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Techniques for extreme attitude suspension of a wind tunnel model in a magnetic suspension and balance systemAlthough small scale magnetic suspension and balance systems (MSBSs) for wind tunnel use have been in existence for many years, they have not found general application in the production testing of flight vehicles. One reason for this is thought to lie in the relatively limited range of attitudes over which a wind tunnel model may be suspended. Modifications to a small MSBS to permit the suspension and control of axisymmetric models over angles of attack from less than zero to over ninety degrees are reported. Previous work has shown that existing arrangement of ten electromagnets was unable to generate one of the force components needed for control at extreme attitudes. Examination of possible solutions resulted in a simple alteration to rectify this deficiency. To generate the feedback signals to control the suspended model, an optical position sensing system using collimated laser beams and photodiode arrays was installed and tested. An analytical basis was developed for distributing the demands for force and moment needed for model stabilization amonge the electromagnets over the full attitude range. This was implemented by an MSBS control program able to continually adjust the distribution for the instantaneous incidence in accordance with prescheduled data. Results presented demonstrate rotations of models from zero to ninety degrees at rates up to ninety degrees per second, with pitching rates rising to several hundred degrees per second in response to step-change demands. A study of a design for a large MSBS suggests that such a system could be given the capability to control a model in six degrees of freedom over an unlimited angle of attack range.
Document ID
19900004929
Acquisition Source
Legacy CDMS
Document Type
Thesis/Dissertation
Authors
Parker, David Huw (Southampton Univ.)
Date Acquired
September 6, 2013
Publication Date
October 1, 1989
Subject Category
Research And Support Facilities (Air)
Report/Patent Number
NAS 1.26:181895
NASA-CR-181895
Accession Number
90N14245
Funding Number(s)
PROJECT: RTOP 505-61-01-02
CONTRACT_GRANT: NSG-7523
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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