Control surfaces in confined spaces : the optimisation of trailing edge tabs to reduce control surface hinge moments

Jaquet, Christopher Denis (2010-03)

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.

Thesis

ENGLISH ABSTRACT: This thesis describes the first project relating to the Control Surfaces in Confined Spaces (CoSICS) project at Stellenbosch University. The aim of CoSICS project is to reduce the size of control surface actuators, and this thesis considers the aileron system of commercial aircraft such as the Airbus A320 and A330. Specifically the project aims to reduce the aileron hinge moment, as this will result in smaller actuators. Possible methods are discussed where aerodynamic forces are used to reduce the aileron hinge moment through the use of a wing-aileron-tab configuration. In order to examine the use of the configuration, first order aerodynamic modelling is performed using two-dimensional thin-aerofoil theory, which is also extended to a basic three-dimensional approximation. To determine the maximum reduction in hinge moment several optimisations are performed where only the tab chord length is varied, both tab and aileron chord lengths are varied, and finally the tab chord length and aileron span are varied. The optimisation methods used, namely the gradient-based sequential quadratic programming (SQP) and a real-encoded genetic algorithm (REGA) are discussed in detail and include general implementations which are then applied to the problem. The optimisations performed are dual-layered where optimal deflection angles are determined as well as the optimal geometry. The results of the optimisation are tested using a roll manoeuvre in a specially developed Simulink simulation environment for this purpose. The study produces results where new hinge moment values are an order of magnitude smaller than those of the old configuration, while maintaining suitable lift and rolling moment coefficients. The optimisation and simulation infrastructure developed in this thesis provides a platform for higher-fidelity models and components being developed in future work to provide higher fidelity results.

AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die eerste projek in die Control Surfaces in Confined Spaces-projek1 (CoSICS-projek) uitgevoer by die Universiteit Stellenbosch. Die doel van die COSICs-projek is om die grootte van beheervlak aktueerders te minimeer en hierdie tesis handel oor die aileron stelsel van kommersiële vliegtuie soos die Airbus A320 en A330. Die doel van hierdie tesisis om die skarnier draaimoment van die aileron te minimeer deur aërodinamiese kragte in te span in ’n vlerk-aileron-hulpvlak konfigurasie. Eerste-orde aërodinamiese modelle is afgelei met behulp van twee-dimensionele dunvlerkteorie en is gebruik om die konfigurasie te analiseer. ’n Eerste orde drie-dimensionele benadering is ook ontwikkel. Om die maksimum vermindering in die skarnier draaimoment te bepaal, is verskeie optimerings uitgevoer waar eers die hulpvlak se koordlengte gevarieer word, daarna beide die aileron en hulp-vlak se koordlengtes en laastens die hulp-vlak se koordlengte en wydte. Die twee optimerings metodes wat gebruik is, nl. ’n sekwensiële kwadratiese programmerings (SKP) tegniek, en ’n reële getal-geënkodeerde genetiese algoritme (RGGA), word bespreek en ontwikkel voor hulle toegepas word op die probleem. Twee-vlak optimerings word uitgevoer waar beide die optimale defleksiehoeke en die optimale geometrie bepaal word. Die resultate van die optimering word daarna getoets deur middel van ’n rol maneuver wat uitgevoer word in ’n Simulink simulasie omgewing wat daarvoor geskep is. Hierdie studie lei tot goeie resultate met skarnier draaimoment waardes ’n ordegrootte kleiner as dié van die vorige stelsel, terwyl goeie waardes van rol-moment en verheffingskrag koëffisiënte behou word. Die optimering en simulasie infrastruktuur wat hier ontwikkel word verskaf ’n platform vir meer akkurate modelle en komponente wat ontwikkel word in toekomstige projekte om meer akkurate resultate te lewer.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/4327
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