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Simulation de la conversion des forces aérodynamiques pour l'avion à commande électrique Fly-By-Wire

Hamza, Dina (2003). Simulation de la conversion des forces aérodynamiques pour l'avion à commande électrique Fly-By-Wire. Mémoire de maîtrise électronique, Montréal, École de technologie supérieure.

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Résumé

L'aéroservoélasticité, étant indispensable à la conception des avions Fly-By-Wire remplissant des performances exigeantes, traite les interactions entre l'aérodynamique, la commande et la structure. Le modèle d'avion ATM développé par la NASA, à l'aide de STARS est considéré afin de valider. Les méthodes P et Pk sont utilisées pour calculer les vitesses de battement où l'instabilité apparaîsse et construire l'enveloppe de vol étant essentielle à la certification. La non-linéarité des forces aérodynamiques rend difficile la résolution du problème, d'où la linéarisation est abordée par LS, MS et la nouvelle conversion MS2LS. En présentant leurs avantages et désavantages, l'influence des retards et du Mach sont considérés pour l'ATM en boucle ouverte et fermée. Les vitesses obtenues de Matlab sont comparées à celles de STARS où une cohérence se manifeste représentant une validation de la théorie d'aéroservoélasticité.

Titre traduit

Simulation of aerodynamic forces' conversion for a Fly-By-Wire aircraft

Résumé traduit

This project in the aeroservoelasticity field was accomplished in order to validate the aeroservoelasticity theory on a Fly-By-Wire (FBW) aircraft in the Active Control Technology (ACT) project at Bombardier Aerospace, and in an international collaboration with the NASA Dryden Flight Research laboratories.

The aeroservoelasticity is a multidisciplinary theory of interactions between unsteady aerodynamic (aero) forces, control system dynamics ( servo) and structural forces (elasticity) on an aircraft. This theory emerged recently as an essential tool to understand and design the modern aircraft equipped with active control systems in order to fulfill flight performances.

Firstly, one of the aeroservoelastic applications is the active flutter suppression, as flutter is an unstable motion caused by the coupling between structural vibrations and the aerodynamic forces. Such unstable excitations can produce the loss of control on an aircraft, weaken its structure, or even the aircraft destruction. The speeds at which the aircraft becomes unstable are the flutter speeds. In the aerospace field, the flight envelope will be constructed by representing the flutter speeds in function of corresponding altitudes. This flight envelope construction is essential in certification of airplanes. The flutter methods P and Pk are considered in this project.

The nonlinear aerodynamic forces represent an obstacle in the understanding and solving of aeroservoelastic problems, from where linearisation approaches were proposed here to approximate unsteady aerodynamic forces expressed in reduced frequency domain into Laplàce domain in motion equations. These approaches are : Least Square method LS, Minimum State method MS, and the conversion method from Least Square to the Minimum State method MS2LS. All these three methods are applied on the airplane then the flutter speeds are calculated.

For the purpose of illustration and validation of the aeroelasticity and aeroservoelasticity concepts, we considered the ATM aircraft model developed by NASA, using STARS computer software. It contains all the components essential to aeroservoelastic analysis, as well as some aeroservoelastic results obtained by NASA. These results are presented in the form of flutter speeds.

Firstly, an aeroelastic analysis is applied on the airplane test model ATM. A comparative study is conducted between flutter speeds obtained through our own flutter methods P and Pk programmed in Matlab, applied also on the ATM model and the results obtained through the Pk and P methods in STARS. The flutter speeds obtained in Matlab are close to those obtained in STARS.

Then, an aeroservoelastic analysis is applied on the ATM model using the conversion aerodynamic methods from the frequency domain into time domain. Those methods are the Least Square LS, the Minimum State MS, and the conversion method from the Least Square LS to the Minimum State method MS2LS. The impact of lag numbers and Mach numbers M considers their advantages and disadvantages. Those analyses consider the ATM airplane in open loop and closed loop (including the controller) systems.

The main contribution in this project is the integration of LS, MS, MS2LS (which is a new method) methods in the aircraft, and the calculation of the flutter speed. A similar comparison on this type of ATM model is achieved for the first time in the literature. Finally, our results expressed in the form of flutter speeds are very much close to values obtained from NASA, which leads to the validation of our aeroservoelasticity theory.

Type de document: Mémoire ou thèse (Mémoire de maîtrise électronique)
Renseignements supplémentaires: "Mémoire présenté à l'École de technologie supérieure comme exigence partielle à l'obtention de la maîtrise en génie de la production automatisée". Comprend une bibliogr.
Mots-clés libres: Actif, Aerodynamique, Aeroservoelastique, Approximation, Avion, Commande, Conversion, Electrique, Force, Methode, Modele, Simulation, Theorie, Test
Directeur de mémoire/thèse:
Directeur de mémoire/thèse
Botez, Ruxandra
Co-directeurs de mémoire/thèse:
Co-directeurs de mémoire/thèse
Bigras, Pascal
Programme: Maîtrise en ingénierie > Génie de la production automatisée
Date de dépôt: 06 mai 2011 20:49
Dernière modification: 14 oct. 2016 21:59
URI: http://espace.etsmtl.ca/id/eprint/745

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