electromagnetically controlled array of formation flying satellites using superconducting magnets.
6. 약 력
1998, KAIST, B.S.
2002, MIT, S.M.
2002.9-2003.1, Research Engineer, NOAO, Tucson AZ
2004.6-2004.9, Fulltime Consultant, Mide Tech. Corp., Medford MA
2003.2-present, Ph.D. Student, MIT Aero/Astro Dept.
7. 문 의 : 기계항공공학부 신상준 교수 (☏ 880-1642)
