Most of the microgrippers developed in recent years still lack of the systematic mechanism design background in the overall design scope of microgripper. The main objective of this investigation is to find new possibilities of design concept in order to enhance the design scope of microgripper. This thesis presents the design and analysis of microgripper for microassembly that are based on the mechanism design perspective, which particularly involves the 3-D working space and planar compliant microgripper. Several feasible solutions of the microgripper with 3-D working space are presented include the use of molten solder self-assembly, hinge mechanism, shape memory alloy, electrostatic-force assembly, and magnetic-force assembly. An atlas of 28 types of planar compliant linkages for two-finger microgripper is presented based on the systematic design procedure. The FEM simulation shows the preliminary satisfactory results that reveal the good agreement with the expected kinematic motion. It can be concluded that the mechanism design concept presented in this study can be integrated into the design work of micro scale actuating device.

No description available.

Microstructure manipulation is a fundamental process to the study of biology and medicine, as well as to advance micro- and nano-system applications. Manipulation of microstructures has been achieved through various microgripper devices developed recently, which lead to advances in micromachine assembly, and single cell manipulation, among others. Only two kinds of integrated feedback have been demonstrated so far, force sensing and optical binary feedback. As a result, the physical, mechanical, optical, and chemical information about the microstructure under study must be extracted from macroscopic instrumentation, such as confocal fluorescence microscopy and Raman spectroscopy. In this research work, novel Micro-Opto-Electro-Mechanical-System (MOEMS) microgrippers are presented. These devices utilize flexible optical waveguides as gripping arms, which provide the physical means for grasping a microobject, while simultaneously enabling light to be delivered and collected. This unique capability allows extensive optical characterization of the structure being held such as transmission, reflection, or fluorescence. The microgrippers require external actuation which was accomplished by two methods: initially with a micrometer screw, and later with a piezoelectric actuator. Thanks to a novel actuation mechanism, the “fishbone”, the gripping facets remain parallel within 1 degree. The design, simulation, fabrication, and characterization are systematically presented. The devices mechanical operation was verified by means of 3D finite element analysis simulations. Also, the optical performance and losses were simulated by the 3D-to-2D effective index (finite difference time domain FDTD) method as well as 3D Beam Propagation Method (3D-BPM). The microgrippers were designed to manipulate structures from submicron dimensions up to approximately 100 µm. The devices were implemented in SU-8 due to its suitable optical and mechanical properties. This work demonstrates two practical applications: the manipulation of single SKOV-3 human ovarian carcinoma cells, and the detection and identification of microparts tagged with a fluorescent “barcode” implemented with quantum dots. The novel devices presented open up new possibilities in the field of micromanipulation at the microscale, scalable to the nano-domain.

The mechanical properties of biomaterials play important roles in performing their specialized functions: synthesizing, storing, and transporting biomolecules; maintaining internal structures; and responding to external environments. Besides biological cells, there are also many other biomaterials that are highly deformable and have a diameter between 1μm and 100μm, comparable to that of most biological cells. For example, many polymeric microcapsules for drug delivery use are spherical particles of micrometers size. In order to mechanically characterize individual micrometer-sized biomaterials, the capability of capturing high-resolution and low-magnitude force feedback is required. This research focuses on the development of micro devices and experimental techniques for quantifying the mechanical properties of alginate-chitosan microcapsules. The micro devices include microelectromechanical systems (MEMS) capacitive force sensors and force-feedback microgrippers, capable of measuring sub-μN forces. Employing the MEMS devices, systems were constructed to perform the micro-scale compression testing of microcapsules. The force sensors are capable of resolving forces up to 110μN with a resolution of 33.2nN along two independent axes. The force sensors were applied to characterizing the mechanical properties of hydrogel microparticles without assembling additional end-effectors. The microcapsules were immobilized by a PDMS holding device and compressed between the sensor probe and holding device. Young's modulus values of individual microcapsules with 1%, 2%, and 3% chitosan coating were determined through the micro-scale compression testing in both distilled deionized (DDI) water and pH 7.4 phosphate buffered saline (PBS). The Young's modulus values were also correlated to protein release rates. Instead of compressing the microcapsule against the wall of the holding device, a force-feedback MEMS microgripper with the capability of directly compressing the microcapsule between two gripping arms has been used for characterizing both the elastic and viscoelastic properties of the microcapsules during micromanipulation. The single-chip microgripper integrates an electrothermal microactuator and two capacitive force sensors, one for contact detection (force resolution: 38.5nN) and the other for gripping force measurements (force resolution: 19.9nN). Through nanoNewton force measurements, closed-loop force control, and visual tracking, the system quantified the Young's modulus values and viscoelastic parameters of alginate microcapsules, demonstrating an easy-to-operate, accurate compression testing technique for characterizing soft, micrometer-sized biomaterials.

The mechanical properties of biomaterials play important roles in performing their specialized functions: synthesizing, storing, and transporting biomolecules; maintaining internal structures; and responding to external environments. Besides biological cells, there are also many other biomaterials that are highly deformable and have a diameter between 1μm and 100μm, comparable to that of most biological cells. For example, many polymeric microcapsules for drug delivery use are spherical particles of micrometers size. In order to mechanically characterize individual micrometer-sized biomaterials, the capability of capturing high-resolution and low-magnitude force feedback is required. This research focuses on the development of micro devices and experimental techniques for quantifying the mechanical properties of alginate-chitosan microcapsules. The micro devices include microelectromechanical systems (MEMS) capacitive force sensors and force-feedback microgrippers, capable of measuring sub-μN forces. Employing the MEMS devices, systems were constructed to perform the micro-scale compression testing of microcapsules. The force sensors are capable of resolving forces up to 110μN with a resolution of 33.2nN along two independent axes. The force sensors were applied to characterizing the mechanical properties of hydrogel microparticles without assembling additional end-effectors. The microcapsules were immobilized by a PDMS holding device and compressed between the sensor probe and holding device. Young's modulus values of individual microcapsules with 1%, 2%, and 3% chitosan coating were determined through the micro-scale compression testing in both distilled deionized (DDI) water and pH 7.4 phosphate buffered saline (PBS). The Young's modulus values were also correlated to protein release rates. Instead of compressing the microcapsule against the wall of the holding device, a force-feedback MEMS microgripper with the capability of directly compressing the microcapsule between two gripping arms has been used for characterizing both the elastic and viscoelastic properties of the microcapsules during micromanipulation. The single-chip microgripper integrates an electrothermal microactuator and two capacitive force sensors, one for contact detection (force resolution: 38.5nN) and the other for gripping force measurements (force resolution: 19.9nN). Through nanoNewton force measurements, closed-loop force control, and visual tracking, the system quantified the Young's modulus values and viscoelastic parameters of alginate microcapsules, demonstrating an easy-to-operate, accurate compression testing technique for characterizing soft, micrometer-sized biomaterials.

Precise manipulation of micro objects became great interest in engineering and science with the advancements in microengineering and microfabrication. In this thesis, a magnetically levitated microgripper is presented for microhandling tasks. The use of magnetic levitation for positioning reveals the problems associated with modeling of complex surface forces and the use of jointed parts or wires. The power required for the levitation of the microgripper is generated by an external drive unit that makes further minimization of the gripper possible. The gripper is made of a biocompatible material and can be activated remotely. These key features make the microgripper a great candidate for manipulation of micro components and biomanipulation. In order to achieve magnetic levitation of microrobots, the magnetic field generated by the magnetic levitation setup is simulated. The magnetic flux density in the air gap region is improved by the integration of permanent magnets and an additional electromagnet to the magnetic loop assembly. The levitation performance is evaluated with millimeter size permanent magnets. An eddy current damping method is implemented and the levitation accuracy is doubled by reducing the positioning error to 20.3 µm. For a MEMS-compatible microrobot design, the electrodeposition of Co-Ni-Mn-P magnetic thin films is demonstrated. Magnetic films are deposited on silicon substrate to form the magnetic portion of the microrobot. The electrodeposited films are extensively characterized. The relationship between the deposition parameters and structural properties is discussed leading to an understanding of the effect of deposition parameters on the magnetic properties. It is shown that both in-plane and out-of-plane magnetized films can be obtained using electrodeposition with slightly differentiated deposition parameters. The levitation of the electrodeposited magnetic samples shows a great promise toward the fabrication of levitating MEMS devices. The end-effector tool of the levitating microrobot is selected as a microgripper that can achieve various manipulation operations such as pulling, pushing, tapping, grasping and repositioning. The microgripper is designed based on a bent-beam actuation technique. The motion of the gripper fingers is achieved by thermal expansion through laser heat absorption. This technique provided non-contact actuation for the levitating microgripper. The analytical model of the displacement of the bent-beam actuator is developed. Different designs of microgripper are fabricated and thoroughly characterized experimentally and numerically. The two microgripper designs that lead to the maximum gripper deflection are adapted for the levitating microrobot. The experimental results show that the levitating microrobot can be positioned in a volume of 3 x 3 x 2 cm^3. The positioning error is measured as 34.3 µm and 13.2 µm when electrodeposited magnets and commercial permanent magnets are used, respectively. The gripper fingers are successfully operated on-the-fly by aligning a visible wavelength laser beam on the gripper. Micromanipulation of 100 µm diameter electrical wire, 125 µm diameter optical fiber and 1 mm diameter cable strip is demonstrated. The microgripper is also positioned in a closed chamber without sacrificing the positioning accuracy.

Precise manipulation of micro objects became great interest in engineering and science with the advancements in microengineering and microfabrication. In this thesis, a magnetically levitated microgripper is presented for microhandling tasks. The use of magnetic levitation for positioning reveals the problems associated with modeling of complex surface forces and the use of jointed parts or wires. The power required for the levitation of the microgripper is generated by an external drive unit that makes further minimization of the gripper possible. The gripper is made of a biocompatible material and can be activated remotely. These key features make the microgripper a great candidate for manipulation of micro components and biomanipulation. In order to achieve magnetic levitation of microrobots, the magnetic field generated by the magnetic levitation setup is simulated. The magnetic flux density in the air gap region is improved by the integration of permanent magnets and an additional electromagnet to the magnetic loop assembly. The levitation performance is evaluated with millimeter size permanent magnets. An eddy current damping method is implemented and the levitation accuracy is doubled by reducing the positioning error to 20.3 µm. For a MEMS-compatible microrobot design, the electrodeposition of Co-Ni-Mn-P magnetic thin films is demonstrated. Magnetic films are deposited on silicon substrate to form the magnetic portion of the microrobot. The electrodeposited films are extensively characterized. The relationship between the deposition parameters and structural properties is discussed leading to an understanding of the effect of deposition parameters on the magnetic properties. It is shown that both in-plane and out-of-plane magnetized films can be obtained using electrodeposition with slightly differentiated deposition parameters. The levitation of the electrodeposited magnetic samples shows a great promise toward the fabrication of levitating MEMS devices. The end-effector tool of the levitating microrobot is selected as a microgripper that can achieve various manipulation operations such as pulling, pushing, tapping, grasping and repositioning. The microgripper is designed based on a bent-beam actuation technique. The motion of the gripper fingers is achieved by thermal expansion through laser heat absorption. This technique provided non-contact actuation for the levitating microgripper. The analytical model of the displacement of the bent-beam actuator is developed. Different designs of microgripper are fabricated and thoroughly characterized experimentally and numerically. The two microgripper designs that lead to the maximum gripper deflection are adapted for the levitating microrobot. The experimental results show that the levitating microrobot can be positioned in a volume of 3 x 3 x 2 cm^3. The positioning error is measured as 34.3 µm and 13.2 µm when electrodeposited magnets and commercial permanent magnets are used, respectively. The gripper fingers are successfully operated on-the-fly by aligning a visible wavelength laser beam on the gripper. Micromanipulation of 100 µm diameter electrical wire, 125 µm diameter optical fiber and 1 mm diameter cable strip is demonstrated. The microgripper is also positioned in a closed chamber without sacrificing the positioning accuracy.

No description available.

The exploration of Microelectromechanical systems (MEMS) represents a crucial aspect in the advancement of modern science and technology. They offer low-cost solutions to miniaturize numerous devices. The increasing use of MEMS applications in biological research has created a pressing need for reliable micromanipulation tools. In this context, microgrippers have emerged as promising tools for the precise handling and characterization of biological samples. This thesis presents a novel biocompatible microgripper that utilizes electrothermal actuation integrated with a rotary capacitive position sensor. To overcome the limited displacement possibilities associated with electrothermal actuators, this microgripper incorporates conjugate surface flexure hinges (CSFH). These hinges enhance the desired tweezers output displacement. The designed microgripper can in principle manipulate biological samples ranging in size from 15 to 120 μm. Based on the sensitivity calculation of the rotary capacitive position sensors, the sensitivity of the displacement measurement is 102 fF/μm. By employing a kinematics modeling approach based on the pseudo-rigid-body method (PRBM), an equation for the displacement amplification factor is developed, and this equation is subsequently verified through FEM-based simulations. By comparing the amplification ratio value obtained from the analytical modeling and simulations, there is an excellent match, with a relative difference of only ~1%, thus demonstrating the effectiveness of the PRBM approach in modeling the kinematics of the structure under investigation. In addition to this, by using analytical modeling based on finite elements method (FEM), the design of the electrothermal actuator and the heat dissipation mechanism is optimized. FEM-based simulations are used to validate the theoretical modeling, demonstrating good agreement between the displacements derived from analytical modeling and simulations. The temperature difference (∆T) across a range from room temperature to 278°C exhibits a relative difference of ~2.8%. Moreover, underpass technology is implemented to ensure that electrical signals or disturbances from other parts of the device, such as the electrothermal actuation system, do not interfere with the operation and integrity of the gripping mechanism. Ultimately, the microgripper is fabricated using conventional MEMS technology from a silicon-on-insulator (SOI) wafer through the deep reactive ion etching (DRIE) technique. The integration of theoretical modeling, simulations, and practical fabrication highlights a compelling approach that has the potential for transformative applications in the field of micromanipulation and biological sample handling. Furthermore, we propose a C-shaped structure with a curved beam mechanism to improve the movement provided by the thermal actuators. The design of experiment (DOE) method is used to optimize the geometrical parameters of our proposed device. Analytical modeling based on Castigliano's second theorem and finite element method (FEM) simulations are used to predict the behavior of the symmetrical C-shaped structure; the results are in good agreement. The MEMS-based rotational structures are fabricated on silicon-on-insulator (SOI) wafers using bulk micromachining and deep reactive ion etching (DRIE). The fabricated devices are tested; our findings reveal that our proposed MEMS rotational structure outperforms the symmetrical lancet structure by 28% in terms of delivered displacement. Furthermore, the experimental results agree well with those obtained through numerical analysis.

Les systèmes micro mécatroniques intègrent dans un volume très réduit des fonctions de natures différentes (électrique, mécanique, thermique, magnétique ou encore optique). Ces systèmes sont des produits finaux ou sont dans des systèmes de taille macroscopique. La tendance à la miniaturisation et à la complexité des fonctions à réaliser conduit à des microsystème en trois dimensions et constitué´es de composants provenant de processus de (micro)fabrication parfois incompatibles. L’assemblage microbotique est une réponse aux challenges de leur réalisation. Pour assurer les opérations d’ assemblage avec des précisions et des résolutions élevées, des capteurs adaptés au micro monde et des outils particuliers de manipulation doivent être utilisés. Les éléments principaux constituants les systèmes de micromanipulation sont les micro-actionneurs.Ces derniers sont souvent faits à base de matériaux actifs parmi lesquels les matériaux Piézoélectriques . Les actionneurs piézoélectriques sont caractérisés par leur très haute résolution (souvent nanométrique), leur grande bande-passante (plus du kHz pour certains micro-actionneurs) et leur grande densité de force. Tout ceci en fait des actionneurs particulièrement intéressants pour le micro-assemblage et la micromanipulation. Cependant,ces actionneurs présentent, en plus de leur comportement non-linéaire, une forte dépendance à l’environnement et aux tâches considérées. De plus, ces tâches de micromanipulation et de micro-assemblage sont confrontées à un manque de capteurs précis et compatibles avec les dimensions du micromonde. Ceci engendre des incertitudes sur les paramètres du élaboré lors de l’identification. En présence du verrou technologique lié à la réalisation des capteurs et des propriétés complexes des actionneurs, il est difficile d’obtenir les performances de haut niveau requises pour réussir les tâches de micromanipulation et de micro-assemblage. C’est notamment la mise au point d’outils de commande convenables qui permet d’atteindre les niveaux de précision et de résolution nécessaires.Les travaux de cette thèse s’inscrivent dans ce cadre. Afin de réussir les tâches de micromanipulation et de micro-assemblage, plusieurs méthodes de commande prenant en compte des incertitudes liées au modèle, comme les approches de commande robustes de type H-inf ont déjà utilisées pour commander les actionneurs piézoélectriques.L’un des inconvénients majeurs de ces méthodes est la dérivation de régulateurs d’ordre élevé qui sont coûteux en calcul et peuvent difficilement être embarqués dans les microsystèmes. Afin de prendre en compte les incertitudes paramétriques des modèles des Systèmes à commander, nous proposons une solution alternative basée sur l’utilisation du calcul par intervalles. Ces techniques du calcul par intervalles sont combinées avec les outils de l’automatique pour modéliser et commander les microsystèmes. Nous chercherons également à montrer que l’utilisation de ces techniques permet d’associer la robustesse et la simplicité des correcteurs dérivés / Micromechatronic systems integrate in a very small volume functions with differentnatures. The trend towards miniaturization and complexity of functions to achieve leadsto 3-dimensional microsystems. These 3-dimensional systems are formed by microroboticassembly of various microfabricated and incompatible components. To achieve theassembly operations with high accuracy and high resolution, adapted sensors for themicroworld and special tools for the manipulation are required. The microactuators arethe main elements that constitute the micromanipulation systems. These actuators areoften based on smart materials, in particular piezoelectric materials. The piezoelectricmaterials are characterized by their high resolution (nanometric), large bandwidth (morethan kHz) and high force density. This why the piezoelectric actuators are widely usedin the micromanipulation and microassembly tasks. However, the behavior of the piezoelectricactuators is non-linear and very sensitive to the environment. Moreover, thedeveloppment of the micromanipulation and the microassembly tasks is limited by thelack of precise and compatible sensors with the microworld dimensions. In the presenceof the difficulties related to the sensors realization and the complex characteristics ofthe actuators, it is difficult to obtain the required performances for the micromanipulationand the microassembly tasks. For that, it is necessary to develop a specific controlapproach that achieves the wanted accuracy and resolution.The works in this thesis deal with this problematic. In order to success the micromanipulationand the microassembly tasks, robust control approaches such as H∞ havealready been tested to control the piezoelectric actuators. However, the main drawbacksof these methods is the derivation of high order controllers. In the case of embedded microsystems,these high order controllers are time consuming which limit their embeddingpossibilities. To address this problem, we propose in our work an alternative solutionto model and control the microsystems by combining the interval techniques with theautomatic tools. We will also seek to show that the use of these techniques allows toderive robust and low-order controllers.