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

[摘要] ENGLISH ABSTRACT: This thesis describes the first project relating to the Control Surfaces in Confined Spaces (CoSICS) projectat 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 momentthrough 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 alsoextended to a basic three-dimensional approximation.To determine the maximum reduction in hinge moment several optimisations are performed where onlythe tab chord length is varied, both tab and aileron chord lengths are varied, and finally the tab chordlength and aileron span are varied. The optimisation methods used, namely the gradient-based sequentialquadratic programming (SQP) and a real-encoded genetic algorithm (REGA) are discussed in detail andinclude general implementations which are then applied to the problem. The optimisations performed aredual-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 simulationenvironment for this purpose.The study produces results where new hinge moment values are an order of magnitude smaller than thoseof the old configuration, while maintaining suitable lift and rolling moment coefficients. The optimisationand simulation infrastructure developed in this thesis provides a platform for higher-fidelity models andcomponents being developed in future work to provide higher fidelity results.

[发布机构] Stellenbosch University