Secure grasping poses a significant challenge in micro-robotics, necessitating the development of efficient gripping mechanisms. This research focuses on the design and optimization of a novel MEMS-based microgripper to address this critical issue. The primary objective is to develop a microgripper with improved performance, specifically tailored for micro-robotic applications. Utilizing the SOIMUMPS fabrication process, the microgripper features an initial gap of 82.21 µm, enabling the gripping and stiffness determination of micro-objects. It incorporates a V-shaped electrothermal actuator and an arched microbeam, serving as an in-plane displacement amplifier. The microgripper's compact size (1.75 mm X 1.92 mm) is achieved through an innovative design concept that utilizes resonance frequency shift for object detection, eliminating the need for a separate sensor. Experimental testing and simulation analysis in COMSOL Multiphysics 4.3a demonstrate the microgripper's effectiveness in achieving grasping. With an actuation voltage below 7 V, it delivers a gripping force of approximately 6 mN, ensuring reliable handling of micro-objects. The gripping stroke of 50 µm further enhances its capabilities. Furthermore, MEMS technology provides distinct advantages such as compact size, low power consumption, and integration potential with electronic devices and integrated circuits (ICs). Performance evaluation reveals excellent repeatability, thermal stability, and low power requirements, enhancing the microgripper's suitability for micro-robotic applications. The validation experiments confirm the microgripper's ability to grasp objects, exemplified by successfully gripping a gold wire. Despite limitations in achieving larger gripping strokes due to fabrication imperfections, optimization efforts have allowed the microgripper to maintain its functionality at a reduced voltage of 4.5V, resulting in a substantial 43.75% reduction in power consumption. This research advances the field of micro-robotics by providing an efficient solution for grasping and stiffness measurement. The designed MEMS-based microgripper offers improved performance, compact size, and low power consumption. These characteristics make it highly suitable for various micro-robotic applications, including micromanipulation and micro-assembly tasks. The outcomes of this work lay the foundation for further advancements in micro-robotics and hold promise for a wide range of applications in diverse fields.

La force de diélectrophorèse (DEP) est utilisée pour manipuler, séparer et positionner différent types des particules (cellules, bactéries, nanotubes de carbone). Dans le but d étudieret de simuler une loi de commande permettant le suivi de la trajectoire d une particule soumise à la force DEP un modèle est nécessaire. Les méthodes utilisées pour simuler la force DEP sont généralement basées soit sur des simulateurs à éléments finis (FEM), soit sur des équations analytiques. Les simulateurs FEM ne permettent pas la variation des paramètres (tensions électriques) lors du calcul de la trajectoire et les équations analytiques sont limitées à des géométries simples des électrodes. Dans ce manuscrit, une méthode hybride basée sur les calculs FEM et analytique est proposée. Cette méthode permet de simuler la trajectoire d une particule en utilisant des géométries complexes et en variant les tensions électriques lors de la simulation. Ce modèle est ensuite validé en le comparant à des relevés expérimentaux. Finalement, une loi de commande, basée sur la commande prédictive généralisée (GPC) est proposée dans le but de contrôler la trajectoire, en profitant de la grande dynamique du déplacement de la particule, et ce malgré les non-linéarités. Cette loi de commande a été validée par des résultats de simulations et une comparaison avec une loi de commande classique. / Micro and nano-particles can be trapped by a non uniform electric field through the effect of dielectrophoretic (DEP) principle. Dielectrophoresis is used to separate, manipulate and detect micro particles in several domains, such as in biological or Carbon Nano-Tubes (CNTs) manipulations. To study and simulate a vision based closed loop control law in order to control the trajectory of micro objects using DEP a numeric model is required. Current methods to simulate the trajectory of micro-particles under a DEP force field are based on finite element modeling (FEM) which requires new simulations when one of its parameters, like the electric voltage, is changed, or on analytic equations which is limited to very simple geometries. In the first section of this manuscript, we propose a hybrid method between analytic and numeric calculation able to simulate complex geometries and to easily change electrode voltage along the trajectory. This numeric model is, then, validated by comparing it with several experimental results. Finally, a control strategy based on the generalized predictive control method is proposed with the aim of controlling the trajectory, taking advantage of the high dynamics despite the non linearity. This control law has been validated by simulation and compared to classical control strategy.

A l’échelle du micromètre, les forces de surface appliquées à l’objet deviennentprépondérantes par rapport aux forces volumiques. Dans le but de s’affranchirdu phénomène d’adhésion causé par ces effets d’échelle, la microrobotique sanscontact apparaît comme une voie prometteuse. Nos travaux sont à la jonctionentre la microrobotique et la chimie des surfaces. L’objectif de cette thèse est deproposer une méthode de micromanipulation innovante exploitant la chimie dessurfaces afin de contrôler les forces électrostatiques. Nous exploitons les chargesélectriques créées par les fonctions chimiques dépendantes du pH lorsqu’elles sontplacées en milieu liquide. La modélisation des interactions entre une surface et unmicro-objet fonctionnalisés repose sur l’exploitation du phénomène de la doublecouche électrique. Deux principes de fonctionnalisation de surface ont été utilisés;les monocouches auto-assemblées (APTES) qui sont facilement mises en oeuvreet les films de polymères (polyaniline, polypyrrole) par voie électrochimique quipermettent d’obtenir des dépôts localisés. Les résultats obtenus mettent en évidencel’intérêt de l’exploitation des forces électrostatiques d’origine chimique pour desapplications de micromanipulation. / On the micrometer scale, surface forces applied to the object are significant comparedto volume forces. In order to overcome the adhesion phenomenon caused by thesescale effects, contactless microrobotics appears promising. Our work is mergingwith microrobotics and chemistry of surfaces. The objective of this thesis is topropose a method of micromanipulation based on innovative surface chemistry tocontrol electrostatic forces. The principle is based on the electric charges generatedby pH dependent chemical functions when placed in liquid medium. Modeling ofthe interaction between a surface and a micro- functionalized object is based onthe exploitation of the phenomenon of the electrical double layer. Two surfacefunctionalization principles were used, (i) self-assembled monolayers (APTES),and (ii) electrodeposition of polymer films (polyaniline , polypyrrole) that enablelocalized deposits. The results highlight the interest of using electrostatic chemicalforces for micromanipulation applications.

Following the first demonstration in 1987 by Arthur Ashkin of trapping of biological objects with infrared laser light, optical tweezers have become increasingly useful and versatile tool in a variety of non-contact micromanipulation experiments in biological applications. In this thesis we demonstrated various applications of optical tweezers in botanical sciences, chemical engineering and anatomical sciences. The investigation of the three-dimensional shape of spinach chloroplasts has been accomplished. This was done using a steerable and a stationary trap system. A trapped rotating calcite crystal positioned close to a chloroplast provided means for inducing the rotation and orientation of chloroplast. The utility of rotating birefringent particles is demonstrated for the first time in biological applications. The stirrer method is a versatile method in orienting any biological object to study its shape and/or structure. Also, we demonstrated the ability of optical tweezers to fix and displace chloroplasts inside a living spinach plant cell. In the second part of the work described in this thesis, the steerable trap was used to study the viscoelastic properties of a polymeric filament that connects a single bacterium to an activated sludge floc. Also we estimated the minimum bonding force that can cause a weak interaction between the bacterium surface and the filament using optical tweezers as a transducer. This force was estimated to be at least 10 pN. These measurements are of value in improving activated sludge flocculation and ultimately the wastewater treatment process. In addition, the steerable trap was used to move small organelles inside large bacteria cells. The repositioning of organelles resulted in creating new internal cell structure. In the final part of the thesis, experiments are described where the laser tweezers system was combined with a cw argon-ion laser microbeam to investigate the fusion of smooth muscle cells and macrophages. In order to minimize the optical damage to the cells, a special arrangement was established to create short pulses for cutting the contact of the cell membrane of the two-fusion cell partners. The effectiveness of the cutting function of the pulsed system when used at 488 nm wavelength varied from cell to cell. The laser parameters such as laser power, pulse duration and repetition rate were varied in order to obtain the best working function of the setup. But overall the results indicate that the relatively long (ms) pulses possible may not be well suited to such applications.

La micromanipulation constitue l'une des fonctions principales de la microrobotique. Elle concerne la manipulation d'objets dont la taille est comprise globalement entre 1 µm et 1 mm. La maîtrise de la manipulation d'objets à ces dimensions représente des enjeux stratégiques et économiques majeurs. La conception et la réalisation de micromanipulateurs se heurtent à un grand nombre de difficultés liées d'une part aux problèmes de fabrication et d'autre part à la complexité des interactions qui se produisent dans le micromonde. Le travail mené dans le cadre de cette étude concerne la conception et la réalisation d'un système de micromanipulation constitué d'une micropince à actionneurs piézoélectriques et d'un micropositionneur utilisant des fils en alliage à mémoire de forme (AMF). La micropince, pour laquelle un modèle physique du comportement dynamique à été développé, est caractérisée par une résolution de positionnement de chaque doigt meilleure que 10 nm, largement compatible avec l'exécution de tâches dans le micromonde. Elle permet également la mesure ou l'estimation des forces exercées sur les objets manipulés. Cette propriété est particulièrement intéressante lorsqu'il s'agit de saisir des micro-objets fragiles (organismes biologiques, microcomposants optiques, électroniques...). Le micropositionneur réalisé est constitué d'une table de micropositionnement et d'un bras portant la micropince. Un microobjet peut être déplacé dans un volume de 6 mm3 avec une résolution de 1 µm. Plusieurs essais de micromanipulation ont été réalisés avec succès. Le système conçu est caractérisé par une grande simplicité de réalisation et par un coût extrêmement bas ce qui permet d'envisager son utilisation dans des applications industrielles et biomédicales.

Micromanipulation is considered a challenging task which requires high precision motion and measurement at the micro scale. When micromanipulation is concerned with living organisms important considerations need to be addressed. These include the physical or chemical properties of micro-organisms, living conditions, responses to the environment and achieving suitably delicate manipulation. Bio-micromanipulation can include micro surgery or cell injection operations, or to determine interaction forces as the basis to investigate behavior and properties of living micro-organisms. In order to achieve suitable bio-micromanipulation appropriate processes and/or sensory systems need to be investigated. This thesis aims to look into the force interaction and sensing addressing two distinctive challenges in the field of bio-micromanipulation. To this end, this thesis presents two major contributions to advancing bio-micromanipulation. Firstly, a novel Haptic Microrobotic Cell Injection System is introduced which is able to assist a bio-operator through haptic interaction. The system introduces a mapping framework which provides an intuitive method for the bio-operator to maneuver the micropipette in a manner similar to handheld needle insertion. To accurately control the microrobot, a neuro-fuzzy modeling and control scheme has been developed. Volumetric, axial and planar haptic virtual fixtures are introduced to guide the bio-operator during cell injection. Aside from improving real-time operator performance using the physical system, the system is novel in facilitating virtual offline operator training. Secondly, a first-of-its-kind micro-pillar based on-chip system for dynamic force measurement of C. elegans motion is introduced. The system comprises a microfabricated PDMS device to direct C. elegans into a matrix of micropillars within a channel mimicking its dwelling environment. An image processing algorithm is able to track the interaction of the C. elegans with the pillars and estimate contact forces based on micropillar deflections. The developed micropillar system is capable of measuring the force with sub-micron resolution while providing a continuous force output spectrum.

Robotic microassembly is a process to leverage intelligent micro-robotic technologies to manipulate and assemble three-dimensional complex micro-electromechanical systems (MEMS) from a set of simple-functional microparts or subsystems. As the development of micro and nano-technologies has progressed in recent years, complex and highly integrated micro-devices are required. Microassembly will certainly play an important role in the fabrication of the next generation of MEMS devices. This work provides advances in robotic microassembly of complex three-dimensional MEMS devices. The following key technologies in robotic microassembly are studied in this research: (i) the design of micro-fasteners with high accuracy, high mechanical strength, and reliable electrical connection, (ii) the development of a microassembly strategy that permits the manipulation of microparts with multiple degrees of freedom (DOFs) and high accuracy, (iii) fully automated microassembly based on computer vision, (iv) micro-force sensor design for microassembly. An adhesive mechanical micro-fastener is developed to assemble micro-devices. Hybrid microassembly strategy, which consists of pick-and-place and pushing-based manipulations, is employed to assemble three-dimensional micro-devices with high flexibility and high accuracy. Novel three-dimensional rotary MEMS mirrors have been successfully assembled using the proposed micro-fastener and manipulation strategy. Fully automatic pick-and-place microassembly is successfully developed based on visual servo control. A vision-based contact sensor is developed and applied to automatic micro-joining tasks. Experimental results show that automatic microassembly has achieved sub-micron accuracy, high efficiency, and high success rate. This work has provided an effective approach to construct the next generation of MEMS devices with high performance, high efficiency, and low cost.

Robotic microassembly is a process to leverage intelligent micro-robotic technologies to manipulate and assemble three-dimensional complex micro-electromechanical systems (MEMS) from a set of simple-functional microparts or subsystems. As the development of micro and nano-technologies has progressed in recent years, complex and highly integrated micro-devices are required. Microassembly will certainly play an important role in the fabrication of the next generation of MEMS devices. This work provides advances in robotic microassembly of complex three-dimensional MEMS devices. The following key technologies in robotic microassembly are studied in this research: (i) the design of micro-fasteners with high accuracy, high mechanical strength, and reliable electrical connection, (ii) the development of a microassembly strategy that permits the manipulation of microparts with multiple degrees of freedom (DOFs) and high accuracy, (iii) fully automated microassembly based on computer vision, (iv) micro-force sensor design for microassembly. An adhesive mechanical micro-fastener is developed to assemble micro-devices. Hybrid microassembly strategy, which consists of pick-and-place and pushing-based manipulations, is employed to assemble three-dimensional micro-devices with high flexibility and high accuracy. Novel three-dimensional rotary MEMS mirrors have been successfully assembled using the proposed micro-fastener and manipulation strategy. Fully automatic pick-and-place microassembly is successfully developed based on visual servo control. A vision-based contact sensor is developed and applied to automatic micro-joining tasks. Experimental results show that automatic microassembly has achieved sub-micron accuracy, high efficiency, and high success rate. This work has provided an effective approach to construct the next generation of MEMS devices with high performance, high efficiency, and low cost.

This study investigated the development potential of equine embryos in vitro after biopsy and vitrification. Twenty embryos were obtained from Quarter Horse, Thoroughbred, and mix-breed light mares between three and ten years old. The twenty embryos were divided into a biopsy (n=10) and control group (n=10). The biopsy group underwent microaspiration biopsy using a micromanipulator to obtain a small tissue sample from the embryo. Both groups were then vitrified using a commercially available technique originally described by Carnevale (2006) at Colorado State \ University. All 20 embryos were cultured in DMEM/Hams F-12 medium under oil at 37°C in 5% CO2 in air (Hinrichs et al., 1990). Embryos were monitored for expansion and hatching. Embryo development was statistically different between the two groups (p<0.05). The biopsy procedure did result in a much lower development potential in the biopsy group as compared to the control group (20% vs. 80%). However, embryos in the biopsy group did show expansion and hatching therefore the combined procedure did not preclude development potential in vitro. Based on these findings, more research needs to be done to increase the success of the combined procedure and the ultimate viability of the embryos needs to be confirmed with the establishment of successful pregnancies.

La "micromanipulation", c'est-à-dire la saisie, le maintien, le déplacement, l'orientation et la dépose de dimensions globalement comprises entre 1 micron et 1 mm concerne de plus en plus de secteurs d'activité tels que l'assemblage de pièces micromécaniques rigides (microroues dentées, microlentilles optiques, circuits hybrides, etc...) ou la manipulation d'éléments biologiques pour la médecine ou les biotechnologies (micro-organismes, cellules, etc...). Les travaux présentés dans ce mémoire ont permis d'aboutir à la mise au point d'une nouvelle micropince à deux doigts de serrage, chacun étant capable de se mouvoir indépendamment dans deux directions perpendiculaires, offrant ainsi quatre degrés de liberté articulaires à la pince. En plus de l'ouverture/fermeture des doigts de la pince, ces mobilités autorisent notamment le centrage et l'orientation des objets entre les mors. Le principe d'actionnement d'un doigt repose sur un actionneur de type poutre piézoélectrique à électrodes répartie, appelé duo-bimorphe, pour lequel un modèle statique de comportement a été établi. Les micropinces développées présentent des courses d'ouverture/fermeture et de montée/descente de, respectivement, 320 microns et 400 microns pour 100 V et des forces de blocage d'environ 55 mN en serrage et 10 mN en montée/descente pour 100 V. Ce mémoire rapporte plusieurs expérimentations dont l'assemblage potentiel d'un pignon de montre, la micromanipulation de cubes de 300 microns de côté sous une binoculaire ou d'objets sphériques de 200 microns de diamètre dans un microscope électronique à balayage. Afin de commander cette micropince, et plus généralement les actionneurs piézoélectriques, une nouvelle commande est proposée permettant un contrôle fin en boucle ouverte des déplacements de l'actionneur. Elle est fondée sur la juxtaposition d'une commande à charge électrique constante et une commande à tension constante. Une réduction de l'hystérésis d'un facteur dix est ainsi obtenue.