Stochastic performance analysis and staged control system designs for space based interferometers

Space based interferometry missions have the potential to revolutionize astrometry, providing observations of unprecedented accuracy. Realizing the full potential of these interferometers poses several significant technological challenges. One of the most significant challenges is regulating the light pathlength, from the collecting telescopes to the combining instrument, with nanometer accuracy, despite the presence of vibration induced by internal and external disturbance sources. Due to the wide range of disturbances that act on the optical instruments, a single actuator with simultaneously large control authority and high bandwidth would be necessary to meet the stabilization requirements. Unfortunately no single actuator can meet these requirements. Therefore, a suite of actuators with overlapping strokes and bandwidths is employed; such a construction is termed a "staged actuation system." The objective in the thesis is to develop "staging control" strategies that specify how to utilize the individual actuators in a staged system to satisfy the stabilization requirements. The first task in the staging control design process is to evaluate how actuator capabilities and constraints affect the system performance. Two analytical techniques, based on stochastic Lyapunov and stochastic linearization methods, are utilized to predict the steady-state, closed-loop performance in the presence of actuator nonlinearities such as saturation and quantization. These nonlinearities can severely restrict the achievable performance, and careful consideration of their effects is vitally important for staged controller designs.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2003

Author dc:creator

• Liu, Kuo-Chia, 1973-

Advisor dc:contributor.advisor

• David W. Miller.

• Aeronautics and Astronautics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/29746

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/29746