Micro-assembly is of crucial importance in industry nowadays. Nevertheless, currently applied processes require improvements. Indeed, when dealing with the assembly of submillimetric components, usually neglected surface forces disturb the manipulation task. They are responsible for the component sticking to the gripper, because of downscaling laws. A promising strategy to tackle adhesion consists in working without contact. The present dissertation is focused on contactless handling with acoustic levitation. The advantages of contactless handling, the physical principles suitable for levitation and their applications are detailed. The opportunity for new handling strategies are shown. Acoustic levitation appears as the most fitted principle for micro-assembly. The elements to model acoustic forces are analysed and performances of existing modellings are assessed. A general numerical model of acoustic forces is implemented and theoretically validated with literature benchmarks. A fully automated modular levitator prototype is designed and used to experimentally validate the implemented numerical model. Specific instrumentations and protocols are developed for the acoustic force measurements. The numerical model is finally applied to the real levitator. Modelling results are used to support experimental observations: the optimisation of the levitator resonance, the influence of the reflector shape, the dynamical study of the component oscillations, the stability with lateral centring forces and rotation torques, the component insertion and extraction from the levitator, the effect of pressure harmonics on the acoustic forces, and the manipulation of non spherical components. Acoustic forces are experimentally measured and a very good agreement with the modellings is obtained. Consequently, the implemented simulation tool can successfully be applied to a complex manipulation task with a component of any shape in a real levitator.

¡@¡@Accompanying with the development of MEMS technology, microstages have been used for many years. Most of the studies on microstages have been aimed at the application of new actuators, materials and fabrication process in recent years. However, the systematic way for designing new microstages with the mechanism conceptual design approach still needs some more input. ¡@¡@The objective of this study is to establish a methodology to design new microstages employing the concept of mechanism design. First of all, new microstages for microassembly have been analyzed according to the basic requirements from the mechanism. Afterwards, the concept of microjoint has been presented and used in the synthesis of microstages. Besides, a flow chart of design procedure has been presented and seven kinds of microstages are achieved accordingly. Finally, the FEM simulation of the synthesized microstage illustrates the desirable results that reveal the good agreement with the expected motion. It is shown that this study can be efficiency applied to the design of micro scale devices.

Due to the potential uses and advantages of 3D microelectromechanical systems (MEMS), research has been ongoing to advance the field. The intention of my reasearch is to explore different gripper designs and their interaction with corresponding components to establish a 3D microassembly system. In order to meet these goals, two grippers were designed using different mechanisms for grasping. At the same time, corresponding parts capable of being constructed into a 3D microstructure were designed to interact with the grippers. The microcomponents were fabricated using PolyMUMPS, a part of the Multi-User MEMS Processes (MUMPS), and experimentation was conducted with the goal of constructing a 3D microstructure. The results were partially successful in that both grippers were able to pick up corresonponding parts and bring them out of plane in order to make them stand up. However, a final 3D microstructure was unfortunately not achieved due to time constraints. This will be left to future researchers who continue the project. On the equpiment side a microassembly system was fully integrated using cameras for vision and motors with micro-resolution for movement. A computer program was used to control each part of the system. The cameras provided feedback from various views, allowing the operator to observe what was happening to the microcomponents. The grippers were attached to one of the motors and manipulated to pick up the parts. The final overall system proved sufficient for microassembly, but had some areas that could be improved upon.

Due to the potential uses and advantages of 3D microelectromechanical systems (MEMS), research has been ongoing to advance the field. The intention of my reasearch is to explore different gripper designs and their interaction with corresponding components to establish a 3D microassembly system. In order to meet these goals, two grippers were designed using different mechanisms for grasping. At the same time, corresponding parts capable of being constructed into a 3D microstructure were designed to interact with the grippers. The microcomponents were fabricated using PolyMUMPS, a part of the Multi-User MEMS Processes (MUMPS), and experimentation was conducted with the goal of constructing a 3D microstructure. The results were partially successful in that both grippers were able to pick up corresonponding parts and bring them out of plane in order to make them stand up. However, a final 3D microstructure was unfortunately not achieved due to time constraints. This will be left to future researchers who continue the project. On the equpiment side a microassembly system was fully integrated using cameras for vision and motors with micro-resolution for movement. A computer program was used to control each part of the system. The cameras provided feedback from various views, allowing the operator to observe what was happening to the microcomponents. The grippers were attached to one of the motors and manipulated to pick up the parts. The final overall system proved sufficient for microassembly, but had some areas that could be improved upon.

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.

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.

In recent years, research efforts in the development of Micro Electro Mechanical Systems, (MEMS) including microactuators and micromanipulators, have attracted a great deal of attention. The development of microfabrication techniques has resulted in substantial progress in the miniaturization of devices such as electronic circuits. However, the research in MEMS still lags behind in terms of the development of reliable tools for post-fabrication processes and the precise and dexterous manipulation of individual micro size objects. Current micromanipulation mechanisms are prone to high costs, a large footprint, and poor dexterity and are labour intensive. To overcome such, the research in this thesis is focused on the utilization of microactuators in micromanipulation. Microactuators are compliant structures. They undergo substantial deflection during micromanipulation due to the considerable surface micro forces. Their dominance in governing micromanipulation is so compelling that their effects should be considered in designing microactuators and microsensors. In this thesis, the characterization of the surface micro forces and automated micromanipulation are investigated. An inexpensive experimental setup is proposed as a platform to replace Atomic Force Microscopy (AFM) for analyzing the force characterization of micro scale components. The relationship between the magnitudes of the surface micro forces and the parameters such as the velocity of the pushing process, relative humidity, temperature, hydrophilicity of the substrate, and surface area are empirically examined. In addition, a precision automated micromanipulation system is realized. A class of artificial neural networks (NN) is devised to estimate the unmodelled micro forces during the controlled pushing of micro size object along a desired path. Then, a nonlinear controller is developed for the controlled pushing of the micro objects to guarantee the stability of the closed loop system in the Lyapunov sense. To validate the performance of the proposed controller, an experimental setup is designed. The application of the proposed controller is extended to precisely push several micro objects, each with different characteristics in terms of the surface micro forces governing the manipulation process. The proposed adaptive controller is capable of learning to adjust its weights effectively when the surface micro forces change under varying conditions. By using the controller, a fully automated sequential positioning of three micro objects on a flat substrate is performed. The results are compared with those of the identical sequential pushing by using a conventional linear controller. The results suggest that artificial NNs are a promising tool for the design of adaptive controllers to accurately perform the automated manipulation of multiple objects in the microscopic scale for microassembly.

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.

In recent years, research efforts in the development of Micro Electro Mechanical Systems, (MEMS) including microactuators and micromanipulators, have attracted a great deal of attention. The development of microfabrication techniques has resulted in substantial progress in the miniaturization of devices such as electronic circuits. However, the research in MEMS still lags behind in terms of the development of reliable tools for post-fabrication processes and the precise and dexterous manipulation of individual micro size objects. Current micromanipulation mechanisms are prone to high costs, a large footprint, and poor dexterity and are labour intensive. To overcome such, the research in this thesis is focused on the utilization of microactuators in micromanipulation. Microactuators are compliant structures. They undergo substantial deflection during micromanipulation due to the considerable surface micro forces. Their dominance in governing micromanipulation is so compelling that their effects should be considered in designing microactuators and microsensors. In this thesis, the characterization of the surface micro forces and automated micromanipulation are investigated. An inexpensive experimental setup is proposed as a platform to replace Atomic Force Microscopy (AFM) for analyzing the force characterization of micro scale components. The relationship between the magnitudes of the surface micro forces and the parameters such as the velocity of the pushing process, relative humidity, temperature, hydrophilicity of the substrate, and surface area are empirically examined. In addition, a precision automated micromanipulation system is realized. A class of artificial neural networks (NN) is devised to estimate the unmodelled micro forces during the controlled pushing of micro size object along a desired path. Then, a nonlinear controller is developed for the controlled pushing of the micro objects to guarantee the stability of the closed loop system in the Lyapunov sense. To validate the performance of the proposed controller, an experimental setup is designed. The application of the proposed controller is extended to precisely push several micro objects, each with different characteristics in terms of the surface micro forces governing the manipulation process. The proposed adaptive controller is capable of learning to adjust its weights effectively when the surface micro forces change under varying conditions. By using the controller, a fully automated sequential positioning of three micro objects on a flat substrate is performed. The results are compared with those of the identical sequential pushing by using a conventional linear controller. The results suggest that artificial NNs are a promising tool for the design of adaptive controllers to accurately perform the automated manipulation of multiple objects in the microscopic scale for microassembly.