Workshop on "Robotic assembly of 3D MEMS".

Proceedings of a workshop proposed in IEEE IROS'2007.The increase of MEMS' functionalities often requires the integration of various technologies used for mechanical, optical and electronic subsystems in order to achieve a unique system. These different technologies have usually process incompatibilities and the whole microsystem can not be obtained monolithically and then requires microassembly steps. Microassembly of MEMS based on micrometric components is one of the most promising approaches to achieve high-performance MEMS. Moreover, microassembly also permits to develop suitable MEMS packaging as well as 3D components although microfabrication technologies are usually able to create 2D and "2.5D" components. The study of microassembly methods is consequently a high stake for MEMS technologies growth. Two approaches are currently developped for microassembly: self-assembly and robotic microassembly. In the first one, the assembly is highly parallel but the efficiency and the flexibility still stay low. The robotic approach has the potential to reach precise and reliable assembly with high flexibility. The proposed workshop focuses on this second approach and will take a bearing of the corresponding microrobotic issues. Beyond the microfabrication technologies, performing MEMS microassembly requires, micromanipulation strategies, microworld dynamics and attachment technologies. The design and the fabrication of the microrobot end-effectors as well as the assembled micro-parts require the use of microfabrication technologies. Moreover new micromanipulation strategies are necessary to handle and position micro-parts with sufficiently high accuracy during assembly. The dynamic behaviour of micrometric objects has also to be studied and controlled. Finally, after positioning the micro-part, attachment technologies are necessary

Design of a Multi-Mode Hybrid Micro-Gripper for Surface Mount Technology Component Assembly

In the last few decades, industrial sectors such as smart manufacturing and aerospace have rapidly developed, contributing to the increase in production of more complex electronic boards based on SMT (Surface Mount Technology). The assembly phases in manufacturing these electronic products require the availability of technological solutions able to deal with many heterogeneous products and components. The small batch production and pre-production are often executed manually or with semi-automated stations. The commercial automated machines currently available offer high performance, but they are highly rigid. Therefore, a great effort is needed to obtain machines and devices with improved reconfigurability and flexibility for minimizing the set-up time and processing the high heterogeneity of components. These high-level objectives can be achieved acting in different ways. Indeed, a work station can be seen as a set of devices able to interact and cooperate to perform a specific task. Therefore, the reconfigurability of a work station can be achieved through reconfigurable and flexible devices and their hardware and software integration and control For this reason, significant efforts should be focused on the conception and development of innovative devices to cope with the continuous downscaling and increasing variety of the products in this growing field. In this context, this paper presents the design and development of a multi-mode hybrid micro-gripper devoted to manipulate and assemble a wide range of micro- and meso-SMT components with different dimensions and proprieties. It exploits two different handling technologies: the vacuum and friction

NanoThermoMechanical Logic Gates for Thermal Computing

Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications require the development of alternative computing technologies. Thermal computing, data processing based on heat instead of electricity, is proposed as a practical alternative and opens a new scientific area at the interface between thermal and computational sciences. We successfully developed thermal AND, OR and NOT logic gates, achieved through the coupling between near-field thermal radiation and MEMS thermal actuation. In the process, we developed two novel non-linear thermal expansion designs of microstructure silicon V-shaped chevron beams which were required to achieve the desired thermal AND gate operation. The successful design paves the way to develop full thermal logic circuits, so we show the design and simulation of a thermal calculator based on binary mathematical computations. This thermal calculator was able to perform the addition of two decimal numbers. Furthermore, we introduce the microfabrication and characterization of the thermal AND and OR logic gates. The thermal AND logic gate consists of two non-linear mechanisms using novel and ingenious chevron mechanisms consisting of spring-assisted reduction and cascading chevrons amplification for the reducing and the amplification mechanisms, respectively. The experimental results show that we achieved non-linearity ratios of thermal expansion of 0.36 and 3.06 for the reducing and the amplification mechanisms, respectively. For the characterization of thermal AND logic gate, for the case when the two inputs were at (i.e., 0,0 case), we achieved an effectiveness of 10.7 % at a heat source temperature of 1549 K. For the thermal OR logic gate, for the cases of (1,0) and (0,1), we achieved an effectiveness of 25.3 % and 23.2 % at an input temperature of 1324 K and 1391 K, respectively. These results are significant breakthroughs in the field of thermal computation science and technology as they demonstrate thermal computing at high temperatures based on demonstrated and easy to manufacture NanoThermoMechanical logic gates. Advisor: Sidy Nda

Development of compliant mechanisms for real-time machine tool accuracy enhancement using dual-servo principle

Ph.DDOCTOR OF PHILOSOPH

Design and realization of a microassembly workstation

With the miniaturization of products to the levels of micrometers and the recent developments in microsystem fabrication technologies, there is a great need for an assembly process for the formation of complex hybrid microsystems. Integration of microcomponents made up of different materials and manufactured using different micro fabrication techniques is still a primary challenge since some of the fundamental problems originating from the small size of parts to be manipulated, high precision necessity and specific problems of the microworld in that field are still not fully investigated. In this thesis, design and development of an open-architecture and reconfigurable microassembly workstation for efficient and reliable assembly of micromachined parts is presented. The workstation is designed to be used as a research tool for investigation of the problems in microassembly. The development of such a workstation includes the design of: (i) a manipulation system consisting of motion stages providing necessary travel range and precision for the realization of assembly tasks, (ii) a vision system to visualize the microworld and the determination of the position and orientation of micro components to be assembled, (iii) a robust control system and necessary fixtures for the end effectors that allow easy change of manipulation tools and make the system ready for the desired task. In addition tele-operated and semi-automated assembly concepts are implemented. The design is verified by implementing tasks in various ranges for micro-parts manipulation. The versatility of the workstation is demonstrated and high accuracy of positioning is shown

NanoThermoMechanical Logic Gates for Thermal Computing

Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications require the development of alternative computing technologies. Thermal computing, data processing based on heat instead of electricity, is proposed as a practical alternative and opens a new scientific area at the interface between thermal and computational sciences. We successfully developed thermal AND, OR and NOT logic gates, achieved through the coupling between near-field thermal radiation and MEMS thermal actuation. In the process, we developed two novel non-linear thermal expansion designs of microstructure silicon V-shaped chevron beams which were required to achieve the desired thermal AND gate operation. The successful design paves the way to develop full thermal logic circuits, so we show the design and simulation of a thermal calculator based on binary mathematical computations. This thermal calculator was able to perform the addition of two decimal numbers. Furthermore, we introduce the microfabrication and characterization of the thermal AND and OR logic gates. The thermal AND logic gate consists of two non-linear mechanisms using novel and ingenious chevron mechanisms consisting of spring-assisted reduction and cascading chevrons amplification for the reducing and the amplification mechanisms, respectively. The experimental results show that we achieved non-linearity ratios of thermal expansion of 0.36 and 3.06 for the reducing and the amplification mechanisms, respectively. For the characterization of thermal AND logic gate, for the case when the two inputs were at (i.e., 0,0 case), we achieved an effectiveness of 10.7 % at a heat source temperature of 1549 K. For the thermal OR logic gate, for the cases of (1,0) and (0,1), we achieved an effectiveness of 25.3 % and 23.2 % at an input temperature of 1324 K and 1391 K, respectively. These results are significant breakthroughs in the field of thermal computation science and technology as they demonstrate thermal computing at high temperatures based on demonstrated and easy to manufacture NanoThermoMechanical logic gates. Advisor: Sidy Nda

Optical MEMS Switches: Theory, Design, and Fabrication of a New Architecture

The scalability and cost of microelectromechanical systems (MEMS) optical switches are now the important factors driving the development of MEMS optical switches technology. The employment of MEMS in the design and fabrication of optical switches through the use of micromachining fabricated micromirrors expands the capability and integrity of optical backbone networks. The focus of this dissertation is on the design, fabrication, and implementation of a new type of MEMS optical switch that combines the advantages of both 2-D and 3-D MEMS switch architectures. This research presents a new digital MEMS switch architecture for 1×N and N×N optical switches. The architecture is based on a new microassembled smart 3-D rotating inclined micromirror (3DRIM). The 3DRIM is the key device in the new switch architectures. The 3DRIM was constructed through a microassembly process using a passive microgripper, key, and inter-lock (PMKIL) assembly system. An electrostatic micromotor was chosen as the actuator for the 3DRIM since it offers continuous rotation as well as small, precise step motions with excellent repeatability that can achieve repeatable alignment with minimum optical insertion loss between the input and output ports of the switch. In the first 3DRIM prototype, a 200×280 microns micromirror was assembled on the top of the electrostatic micromotor and was supported through two vertical support posts. The assembly technique was then modified so that the second prototype can support micromirrors with dimensions up to 400×400 microns. Both prototypes of the 3DRIM are rigid and stable during operation. Also, rotor pole shaping (RPS) design technique was introduced to optimally reshape the physical dimensions of the rotor pole in order to maximize the generated motive torque of the micromotor and minimize the required driving voltage signal. The targeted performance of the 3DRIM was achieved after several PolyMUMPs fabrication runs. The new switch architecture is neither 2-D nor 3-D. Since it is composed of two layers, it can be considered 2.5-D. The new switch overcomes many of the limitations of current traditional 2-D MEMS switches, such as limited scalability and large variations in the insertion loss across output ports. The 1×N MEMS switch fabric has the advantage of being digitally operated. It uses only one 3DRIM to switch the light signal from the input port to any output port. The symmetry employed in the switch design gives it the ability to incorporate a large number of output ports with uniform insertion losses over all output channels, which is not possible with any available 2-D or 3-D MEMS switch architectures. The second switch that employs the 3DRIM is an N×N optical cross-connect (OXC) switch. The design of an N×N OXC uses only 2N of the 3DRIM, which is significantly smaller than the N×N switching micromirrors used in 2-D MEMS architecture. The new N×N architecture is useful for a medium-sized OXC and is simpler than 3-D architecture. A natural extension of the 3DRIM will be to extend its application into more complex optical signal processing, i.e., wavelength-selective switch. A grating structures have been selected to explore the selectivity of the switch. For this reason, we proposed that the surface of the micromirror being replaced by a suitable gratings instead of the flat reflective surface. Thus, this research has developed a rigorous formulation of the electromagnetic scattered near-field from a general-shaped finite gratings in a perfect conducting plane. The formulation utilizes a Fourier-transform representation of the scattered field for the rapid convergence in the upper half-space and the staircase approximation to represent the field in the general-shaped groove. This method provides a solution for the scattered near-field from the groove and hence is considered an essential design tool for near-field manipulation in optical devices. Furthermore, it is applicable for multiple grooves with different profiles and different spacings. Each groove can be filled with an arbitrary material and can take any cross-sectional profile, yet the solution is rigorous because of the rigorous formulations of the fields in the upper-half space and the groove reigns. The efficient formulation of the coefficient matrix results in a banded-matrix form for an efficient and time-saving solution

Design and implementation of rotational degrees of freedom into microrobotics platform

The strength of the individual paper fiber bonds (IPFB) is the key parameter which determines the mechanical quality of paper hand sheets. Currently, most of the strength measurements are still done on hand-sheet level because of the absence of high throughput IPFB strength measurement tools. Micro and Nanosystems research group of Tampere University of Technology recognized the demand for an IPFB characterization system and built a microrobotics platform. However, the current configuration of the platform is not able to rotate the microgripper which limits the measurements such as Z-directional bond breaking and shear mode bond breaking. Moreover, this configuration is not capable of dealing with twisted fibers. This thesis addresses these problems and introduces addition of two more degrees of rotation to the current platform. This modification of microrobotic platform will enable the bond strength measurement of IPFBs in desired pure modes which will enhance the paper fiber scientist`s understanding of IPFBs breaking process. Bond strength measurement with the current platform provides data that is a combination of normal and shear forces which is not desired. After the modifications provided by this thesis, the microrobotic platform will be able to separate the shear force and the normal force during shear mode bond breaking. In the Z-directional bond strength measurement, it is essential to know which fiber is on the top whereas the platform does not fulfill this requirement. The rotation of the microgripper and thus, the fibers will reveal the orientation of the IPFBs. Moreover, the rotation of the microgripper enables the user to untwist the twisted fibers by rotating from one end while the other end is fixed with another microgripper. Forward kinematics of the modified system is calculated through Matlab and compared with the real system. The errors between the ideal system and real system are reduced significantly by modifying the parameters in the overall transformation matrix which ensures that the modified microrobotic platform is now capable of solving all three problems discussed above. Maximum errors are decreased 90.65% (from 107 micrometers to 10 micrometers) at the X-axis, 82.47% (from 97 micrometers to 17 micrometers) at the Y-axis and 87.17% (from 195 micrometers to 25 micrometers) at the Z-axis

Visual Servoing

The goal of this book is to introduce the visional application by excellent researchers in the world currently and offer the knowledge that can also be applied to another field widely. This book collects the main studies about machine vision currently in the world, and has a powerful persuasion in the applications employed in the machine vision. The contents, which demonstrate that the machine vision theory, are realized in different field. For the beginner, it is easy to understand the development in the vision servoing. For engineer, professor and researcher, they can study and learn the chapters, and then employ another application method