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Efficient and robust algorithms for trim and stability analysis of advanced rotorcraft simulations

Part of: 75 year anniversary of Aeronautical Engineering at Glasgow University

Published online by Cambridge University Press:  04 July 2016

J. S. G. McVicar  and
R. Bradley
J. S. G. McVicar
Affiliation:
Department of MathematicsGlasgow Caledonian University, Glasgow, UK
R. Bradley
Affiliation:
Department of MathematicsGlasgow Caledonian University, Glasgow, UK
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Abstract

This paper derives innovative techniques for use in the trimming and stability analysis of advanced rotorcraft simulations. It begins by exploiting the symmetry of the rotor to produce an efficient definition of periodic trim which is applicable to rotorcraft simulations. This definition is then expanded to produce a trimming algorithm which is capable of concurrently ascertaining the initial conditions and control inputs necessary to trim latest generation simulation models to a specified periodic trim state. The algorithm is based on a periodic shooting approach with Newton-Raphson iteration and exploits the symmetry of the rotor to minimise computational workload. The definition of periodic trim is then further developed to produce a technique by which the stability characteristics of rotorcraft can be ascertained from advanced simulation models. This technique is based on a Floquet approach and again exploits the symmetry of the rotor to reduce computational burden. The paper concludes by presenting results obtained when the stability characteristics of a tiltrotor simulation model are investigated.

Type
Research Article
Information
The Aeronautical Journal , Volume 101 , Issue 1008 , October 1997 , pp. 375 - 387
Copyright
Copyright © Royal Aeronautical Society 1997 

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