<p>Development of modern aircraft has become more and more expensive and time consuming. In order to minimize the development cost, an improvement of the conceptual design phase is needed. The desired goal of the project is to enhance the functionality of an in house produced framework conducted at the department of machine design, consisting of parametric models representing a large variety of aircraft concepts.</p><p>The first part of the work consists of the construction of geometric aircraft control surfaces such as flaps, aileron, rudder and elevator parametrically in CATIA V5.</p><p>The second part of the work involves designing and simulating an Inverse dynamic model in Dymola software.</p><p>An Excel interface has been developed between CATIA and Dymola. Parameters can be varied in the interface as per user specification; these values are sent to CATIA or Dymola and vice versa. The constructed concept model of control surfaces has been tested for different aircraft shapes and layout. The simulation has been done in Dymola for the control surfaces.</p>

Development of modern aircraft has become more and more expensive and time consuming. In order to minimize the development cost, an improvement of the conceptual design phase is needed. The desired goal of the project is to enhance the functionality of an in house produced framework conducted at the department of machine design, consisting of parametric models representing a large variety of aircraft concepts. The first part of the work consists of the construction of geometric aircraft control surfaces such as flaps, aileron, rudder and elevator parametrically in CATIA V5. The second part of the work involves designing and simulating an Inverse dynamic model in Dymola software. An Excel interface has been developed between CATIA and Dymola. Parameters can be varied in the interface as per user specification; these values are sent to CATIA or Dymola and vice versa. The constructed concept model of control surfaces has been tested for different aircraft shapes and layout. The simulation has been done in Dymola for the control surfaces.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: This thesis forms part of the Control Surfaces in Confined Spaces (CoSICS) project conducted at Stellenbosch University. The aim of this project is reduction of control surface actuator footprints on the existing wing structures of commercial airliners such as the Airbus A320 and A330. This is achieved by reducing control surface hinge moments through the application of trailing edge tabs. This results in smaller actuator requirements. The first tier of the project focussed on the geometric optimisation of the tab applied to an aileron. This thesis focusses on the development of dynamic control of the aileron through either tab-only or concurrent tab and aileron actuation. In the effort to develop dynamic control, a fully coupled generalised dynamic model of the tab and aileron is derived and presented. Through linearisation of this model, linear controllers are developed. Two distinctly different controllers are presented; the first controller makes use of classical methods for control of the tab-only actuated aileron and the second controller makes use of modern control techniques such as full state feedback to facilitate controlled concurrent tab and aileron actuation. Each proposed controller is evaluated in terms of dynamic performance, robustness, disturbance rejection and noise immunity. Based on the controller development, a summary of dynamic actuator requirements is given. Practical verification of the model and the controller performance is then undertaken. The development of the necessary hardware and software is also presented. The concept of aileron control through tab-only actuation and concurrent tab and aileron actuation is then validated. Conclusion are then drawn about the accuracy of the theoretical model and the practical performance of the controllers. The thesis is concluded with recommendations for future work to increase the fidelity of the model. Important aspects about the practical implementation of the concept on commercial jetliners are also summarised. / AFRIKAANSE OPSOMMING: Hierdie tesis is deel van die Control Surfaces in Confined Spaces1 projek by Stellenbosch Universiteit. Die doel van hierdie projek behels die verkleining van die aktueerder spasie en ondersteunings struktuur vereistes, op die bestaande vlerk struktuur van kommersiële vliegtuie soos die Airbus A320 en Airbus A330. Dit is bereik deur die vermindering van die beheeroppervlak skarnier se draaimoment met behulp van aerodinamiese hulpvlakke. Kleiner aktueerders word dus benodig. Die eerste stadium van die projek fokus op die geometriese optimisering van die hulpvlak op ’n aileron. Hierdie tesis fokus op die ontwikkeling van dinamiese beheer van die aileron deur middel van hulpvlak aktueering alleenlik of met die gelyktydige aktueering van die hulpvlak en aileron. In die proses van onwikkeling is ’n volgekoppelde veralgemeende dinamiese model van die hulpvlak en aileron afgelei en voorgelê. Deur middel van linearisasie van die model is linieêre beheerders ontwikkel. Tans is twee verskillende beheerders ontwikkel. Die eerste beheerder is gebaseer op die klassieke metodes en maak staat op die aktueering van die hulpvlak alleenlik. Die tweede beheerder maak gebruik van moderne beheer tegnieke soos vol toestand terugvoer om gelyktydige hulpvlak en aileron aktueering te realiseer. Die beheerders is elk geëvalueer in terme van dinamiese gedrag, robuustheid, versteurings verwerping en ruis verwerping. Die beheerstelsel ontwikkeling lei tot ’n opsomming van die dinamiese aktueerder vereistes. Dit word gevolg deur praktiese verifikasie van die model en die beheerstelsel gedrag. ’n Opsomming van die ontwikkeling van nodige hardeware en sagteware word voorgelê. In hierdie proses is die konsep van beide hulpvlak alleenlike aktueering en gelyktydige hulpvlak en aileron aktueering bewys. Gevolgtrekkings word gemaak oor die akkuraatheid van die model en die praktiese gedrag van die beheerders. Die tesis word afgerond met voorstelle vir toekomstige werk wat die model se betroubaarheid kan verbeter. Verder word belangrike punte oor die praktiese aspekte van konsep implementering op kommersiële vliegtuie ook uitgelig.

This thesis deals with the control system of two-seater aircraft corresponding to CS-23 Level 2. First load calculations of each control surface are performed using the proses described in previous CS-23 regulation. This load is calculated trought the steering mechanism to control elements in cockpit. The resulting forces on the control elements are compared with the requi-rements in CS-23. Because the steering forces meets requirements is not necessary to propose changes in steering kinematics. However, there are further suggested ways of adjusting the control in case the external load would increase during further development of the airplane. At the end, the strength calculation of entire mechanism is preformed.

The natural unsteadiness in the post-breakdown flowfield of a 75° sweep delta wing at 40° angle of attack was studied with dual and single point hot-wire anemometry in the Engineering Science and Mechanics (ESM) Wind Tunnel at a Reynolds number Re = 210,000. Data were taken in five crossflow planes surrounding the wing's trailing edge. Results showed a dominant narrowband Strouhal frequency of St = 1.5 covering approximately 80% of the area with lower-intensity broadband secondary frequencies over 15% of that region. Cross-correlations between a fixed and traversing wire were calculated and phase and coherences mapped to determine the convection speed and trajectory of the helical mode instability. High-speed Particle Image Velocimetry (PIV) was conducted over a 75° sweep delta wing at 40° angle of attack in the ESM Water Tunnel II at Re = 45,000. Data were taken along the axis of the vortex in the breakdown flowfield at a speed of 0.1% of the convective time scale of the flow. Animations of instantaneous streamlines and velocity vectors revealed the impression of a helically spiralling vortex core on the measurement plane. Spectral analysis of the PIV data showed reduced frequencies which confirmed those found with the single-point measurements made in the ESM Wind Tunnel. The effect of four novel control surfaces on the breakdown flowfield of the delta wing was studied with surface pressure measurements along the axis of the vortex in the ESM Wind Tunnel. The apex flap was found effective and delayed vortex breakdown by 8° for a fixed wing. The flowfield was characterized over the delta wing executing a pitch-up maneuver at a reduced frequency of 0.06. Surface pressure measurements were taken in the ESM Wind Tunnel and Laser Doppler Velocimetry (LDV) was employed in the ESM Water Tunnel I as both the unmodified wing and then the wing with an apex flap deployed at an optimal angle <font face="Symbol">b</font> = 15° executed the pitch-up. Both sets of data confirmed the hysteresis of the flowfield. The LDV data, taken in two crossflow planes throughout the maneuver, showed an asymmetric breakdown development. As a practical extension of the study of the breakdown wake flowfield, hot-wire measurements were made over an F/A-18 model to determine the spectral characteristics of the flowfield. Three-dimensional vortex interactions were investigated with helium bubble flow visualization in the VPI Stability Tunnel. / Ph. D.

La surveillance des systèmes industriels et/ou embarqués constitue une préoccupation majeure en raison de l’accroissement de leur complexité et des exigences sur le respect des profilsde mission. La détection d’anomalies tient une place centrale dans ce contexte. Fondamentalement,les procédures de détection à base de modèles consistent à comparer le fonctionnement réel dusystème avec un fonctionnement de référence établi à l’aide d’un modèle sans défaut. Cependant,les systèmes à surveiller présentent souvent des dynamiques non linéaires et difficiles à caractériserde manière exacte. L’approche retenue dans cette thèse consiste à englober leur influencepar des incertitudes bornées. La propagation de ces incertitudes permet l’évaluation de seuils dedécision visant à assurer le meilleur compromis possible entre sensibilité aux défauts et robustesseaux perturbations tout en préservant une complexité algorithmique raisonnable. Pour cela, unepart importante du travail porte sur l’extension des classes de modèles dynamiques à incertitudesbornées pour lesquels des observateurs intervalles peuvent être obtenus avec les preuves d’inclusionet de stabilité associées. En s’appuyant sur des changements de coordonnées variant dans letemps, des dynamiques LTI, LPV et LTV sont considérées graduellement pour déboucher sur desclasses de dynamiques Non Linéaires à Incertitudes Bornées continues (NL-IB). Une transformationdes modèles NL-IB en modèles LPV-IB a été utilisée. Une première étude sur les non-linéaritésd’une dynamique de vol longitudinal est présentée. Un axe de travail complémentaire porte surune caractérisation explicite de la variabilité (comportement aléatoire) du bruit de mesure dansun contexte à erreurs bornées. En combinant cette approche à base de données avec celle à basede modèle utilisant un prédicteur intervalle, une méthode prometteuse permettant la détection dedéfauts relatifs à la position d’une surface de contrôle d’un avion est proposée. Une étude portenotamment sur la détection du blocage et de l’embarquement d’une gouverne de profondeur. / The monitoring of industrial and/or embedded systems is a major concern accordingto their increasing complexity and requirements to respect the mission profiles. Detection of anomaliesplays a key role in this context. Fundamentally, model-based detection procedures consist incomparing the true operation of the system with a reference established using a fault-free model.However, the monitored systems often feature nonlinear dynamics which are difficult to be exactlycharacterized. The approach considered in this thesis is to enclose their influence through boundeduncertainties. The propagation of these uncertainties allows the evaluation of thresholds aimingat ensuring a good trade-off between sensitivity to faults and robustness with respect to disturbanceswhile maintaining a reasonable computational complexity. To that purpose, an importantpart of the work adresses the extension of classes of dynamic models with bounded uncertaintiesso that interval observers can be obtained with the related inclusion and stability proofs. Based ona time-varying change of coordinates, LTI, LPV and LTV dynamics are gradually considered tofinally deal with some classes classes of nonlinear continuous dynamics with bounded uncertainties.A transformation of such nonlinear models into LPV models with bounded uncertainties has beenused. A first study on nonlinearities involved in longitudinal flight dynamics is presented. A complementarywork deals with an explicit characterization of measurement noise variability (randombehavior of noise within measurement) in a bounded error context. Combining this data-drivenapproach with a model-driven one using an interval predictor, a promising method for the detectionof faults related to the position of aircraft control surfaces is proposed. In this context, specialattention has been paid to the detection of runaway and jamming of an elevator.

[pt] Pontes com vãos superiores a 2.000 m tornam-se muito sensíveis à ação do vento, particularmente ao drapejamento. Nesta tese é estudado um método para a supressão do drapejamento em pontes de grandes vãos através de um controle aerodinâmico ativo. Apresentam-se técnicas analíticas de projeto para o controle ativo do sistema aero elástico constituído pelo tabuleiro e por duas superfícies de controle. Estas técnicas são baseadas em aproximações racionais das cargas aerodinâmicas não permanentes (ou auto-excitadas) no domínio Laplaciano, no qual as equações de movimento são representadas por equações matriciais de coeficientes constantes. A primeira parte da tese é dedicada à formulação matricial das funções racionais conhecida como Minimum State, assim como a aplicações a dados aerodinâmicos obtidos experimentalmente para vários tipos de seções transversais de pontes. A precisão das aproximações é calculada. Desenhos dos derivativos aerodinâmicos, dados sob forma de tabelas, e das respectivas aproximações, são elaborados para fins de comparação. Em seguida, são apresentadas as equações em espaço de estado descrevendo o comportamento aeroelástico de uma seção transversal de ponte. A partir dos dados geométricos e características dinâmicas de uma determinada ponte, (massa, momento de inertia polar, frequências naturais e fatores de amortecimento), e assumindo a semelhança geométrica entre as seções transversais da ponte em verdadeira grandeza e do modelo em escala do qual os derivativos aerodinâmicos foram extraídos, é possível calcular a velocidade crítica desta ponte, utilizando os programas em linguagem MATLAB apresentados no corpo deste trabalho. Esta parte da tese mostra ser possível construir um catálogo com vários perfis de pontes, caracterizados por derivativos aerodinâmicos variáveis em função de frequências reduzidas adimensionais, e das funções racionais correspondentes. A segunda parte é dedicada à fomulação das equações de movimento em espaço de estado, descrevendo o comportamento aeroelástico do sistema tabuleiro - superfícies de controle. As equações resultantes são ampliadas com novos estados aerodinâmicos responsáveis pela modelagem da influência do fluxo de ar sobre o tabuleiro e sobre as superfícies de controle em movimento. As equações de movimento são função da velocidade média do vento incidente. A dependência da equação de movimento à velocidade do vento motivou a aplicação dos conceitos de realimentação de ganhos, constante e variável, ao problema da supressão do drapejamento, os quais são apresentados separadamente em dois capítulos.O enfoque de ganho variável de saída é formulado em termos de minimização de um índice de desempenho dimensionalmente proporcional à soma do trabalho realizado pelas superfícies de controle e da energia cinética proporcional à velocidade vertical do tabuleiro. Apresenta-se também em detalhe um método sistemático para determinar a matriz de controle de ganhos variável, aplicada ao caso hipotético da ponte de Gibraltar. Neste caso, o conceito de realimentação de ganhos variável mostrou-se muito efetivo em suprimir o drapejamento do tabuleiro da ponte. Diferentes características geométricas e dinâmicas de outras pontes podem ser introduzidas nos programas MATLAB apresentados no Apêndice, para obtenção da velocidade crítica nos casos de tabuleiros isolados, tabuleiros com asas estacionárias e tabuleiros com asas giratórias ativamente controladas, para supressão do drapejamento do tabuleiro. / [en] Long span bridges, with main spans beyond 2.000 m become highly sensitive to wind action, particularly to flutter. An active aerodynamic control method of suppressing flutter of very long span bridges is studied in this thesis. Analytical design techniques for active control of the aeroelastic system consisting of the bridge deck and two control surfaces are presented. These techniques are based on a rational approximation of the unsteady aerodynamic loads in the entire Laplace domain, which yieds matrix equations of motion with constant coefficientes. The first part of this thesis is dedicated to the matrix formulation of the rational functions known as Minimum State and to applications to aerodynamic data obtained experimentally for various types of bridge profiles. The precision of the approximations iscalculated, and plots of the approximation functions compared to the available tabular data are drawn. Next, the state-space equations of motion describing the aeroelastic behaviour of a section of a bridge deck is presented. Given the dynamic data of a bridge structure (mass, rotational mass moment of inertia, natural frequencies, stiffness and damping ratios), and assuming that a geometric similitude exists between the profiles of the full-scale bridge deck and the sectional model from which the frequency dependent aerodynamic data was extracted, it is possible to calculate the critical velocity of that particular bridge. This part of the thesis shows that it is possible to build up a catalog of several profiles, characterized by frequency dependent aerodynamic data and the corresponding rational functions. The second part is dedicated to the formulation of the state-space equations of motion describing the aeroelastic behaviour of the entire system consisting of the bridge deck and control surfaces. The resulting equation includes new aerodynamic states which model the air flow influence on the moving deck. The equation of motion is a function of the mean velocity of the incoming wind. The dependence of the equation of motion on the wind velocity motivated the application of a constant and a variable-gain feedback concept to the problem of flutter suppressing, which are presented separatelly. The output variable-gain approach is formulated in terms of minimizing a performance index dimensionally proportional to the sum of the work done by the rotating control surfaces and the kinetic energy of the heaving velocity. A sistematic method to determine the matrix of variable control gains is shown in detail, as applied to the hypothethical case of Gibraltar bridge. Application of the variablegain feedback concept was found to be very effective in suppressing flutter of the bridge deck. Different geometric and dynamic characteristics can be introduced in the MATLAB programs included in this work, in order to obtain the critical velocities of a bridge deck alone, a bridge deck with stationary wings and a bridge with moving wings activelly controled.