Noise emission is a major drawback of the positive displacement machine. The noise source can be divided into structure borne noise source (SBNS) and fluid borne noise source (FBNS). Passive techniques such as valve plate optimization have been used for noise reduction of axial piston machines. However, passive techniques are only effective for limited operating conditions or at least need compromises in design. In this paper, active vibration control of swash plate is investigated for vibration and noise reduction over a wide range of operating conditions as an additional method to passive noise reduction techniques. A 75cc pump has been modified for implementation of active vibration control using the swash plate. One tri-axial acceleration sensor and one angle sensor are installed on the swash plate and a high speed servovalve is used for the swash plate actuation. The multi-frequency two-weight least mean square (LMS) filter synthesizes the servovalve input signal to generate a destructive interference force which minimizes the swash plate vibration. An experimental test setup has been realized using Labview field-programmable gate array (FPGA) via cRIO. Simulation and experimental studies are conducted to investigate the possibility of active vibration control.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21091号 / 工博第4455号 / 新制||工||1692(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 五十嵐 晃, 教授 八木 知己, 准教授 古川 愛子 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Dans cette thèse, nous proposons des solutions pour la conception de systèmes de contrôle actif de vibration robustes (AVC). Le manuscrit de thèse comporte deux grandes parties.Dans la première, les problèmes d'incertitude paramétrique dans les systèmes de contrôle actif de vibration sont étudiés. En plus des incertitudes sur la fréquence des perturbations, nous avons trouvé que la présence de zéros complexes peu amortis soulevait des problèmes de conception difficiles, même pour des systèmes et des modèles parfaitement connus. Dans ce contexte, nous avons proposé des solutions pour le problème linéaire. Une procédure améliorée d'identification en boucle fermée a été développée pour réduire les incertitudes dans l'identification de ces zéros. Pour traiter les incertitudes sur la perturbation, l'adaptation de la fréquence est de toute façon incontournable.La seconde partie est consacrée au développement et/ou à l'amélioration de deux algorithmes, désormais classiques, de compensation par feedback adaptatif direct, fondés sur la paramétrisation de Youla-Kučera. Le premier résulte de l'amélioration d'un précédent travail (Landau et al., 2005) ; les contributions concernent la synthèse du contrôleur central robuste et l'utilisation optionnelle de la surparamétrisation du filtre Q-FIR (réponse à temps fini) avec pour effet de minimiser l'effet « waterbed » sur la fonction de sensibilité de sortie. Le second algorithme présente une structure hybride directe/indirecte qui utilise un filtre Q-IIR (à temps de réponse infini). Les améliorations sont dues principalement au dénominateur du filtre, obtenu à partir d'une estimation de la perturbation. Cette solution permet également de simplifier la conception du contrôleur central.Les algorithmes ont été testés, comparés et validés sur un procédé réel du laboratoire Gipsa-lab, dans le cadre d'un benchmark international. / In this thesis, solutions for the design of robust Active Vibration Control (AVC) systems are presented. The thesis report is composed of two main parts.In the first part of the thesis uncertainties issues in Active Vibration Control systems are examined. In addition of the uncertainties on the frequency of the disturbances it has been found that the presence of low damped complex zeros raise difficult design problems even if plant and models are perfectly known. Solutions for the linear control in this context have been proposed. In order to reduce the uncertainties in the identification of low complex zeros and improved closed loop identification procedure has been developed. To handle the uncertainties on the disturbance frequency adaptation has any way to be used.The second part is concerned with the further development and/or the improvement of the now classical direct adaptive feedback compensation algorithms using Youla Kucera controller parametrization. Two new solutions have been proposed in this context. The first one results from the improvement of a previous work (Landau et al., 2005). The contributions are a new robust central controller design to the optional use of over parameterization of the Q-FIR filter which aims to ensure a small waterbed effect for the output sensitivity function and therefore reducing the unwanted amplification. The second algorithm presents a mixed direct/indirect structure which uses a Q-IIR filter. The improvements are mainly the effect of the Q filter denominator, which is obtained from a disturbance identification. This solution in addition drastically simplifies the design of the central controller.The algorithms have been tested, compared and validated on an international benchmark setup available at the Control System Department of GIPSA-Lab, Grenoble, France.

Dans cette thèse, nous présentons des solutions pour la conception des systèmes de contrôle actif de vibrations. Dans la première partie, des méthodes de contrôle par action anticipatrice (feedforward) sont développées. Celles-ci sont dédiées à la suppression des perturbations bande large en utilisant une image de la perturbation mesurée par un deuxième capteur, en amont de la variable de performance à minimiser. Les algorithmes présentés dans cette mémoire sont conçus pour réaliser de bonnes performances et maintenir la stabilité du système en présence du couplage positif interne qui apparaît entre le signal de commande et l'image de la perturbation. Les principales contributions de cette partie sont l'assouplissement de la condition de « Stricte Positivité Réelle » (SPR) par l'utilisation des algorithmes d'adaptation « Intégrale + Proportionnelle » et le développement de compensateurs à action anticipatrice (feedforward) sur la base de la paramétrisation Youla-Kučera. La deuxième partie de la thèse concerne le rejet des perturbations bande étroite par contre-réaction adaptative (feedback). Une méthode d'adaptation indirecte est proposée pour le rejet de plusieurs perturbations bande étroite en utilisant des filtres Stop-bande et la paramétrisation Youla-Kučera. Cette méthode utilise des Filtres Adaptatifs à Encoche en cascade pour estimer les fréquences de perturbations sinusoïdales puis des Filtres Stop-bande pour introduire des atténuations aux fréquences estimées. Les algorithmes sont vérifiés et validés sur un dispositif expérimental disponible au sein du département Automatique du laboratoire GIPSA-Lab de Grenoble. / In this thesis, solutions for the design of robust Active Vibration Control (AVC) systems are presented. The thesis report is composed of two parts. In the first one, feedforward adaptive methods are developed. They are dedicated to the suppression of large band disturbances and use a measurement, correlated with the disturbance, obtained upstream from the performance variable by the use of a second transducer. The algorithms presented in this thesis are designed to achieve good performances and to maintain system stability in the presence of the internal feedback coupling which appears between the control signal and the image of the disturbance. The main contributions in this part are the relaxation of the Strictly Positive Real (SPR) condition appearing in the stability analysis of the algorithms by use of “Integral + Proportional” adaptation algorithms and the development of feedforward compensators for noise or vibration reduction based on the Youla-Kučera parameterization. The second part of this thesis is concerned with the negative feedback rejection of narrow band disturbances. An indirect adaptation method for the rejection of multiple narrow band disturbances using Band-Stop Filters (BSF) and the Youla-Kučera parameterization is presented. This method uses cascaded Adaptive Notch Filters (ANF) to estimate the frequencies of the disturbances' sinusoids and then, Band-stop Filters are used to shape the output sensitivity function independently, reducing the effect of each narrow band signal in the disturbance. The algorithms are verified and validated on an experimental setup available at the Control Systems Department of GIPSA-Lab, Grenoble, France.

Smart structure control systems commonly use piezoceramic sensors or accelerometers as vibration measurement devices. These measurement devices often produce noisy and/or low-precision signals, which makes it difficult to measure small-amplitude vibrations. Laser interferometry devices pose as an alternative high-precision position measurement method, capable of nanometer-scale resolution. The aim of this research is to utilize a model-based design approach to develop and implement a real-time Linear Quadratic Gaussian (LQG) regulator for a piezoelectric actuated smart structure using a high-precision laser interferometry measurement system to suppress the excitation of vibratory modes. The analytical model of the smart structure is derived using the extended Hamilton Principle and Euler-Bernoulli beam theory, and the equations of motion for the system are constructed using the assumed-modes method. The analytical model is organized in state-space form, in which the effects of a low-pass filter and sampling of the digital control system are also accounted for. The analytical model is subsequently validated against a finite-element model in Abaqus, a lumped parameter model in Simscape Multibody, and experimental modal analysis using the physical system. A discrete-time proportional-derivative (PD) controller is designed in a heuristic fashion to serve as a baseline performance criterion for the LQG regulator. The Kalman Filter observer and Linear Quadratic Regulator (LQR) components of the LQG regulator are also derived from the state-space model. It is found that the behavior of the analytical model closely matches that of the physical system, and the performance of the LQG regulator exceeds that of the PD controller. The LQG regulator demonstrated quality estimation of the state variables of the system and further constitutes an exceptional closed-loop control system for active vibration control and disturbance rejection of the smart structure.

FAPEMIG - Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Esta Dissertação versa sobre a análise de confiabilidade de estruturas sujeitas a controle ativo e passivo de vibrações, com ênfase na aplicação dos métodos de confiabilidade de primeira ordem (FORM, First Order Reliability Method) e segunda ordem (SORM, Second Order Reliability Method). Esses são usados para calcular o índice de confiabilidade e, consequentemente, a probabilidade de falha de estruturas, considerando variáveis aleatórias modeladas segundo funções densidade de probabilidade. Três técnicas de controle são avaliadas: controle ativo empregando atuadores piezelétricos; controle passivo por absorvedores dinâmicos de vibrações e controle passivo baseado em atuadores piezelétricos conectados a circuitos shunt ressonantes. Para cada caso, são definidas funções de estado limite que descrevem limites operacionais e/ou requisitos de projeto, cuja avaliação é baseada em respostas obtidas por meio de modelos de elementos finitos das estruturas analisadas. Para cada uma das técnicas de controle, aplicações numéricas dos métodos FORM e SORM são realizadas considerando como estrutura principal uma treliça plana. Para efeito de avaliação da precisão das estimações de confiabilidade fornecidas por estes métodos, foram também utilizadas Simulações de Monte Carlo. A partir dos resultados, são discutidas as características específicas observadas para cada técnica de controle. Em específico, para duas delas foram identificados domínios de segurança e de falha de formas atípicas, em cujos casos, fica inviabilizado o uso dos métodos FORM e SORM. De modo geral, os resultados confirmam a importância e a conveniência de se aplicarem os métodos de análise de confiabilidade a estruturas sujeitas a procedimentos de controle de vibrações. / This dissertation is devoted to the reliability analysis of structures subjected to active and passive vibration control, with emphasis on the use of First Order Reliability Method (FORM) and Second Order Reliability Method (SORM). These methods are used to evaluate the reliability indices and the associated failure probability, considering that the random variables are modeled by probability density functions. Three techniques of vibration control are considered, namely: active control using PZT stack actuators, passive control based on dynamic vibration absorbers, and passive control based on piezoelectric transducers connected to resonant shunt circuits. For each technique, limit state functions are defined related to the operational limitations or design requirements. Their evaluation is made from structural responses obtained from finite element models. For each control technique, numerical applications of FORM and SORM are carried-out for a two-dimensional truss, defined as the structure of interest. To assess the accuracy of the reliability estimations provided by those methods, Monte Carlo Simulations are also performed. The numerical results enable to put in evidence specific characteristics of each control technique as related to reliability. Specifically, for two of them it is verified the occurrence of atypical geometrical forms of the safety and failure domains, which preclude the use of FORM and SORM. In general, the results confirm the importance and convenience of performing reliability assessment of structures subjected to vibration control procedures. / Dissertação (Mestrado)

Cette recherche vise à résoudre un problème particulier du contrôle de vibration des structures intelligentes. Notre objectif est de réduire les vibrations dans une zone spécifique de la structure intelligente avec une perturbation qui couvre une large gamme de fréquences. De plus, dans cette zone spécifique, ni l'actionnement ni la détection ne sont possibles.Ici, nous faisons face à plusieurs défis principaux. Premièrement, nous devons contrôler les vibrations d’une zone spécifique de la structure, alors que nous n’avons accès aux mesures que dans d’autres zones. Deuxièmement, la large bande passante de la perturbation implique que nombreux modes doivent être contrôlés au même temps, ce qui nécessite l'utilisation de plusieurs actionneurs et capteurs. Cela conduit à un contrôleur MIMO difficile à obtenir avec les méthodes classiques de conception de contrôleur. Troisièmement, il faut éviter le problème de propagation, qui consiste à garantir la stabilité en boucle fermée lorsque le contrôleur basé sur un modèle est appliqué à la configuration réelle. Pour relever ces défis, nous étudions deux stratégies de contrôle: le contrôle centralisé et le contrôle distribué.Pour le contrôle centralisé, nous proposons une méthodologie qui nous permet d’obtenir un contrôleur MIMO simple permettant de relever ces défis. Tout d'abord, plusieurs techniques de modélisation et d’identification sont appliquées pour obtenir un modèle précis d'ordre faible de la structure intelligente. Ensuite, une méthode de synthèse basée sur le contrôle H_∞ avec un critère H_∞ particulièrement proposé est appliquée. Ce critère H_∞ intègre plusieurs objectifs de contrôle, y compris les défis principaux. En particulier, le problème de débordement se transforme en un problème de stabilité robuste et sera garanti en utilisant ce critère. Le contrôleur H_∞ obtenu est une solution standard du problème H_∞. Le contrôleur final est obtenu en simplifiant ce contrôleur H_∞ sans perdre la stabilité en boucle fermée ni dégrader les performances. Cette méthodologie est validée sur une structure de poutre avec des transducteurs piézoélectriques et la zone centrale est celle où les vibrations devraient être réduites. L'efficacité du contrôleur obtenu est validée par des simulations et des expériences.Pour le contrôle distribué, on considère la même structure de poutre et les mêmes objectifs de contrôle. Il existe des méthodes visant à concevoir des contrôleurs distribués pour les systèmes spatialement interconnectés. Cette recherche propose une méthode basée sur la FEM, associée à plusieurs techniques de réduction de modèle, permettant de discrétiser spatialement la structure de poutre et d'en déduire les modèles d’espace d'état des sous-systèmes interconnectés. La conception des contrôleurs distribués ne sera pas abordée dans cette recherche. / This research aims at solving a particular vibration control problem of smart structures. We aim at reducing the vibration in a specific zone of the smart structure under the disturbance that covers a wide frequency band. Moreover, at this specific zone, neither actuation nor sensing is possible.Here we face several main challenges. First, we need to control the vibration of a specific zone of the structure while we only have access to measurements at other zones. Second, the wide bandwidth of the disturbance implies that numerous modes should be controlled at the same time which requires the use of multiple actuators and sensors. This leads to a MIMO controller which is difficult to obtain using classical controller design methods. Third, the so-called spillover problem must be avoided which is to guarantee the closed-loop stability when the model-based controller is applied on the actual setup. To tackle these challenges, we investigate two control strategies: the centralized control and the distributed control.For centralized control, we propose a methodology that allows us to obtain a simple MIMO controller that accomplishes these challenges. First, several modeling and identification techniques are applied to obtain an accurate low-order model of the smart structure. Then, an H_∞ control based synthesis method with a particularly proposed H_∞ criterion is applied. This H_∞ criterion integrates multiple control objectives, including the main challenges. In particular, the spillover problem is transformed into a robust stability problem and will be guaranteed using this criterion. The obtained H_∞ controller is a standard solution of the H_∞ problem. The final controller is obtained by further simplifying this H_∞ controller without losing the closed-loop stability and degrading the performance. This methodology is validated on a beam structure with piezoelectric transducers and the central zone is where the vibration should be reduced. The effectiveness of the obtained controller is validated by simulations and experiments.For distributed control, we consider the same beam structure and the same control objectives. There exist methods aiming at designing distributed controllers of spatially interconnected system. This research proposes a FEM based method, combined with several model reduction techniques, that allows to spatially discretize the beam structure and deduce the state-space models of interconnected subsystems. The design of distributed controllers will not be tackled in this research.