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The medical community has expressed a need for flexible medical instruments. Hence, this work investigates the possibility to use "flexible fluidic actuators" to develop such flexible instruments. These actuators are driven by fluid, i.e. gas or liquid, and present a flexible structure, i.e. an elastically deformable and/or inflatable structure. Different aspects of the study of these actuators have been tackled in the present work: • A literature review of these actuators has been established. It has allowed to identify the different types of motion that these actuators can develop as well as the design principles underlying. This review can help to develop flexible instruments based on flexible fluidic actuators. • A test bench has been developed to characterize the flexible fluidic actuators. • A interesting measuring concept has been implemented and experimentally validated on a specific flexible fluidic actuator (the "Pneumatic Balloon Actuator", PBA). Ac- cording to this principle, the measurements of the pressure and of the volume of fluid supplied to the actuator allow to determine the displacement of the actuator and the force it develops. This means being able to determine the displacement of a flexible fluidic actuator and the force it develops without using a displacement sensor or a force sensor. This principle is interesting for medical applications inside the human body, for which measuring the force applied by the organs to the surgical tools remains a problem. The study of this principle paves the way for a lot of future works such as the implemen- tation and the testing of this principle on more complex structures or in a control loop in order to control the displacement of the actuator (or the force it develops) without using a displacement or a force sensor. • A 2D-model of the PBA has been established and has helped to better understand the physics underlying the behaviour of this actuator. • A miniaturization work has been performed on a particular kind of flexible fluidic actu- ator: the Pleated Pneumatic Artificial Muscle (PPAM). This miniaturization study has been made on this type of actuator because, according to theoretical models, minia- turized PPAMs, whose dimensions are small enough to be inserted into MIS medical instruments, could be able to develop the forces required to allow the instruments to perform most surgical actions. The achieved miniaturized muscles have a design similar to that of the third generation PPAMs developed at the VUB and present a total length of about 90 mm and an outer diameter at rest of about 15 mm. One of the developed miniaturized PPAMs has been pressurized at p = 1 bar and it was able to develop a pulling force F = 100 N while producing a contraction of 4 %. Propositions have been made regarding a further miniaturization of the muscles.

Dans cette thèse, les problématiques de la modélisation et du contrôle robuste de l’attitude des grandes structures spatiales flexibles sont considérées. Afin de satisfaire les performances de pointage requises dans les scénarios des futures missions spatiales, nous proposons d’optimiser directement une loi de commande d’ordre réduit sur un modèle de validation d’ordre élevé et des critères qui exploitent directement la structure du modèle. Ainsi, les travaux de cette thèse sont naturellement divisés en deux parties : une partie relative à l’obtention d’un modèle dynamique judicieusement structuré du véhicule spatial qui servira à l’étape de synthèse ; une seconde partie concernant l’obtention de la loi de commande.Ces travaux sont illustrés sur l’exemple académique du système masses-ressort, qui est la représentation la plus simple d’un système flexible à un degré de liberté. En complément, un cas d’étude sur un satellite géostationnaire est traité pour valider les approches sur un exemple plus réaliste d’une problématique industrielle. / In this thesis, modeling and robust attitude control problems of large flexible space structures are considered. To meet the required pointing performance of future space missions scenarios, we propose to directly optimize a reduced order control law on high order model validation and criteria that directly exploit the model structure. Thus, the work of this thesis is naturally divided into two parts : one part on obtaining a wisely structured dynamic model of the spacecraft to be used in the synthesis step, a second part about getting the law control. This work is illustrated on the example of the academic spring-masses system, which is the simplest representation of a one degree of freedom flexible system. In addition, a geostationary satellite study case is processed to validate developed approaches on a more realistic example of an industrial problem.

<p>In this master thesis, control algoritms using arm side sensors are investigated for an industrial robot. The sensors can be position encoders placed after the gearbox and accelerometers on the robot arms. Control strategies are discussed and evaluated for different models of the robot, after which chosen strategies are applied to a realistic model. </p><p>Control algoritms using arm side sensors (LQ, dual-loop and PD-PID) are compared to a PID-controller that only uses measurements of motor position for feedback control. The comparison are done with respect to disturbance rejection, oscillation damping, robustness and tracking performance of a reference trajectory. </p><p>Results from tests with the realistic robot modell shows that disturbance rejection was improved a factor 2 to 5 while tracking performance was improved a factor 4 to 5 according to maximum deviation from the reference path. At the same time good re-sults are achieved regarding oscillation damping and robustness.</p>

In this master thesis, control algoritms using arm side sensors are investigated for an industrial robot. The sensors can be position encoders placed after the gearbox and accelerometers on the robot arms. Control strategies are discussed and evaluated for different models of the robot, after which chosen strategies are applied to a realistic model. Control algoritms using arm side sensors (LQ, dual-loop and PD-PID) are compared to a PID-controller that only uses measurements of motor position for feedback control. The comparison are done with respect to disturbance rejection, oscillation damping, robustness and tracking performance of a reference trajectory. Results from tests with the realistic robot modell shows that disturbance rejection was improved a factor 2 to 5 while tracking performance was improved a factor 4 to 5 according to maximum deviation from the reference path. At the same time good re-sults are achieved regarding oscillation damping and robustness.

Στην παρούσα διατριβή διερευνήθηκε η δυνατότητα του GPS-RTS στη μελέτη ταλαντώσεων ως προς την ακρίβεια προσδιορισμού του εύρους και της συχνότητας ταλάντωσης και το διάστημα των συχνοτήτων που μπορούν να καταγραφούν, με βάση συσκευή παραγωγής ελεγχόμενων εξαναγκασμένων ταλαντώσεων και ακολουθήθηκε στατιστική ανάλυση δεδομένων. Τα πειράματα βασίστηκαν στην σύγκριση των καταγραφών ταλαντώσεων γνωστών χαρακτηριστικών που δημιούργησε η συσκευή και την σύγχρονη καταγραφή τους με τα όργανα GPS και RTS και εν μέρη άμεση οπτική παρατήρηση. Κατά την φάση των πειραμάτων αντιμετωπίστηκαν προβλήματα απώλειας των μετρήσεων τα οποία εκτιμάται ότι μπορούν να αντιμετωπιστούν με κατάλληλη συνδεσμολογία για το GPS και κατάλληλο λογισμικό για το RTS Οι χρονοσειρές που προέκυψαν από περισσότερα από 100 πειράματα αναλύθηκαν με συμβατικές στατιστικές μεθόδους (π.χ. έλεγχο χονδροειδών σφαλμάτων) και φασματική ανάλυση με βάση τις μεθόδους: FFT, το περιοδόγραμμα Lomb και την Φασματική Ανάλυση Ελαχίστων Τετραγώνων (LSSA). Με βάση τις προτεινόμενες μεθόδους αναλύσεων προέκυψαν τα παρακάτω: • το GPS μπορεί να καταγράψει με ακρίβεια ταλαντώσεις με συνολικό εύρος ≥4cm για συχνότητες διέγερσης ≤4 Hz ενώ μπορεί να προσδιορίσει την συχνότητα ταλάντωσης ακόμα για διέγερση των 4 Hz και • το RTS μπορεί να καταγράψει με ακρίβεια ταλάντωσης με συνολικό εύρος ταλάντωσης της τάξης του 1 cm και μπορεί να προσδιορίσει με ακρίβεια την συχνότητα διέγερσης για χαμηλόσυχνές ταλαντώσεις (μέχρι και 1 Hz). Συμπερασματικά, οι μέθοδοι επίγειων αλλά και δορυφορικών μεθόδων μπορούν να χρησιμοποιηθούν για την παρακολούθηση των ταλαντώσεων/μετακινήσεων των εύκαμπτων κατασκευών, ενώ με βελτίωση των διατάξεών τους και των λογισμικών τους με στόχο να αντιμετωπιστούν τα προβλήματα που παρουσιάστηκαν, αναμένεται ακόμα καλύτερη ακρίβεια. / At the present study, the ability of GPS-RTS was examined for the oscillation monitoring.At the present thesis, the performance of the modern geodetic methods, GPS and RTS, for the oscillation monitoring was examined. In order to assess the performance of the two methods the study was based on known oscillations which were produced by a special oscillation device and the records of GPS and RTS which were monitoring the oscillations. The estimate of the performance was based on the comparison of the known oscillation characteristics (displacement and frequency) and those which were arose by the analysis of the GPS-RTS records. During the oscillation experiments many problems were faced and especially with interruptions at the GPS and RTS records, which can be solved by a more appropriate connection between the antenna and the receiver of the GPS system and the use of a more advanced software for the RTS. Time series, based on the GPS-RTS records of more than 100 oscillations experiments, were analysed with compatible statistical and frequency domain analysis methods: FFT, LSSA (Least Square Spectrum Analysis) and Lomb. According to the analysis: • GPS can define accurately the total oscillation displacement when it is ≥4cm and the frequency when it is ≤4 Hz and • RTS can define accurately the total oscillation displacement when it is ≥1cm and the frequency when it is ≤1 Hz. According to the analysis, the two geodetic methods proved to be very accurate for the oscillation monitoring of flexible structures and their performance can be improved with the use of more sophisticated software for the RTS and connections for the GPS.

[pt] A multiprogamação caracteriza-se pelo compartilhamento dos recursos da máquina por vários processos usuários. O ambiente de computação propício para execução destes processos deve incluir dispositivos para relocação de endereços, proteção de memória, estados supervisor e usuário, e uma estrutura flexível de entrada e saída. A implementação de tais sistemas com microprocessadores de 8 bits é problemática, devido ao seu desempenho aquém do desejável para tal propósito. Com o INTEL 8086 iniciou-se a geração dos microprocessadores de 16 bits, com desempenho comparável aos processadores de pequenos minicomputadores. Apesar deste desempenho, esta partilha é voltada par as mesmas aplicações dos microprocessadores de 8 bits: processamento dedicado e sistemas monoprogramados. Por isso não foram previstos mecanismos de suporte à multiprogramação. Esta dissertação apresenta um microcomputador para multiprogramação, baseado no INTEL 8086, em que várias facilidades foram implementadas, por lógica externa, para este fim. São descritos e analisados os vários dispositivos desenvolvidos para que fosse criado um ambiente propício para multiprogramação sem que se deteriorasse o desempenho do processador. Este trabalho recebeu auxílio do CNPq, processo nº 40.2029180, como parte do projeto MULTIPUC. / [en] Machine resources are shared by many processes in multiprogramming systems. The suitable environment to run these processes must include devices for address relocation, memory protection, supervisor and user modes of operation and a flexible input/output structure. It is very hard to implement such systems with 8 bits microprocessors, because their performances don`t file the desirable requirements. The 16 bits microprocessors generation, witch began with INTEL 8086, brougth more powerful processors, with performances as good as the small minicomputers processors. Nevertheless, INTEL 8086 was designed for the same applications as the 8 bits processors: dedicated processing and monoprogrammed systems. It doesn´t support multiprogramming applications. This work presents a microcomputer for multiprogramming, based on INTEL 8086. Many facilities are implemented, with external logic, to create a multiprogramming environmen without degenerate the processor performance. This work was supported by CNPq grant 40.2029180 as part of the project MULTIPUC.

Two-dimensional analysis of four types of water-filled tube dams is carried out: an apron-tube dam, a single baffle tube dam, a sleeved tube dam, and a stacked tube dam. Since the analysis of the water-filled tube dam involves highly nonlinear geometric deformations and interactions with soil, fluid, and structure, it is solved numerically with the explicit finite difference program FLAC. The tube is numerically modeled with beam elements. The predicted contact regions are modeled with interface elements. The Mohr-Coulomb constitutive model is used for the soil. Water inside and outside of the tube is modeled as hydrostatic pressure and the pressures are continuously updated as the configuration of the tube is changed. The change of the internal water pressure head (IWPH) for maintaining a constant tube area during the deformation is simulated. The simulation is achieved by two iterative procedures, the secant method and the factored secant method. The numerical analysis results show good agreement with the experimental results overall: the deformation of the tube(s), the IWPH changes, and the critical external water heights. From the numerical simulation of the experiments and the parametric studies, the behavior of each type of water-filled tube dam is clarified. Also, the failure modes of the tube dams are examined. The failure mode of a tube dam depends on the configuration and IWPH of the tube dam and the characteristics of the soil surface. / Ph. D.

The medical community has expressed a need for flexible medical instruments. Hence, this work investigates the possibility to use "flexible fluidic actuators" to develop such flexible instruments. These actuators are driven by fluid, i.e. gas or liquid, and present a flexible structure, i.e. an elastically deformable and/or inflatable structure. Different aspects of the study of these actuators have been tackled in the present work:<p>• A literature review of these actuators has been established. It has allowed to identify the different types of motion that these actuators can develop as well as the design principles underlying. This review can help to develop flexible instruments based on flexible fluidic actuators.<p>• A test bench has been developed to characterize the flexible fluidic actuators.<p>• A interesting measuring concept has been implemented and experimentally validated on a specific flexible fluidic actuator (the "Pneumatic Balloon Actuator", PBA). Ac- cording to this principle, the measurements of the pressure and of the volume of fluid supplied to the actuator allow to determine the displacement of the actuator and the force it develops. This means being able to determine the displacement of a flexible fluidic actuator and the force it develops without using a displacement sensor or a force sensor. This principle is interesting for medical applications inside the human body, for which measuring the force applied by the organs to the surgical tools remains a problem.<p>The study of this principle paves the way for a lot of future works such as the implemen- tation and the testing of this principle on more complex structures or in a control loop in order to control the displacement of the actuator (or the force it develops) without using a displacement or a force sensor.<p>• A 2D-model of the PBA has been established and has helped to better understand the physics underlying the behaviour of this actuator.<p>• A miniaturization work has been performed on a particular kind of flexible fluidic actu- ator: the Pleated Pneumatic Artificial Muscle (PPAM). This miniaturization study has been made on this type of actuator because, according to theoretical models, minia- turized PPAMs, whose dimensions are small enough to be inserted into MIS medical instruments, could be able to develop the forces required to allow the instruments to perform most surgical actions. The achieved miniaturized muscles have a design similar to that of the third generation PPAMs developed at the VUB and present a total length of about 90 mm and an outer diameter at rest of about 15 mm. One of the developed miniaturized PPAMs has been pressurized at p = 1 bar and it was able to develop a pulling force F = 100 N while producing a contraction of 4 %.<p>Propositions have been made regarding a further miniaturization of the muscles. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

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