Esta dissertação apresenta o desenvolvimento da teoria de dinâmica de voo e o conceito de controle a ser aplicado na modelagem e simulação de voo de um VANT com decolagem e pouso vertical proposto. Um conceito de aeronave de asa semi-tandem é projetado e os coeficientes aerodinâmicos, propriedades inerciais e parâmetros de controle são estimados, o que permitiu a implementação da teoria proposta. O modelo fez uso das equações de movimento multi-corpos onde a aeronave é dividida em partes de forma que a asa, o estabilizador horizontal e os rotores sejam entidades independentes. Além disso, o sucesso da fase de transição de voo pairado para cruzeiro e de cruzeiro para voo pairado pode ser verificado se houver a possibilidade da aeronave trimar ao longo do regime de velocidades de voo, em outras palavras, se houver uma combinação de estados de movimento que mantenha a aeronave estável do voo pairado para a condição de cruzeiro. Assim, as curvas de trimagem que expressam os estados são calculadas usando a minimização de uma função de custo envolvendo a soma dos quadrados de alguns dos estados de movimento, definidos pelas equações de movimento mencionadas anteriormente. Tal minimização é realizada usando o algoritmo Simplex Sequencial. Além disso, é apresentada uma estratégia de controle que estabiliza a aeronave durante a transição de voo pairado para configuração de cruzeiro, que é testada em simulação computacional de um voo longitudinal acelerado e desacelerado, ou seja, de voo pairado para cruzeiro e de cruzeiro para voo pairado. Finalmente, um protótipo da aeronave estudada é apresentado. / This thesis presents the development of the flight dynamics theory and control concept to be applied in the modeling and flight simulation of a proposed VTOL UAV. A semi-tandem wing aircraft concept is designed and the aerodynamic coefficients, inertial properties and controls parameters are estimated, which allowed the implementation of the proposed theory. The model made use of the multi-body equations of motion where the aircraft is divided in parts so that the wing, horizontal stabilizer and rotors are independent entities. Additionally, the success of the transition phase from hovering to cruise and from cruise to hovering can be verified if there is the possibility of the aircraft to trim along the flight speed regime, in other words, if there is a combination of states of motion that keep the aircraft stable from hover to cruise condition. So, the trim curves expressing the states are computed using the minimization of a cost function involving the sum of the squares of some of the states of motion, defined through the equations of motion previously mentioned. Such minimization is performed using the Sequential Simplex algorithm. Moreover, a control strategy that stabilizes the aircraft while it transitions from hovering to cruise configuration is presented, which is tested in computer simulation of an accelerated and decelerated longitudinal flight, that is, from hovering to cruise condition, and from cruise to hovering condition. Finally, a prototype of the aircraft studied is presented.

Esta dissertação apresenta o desenvolvimento da teoria de dinâmica de voo e o conceito de controle a ser aplicado na modelagem e simulação de voo de um VANT com decolagem e pouso vertical proposto. Um conceito de aeronave de asa semi-tandem é projetado e os coeficientes aerodinâmicos, propriedades inerciais e parâmetros de controle são estimados, o que permitiu a implementação da teoria proposta. O modelo fez uso das equações de movimento multi-corpos onde a aeronave é dividida em partes de forma que a asa, o estabilizador horizontal e os rotores sejam entidades independentes. Além disso, o sucesso da fase de transição de voo pairado para cruzeiro e de cruzeiro para voo pairado pode ser verificado se houver a possibilidade da aeronave trimar ao longo do regime de velocidades de voo, em outras palavras, se houver uma combinação de estados de movimento que mantenha a aeronave estável do voo pairado para a condição de cruzeiro. Assim, as curvas de trimagem que expressam os estados são calculadas usando a minimização de uma função de custo envolvendo a soma dos quadrados de alguns dos estados de movimento, definidos pelas equações de movimento mencionadas anteriormente. Tal minimização é realizada usando o algoritmo Simplex Sequencial. Além disso, é apresentada uma estratégia de controle que estabiliza a aeronave durante a transição de voo pairado para configuração de cruzeiro, que é testada em simulação computacional de um voo longitudinal acelerado e desacelerado, ou seja, de voo pairado para cruzeiro e de cruzeiro para voo pairado. Finalmente, um protótipo da aeronave estudada é apresentado. / This thesis presents the development of the flight dynamics theory and control concept to be applied in the modeling and flight simulation of a proposed VTOL UAV. A semi-tandem wing aircraft concept is designed and the aerodynamic coefficients, inertial properties and controls parameters are estimated, which allowed the implementation of the proposed theory. The model made use of the multi-body equations of motion where the aircraft is divided in parts so that the wing, horizontal stabilizer and rotors are independent entities. Additionally, the success of the transition phase from hovering to cruise and from cruise to hovering can be verified if there is the possibility of the aircraft to trim along the flight speed regime, in other words, if there is a combination of states of motion that keep the aircraft stable from hover to cruise condition. So, the trim curves expressing the states are computed using the minimization of a cost function involving the sum of the squares of some of the states of motion, defined through the equations of motion previously mentioned. Such minimization is performed using the Sequential Simplex algorithm. Moreover, a control strategy that stabilizes the aircraft while it transitions from hovering to cruise configuration is presented, which is tested in computer simulation of an accelerated and decelerated longitudinal flight, that is, from hovering to cruise condition, and from cruise to hovering condition. Finally, a prototype of the aircraft studied is presented.

<p>Active vibration control to reduce vibrations and structure borne noise is considered using a powerful multi-disciplinary virtual design environment which enables control system design to be considered as an integral part of the overall vehicle design.</p><p>The main application studied is active automotive engine vibration isolation where, first, the potential of large frequency band multi-input multi-output H₂ feedback control is considered. Facilitated by the virtual environment, it is found necessary to take non-linear characteristics into account to achieve closed-loop stability.</p><p>A physical explanation to why receiver structure flexibility insignificantly affect the open and closed-loop characteristics in case of total force feedback in contrast to acceleration feedback is then given. In this context, the inherent differences between model order reduction by modal and by balanced truncation are being stressed.</p><p>Next, applying state-of-the-art algorithms for recursive parameter estimation, time-domain adaptive filtering is shown to lack sufficient tracking performance to deal with multiple spectral components of transient engine excitations corresponding to rapid car accelerations.</p><p>Finally, plant non-linearity as well as transient excitation are successfully handled using narrow band control based on feedback of disturbance states estimates. To deal with the non-linear characteristics, an approach to generate linear parameter varying descriptions of non-linear systems is proposed. Parameter dependent quadratic stability is assessed using a derived affine closed-loop system representation.</p><p>This thesis also considers actuator saturation induced limit cycles for observer-based state feedback control systems encountered when dealing with the active isolation application. It is stressed that the fundamental observer-based anti-windup technique could imply severely deteriorated closed-loop characteristics and even sustained oscillations. That is in the case when the observer is fed by the saturated control signal in contrast to the computed one. Based on piecewise affine system descriptions, analytical tools to conclude about limit cycles and exponential closed-loop stability are provided for the two observer implementations.</p>

Active vibration control to reduce vibrations and structure borne noise is considered using a powerful multi-disciplinary virtual design environment which enables control system design to be considered as an integral part of the overall vehicle design. The main application studied is active automotive engine vibration isolation where, first, the potential of large frequency band multi-input multi-output H2 feedback control is considered. Facilitated by the virtual environment, it is found necessary to take non-linear characteristics into account to achieve closed-loop stability. A physical explanation to why receiver structure flexibility insignificantly affect the open and closed-loop characteristics in case of total force feedback in contrast to acceleration feedback is then given. In this context, the inherent differences between model order reduction by modal and by balanced truncation are being stressed. Next, applying state-of-the-art algorithms for recursive parameter estimation, time-domain adaptive filtering is shown to lack sufficient tracking performance to deal with multiple spectral components of transient engine excitations corresponding to rapid car accelerations. Finally, plant non-linearity as well as transient excitation are successfully handled using narrow band control based on feedback of disturbance states estimates. To deal with the non-linear characteristics, an approach to generate linear parameter varying descriptions of non-linear systems is proposed. Parameter dependent quadratic stability is assessed using a derived affine closed-loop system representation. This thesis also considers actuator saturation induced limit cycles for observer-based state feedback control systems encountered when dealing with the active isolation application. It is stressed that the fundamental observer-based anti-windup technique could imply severely deteriorated closed-loop characteristics and even sustained oscillations. That is in the case when the observer is fed by the saturated control signal in contrast to the computed one. Based on piecewise affine system descriptions, analytical tools to conclude about limit cycles and exponential closed-loop stability are provided for the two observer implementations.

Die Arbeit befasst sich mit der Entwicklung automatischer Lenkungen, die die von Schienenfahrzeugen bekannte Spurtreue auf n-gliedrige, mehrachsgelenkte Straßenfahrzeuge übertragen. Spurtreu bedeutet folglich, dass die Lenkachsmittelpunkte keinen seitlichen Versatz zueinander aufweisen. Dafür wird ein modellbasiertes automatisches Lenkverfahren systematisch konzipiert, entworfen und erprobt, das sowohl eine vollautomatische Spurführung als auch eine halbautomatische Nachführung erlaubt. Die modellbasierten automatischen Lenkungen unterliegen keinen praktisch relevanten Einschränkungen. Das wird durch die Verwendung einer Steuerungsstruktur mit zwei Freiheitsgraden erreicht, die aus einer modellbasierten Vorsteuerung und einem Rückführregler besteht. In der Vorsteuerung werden die Lenkwinkel aller Achsen berechnet, mit denen der Sollweg theoretisch spurtreu befahren wird. Durch den Einsatz eines speziell angepassten, modularen Mehrkörpermodells gelingt diese Berechnung allgemein für eine Klasse n-gliedriger Fahrzeuge. Zum Ausgleich von nicht vermeidbaren Modellunbestimmtheiten und nicht gemessenen Störungen werden ein nichtlinearer Mehrgrößenregler sowie achs-individuelle lineare Eingrößenregler entworfen und miteinander verglichen. Simulationen und Fahrversuche zeigen, dass das entwickelte Verfahren in einem weiten Geschwindigkeitsbereich robust gegenüber typischen Einflussgrößen wie Fahrbahn- und Beladungszustand ist.

Im Rahmen des Exzellenzclusters MERGE an der TU Chemnitz erfolgt die Entwicklung eines kontinuierlichen großserientauglichen Verfahrens zur Herstellung komplexer geschlossener Strukturbauteile. Hierbei werden vorimprägnierte faserverstärkte thermoplastische Halbzeuge (thermoplastische Tapes) in einem Kombinationsverfahren aus thermoplastischen Tapelegen und Tapewickeln verarbeitet. Für dieses kontinuierliche Orbitalwickelverfahren wurde ein spezieller Technologiedemonstrator entwickelt mit dessen Hilfe Machbarkeitsstudien zur Erbringung des Funktionsnachweises durchgeführt werden. Die oben genannte Versuchsanlage ermöglicht die Erzeugung rotationssymmetrischer Profile, die zudem einen inkonstanten Querschnitt aufweisen können. Für die Anlagenkonzeptionierung wurde ein Beispielprofil eines Strukturbauteils ausgewählt und die Anlagendimensionierung durchgeführt. Basierend auf dem Entwurf werden zur Anlagendimensionierung die Parameter der Einzelantriebe mit Hilfe inverser Kinematik simulativ und analytisch abgeleitet und durch anschließende Simulation in CreoElements/Pro® vervollständigt. Die konstruktive Realisierung erfolgte mittels Solid Works. Die abschließende simulative Validierung wurde wiederum mittels CreoElements/Pro® durchgeführt. Diese Arbeiten entstanden im Rahmen des Bundesexzellenzclusters EXC 1075 "Technologiefusion für multifunktionale Leichtbaustrukturen" und wurde von der Deutschen Forschungsgemeinschaft gefördert. Die Autoren danken für die finanzielle Unterstützung.

Für die effiziente Blechtafelbearbeitung mit hoher Prozesssicherheit und Teilequalität ist die positions- und winkelgenaue Ausrichtung der Rohblechtafeln vor dem Bearbeitungsprozess erforderlich. Dieser Beitrag untersucht vibrationsbasierte Ausrichtkonzepte mittels Mehrkörpersystem-Simulation. Die entwickelten Simulationsmodelle ermöglichen die Charakterisierung und den Vergleich der Konzepte hinsichtlich der Bewegungs- und Ausrichteigenschaften sowie der erforderlichen Antriebskraft. / Efficient, reliable, and qualitative sheet metal processing requires both positional and angular alignment of the raw metal sheets prior to the manufacturing process. This paper investigates different vibration-based alignment concepts using a multi-body system simulation. The simulation model is then used to characterize and compare, with respect to the motion and alignment properties as well as the required driving force, the diverse vibration-based alignment concepts.

Piston rings are installed in the piston and cylinder wall, which does not have a perfect round shape due to machining tolerances or external loads e.g. head bolts tightening. If the ring cannot follow these deformations, a localized lack of contact will occur and consequently an increase in the engine blow-by and lubricant oil consumption. Current 2D computational methods can not implement such effects – more complex model is necessary. The presented master’s thesis is focused on the developement of a flexible 3D piston ring model able to capture local deformations. It is based on the Timoshenko beam theory in cooperation with MBS software Adams. Model is then compared with FEM using software ANSYS. The validated piston ring model is assembled into the piston/cylinder liner and very basic simulations are run. Finally, future improvements are suggested.

This work deals with the matter of powertrain vibration reduction, focusing on the transmission. These units, depending on the purpose of utilization, consist of a high number of dimensionally complex components. These need to possess features, selected already in the design phase, which would guarantee smooth and quiet operation. A properly designed tooth profile and the related specified accuracy of manufacturing are one of the most important features. The basic function and the purpose of transmissions application indicate a relatively wide range of operating speeds and transmitted loads. Moreover, combination of both loading with improperly designed string’s parameter can cause a number of various problems. The vibration initiation with related noise from gear mesh belong to the most significant sources of issues. There are multiple mechanisms of oscillation initiation. Even when using the latest trends in the development of teeth, when their shape is upgraded and developed to meet specifically given load range, the above mentioned irregularity of transferred torque cannot be completely eliminated. Therefore, it is necessary, already in the design phase, to eliminate the transmission paths by which are vibrations transmitting to other components. People perceive this action in the form of vibration, noise, or temperature change in the surroundings. With the increasing comfort levels and number of produced vehicles the reduction of vibration and noise of machinery parts becomes stricter, including gears. The experimental approach is primarily used to assess the accuracy of designed gearboxes, but it is a very expensive and a time consuming method. Therefore, it is necessary to develop a process that utilizes both numerical simulation and experimental approach but also combines the advantages of both, particularly time and cost savings and comparability of results. For this purpose, the experimental gearbox is designed and manufactured including the single-stage gear enabling variable configurations in terms of the ratio change. The gearbox is subjected to numerical simulation of different complexity levels, as well as technical experiment. Furthermore, the universal virtual prototype in Multi-Body System ADAMS is created, which reflects the impact of several key parameters for proper functionality, such as axial distance, backlash, gear mesh stiffness, shaft mounting stiffness (bearings) and modal properties of the shafts and gearbox housing. Last but not least, the impact of imbalance or irregularity of input shaft speed is incorporated. The last part focuses on a brief description of the application of the presented methodology – modelling of vibrations on the tractor gearbox.

In slide chain conveyors vibrations often appear. These cause detrimental effects in conveying process and decrease the durability of chains. To study the vibrations, a multi-body simulation model has been developed, in which rheological elements are used to represent the dynamic effects. A focus was determining material values required for the model. These were identified by hysteresis experiments. Finally, the model was verified by comparing simulation results with measurements in the conveyor system. / In Gleitkettenfördersystemen werden häufig Schwingungen der Kette beobachtet, die einen zuverlässigen Förderprozess auf diesen Anlagen beeinträchtigen können. Ziel dieser Arbeit ist die Erforschung dieser Schwingungen mit Hilfe von einem Mehrkörpersimulationsmodell. Zur Abbildung der dynamischen Effekte wurden rheologische Elemente verwendet. Ein Schwerpunkt lag bei der Ermittlung der für das Modell notwendigen Materialkennwerte. Diese wurden mit Hilfe von Hystereseversuchen herausgefunden. Zum Schluss wurde das Modell über einen Abgleich zwischen Simulation und Messung im Fördersystem verifiziert.