Title:
Adaptive Control for a Microgravity Vibration Isolation System

dc.contributor.author Yang, Bong-Jun
dc.contributor.author Calise, Anthony J.
dc.contributor.author Craig, James I.
dc.contributor.author Whorton, Mark S.
dc.contributor.corporatename Georgia Institute of Technology. School of Aerospace Engineering
dc.contributor.corporatename United States. National Aeronautics and Space Administration
dc.contributor.corporatename George C. Marshall Space Flight Center
dc.date.accessioned 2010-11-11T21:12:53Z
dc.date.available 2010-11-11T21:12:53Z
dc.date.issued 2005
dc.description.abstract Most active vibration isolation systems that try to a provide quiescent acceleration environment for space-science experiments have utilized linear design methods. In this report, we address adaptive control augmentation of an existing classical controller that combines a high-gain acceleration inner-loop feedback together with a low-gain position outer-loop feedback to regulate the platform about its center position. The control design considers both parametric and dynamic uncertainties because the isolation system must accommodate a variety of payloads having different inertial and dynamic characteristics. We show how adaptive control is beneficial in three important aspects in design of a controller for uncertain systems: performance, robustness, and transient responses. First, performance is treated in the setting that an accelerometer and an actuator is located at the same location, as is the current hardware configuration for g-LIMIT. Second, robustness for the control system becomes more of an issue when the sensor is non-collocated with the actuator. We illustrate that adaptive control can stabilize otherwise unstable dynamics due to the presence of unmodelled dynamics. Third, transient responses of the position of the isolation system are significantly influenced by a high-gain acceleration controller when it includes integral action. An important aspect of the g-LIMIT is the accelerometer bias and the deviation of the platform it causes as a result of integral control. By employing adaptive neural networks for both the inner-loop and outer-loop controllers, we illustrate that adaptive control can improve both steady-state responses and transient responses in position. A feature in the design is that high-band pass and low pass filters are applied to the error signal used to adapt the weights in the neural network and the adaptive signals, so that the adaptive processes operate over targeted ranges of frequency. This prevents the inner and outer loop adaptive processes from interfering with each other. en_US
dc.description.sponsorship Research Supported by: NASA Marshall Space Flight Center, Huntsville, AL Grant No. NAG8-1292. en_US
dc.identifier.citation Adaptive Control for a Microgravity Vibration Isolation System. Bong-Jun Yang, Anthony J. Calise, James I. Craig, Mark S. Whorton. NASA Marshall Space Flight Center, Huntsville, Alabama, 2005. en_US
dc.identifier.uri http://hdl.handle.net/1853/35922
dc.language.iso en_US en_US
dc.publisher Georgia Institute of Technology en_US
dc.subject Microgravity en_US
dc.subject Linear design methods en_US
dc.subject Adaptive control en_US
dc.title Adaptive Control for a Microgravity Vibration Isolation System en_US
dc.type Text
dc.type.genre Technical Report
dspace.entity.type Publication
local.contributor.author Craig, James I.
local.contributor.corporatename Daniel Guggenheim School of Aerospace Engineering
local.contributor.corporatename Aerospace Design Group
local.contributor.corporatename College of Engineering
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relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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