Active Vibration Suppression via LQG/LTR; Analytic and Experimental Results for the PACOSS Dynamic Test Article

Item

Title
Active Vibration Suppression via LQG/LTR; Analytic and Experimental Results for the PACOSS Dynamic Test Article
Report Number
WL-TR-91-3078 Volume I, p. CAA-1 thru CAA-22
Creator
Gehling, Russell N.
Corporate Author
Martin Marietta Astronautics Group
Laboratory
Wright Laboratory
Date
1991
Date Issued
1991-08
Extent
22
Contract
Laboratory Research - No Contract
DoD Project
2401
DoD Task
2401-04
Identifier
ADA241311
Format
1 online resource
Abstract
Future large space systems (LSS) will possess high modal density at low frequencies, and mission performance requirements will necessitate control bandwidths encompassing these modal frequencies. This situation has potential for adverse controls/structure interaction (CSI) detrimental to system performance. The Passive and Active Control of Space Structures (PACOSS) program has investigated the design, analysis, and verification of passive and active damping strategies applied to LSS. This paper discusses the results of an experiment in which a Linear Quadratic Gaussian with Loop Transfer Recovery (LQG/LTR) design technique was applied to the PACOSS Dynamic Test Article (OTA) for the purpose of high authority vibration suppression. In general, the LQG/LTR control demonstrated high sensitivity to design model
accuracy. Actual performance was significantly less than predicted, even though the control design utilized an accurate test-verified model. The results of this experiment indicate that analytic LSS models which are quite accurate by structural dynamics standards may be insufficient for use as design models in modern control algorithms. However, passive damping designed into LSS
flexible modes will simplify the active control design and implementation in terms of sensor/actuator requirements, design model order, real time computing requirements, and overall system robustness.
Description
Future large space systems (LSS) will possess high modal density at low frequencies, and mission performance requirements will necessitate control bandwidths encompassing these modal frequencies. This situation has potential for adverse controls/structure interaction (CSI) detrimental to system performance. The Passive and Active Control of Space Structures (PACOSS) program has investigated the design, analysis, and verification of passive and active damping strategies applied to LSS. This paper discusses the results of an experiment in which a Linear Quadratic Gaussian with Loop Transfer Recovery (LQG/LTR) design technique was applied to the PACOSS Dynamic Test Article (OTA) for the purpose of high authority vibration suppression. In general, the LQG/LTR control demonstrated high sensitivity to design model
accuracy. Actual performance was significantly less than predicted, even though the control design utilized an accurate test-verified model. The results of this experiment indicate that analytic LSS models which are quite accurate by structural dynamics standards may be insufficient for use as design models in modern control algorithms. However, passive damping designed into LSS
flexible modes will simplify the active control design and implementation in terms of sensor/actuator requirements, design model order, real time computing requirements, and overall system robustness.
Distribution Classification
1
Distribution Conflict
No
DTIC Record Exists
No
Illinois Tech Related
No
Photo Quality
Complete
Report Availability
Full text available
Type
article
Is Part Of
Proceedings of Damping '91: 13-15 February 1991 San Diego, California (Pages AAC-1 through DCC-19)
Media
article12