No description available.

Boom cranes are one of the most dynamically complicated types of cranes because they possess rotational joints as opposed to the linear tracks of bridge and gantry cranes. In addition, if the boom crane is placed on a mobile base, additional complexity is added to the system. However, mobile boom cranes have huge potential benefits as they can be quickly transported from one location to another. Furthermore, if they utilize their mobile base during lifting operations, then they can have an extremely large workspace. All cranes share the same limiting weakness; the payload oscillates when the crane moves. A command-generation approach is taken to control the payload oscillation. Input shaping is one such command-generation technique that modifies the original reference command by convolving it with a series of impulses. The shaped command produced by the convolution can then move the crane without inducing payload oscillation. Input shaping can accommodate parameter uncertainties, nonlinearities, multiple modes of vibration, and has been shown to be compatible with human operators. This thesis focuses on three aspects of mobile boom cranes: 1) dynamic analysis, 2) input-shaping control, and 3) experimental testing. A majority of the thesis focuses on analyzing and describing the complicated dynamics of mobile boom cranes. Then, various input-shaping controllers are designed and tested, including two-mode shapers for double-pendulum dynamics. In order to experimentally verify the simulation results, a small-scale mobile boom crane has been constructed. The details of the mobile boom crane and its important features are presented and discussed. Details of the software used to control the crane are also presented. Then, several different experimental protocols are introduced and the results presented. In addition, a set of operator performance studies that analyze human operators maneuvering the mobile boom crane through an obstacle course is presented.

No description available.

A Magnetorheological damper is a commonly used component in semi-active suspensions that achieves a high force capacity and better performance than a passive system, without the added expense and power draw of a fully active system, all while maintaining failsafe performance. To fully exploit the capabilities of an MR Damper, a high fidelity controller is required that is simple and easy to implement, yet does not compromise the accuracy or precision needed in many high-performance applications. There is a growing need for this level of operation, and this proposed work addresses these requirements by creating an empirically derived invertible model that enables the development of more accurate command signals by capturing the effect of temperature on a MR Damper's performance capabilities. Furthermore, this solution is specifically tailored for real-time application and does not require force feedback. Thus it requires low computation power and minimizes end-user cost by eliminating the need for additional high cost sensors such as load cells. A notable observation that resulted from the development of this proposed model was the difference in behavior between on and off states. Additionally a unique behavior was recognized with respect to the transition between high speed and low speed damping. For validation, the proposed model was compared against experimental data as well as an industry standard Spencer model; it produced excellent results in both cases with minimal error. / Master of Science

Η αυτόματη πλοήγηση πλοίων αποτελεί ένα αντικείμενο ιδιαίτερης μελέτης κατά τα τελευταία χρόνια. Αυτό οφείλεται αφενός στην μεγάλη χρησιμότητα της εφαρμογής της, αφετέρου στην δυσκολία μαθηματικής περιγραφής και μοντελοποίησης των αντίστοιχων συστημάτων. Κατά την διπλωματική εργασία αυτή, σχεδιάστηκε ένας ελεγκτής ανοικτού βρόχου εμπροσθογενούς δράσης, με τη βοήθεια πειραματικών μετρήσεων, που σε συνδυασμό με τους συνήθεις πλέον PD και ασαφείς ελεγκτές, υλοποιήθηκε με σκοπό τον πειραματικό έλεγχο της θέσης και του προσανατολισμού του μοντέλου ενός πραγματικού πλοίου. / Control in ship navigation is a field of excess research during the last few years. The increasing need for automated ship navigation, combined with the challenging to describe and model systems of ships and other vessels, has led to many great works on this area. In this diploma thesis an open loop feedforward controller was designed using experimental data. This controller was used together with PD and Fuzzy controllers to control the position and the orientation of a model ship.

Le développement récent en micro- et nanotechnologies (dans des domaines tels que l’horlogerie,l’électronique, l’optique, le biomédical, . . .) a créé un fort besoin concernant des systèmes capables de manipuler et d’assembler des objets de plus en plus petits. La conception de stations robotisées, capables de manipuler des micro-objets, s’est multipliée à travers le monde, faisant intervenir des actionneurs de haute résolution adaptés au micro monde, ainsi que de nombreux capteurs.Ce mémoire ouvre une nouvelle voie pour le développement de robots de micromanipulation. Il présente la conception, la modélisation, la fabrication et la commande d’un nouveau concept de micro robot, le DiMiBot (Digital MicroroBot). Il s’agit du premier micro robot numérique – inspiré ´e de l’ ´électronique numérique – qui fait intervenir des actionneurs binaires pour générer un déplacement discret d’une grande précision sans nécessiter de capteur (en boucle ouverte). Ces actionneurs binaires extrêmement répétables et robustes (les modules bistables), assurent chacun un déplacement précis de 25 μm. Ils sont associés de manière monolithique à une architecture robotique parallèle flexible, assurant la génération d’un espace de travail discret, dont les 2N (N est le nombre de modules bistables utilisés au sein du DiMiBot) positions distincts atteignables sont parfaitement stables, répétables et robustes mécaniquement. Elles sont réparties de manière homogène dans un carré de 10,5 μm de côté La micro fabrication du premier prototype de micro robot numérique en silicium – faisant suite `a un dimensionnement minutieux en élément finis – a été réalisé au sein de la salle blanche MIMENTO de l’institut FEMTO-ST. Ce DiMiBot possédant 4 modules bistables assure une résolution de 3,5 μm pour une répétable de chacune des 16 positions atteignables de 90 nm. / With the current expansion of micro- and nano-technologies (in such domains as watchmaking, electronics,optics, biomedical, . . .), came the necessity to build systems able to manipulate and make the assembly ofsmaller and smaller objects. Design of robotic stations, able to manipulate micro-objects, expanded all over theworld, making use of high resolution actuators and numerous sensors adapted to the microworld.This thesis opens a new paradigm in the design of micromanipulation robotics. We present the design, modeling,fabrication and control of a new microrobot, the DiMiBot (Digital MicroroBot). It is the first digital microrobot— inspired from digital electronics — which makes use of binary actuators for the generation of discretedisplacements with high accuracy without any sensors (open-loop control). These highly repeatable and robustbinary actuators (bistable modules) generate an accurate displacement of 25 μm. They are monolithicallyconbined with a parallel flexible architecture, allowing the generation of a discrete workspace, in which all the2N (N is the number of bistable modules used) distinct reachable positions are perfectly stable, repeatable andmechanically robust. They are evenly spread inside a 10.5 μm length square.After dimensioning, the first digital microrobot prototype in silicon was microfabricated in MIMENTO clean-roomof FEMTO-ST institute. This DiMiBot has 4 bistable modules and generates a workspace of 3.5 μm resolutionwith 90 nm repeatability

The Finite Element Method (FEM) based computational mechanics is applied to simulate the optimal attenuation of vibrations in actively controlled structures. The simulation results provide the forces to be generated by actuators, as well as the structures response. Vibrations can be attenuated by applying either open loop or closed loop control strategies. In open loop control, the control forces for a given initial (or disturbed) configuration of the structure are determined in terms of time, and can be preprogrammed in advance. On the other hand, the control forces in closed loop control depend only on the current state of the system, which should be continuously monitored. Optimal attenuation is obtained by solving the optimality equations for the problem derived from the Pontryagins principle. These equations together with the initial and final boundary conditions constitute the two-point-boundary-value (TPBV) problem. <p>Here the optimal solutions are obtained by applying an analogy (referred to as the beam analogy) between the optimality equation and the equation for a certain problem of static beams in bending. The problem of analogous beams is solved by the standard FEM in the spatial domain, and then the results are converted into the solution of the optimal vibration control problem in the time domain. The concept of the independent-modal-space-control (IMSC) is adopted, in which the number of independent actuators control the same number of vibrations modes. <p>The steps of the analogy are programmed into an algorithm referred to as the Beam Analogy Algorithm (BAA). As an illustration of the approach, the BAA is used to simulate the open loop vibration control of a structure with several sets of actuators. Some details, such as an efficient meshing of the analogous beams and effective solving of the target condition are discussed. <p> Next, the BAA is modified to handle closed loop vibration control problems. The algorithm determines the optimal feedback gain matrix, which is then used to calculate the actuator forces required at any current state of the system. The methods accuracy is also analyzed.

The Finite Element Method (FEM) based computational mechanics is applied to simulate the optimal attenuation of vibrations in actively controlled structures. The simulation results provide the forces to be generated by actuators, as well as the structures response. Vibrations can be attenuated by applying either open loop or closed loop control strategies. In open loop control, the control forces for a given initial (or disturbed) configuration of the structure are determined in terms of time, and can be preprogrammed in advance. On the other hand, the control forces in closed loop control depend only on the current state of the system, which should be continuously monitored. Optimal attenuation is obtained by solving the optimality equations for the problem derived from the Pontryagins principle. These equations together with the initial and final boundary conditions constitute the two-point-boundary-value (TPBV) problem. <p>Here the optimal solutions are obtained by applying an analogy (referred to as the beam analogy) between the optimality equation and the equation for a certain problem of static beams in bending. The problem of analogous beams is solved by the standard FEM in the spatial domain, and then the results are converted into the solution of the optimal vibration control problem in the time domain. The concept of the independent-modal-space-control (IMSC) is adopted, in which the number of independent actuators control the same number of vibrations modes. <p>The steps of the analogy are programmed into an algorithm referred to as the Beam Analogy Algorithm (BAA). As an illustration of the approach, the BAA is used to simulate the open loop vibration control of a structure with several sets of actuators. Some details, such as an efficient meshing of the analogous beams and effective solving of the target condition are discussed. <p> Next, the BAA is modified to handle closed loop vibration control problems. The algorithm determines the optimal feedback gain matrix, which is then used to calculate the actuator forces required at any current state of the system. The methods accuracy is also analyzed.

No description available.

Denna avhandling behandlar analys och styrning av den modulära multinivå omvandlaren (M2C). M2C är en lovande omvandlarteknologi för högspända högeffekttillämpningar. Anledningen till detta är låg distorsion i utstorheterna kan uppnås med låg  medelswitchfrekvens per switch och utan utgångsfilter. Med M2C har utspänningen så lågt övertonsinnehåll att drift av högeffektmotorer är möjlig utan reduktion av märkeffekten. Emellertid innebär det stora antalet styrda switchar att styrningen blir mer komplex än för motsvarande tvånivåomvandlare. Styrningen av M2C måste måste konstrueras så att submodulernas kondensatorspänningar balanseras och är stabila oberoende av driftfall. En aktiv mekanism för val av submoduler, som är integrerad i modulatorn, har visat sig vara effektiv för att ombesörja den interna balanseringen av omvandlararmarna. Utöver balanseringen av de individuella kondensatorerna krävs en strategi för styrning av den totalt upplagrade energin i omvandlaren. Med utgångspunkt i en analytisk beskrivning av omvandlaren föreslås styrlagar för både öppen styrning och sluten reglering, vilka genom både simuleringar och med hjälp av experiment har visat sig vara stabila i hela arbetsområdet. Den potentiella växelverkan mellan den inre omvandlarstyrningen och en yttre strömreglering undersöks också. Både simuleringar och experiment bekräftar att eventuell interaktion inte innebär några avsevärda problem vare sig för omvandlaren eller motorn. En  hårdvaruimplementering av en nedskalad trefasig 10kVA-omvandlare har genomförts för att verifiera modellering och styrning. Implementeringen av styrningen beskrivs i detalj. Styrningen är anmärkningsvärt snabb och kan utökas till godtyckligt antal nivåer. Den kan därför användas för en fullskaleimplementering i MW-klassen. / This thesis deals with the analysis and control of the modular multilevel converter (M2C). The M2C is a promising converter technology for various high-voltage high-power applications. The reason to this is that low-distortion output quantities can be achieved with low average switching frequencies per switch and without output filters. With the M2C the output voltage has such a low harmonic content that high-power motors can be operated without any derating. However, the apparent large number of devices, requires more complex converter control techniques than a two-level counterpart. The internal control of an M2C must be designed so that the submodule capacitor voltages are equalized and stable independent of the loading conditions. An active submodule selection mechanism, included in the modulator, has been shown able to provide voltage sharing inside the converter arm. Apart from the individual capacitor voltage sharing, a strategy has to be designed to ensure that the total amount of energy stored inside the converter will always be controlled. Based on an analytical description of the converter, both feedback and open-loop control methods are suggested, simulated and experimentally evaluated, which will ensure stable operation in the whole operation range. The potential interaction of the internal controllers with an external motor current controller is also investigated. Both simulation and experimental results show that any interaction will not result in any problems neither for the converter nor for the motor control itself. A hardware implementation of a down-scaled 10 kVA three-phase laboratory prototype converter is performed, in order to evaluate the modeling and the controllers developed. The controller implementation is described in detail, as it exhibits remarkably fast response, and can be expanded up to an arbitrary number of levels. Therefore it can be used even by a full-scale converter implementation in the MW range. / QC 20110628