This dissertation performs a simulation investigation into the nonlinear static and dynamic characteristics of electrostatically driven shaped micro-actuators in micro-electro-mechanical systems (MEMS). The model proposed in the current nonlinear pull-in deflection study considers various boundary conditions for the electrostatically actuated structures, e.g. the cantilever beam and the fixed-fixed beam, and takes account of the electrical field fringing effect and the axial residual stress. Initially, the Adomian decomposition method is employed to evaluate the response of a micro-actuator incorporating a rectangular micro-beam and a flat electrode by obtaining the closed-form solution of the corresponding nonlinear equation. Since no iteration is required in solving the nonlinear deformation, this decomposition method is one of the most efficient methods available for evaluating the unstable pull-in behavior of an electrostatically driven micro-actuator. The present study implements both small and large deflection assumptions when simulating the response of the micro-actuator in order to explore the possible effects of the two models on the accuracy of the simulation results. The shaped micro-beam with a curved electrode micro-actuator is further assessed using the differential quadrature method (DQM) to examine the influence of the nonlinear pull-in effect. This dissertation also studies the contact force and the pull-in deflection of shaped micro-tweezers. The DQM is employed to solve the nonlinear interaction between the curved electrostatic field force and the corresponding deflection of the shaped cantilever actuators. The numerical results confirm the ability of the DQM to treat this form of nonlinear actuator problem accurately, efficiently and systematically. To evaluate the dynamic characteristics of the electrostatic micro-actuator, the DQM is applied to solve the natural frequencies of a fixed-fixed shaped beam vibrating around its statically deflected position under electrostatic loading. The proposed model not only takes account of the nonlinear interaction between the curved electrostatic field force and the restoring force of the shaped micro-beam, but also considers mid-plane stretching, axial residual stress, and electrical field fringing effects. It is shown that an excellent agreement exists between the simulation results obtained using the proposed model and those measured experimentally. This study also investigates the micro-beam and electrode shape effect on the natural frequencies of the actuator system. The analytical results indicate that variations in the shape of the micro-beam or of the electrode not only influence the electrostatic field distribution, but also significantly alter the dynamic characteristics of the micro-actuator. Furthermore, the results demonstrate that the shaped micro-beam with a curved electrode micro-actuator increases the working voltage range of the micro-actuator by a factor of approximately six times compared to that of a micro-actuator incorporating a rectangular micro-beam and a flat electrode. A continuing trend nowadays is the integration of micro-electro-mechanical devices with electronic circuitry to fabricate MEMS devices such as micro-switches, optical micro-mirrors, etc. It is known that when an electrical voltage is applied to these devices, the micro-actuators will undergo a residual vibration before reaching their permanent position. Hence, this dissertation investigates the residual vibration phenomenon of cantilever beam type micro-switches with air squeeze-film damping between the micro-beam and substrate. The present simulations of various shaped micro-actuators provide an understanding of the nonlinear static and dynamic behaviors of these devices and as such provide designers with the information required to properly and accurately control the device operating range during the design stage.

<p>In this thesis a multilayer actuator structure is developed for the I-SWARM project. In order to build an energy efficient and low voltage actuator system for the 3x3x3 mm3 robot, the resonance drive mode in combination with a ten layer multilayer structure build upon the most suitable substrate material was used. Two different sizes of the locomotion module were built. The first one is five times larger than the small version. It has five active layers and is simpler to work with and to test. The small module has three 2x0.4 mm can-tilevers on a 3x3mm body and ten active layers.</p><p>The multilayer process involve easily defined flexible printed circuit (FPC) board as substrate material, spin coating piezoelectric poly(vinylidenefluoride- tetrafluoroethylene) P(VDF-TrFE) as active stack material, and evaporated aluminum electrodes on each active polymer layer. By using different shadow masks for each electrode layer, special inter con-tact areas can be contacted from above after the polymer has been removed by an Inductively Coupled Plasma (ICP) etch. The contours of the locomo-tion module was etched in a Reactive Ion Etch (RIE) equipment. Both the cupper layer in the FPC and the electrode layers of the active stack, were used as etch mask.</p><p>The deflections of the cantilevers were measured at low voltages to ensure as realistic drive voltage as possible for the I-SWARM robot. The large struc-ture showed a 250 µm deflection at 4 V and 170 Hz resulting in a Q-value of 19. The deflection of the small structure was 8 µm at 3.3 V and 5000 Hz and the measured Q-value was 31.</p>

The goal of this work is to quantify the key design parameters such as the load capacity, actuation force, positioning repeatability, and reliability for droplet-based electrowetting actuators. Due to the fact that surface tension dominates gravity at both the mesoscale and microscale, droplet-based actuators can provide adequate force in manipulation tasks at those scales. Electrowetting, which uses an electric field to modulate the apparent surface tension of the liquid-ambient, provides a method to actuate droplets, which in turn transports the object carried by the droplet. Most previous electrowetting actuation efforts have concentrated on manipulating droplets in a closed two-plate configuration. In these configurations, a voltage potential is applied between a series of electrodes. The droplets can merge, split, and mix with only a voltage input, and without any external machinery. While some mechanical actuation demonstrations have been done, limited studies have been performed to investigate the key actuation performance characteristics of droplet-based actuators carrying solid objects. Design criteria for using droplets to carry solid components are still not well defined. The first part of this work provides fundamental understanding of the forces in electrowetting-based droplet actuation. The actuation force during electrowetting was experimentally validated according to the governing relation (Young–Lippmann equation) on a custom-designed testing apparatus. The results from the experiments show that the electrowetting actuation force is independent of surface tension below saturation, but the peak force is proportional to surface tension. Higher surface/interfacial tension would increase the actuation force in the horizontal direction, as well as the speed of the actuator. The second part of the dissertation demonstrates two actuation configurations based on electrowetting. The first actuator uses a droplet to carry a solid object and can be actuated in discrete steps to function as a micro-stepping linear motor. By implementing a leaky dielectric coating, the droplet/substrate contact area acts as an electrical diode. By varying the duty cycle of a square waveform, a range of droplet/part equilibrium position combinations are established. The underlying actuation mechanism was investigated and the position versus duty cycle relation was shown to be symmetrical but non–linear around the center of the electrodes. In contrast to the conventional electrowetting control scheme, the proposed actuation method required no feedback control loop while achieving a repeatability of less than 0.8% of the droplet diameter. Positioning matched a theoretical model based on idealized electrical elements to within 2.5% of the droplet diameter. The second type of electrowetting actuation uses metal-semiconductor diodes (Schottky diodes) in place of electrochemical diodes. This configuration uses only one pair of electrodes to actuate the droplet over a large distance (5X or more the droplet diameter). While the actuation concept had been previously demonstrated, the reliability of the diodes were shown to be insufficient. The new diodes actuated without degradation under repeated actuation (2000 cycles). Comparing this to electrochemical diodes, a 50% reduction in actuation voltage was also accomplished by Schottky diodes. The measured maximum speed also increased from 32 mm/s (electrochemical diodes) to 240 mm/s (Schottky), a 7.5 fold improvement. The last part of this dissertation used numerical simulations to investigate the load bearing capability and the stiffness variation of droplet-based actuators. The vertical force and stiffness - which are the primary figure of merit in designing droplet-based actuators are quantified. Three types of loading conditions were analyzed using simulation software and a simple analytical equation is shown to provide a useful approximation of the droplet force and stiffness. The results were further used in various case studies to demonstrate the optimal design strategy when using an electrowetting driven droplet as a fluidic bearing.

In this thesis a multilayer actuator structure is developed for the I-SWARM project. In order to build an energy efficient and low voltage actuator system for the 3x3x3 mm3 robot, the resonance drive mode in combination with a ten layer multilayer structure build upon the most suitable substrate material was used. Two different sizes of the locomotion module were built. The first one is five times larger than the small version. It has five active layers and is simpler to work with and to test. The small module has three 2x0.4 mm can-tilevers on a 3x3mm body and ten active layers. The multilayer process involve easily defined flexible printed circuit (FPC) board as substrate material, spin coating piezoelectric poly(vinylidenefluoride- tetrafluoroethylene) P(VDF-TrFE) as active stack material, and evaporated aluminum electrodes on each active polymer layer. By using different shadow masks for each electrode layer, special inter con-tact areas can be contacted from above after the polymer has been removed by an Inductively Coupled Plasma (ICP) etch. The contours of the locomo-tion module was etched in a Reactive Ion Etch (RIE) equipment. Both the cupper layer in the FPC and the electrode layers of the active stack, were used as etch mask. The deflections of the cantilevers were measured at low voltages to ensure as realistic drive voltage as possible for the I-SWARM robot. The large struc-ture showed a 250 µm deflection at 4 V and 170 Hz resulting in a Q-value of 19. The deflection of the small structure was 8 µm at 3.3 V and 5000 Hz and the measured Q-value was 31.

The focus of this work involves optical and RF (radio frequency) applications of novel microactuation and self-assembly techniques in MEMS (Microelectromechanical systems). The scaling of physical forces into the micro domain is favorably used to design several types of actuators that can provide large forces and large static displacements at low operation voltages. A self-assembly method based on thermally induced localized plastic deformation of microstructures has been developed to obtain truly three-dimensional structures from a planar fabrication process. RF applications include variable discrete components such as capacitors and inductors as well as tunable coupling circuits. Optical applications include scanning micromirrors with large scan angles (>90 degrees), low operation voltages (<10 Volts), and multiple degrees of freedom. One and two-dimensional periodic structures with variable periods and orientations (with respect to an incident wave) are investigated as well, and analyzed using optical phased array concepts. Throughout the research, permanent tuning via plastic deformation and power-off latching techniques are used in order to demonstrate that the optical and RF devices can exhibit zero quiescent power consumption once their geometry is set.

The focus of this work involves optical and RF (radio frequency) applications of novel microactuation and self-assembly techniques in MEMS (Microelectromechanical systems). The scaling of physical forces into the micro domain is favorably used to design several types of actuators that can provide large forces and large static displacements at low operation voltages. A self-assembly method based on thermally induced localized plastic deformation of microstructures has been developed to obtain truly three-dimensional structures from a planar fabrication process. RF applications include variable discrete components such as capacitors and inductors as well as tunable coupling circuits. Optical applications include scanning micromirrors with large scan angles (>90 degrees), low operation voltages (<10 Volts), and multiple degrees of freedom. One and two-dimensional periodic structures with variable periods and orientations (with respect to an incident wave) are investigated as well, and analyzed using optical phased array concepts. Throughout the research, permanent tuning via plastic deformation and power-off latching techniques are used in order to demonstrate that the optical and RF devices can exhibit zero quiescent power consumption once their geometry is set.

Det här är ett examensarbete för högskoleingenjörsexamen i innovationsteknik och design. Fokus på projektet är att validera det fortsatta arbetet inom ett pågående produktutvecklingsprojekt av ett taktilt hörhjälpmedel. Projektets syfte är att undersöka forskning och teknik kopplat till taktil stimulering för att uppfatta ljud, och använda det som grund för beslutsfattning gällande den fortsatta inriktningen på utvecklingsprojektet. Målen för projektet är att leverera en sammanställning av aktuell forskning; en funktionsprototyp för testning av det senaste konceptet; samt resultat och analys av genomförda tester av det senaste konceptet gjorda med prototypen. Relevant och aktuell forskning och teknik kring sensorisk substitution för ljud-till-känsel-system har sammanställts. Forskningssammanställningen visar att sensorisk substitution för överföring av ljudinformation via hudens känselsinne är möjligt om tekniken fungerar och anpassas för ändamålet. Utifrån sammanställningen togs beslutet att fortsätta arbetet med att testa det senast framtagna konceptet inom utvecklingsprojektet. Detta koncept består av elektromagnetiska aktuatorer där spolarna fungerar som rörlig del, och aktuatorerna är satta i matrisformation. En funktionsprotototyp tillverkades för att testa hur spel mellan aktuatorerna påverkas av att ha spolen som rörlig del, och om aktuatorerna kan röra sig utan att påverkas av närliggande aktuatorer. Resultaten från testerna visar att den rörliga spolen löser tidigare problem med spel mellan aktuatorerna. Analysen av testresultaten har sammanställts i en FMEA och visar att även om grundpremissen för konceptet fungerar, finns det många risker som behöver hanteras i det framtida arbetet av produktutvecklingen. / This is a bachelor thesis in innovation and design engineering. The focus of this thesis is to validate the continuing work of an ongoing product development project developing a tactile hearing aid.  The purpose is to investigate research and technical solutions regarding tactile stimulation for sound perception and to use this as a basis for decision making for the continuing work of the product development project. The goal of this thesis is to deliver a compilation of state-of-the-art research; a works-like prototype for testing of the latest concept; and the results and analysis of tests performed with the prototype. A compilation was made of relevant research and technical solutions regarding sensory substitution for sound-to-touch systems. The compilation shows that sensory substitution for sound information transfer via the sense of touch is possible if the technical aspects work and are adapted for this purpose. Based on the results from the compilation a decision was made to continue the work by testing the development project’s latest actuator concept. The concept is based on solenoid actuators where the coils work as moving parts, and the actuators are set in a matrix formation. A works-like prototype of the actuators was made to test how play between the actuators is affected by having the coil as the moving part and whether the actuators can move without being affected by the actuators around them. The test results show that the moving coil solves the earlier problems regarding play between the actuators. The analysis of the test results has been compiled in a FMEA and shows that even though the basic premise of the concept works, there are a lot of risks which must be addressed during the continuing work on the product development.

Afin d'atteindre leur cible, les projectiles guidés d'artillerie nécessitent d'être dotés d'un dispositif de pilotage. Des surfaces de contrôle déployables et orientables sont donc nécessaires. Toutefois, le montage de gouvernes ajustables sur une ogive est une tâche mécaniquement ardue. En effet, lors du tir effectué par canon, l'équipement de bord subit une accélération significative, ce qui implique que des liaisons mécaniques particulièrement robustes doivent être conçues entre les ailettes et le corps. Cette technologie est bien maîtrisée lorsqu'elle est employée sur des projectiles de gros calibre, mais devient bien plus compliquée quand elle doit être adaptée pour être intégrée dans des petits ou moyens calibres. Néanmoins, dans des conditions de vol supersonique, des ondes de choc qui interagissent avec des surfaces solides sont susceptibles de considérablement modifier la distribution de pression. Ce principe a permis d'imaginer une méthode alternative de pilotage de projectiles supersoniques en exploitant des ondes de choc générées au moyen de petites perturbations créées à partir d'un micro-actionneur de forme cylindrique, aussi appelé micro-plot. Comme les forces de portance exercée sur un corps sont essentiellement dues à une pression appliquée sur de grandes surfaces, il a été choisi de se baser sur une configuration stabilisée par empennage. En vue de simplifier l'étude, le travail a été effectué sur un projectile académique de référence bien connu appelé le Basic Finner.Des expériences ont tout d'abord été effectuées dans la soufflerie supersonique de l'ISL sur une plaque plane comportant un plot et deux ailettes verticales. Ces mesures ont permis de valider la capacité de simulations numériques stationnaires RANS à prédire à la fois la distribution pariétale de la pression que génère un tel actionneur et le champ de vitesse de l'écoulement dans son voisinage. Les distributions de pression et de vitesse ont été mesurées en utilisant des méthodes optiques appelés Pressure Sensitive Paints (PSP) et Particle Image Velocimetry (PIV) afin d'être comparés avec les résultats de la CFD. Une étude paramétrique a ensuite été menée en se basant exclusivement sur ces simulations RANS. Ces calculs ont permis de déterminer l'emplacement optimal pour lequel le plot est le plus efficace sur toute l'enveloppe de vol du projectile. A partir de cette position optimale, deux configurations spécifiques ne générant aucun moment de roulis ont été étudiées numériquement et comparés en termes d'efficacité. En utilisant les coefficients aérodynamiques résultants de ce travail, des simulations de trajectoires à 6 degrés de liberté (6-DOF) ont été réalisées avec le code de BALCO (OTAN). Celles-ci ont permis de déterminer la déviation potentielle qui peut être obtenue sur une des deux configurations retenues en employant un tel micro-actionneur. Ces simulations 6-DOF ainsi que l'effet de du plot sur le projectile ont enfin été validés lors d'une campagne d'essai en vol libre qui a eu lieu sur le champ de tir de l'ISL. / In order to reach their target, guided artillery projectiles need some steering capability. Folding and adjustable control surfaces are thus necessary. However, mounting adjustable rudders on a shell is a difficult task, mechanically speaking. Indeed, during the gun launch, the onboard equipment undergoes significant acceleration so that robust mechanical joints have to be designed between the rudders and the body. This technique performs very well on large-caliber projectiles, but becomes more complicated when it has to be embedded in small- or medium-caliber ones. Nevertheless, under supersonic flight conditions, shock waves interacting with solid surfaces are likely to strongly modify the pressure distribution. This principle made it possible to imagine a way of steering small-caliber vehicles using shock waves generated by means of small disturbances created by a cylindrical-shaped micro-actuator, also called micro-pin. As lift forces exerted on a body are mainly due to the pressure applied to large surfaces, a finned configuration has been chosen. To simplify the study, the work has been conducted on the Basic Finner, a well known academic reference projectile.Experiments were first performed in the ISL supersonic wind tunnel on a flat plate on which a pin and two vertical projectile-like fins were mounted in order to validate the capability of steady RANS numerical simulations to predict both the pressure footprint of such an actuator and the flow velocity in its vicinity. Pressure and velocity distributions have been measured by using optical methods called Pressure-Sensitive Paint (PSP) and Particle Image Velocimetry (PIV) in order to be compared with the calculation results. A parametric study was then conducted with these RANS simulations so that the optimum location for which the pin is the most effective over the complete flight envelope of the projectile could be determined. Using this optimum position two specific no-roll momentum configurations were studied numerically and compared in terms of effectiveness. By using the aerodynamic coefficients resulting from this work, 6-Degree-Of-Freedom (6-DOF) trajectory simulations were performed with the NATO BALCO code on one of these configurations in order to determine the potential deviation which can be obtained with such an actuator. These 6-DOF simulations as well as the pin effect on the projectile could finally be validated during a free-flight campaign that took place at the ISL open-range testing site.

Cette thèse traite le sujet du micro-actionnement multistable employant des radiations optiques pour atteindre les différentes positions offertes par le micro-actionneur. Dans le cadre des travaux réalisés, un mécanisme bistable reposant sur un principe de doubles poutres préformées situées en position antagoniste est proposé, et, sur cette brique élémentaire, un micro-actionneur quadristable a été conçu. Afin de valider le principe de fonctionnement de micro-actionneur, des procédés de fabrication Laser (sur le matériau « médium - MDF») puis DRIE (sur un wafer SOI de silicium) ont été utilisés. Sur le prototype en silicium, permettant une réduction des courses du rang interne et du rang externe du micro-actionneur, celles-ci ont été fixées à 300 µm et 200 µm respectivement. L’actionnement à distance de ce micro-actionneur a été prouvé en utilisant le chauffage laser d’un élément actif en Nitinol structuré par un dépôt de SiO2, ceci générant un effet « deux sens » de l’élément actif permettant d’annuler la charge sur les poutres du micro-actionneur une fois celui-ci déclenché puis en position stable. L’utilisation d’un banc expérimental incluant une membrane MEMS de balayage laser a permis de démontrer la quadristabilité du micro-actionneur sur 90 000 cycles. Afin de réduire davantage la course de ce micro-actionneur, des concepts de dispositifs de réduction de course ont été développés pour démontrer, à partir de prototypes fabriqué en MDF par usinage laser, la capacité à atteindre une course de 1 µm. Enfin, à la suite de ces travaux de réduction de course, un concept de nano-actionneur multistable a été proposé. Ce nano-actionneur est composé de quatre modules bistables liés et disposés en parallèle pour offrir 16 positions discrètes sur une course rectiligne. Les simulations de cet actionneur montrent la possibilité d’atteindre les 15 positions espacées de 10 nm sur une course de 150 nm. / In this work, a bistable mechanism based on antagonistic pre-shaped double beams was proposed. Employing the proposed bistable mechanism, a quadristable micro-actuator was designed. ln order to validate the quadristability of the device, a meso-scaled prototype was fabricated from MDF by laser cutting. After the quadristability was experimentally confirmed, a quadristable micro-actuator was realized on SOl wafer using DRIE technique. Strokes for inner row and outer row were reduced to 300 µm and 200 µm respectively. For the actuation of the quadristable micro-actuator,laser heated SMA elements with deposited Si02 layer were used to realize the optical wireless actuation. With the help of a laser beam steering micro-mirror, both inner row and outer row were successfully actuated. ln order to further reduce the stroke, a bistable actuator with stroke reducing structure was designed and a prototype eut from MDF was tested. Bistability was validated and a stroke of 1µm was experimentally achieved. Based on this bistable module, a multistable nano-actuator, which contains four parallel coupled bistable modules,was designed and simulated. The simulated result have indicated that it was capable of outputs 16 discrete stable positions available from 0 nm to 150 nm with a step of 10 nm between two stable positions.

Le but du travail est de montrer la faisabilité du tissage de filament de très faible diamètre (de l'ordre de 10 à 25 -tm) et de matières différentes (cuivre, or, polyester...). Les essais du comportement mécanique (traction, fatigue) du micro filament de cuivre ont montré la possibilité du tissage de ce type du filament à cette échelle. A partir de ces résultats, il est possible d'entrevoir des solutions techniques de tissage pour réaliser des tissus à partir de ces filaments. Ce travail a permis donc de concevoir les différentes parties de la machine de micro tissage : système d'alimentation des fils de chame, système de formation de la foule, système d'insertion du fil de trame, système de mouvement du peigne, système d'appel et de stockage du tissu. Le système de formation de la foule de type Jacquard représente le cœur de la machine à tisser. Il lève un verrou technologique persistant depuis de très nombreuses années. Les résultats prometteurs des micros actionneurs fluidiques ont permis de montrer la faisabilité du micro tissage. Ils ont permis également de valider le procédé de la fabrication d'un bloc des plusieurs actionneurs capable de séparer les filaments de chaîne pour former la foule. Le logiciel de contrôle et de dessin conçu permet à la fois de réaliser des armures et de les compiler en format convenable pour pouvoir les transmettre à la carte de contrôle. Cette dernière permet de contrôler les différentes parties de la machine à tisser. / The aim of this work is to demonstrate the feasibility ofweaving filaments of very small diameter (about 10 to 25 -tm) made ofvarious materials (copper, gold, polyester, etc...). The possibility of weaving copper micro filaments at this scale has been proved via the fatigue and traction mechanical tests. According to these results, it was possible to foresee weaving technical solutions to produce fabrics from these micro filaments. This work has permitted the design of the different parts of the micro weaving machine: warp let-off system, warp shedding system, filling insertion system, beat-up system and take-up system. Warp shedding system of Jacquard type represents the heart of the weaving machine. It solved the complicated technical problem ofweaving materials that persists since many years. The positive results of micro fluidic actuators have demonstrated the feasibility of micro weaving. They have also validated the process of manufacturing a block of severa! actuators capable of separating the warp filament's to form the shed. The created software of control and design allows to make weaves and to compile them into a convenient format to be transmitted to the control card. This card controls the different parts of the weaving machine.