Pseudospectral Feedback Control: Foundations, Examples and Experimental Results
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Authors
Ross, I. Michael
Sekhavat, Pooya
Fleming, Andrew
Gong, Qi
Subjects
aerospace control , feedback , open loop systems , optimal control , space vehicles
Advisors
Date of Issue
2006-08-21
Date
August 21-24 2006
Publisher
American Institute of Aeronautics and Astronautics (AIAA)
Language
Abstract
Suppose optimal open-loop controls could be computed in real time. This implies optimal feedback control. These controls are, typically, nonsmooth. Nonsmooth controls raise fundamental theoretical problems on the existence and uniqueness of feedback solutions. A simple, yet powerful, approach to address these theoretical issues is the concept of a on fourth- solution that is closely linked to the practical implementation of zero-order-hold control sampling. In other words, even traditional feedback controls involve open-loop controls through the process of sampling. In this paper, we advance the notion of Caratheodory solutions that use the sampling intervals to compute optimal open-loop controls. A sampling theorem is developed which indicates that the Lipschitz constant of the dynamics is a fundamental sampling frequency. This places computation at the level of first principles in describing the foundations for achieving feedback. We obtain these controls by way of Pseudospectral (PS) methods as these techniques can generate optimal open-loop controls within fractions of a second even when implemented in a MATLAB environment running on legacy computer hardware. In order to facilitate an exposition of the proposed ideas to a wide audience, we introduce the core principles only while relegating the intricate details to numerous recent references. These principles are then applied to generate PS feedback controls for the slew maneuvering of NPSAT1, a spacecraft conceived, designed and built at the Naval Postgraduate School and scheduled to be launched in Fall 2007.
Type
Conference Paper
Description
The article of record as published may be located at http://dx.doi.org/10.2514/6.2006-6354
Proceedings of AIAA-Guidance, Navigation, and Control Conference and Exhibit ; Paper no. AIAA 2006-6354, Keystone, Colorado, Aug. 21-24, 2006
Proceedings of AIAA-Guidance, Navigation, and Control Conference and Exhibit ; Paper no. AIAA 2006-6354, Keystone, Colorado, Aug. 21-24, 2006
Series/Report No
Department
Mechanical & Astronautical Engineering
Organization
Naval Postgraduate School (U.S.)
American Institute of Aeronautics and Astronautics (AIAA)
American Astronomical Society (AAS)
Identifiers
NPS Report Number
Sponsors
Funder
NA
Format
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.