L’objectif de cette thèse est de développer de nouveaux robots qui combinent dextérité, compacité et précision afin de réaliser des tâches de micromanipulation complexes dans des environnements confinés. Ainsi, deux architectures robotiques parallèles ont été développées. La première est un poignet à 4 degrés de liberté (DDL) en rotation et la seconde est un robot redondant à 7 DDL. Les deux structures intègrent la fonction de préhension grâce à une plateforme configurable et un actionnement déporté. L’étude géométrique et cinématique des deux robots ainsi que des résultats expérimentaux validant les deux architectures sont présentés. Pour miniaturiser le robot à 7 DDL, les liaisons mécaniques (rotules) ont été remplacées par des liaisons en élastomère (PDMS). Cette solution permet, entre autres, d’éliminer les jeux mécaniques au niveau des articulations tout en gardant une grande plage de déplacement. Cependant, comme le comportement de telles articulations ne correspond pas parfaitement à des liaisons rotules, un modèle de robot prenant en compte le comportement élastique de ces articulations a été développé. Afin de réaliser la structure à l’échelle désirée (jambes et liaisons à 400 µm de côté), un nouveau processus de micro-fabrication en salle blanche a été développé. Contrairement aux méthodes existantes, le nouveau processus permet de réduire le nombre d’étapes de gravure et d’intégrer différents types d’élastomères à des microstructures robotiques en silicium. Enfin, le micro-robot a été réalisé et les capacités de déplacement dans les 6 DDL en plus de la préhension ont été validées. Les applications visées des robots développées dans cette thèse sont le micro/nano-assemblage, la manipulation de cellules biologiques et la chirurgie mini-invasive, notamment en neurochirurgie. / The objective of this thesis is the development of new robots that combine dexterity, compactness and precision to perform complex micromanipulation tasks in confined environments. Thus, two parallel robotic structures have been developed. The first is a wrist that can insure 4 degrees of freedom (DOF) in rotation and the second is a redundant robot with 7 DOF. Both structures integrate the grasping function thanks to a configurable platform and a deported actuation. The kinematic study of the two robots and the experimental results validating the two architectures are presented. To miniaturize the 7 DOF robot, the mechanical joints (spherical) have been replaced by elastomeric articulations (PDMS). This solution allows, among others, to eliminate the mechanical backlash in the joints while keeping a large range of movements. However, as the behavior of such joints does not correspond perfectly to spherical joints, a model for the robot taking into account the elastic behavior of these joints has been developed. In order to made the structure on the desired scale (the cross sectional side of its legs and connections are 400 µm), a new microfabrication process in the clean room has been developed. Unlike the existing methods, the new process reduces the number of etching steps and allow the integration of different types of elastomers into silicon robotic microstructures. Finally, the micro-robot was realized and the displacement capacities in the 6 DOF with the grasping were validated. The targeted applications by the developed robots in this thesis are micro / nano-assembly, manipulation of biological cells and minimally invasive surgery, particularly in neurosurgery.

Dans le domaine du développement d'outils de micromanipulation de haute précision pour le biomédical, les microrobots mobiles immergés font figures de technologie émergente prometteuse pour des applications in-vitro, puis à plus long terme pour l'in-vivo. Mes travaux portent sur l'étude de la propulsion de microrobots par voie magnétique dans des fluides circulant dans des microcanaux, à une échelle où les phénomènes d'adhérence et d'amortissement prévalent. Leur application pour des opérations de transduction est développée dans un deuxième volet.Un dispositif d'asservissement par vision à haute fréquence d’échantillonnage (~5kHz) a été développé rendant possible le contrôle sous champ magnétique uniforme ou gradient. Les performances du système ont notamment demandé l’implémentation d'une interface multi-tâches afin de pouvoir acquérir et traiter les images en parallèle de l'actuation du robot. L'analyse de la dynamique permet de mieux appréhender les phénomènes parfois imprévisibles liés au déplacement du robot, MagPol, intégré dans une puce microfluidique. Il peut réciproquement servir de capteur dans son environnement fluidique.Ce design original de robot a été conçu pour la micromanipulation et permet également d'explorer des nouvelles stratégies de déplacement. Ces capacités ont été éprouvées sur des objets de même taille qu'en biologie cellulaire (billes, bulles).Enfin, une démonstration de l'asservissement visuel en planification de tâche a été effectuée. Sous réserve de posséder un algorithme suffisamment performant, l'échantillonnage haute fréquence en temps réel devient possible et l'observation de performances sur des trajectoires complexes est démontrée. Les performances, la portabilité et la reproductibilité du système démontrent des capacités de transduction à haut débit qui sont très prometteuses pour l'aspect applicatif. / In the research for new high performances tool for micrometric scale manipulation, mobile microrobots immersed are considered as a promising technology for in-vitro applications, and with a long term view in-vivo. My work focuses on the propulsion study of mobile microrobots immersed in microfluidic channels controlled through electromagnets. At this scale, surface and damping phenomena predominates. Application for transduction operation is developed in a second part.A high sampling rate (≈5kHz) visual servoing setup have been developed making a control possible through uniform and gradient magnetic field. Performances of the system have notably required a multi-thread programmed user interface to acquire and analyze the frame in parallel of the robot actuation. Dynamic analysis allow to better apprehend the perturbation dynamics of the robot MagPol, integrated in a microfluidic chip. It can reciprocally serve as a sensor for in fluidic environment.MagPol design has been originally conceived for micromanipulation, and also allows to explore new displacement strategies. Its capacities have been tested on beads and bubbles equivalent to cell biology characteristic size (10µm – 100µm).Finally, a demonstration of planned trajectory using visual servoing was accomplished. Though it has required an algorithm sufficiently efficient, high frequency real-time sampling is possible and lead to control and post observation on complex trajectory. Global performances, repeatability and portability of our system has demonstrated its capacities as a high-throughput transducer, promising for single microagent applications.

Nous présentons dans cette thèse les différentes étapes de conception d'une plateforme microrobotique dédiée au positionnement sous faisceau de lumière d'objets de dimensions micrométriques. Cette plateforme a pour vocation de mettre en oeuvre des méthodologies d'asservissement et de suivi de position de micro-objets placés au coeur même d'un faisceau de lumière. L'objectif final étant de caractériser des micro/nano-matériaux par diffraction et diffusion des rayons X. Les différentes contraintes technologiques rencontrées par les systèmes de micro-nanomanipulation actuels en environnement synchrotron nous ont amené à concevoir une plateforme microrobotique de manipulation duale utilisant des sondes de microscope à force atomique (AFM). Diverses méthodologies de préhension avec une ou deux sondes AFM avec capteur de force intégré - ont été proposées en vue d'évaluer chacune d'entre-elles dans un contexte de positionnement tridimensionnel. Une stratégie de commande des micromanipulateurs à double étage est mise en oeuvre pour assurer l'asservissement de position des sondes AFM lors des tâches d’approche et de transport du micro-échantillon sous test. Afin d’augmenter la robustesse de positionnement vis-à-vis des erreurs de modélisation, des perturbations extérieures et des bruits de mesure, nous avons proposé une commande robuste de type H∞, avec optimisation des paramètres de pondération à partir d’algorithmes génétiques. De plus, les erreurs aléatoires d’alignement du faisceau de lumière avec l’objet sont corrigées en temps-réel par l’utilisation d’estimateurs de position (filtres de Kalman et particulaire). Finalement, des tâches microrobotiques automatisées de micro-préhension, de transport et de positionnement de microobjets sphériques de 8 μm de diamètre placés sous faisceau de lumière laser ont été réalisées avec succès. Le « benchmark » proposé est en cours de transfert au sein du European Synchrotron Radiation Facility (ESRF) à Grenoble pour validation sous faisceau de rayons X. / We present in this thesis the various stages in the design of a microrobotics platform dedicated to the manipulation of micro/nano objects in a synchrotron environment. It is composed of dual micro/nano manipulators in order to handle and to maintain a micro/nano-sample through the focus of a X-ray or laser beam for material characterization and analysis. The main idea is to control and to drive in a robust way the micro/nanomanipulators by focusing the beam on the center part of the handled micro-object. A microgripper based on two Atomic Force Microscope (AFM) tips with integrated piezoresistive force sensors is proposed. First, the dual manipulators are controlled cooperatively by combining the different actuator dynamics to track a laser beam with nanometer precision. A robust control strategy based on H∞ control ensures a robust microhandling task under the focus of the laser beam whatever the external perturbations involved and parametric model uncertainties. The Genetic Algorithm (GA) approach is used to compute the parameter weighting functions in to obtain an optimal H∞ controller. Then, we propose to compensate the laser beam variations (thermal drift, mechanical variations) by estimating the position of the laser beam using stochastic estimators (Kalman and particle filters). To this aim, the maximum intensity of the laser beam is measured and tracked in real-time by a four-quadrant photodiode sensor. Finally, experimental results performed of micro-spheres (diameter: 8 μm) demonstrate the robustness of the robotic microhandling tasks using the proposed control scheme strategy.

La microrobotique est un domaine de recherche en croissance rapide et les microsystèmes sont très demandés par un large éventail de notre vie. Aujourd’hui, des solutions d'automatisation massive sont déjà disponibles pour la production en série des microsystèmes, tandis que la production de petites quantités s'appuie principalement sur des processus manuels en l'absence de système de micro-manipulation flexible. Un processus manuel impose des contraintes à la productivité et la précision, ce qui accroît les difficultés pour les petites et moyennes entreprises à conquérir leur place sur le marché international. Dans ce contexte, la société pionnière pour la microrobotique Percipio Robotics a proposé une plate-forme cobotique Chronogrip, qui vise à gérer la micro-manipulation flexible. Toutefois, la solution n'est pas encore complète et il y a trois principaux défis à résoudre :• la dynamique de l'actionneur piézo-électrique stick-slip n'est pas entièrement comprise, ce qui retarde le développement des stratégies de suivi de trajectoire;• les interfaces haptiques ont peu de bande passante en raison des propriétés mécaniques, par conséquent il n'y a aucune option disponible qui soit capable de reproduire des informations haptiques de haute dynamique depuis le micromonde;• pour la micro-manipulation à la pince dans l'horlogerie, aucune interface haptique existante n'est en mesure d'assurer un fonctionnement intuitif et efficace.L’objectif de la thèse consiste à répondre à ces trois défis. La première partie de la thèse est consacrée à l'élaboration d'un modèle dynamique non linéaire de l'actionneur piézo-électrique stick-slip. Le résultat montre qu'il est le premier modèle dynamique qui puisse décrire la dynamique de l'actionneur dans des domaines temporels et fréquentiels, pour les fonctionnements en sous-pas et en grand déplacement, et à la fois pour les directions vers l'avant et l’arrière. La deuxième partie de la thèse est consacrée à développer une méthode pour étendre la bande passante d’une interface haptique en double étage en utilisant la technique de signal crossover. Le résultat montre que la bande passante est uniformément étendue à 1 kHz, ce qui rend possible la reproduction des phénomènes de haute dynamique depuis le micromonde. La troisième partie de la thèse vise à concevoir une interface haptique intuitive dédiée aux opérations d’horlogerie à la pince. Le design est également compatible avec l'utilisation conventionnelle d’une pince. Il est prévu d'intégrer tous les résultats de ces trois sujets de recherches dans la plate-forme de cobotique Chronogrip afin d’améliorer la productivité et l'efficacité de la micro-manipulation. / Microrobotics is a fast growing field of research and microsystems are in high demand from across a wide spectrum of our life. Nowadays, mass automation solutions are already available for large batch production of microsystems, while small batch production mainly relies on handmade processes due to the lack of flexible micro-manipulation system. Handmade processes have limited productivity and accuracy, which makes it more and more difficult for small and medium-sized enterprises to conquer their place on the international market. Under such circumstances, pioneer microrobotics company Percipio Robotics has proposed a desktop cobotic platform, Chronogrip, which aims to handle flexible micro-manipulation. However, the solution is not yet complete and there are three main challenges to resolve:• the dynamics of the piezoelectric stick-slip actuator is not fully understood, which delays the development of trajectory tracking strategies;• existing haptic interfaces have limited bandwidth due to their mechanical properties, consequently there is no available option that is able to render high dynamic haptic information from the microworld;• for tweezers-based micro-manipulation in watchmaking process, no existing haptic interface is able to provide intuitive and effective operation.The objective of thesis is to address these three issues. The first part of the thesis is dedicated to the development of nonlinear dynamic model of the piezoelectric stick-slip actuator. The result shows that it is the first dynamic model which can describe the actuator dynamics in time and frequency domain, for stepping and scanning mode, and for both forward and backward motion. The second part of the thesis is devoted to develop a method to extend the bandwidth of dual-stage haptic interface by using the signal crossover technique. The result shows that the bandwidth is uniformly extended to 1 kHz, which makes it possible to reproduce high dynamic phenomena from the microworld. The third part of the thesis aims to design an intuitive haptic interface for tweezers-based watchmaking operations. The design is also compatible with conventional tweezers-based usage. It is expected to integrate all of the three research results into the cobotic platform Chronogrip to enhance the productivity and effectiveness of micro-manipulation.

Mechanical manipulation and characterization of biological cells have wide applications in genetics, reproductive biology, and cell mechanics. This research focuses on (1) the development of enabling microrobotic systems and techniques for automated cell microinjection and in situ mechanical characterization; and (2) the demonstration of molecule efficacy testing and cell quality assessment with the new technologies. Targeting high-speed cell injection for molecule screening, a first-of-its-kind automated microrobotic cell injection system is developed for injecting foreign materials (e.g., DNA, morpholinos, and proteins) into zebrafish embryos (~1.2 millimeter) and mouse oocytes/embryos (~100 micrometers), which overcomes the problems inherent in manual operation, such as long learning curves, human fatigue, and large variations in success rates due to poor reproducibility. Novel cell holding devices are developed for immobilizing a large number of embryos into a regular pattern, greatly facilitating sample preparation and increasing the sample preparation speed. Leveraging motion control and computer vision techniques, the microrobotic system is capable of performing robust cell injection at a high speed with high survival, success, and phenotypic rates. The mouse embryo injection system is applied to molecule testing of recombinant mitochondrial proteins. The efficacy of an anti-apoptotic Bcl-xL (Delta_TM) protein is, for the first time, quantitatively evaluated for enhancing the development competence of mouse embryos. For cell quality assessment, this research develops a vision-based technique for real-time cellular force measurement and in situ mechanical characterization of individual cells during microinjection. A microfabricated elastic device and a sub-pixel computer vision tracking algorithm together resolve cellular forces at the nanonewton level. Experimental results on young and old mouse oocytes demonstrate that the in situ obtained force-deformation data can be used for mechanically distinguishing healthy mouse oocytes from those with cellular dysfunctions. This work represents the first study that quantified the mechanical difference between young and old mouse oocytes, promising a practical way for oocyte quality assessment during microinjection.

Mechanical manipulation and characterization of biological cells have wide applications in genetics, reproductive biology, and cell mechanics. This research focuses on (1) the development of enabling microrobotic systems and techniques for automated cell microinjection and in situ mechanical characterization; and (2) the demonstration of molecule efficacy testing and cell quality assessment with the new technologies. Targeting high-speed cell injection for molecule screening, a first-of-its-kind automated microrobotic cell injection system is developed for injecting foreign materials (e.g., DNA, morpholinos, and proteins) into zebrafish embryos (~1.2 millimeter) and mouse oocytes/embryos (~100 micrometers), which overcomes the problems inherent in manual operation, such as long learning curves, human fatigue, and large variations in success rates due to poor reproducibility. Novel cell holding devices are developed for immobilizing a large number of embryos into a regular pattern, greatly facilitating sample preparation and increasing the sample preparation speed. Leveraging motion control and computer vision techniques, the microrobotic system is capable of performing robust cell injection at a high speed with high survival, success, and phenotypic rates. The mouse embryo injection system is applied to molecule testing of recombinant mitochondrial proteins. The efficacy of an anti-apoptotic Bcl-xL (Delta_TM) protein is, for the first time, quantitatively evaluated for enhancing the development competence of mouse embryos. For cell quality assessment, this research develops a vision-based technique for real-time cellular force measurement and in situ mechanical characterization of individual cells during microinjection. A microfabricated elastic device and a sub-pixel computer vision tracking algorithm together resolve cellular forces at the nanonewton level. Experimental results on young and old mouse oocytes demonstrate that the in situ obtained force-deformation data can be used for mechanically distinguishing healthy mouse oocytes from those with cellular dysfunctions. This work represents the first study that quantified the mechanical difference between young and old mouse oocytes, promising a practical way for oocyte quality assessment during microinjection.

Micro-electro-mechanical systems (MEMS) technology has had an increasing impact on industry and our society. A wide range of MEMS devices are used in every aspects of our life, from microaccelerators and microgyroscopes to microscale drug-delivery systems. The increasing complexity of microsystems demands diverse microfabrication methods and actuation strategies to realize. Currently, it is challenging for existing microfabrication methods—particularly 3D microfabrication methods—to integrate multiple materials into the same component. This is a particular challenge for some applications, such as microrobotics and microfluidics, where integration of magnetically-responsive materials would be beneficial, because it enables contact-free actuation. In addition, most existing microfabrication methods can only fabricate flat, layered geometries; the few that can fabricate real 3D microstructures are not cost efficient and cannot realize mass production. This dissertation explores two solutions to these microfabrication problems: first, a method for integrating magnetically responsive regions into microstructures using photolithography, and second, a method for creating three-dimensional freestanding microstructures using a modified micromolding technique. The first method is a facile method of producing inexpensive freestanding photopatternable polymer micromagnets composed NdFeB microparticles dispersed in SU-8 photoresist. The microfabrication process is capable of fabricating polymer micromagnets with 3 µm feature resolution and greater than 10:1 aspect ratio. This method was used to demonstrate the creation of freestanding microrobots with an encapsulated magnetic core. A magnetic control system was developed and the magnetic microrobots were moved along a desired path at an average speed of 1.7 mm/s in a fluid environment under the presence of external magnetic field. A microfabrication process using aligned mask micromolding and soft lithography was also developed for creating freestanding microstructures with true 3D geometry. Characterization of this method and resolution limits were demonstrated. The combination of these two microfabrication methods has great potential for integrating several material types into one microstructure for a variety of applications.

Micro- and nanorobots (MNRs) are small autonomous devices capable of performing complex tasks and have been demonstrated for a variety of non-invasive biomedical applications, such as tissue engineering, drug delivery or assisted fertilization. However, translating such approaches to an in vivo environment is critical. Current imaging techniques do not allow localization and tracking of single or few micromotors at high spatiotemporal resolution in deep tissue. This thesis addresses some of these limitations, by exploring the use of two optical-based techniques (IR and photoacoustic imaging (PAI)) and a combination of both US and PAI. First, we employ an IR imaging setup to visualize mobile reflective micromotors under scattering phantoms and ex vivo mouse skull tissues, without using any labels. The reflective micromotor reflects more than tenfold the light intensity of a simple particle. However, the achieved penetration depth was ca. 100 μm (when using ex vivo tissues), limiting this technique to superficial biomedical applications. In this regard, PAI plays a role that combines the advantages of US such as penetration depth and real-time imaging with the molecular specificity of optics. For the first time, in this thesis, this method is evaluated for dynamic process monitoring, in particular for tracking single micromotor in real-time below ~1 cm deep phantom and ex vivo tissue. However, the precise function control of MNRs in living organisms, demand the combination of both anatomical and functional imaging methods. Therefore, in the end, we report the use of a hybrid US and PA system for the real-time tracking of magnetically driven micromotors (single and swarms) in phantoms, ex vivo, and in vivo (in mice bladder and uterus), envisioning their application for targeted drug-delivery. This achievement is of great importance and opens the possibilities to employ medical micromotors in a living organism and perform a medical task while being externally controlled and monitored.:ABSTRACT 1 1 INTRODUCTION 5 1.1 Motivation 5 1.2 Background 7 1.2.1 Microrobotics 7 1.2.2 Medical Imaging 9 1.3 Objectives and Structure of Thesis 12 2 FUNDAMENTALS 15 2.1 Optical Imaging 15 2.1.1. Reflection-based Imaging 17 2.1.2. Fluorescence-based Imaging 18 2.1.1 Light-Tissue Interaction 20 2.2 Photoacoustic Imaging 23 2.2.1 Theory 23 2.2.2 Implementation 25 2.3 Ultrasound Imaging 26 2.3.1 Theory 26 2.3.2 Implementation 28 3 MATERIALS AND METHODS 30 3.1 Fabrication of Magnetic Micropropellers 30 3.1.1 3D Laser Lithography of Polymeric Resin 30 3.1.2 Self-assembly of SiO2 Particles 31 3.1.3 Electron Beam Evaporation 32 3.1.4 Surface Functionalization 33 3.2 Fabrication of Phantom Tissue and Microfluidic Channels 34 3.2.1 Fabrication of PDMS-Glycerol Phantom 34 3.2.2 Fabrication of Agarose Phantom 35 3.2.3 Phantom based on Ex vivo Tissues (Chicken Breast and Mice Skull) 36 3.2.4 Microfluidic Channel Platform 37 3.3 Sample Characterization 38 3.3.1 Optical Microscopy 38 3.3.2 Scanning Electron Microscopy 38 3.4 Magnetic Actuation 39 3.4.1 Magnetic Force 39 3.4.2 Magnetic Torque 39 3.5 Ethic Statement for Mice Experiments 41 4 OPTICAL IMAGING OF MICROROBOTS 42 4.1 Concept of Reflective Micromotors 42 4.2 Fabrication of Reflective Micromotors 44 4.3 IR Imaging Actuation Setup 45 4.4 Actuation and Propulsion Performance below Phantom 47 4.5 Actuation and Propulsion Performance below Ex Vivo Skull Tissue 50 4.6 Actuation and Propulsion Performance in Blood 51 5 PHOTOACOUSTIC IMAGING OF MICROROBOTS 55 5.1 Absorbers for Deep Tissue Imaging 55 5.2 Absorber Micromotor Design and Fabrication 56 5.3 Photoacoustic Imaging Setup 58 5.4 Actuation Performance below Phantom Tissue 60 5.5 Actuation Performance below Ex Vivo Tissue 65 6 HYBRID ULTRASOUND AND PHOTOACOUSTIC IMAGING 67 6.1 Hybrid Ultrasound/Photoacoustic System 68 6.2 Fabrication and Characterization of Micromotors 69 6.3 Actuation and Propulsion Performance below Phantom 69 6.4 Actuation and Propulsion Performance below Ex Vivo Tissues 71 6.5 Actuation and Propulsion Performance in Mice 72 6.5.1 Swimming of Micromotors in Bladder 72 6.5.2 Actuation of Micromotors in Uterus 74 6.5.3 3D Multispectral Imaging 76 6.5.4 Towards Targeted Drug Delivery 77 7 SUMMARY AND PERSPECTIVES 80 7.1 Summary 80 7.2 Future Perspectives 83 7.2.1 Contrats Enhancing Labels 84 7.2.2 Novel Imaging Concepts 85 8 REFERENCES 88 9 APPENDIX 105 List of Figures 105 List of Tables 107 Abbreviations 108 List of Publications 109 Acknowledgements 110 Selbstständigkeitserklärung 111 Curriculum Vitae 112

Un nombre de sujets concernant la microrobotique numérique ont été abordés dans le cadre de cette the` se. Une nouvelle génération du microrobot numérique ”DiMiBot” a e´ te´ proposé ce qui rend le DiMiBot plus précis, plus contrôlable et plus petit. La nouvelle structure est formée de deux modules multistables seulement, ce qui ajoute des fonctionnalités´ s importantes comme l’augmentation du nombre de positions avec une taille plus réduite et la capacité´ de réaliser des trajectoires complexes dans l’espace de travail. Le principe du nouveau module multistable combine les avantages des microactionneurs pas à pas en termes du principe et du concept numérique en termes de la répétabilité et la robustesse en boucle ouverte. Un mécanisme de positionnement précis, capable de compenser les incertitudes de fabrication a e´ te´ développé et utilise´ pour assurer un positionnement précis. En parallèle, des modèles analytiques ont e´ te´ développés pour les principaux composants dans le DiMiBot: poutres flambées préformées et actionneurs e´ électrothermiques en U. Des méthodes de conception ont été développées par la suite qui permettent de choisir les dimensions optimales garantissant les performances requises en respectant les spécifications et limites de design. Des prototypes de modules multistables, fabrique´ s dans la salle Blanche MIMENTO, ont montré´ un bon Fonctionnement dans les expériences. / A number of topics concerning digital microrobotics were addressed in this thesis. A new generation of the digital microrobot ”DiMiBot” was proposed with several advantages making the DiMiBot more accurate, more controllable and smaller. The new structure consists of only two multistable modules which adds some important features such as increasing the number of positions with smaller size and the ability to realize complex trajectories in the workspace. The principle of the new multistable module combines the advantages of the stepping microactuators in terms of the principle and of the digital concept in terms of the repeatability and robustness without feedback. The accuracy is ensured with an accurate positioning mechanism that compensate the fabrication tolerances. In parallel, analytical models was developed for the main components in the DiMiBot: preshaped curved beams and U-shaped electrothermal actuators. Subsequently, design methods were developed that allow choosing the optimal dimensions that ensure the desired outputs and respecting the design specifications and limitations. Multistable module prototypes, fabricated in the clean room MIMENTO, showed a proper functioning in the experiments.