Micropositioning and Fast Transport Using a Contactless Micro-Conveyor

International audienceThe micro-conveyor is a 9 x 9 mm2 manipulation surface able to move millimeter-sized planar objects in the four cardinal directions using air flows. Thanks to a specific design, the air flow comes through a network of micro-channels connected to an array of micro-nozzles. Thus, the micro-conveyor generates an array of tilted air jets that lifts and moves the object in the required direction. In this paper, we characterize the device for transport and positioning tasks and evaluate its performances in terms of speed, resolution and repeatability. We show that the micro-conveyor is able to move the object with a speed up to 137 mm* s-1 in less than 100 ms whereas the positioning repeatability is around 17.7 µm with feedback control. The smallest step the object can do is 0.3 µm (positioning resolution). Moreover, we estimated thanks to a dynamic model that the speed could reach 456 mm* s-1 if several micro-conveyors were used to form a conveying line

Design and optimal control of a multistable, cooperative microactuator

In order to satisfy the demand for the high functionality of future microdevices, research on new concepts for multistable microactuators with enlarged working ranges becomes increasingly important. A challenge for the design of such actuators lies in overcoming the mechanical connections of the moved object, which limit its deflection angle or traveling distance. Although numerous approaches have already been proposed to solve this issue, only a few have considered multiple asymptotically stable resting positions. In order to fill this gap, we present a microactuator that allows large vertical displacements of a freely moving permanent magnet on a millimeter-scale. Multiple stable equilibria are generated at predefined positions by superimposing permanent magnetic fields, thus removing the need for constant energy input. In order to achieve fast object movements with low solenoid currents, we apply a combination of piezoelectric and electromagnetic actuation, which work as cooperative manipulators. Optimal trajectory planning and flatness-based control ensure time- and energy-efficient motion while being able to compensate for disturbances. We demonstrate the advantage of the proposed actuator in terms of its expandability and show the effectiveness of the controller with regard to the initial state uncertainty

Distributed Electro-Mechanical Coupling Effects in a Dielectric Elastomer Membrane Array

Background Dielectric elastomer (DE) transducers permit to efectively develop large-deformation, energy-efcient, and compliant mechatronic devices. By arranging many DE elements in an array-like confguration, a soft actuator/sensor system capable of cooperative features can be obtained. When many DE elements are densely packed onto a common elastic membrane, spatial coupling efects introduce electro-mechanical interactions among neighbors, which strongly afect the system actuation and sensing performance. To efectively design cooperative DE systems, those coupling efects must be systematically characterized and understood frst. Objective As a frst step towards the development of complex cooperative DE systems, in this work we present a systematic characterization of the spatial electro-mechanical interactions in a 1-by-3 array of silicone DEs. More specifcally, we investigate how the force and capacitance characteristics of each DE in the array change when its neighbors are subject to diferent types of mechanical or electrical loads. Force and capacitance are chosen for this investigation, since those quantities are directly tied to the DE actuation and sensing behaviors, respectively. Methods An electro-mechanical characterization procedure is implemented through a novel experimental setup, which is specifcally developed for testing soft DE arrays. The setup allows to investigate how the force and capacitance characteristics of each DE are afected by static deformations and/or electrical voltages applied to its nearby elements. Diferent combinations of electro-mechanical loads and DE neighbors are considered in an extensive experimental campaign. Results The conducted investigation shows the existence of strong electro-mechanical coupling efects among the diferent array elements. The interaction intensity depends on multiple parameters, such as the distance between active DEs or the amount of deformation/voltage applied to the neighbors, and provides essential information for the design of array actuators. In some cases, such coupling efects may lead to changes in force up to 9% compared to the reference confguration. A further coupling is also observed in the DE capacitive response, and opens up the possibility of implementing advanced and/or distributed self-sensing strategies in future applications. Conclusion By means of the conducted experiments, we clearly show that the actuation and sensing characteristics of each DE in the array are strongly infuenced by the electro-mechanical loading state of its neighbors. The coupling efects may signifcantly afect the overall cooperative system performance, if not properly accounted for during the design. In future works, the obtained results will allow developing cooperative DE systems which are robust to, and possibly take advantage of, such spatial coupling efects

Modeling, simulation and control of microrobots for the microfactory.

Future assembly technologies will involve higher levels of automation in order to satisfy increased microscale or nanoscale precision requirements. Traditionally, assembly using a top-down robotic approach has been well-studied and applied to the microelectronics and MEMS industries, but less so in nanotechnology. With the boom of nanotechnology since the 1990s, newly designed products with new materials, coatings, and nanoparticles are gradually entering everyone’s lives, while the industry has grown into a billion-dollar volume worldwide. Traditionally, nanotechnology products are assembled using bottom-up methods, such as self-assembly, rather than top-down robotic assembly. This is due to considerations of volume handling of large quantities of components, and the high cost associated with top-down manipulation requiring precision. However, bottom-up manufacturing methods have certain limitations, such as components needing to have predefined shapes and surface coatings, and the number of assembly components being limited to very few. For example, in the case of self-assembly of nano-cubes with an origami design, post-assembly manipulation of cubes in large quantities and cost-efficiency is still challenging. In this thesis, we envision a new paradigm for nanoscale assembly, realized with the help of a wafer-scale microfactory containing large numbers of MEMS microrobots. These robots will work together to enhance the throughput of the factory, while their cost will be reduced when compared to conventional nanopositioners. To fulfill the microfactory vision, numerous challenges related to design, power, control, and nanoscale task completion by these microrobots must be overcome. In this work, we study two classes of microrobots for the microfactory: stationary microrobots and mobile microrobots. For the stationary microrobots in our microfactory application, we have designed and modeled two different types of microrobots, the AFAM (Articulated Four Axes Microrobot) and the SolarPede. The AFAM is a millimeter-size robotic arm working as a nanomanipulator for nanoparticles with four degrees of freedom, while the SolarPede is a light-powered centimeter-size robotic conveyor in the microfactory. For mobile microrobots, we have introduced the world’s first laser-driven micrometer-size locomotor in dry environments, called ChevBot to prove the concept of the motion mechanism. The ChevBot is fabricated using MEMS technology in the cleanroom, following a microassembly step. We showed that it can perform locomotion with pulsed laser energy on a dry surface. Based on the knowledge gained with the ChevBot, we refined tits fabrication process to remove the assembly step and increase its reliability. We designed and fabricated a steerable microrobot, the SerpenBot, in order to achieve controllable behavior with the guidance of a laser beam. Through modeling and experimental study of the characteristics of this type of microrobot, we proposed and validated a new type of deep learning controller, the PID-Bayes neural network controller. The experiments showed that the SerpenBot can achieve closed-loop autonomous operation on a dry substrate

Contribution au micro-actionnement multi-stable piloté par radiations optiques

In this work, a bistable mechanism based on antagonistic pre-shaped double beams was proposed. Employing the proposed bistable mechanism, a quadristable micro-actuator was designed. ln order to validate the quadristability of the device, a meso-scaled prototype was fabricated from MDF by laser cutting. After the quadristability was experimentally confirmed, a quadristable micro-actuator was realized on SOl wafer using DRIE technique. Strokes for inner row and outer row were reduced to 300 µm and 200 µm respectively. For the actuation of the quadristable micro-actuator,laser heated SMA elements with deposited Si02 layer were used to realize the optical wireless actuation. With the help of a laser beam steering micro-mirror, both inner row and outer row were successfully actuated. ln order to further reduce the stroke, a bistable actuator with stroke reducing structure was designed and a prototype eut from MDF was tested. Bistability was validated and a stroke of 1µm was experimentally achieved. Based on this bistable module, a multistable nano-actuator, which contains four parallel coupled bistable modules,was designed and simulated. The simulated result have indicated that it was capable of outputs 16 discrete stable positions available from 0 nm to 150 nm with a step of 10 nm between two stable positions.Cette thèse traite le sujet du micro-actionnement multistable employant des radiations optiques pour atteindre les différentes positions offertes par le micro-actionneur. Dans le cadre des travaux réalisés, un mécanisme bistable reposant sur un principe de doubles poutres préformées situées en position antagoniste est proposé, et, sur cette brique élémentaire, un micro-actionneur quadristable a été conçu. Afin de valider le principe de fonctionnement de micro-actionneur, des procédés de fabrication Laser (sur le matériau « médium - MDF») puis DRIE (sur un wafer SOI de silicium) ont été utilisés. Sur le prototype en silicium, permettant une réduction des courses du rang interne et du rang externe du micro-actionneur, celles-ci ont été fixées à 300 µm et 200 µm respectivement. L’actionnement à distance de ce micro-actionneur a été prouvé en utilisant le chauffage laser d’un élément actif en Nitinol structuré par un dépôt de SiO2, ceci générant un effet « deux sens » de l’élément actif permettant d’annuler la charge sur les poutres du micro-actionneur une fois celui-ci déclenché puis en position stable. L’utilisation d’un banc expérimental incluant une membrane MEMS de balayage laser a permis de démontrer la quadristabilité du micro-actionneur sur 90 000 cycles. Afin de réduire davantage la course de ce micro-actionneur, des concepts de dispositifs de réduction de course ont été développés pour démontrer, à partir de prototypes fabriqué en MDF par usinage laser, la capacité à atteindre une course de 1 µm. Enfin, à la suite de ces travaux de réduction de course, un concept de nano-actionneur multistable a été proposé. Ce nano-actionneur est composé de quatre modules bistables liés et disposés en parallèle pour offrir 16 positions discrètes sur une course rectiligne. Les simulations de cet actionneur montrent la possibilité d’atteindre les 15 positions espacées de 10 nm sur une course de 150 nm

Beitrag zur Gestaltung und Herstellung einer integrierten Mikropositionierungssystem

Modern positioning systems are significantly applied in many engineering fields dealing with products emerging from different technologies at macro-, micro- and nanoscale. These systems are the back-bone systems behind any manipulation task in these areas. Currently, miniaturization trend have led numerous scientific communities to realize down scaled versions of these systems with a footprint size up to few hundreds of millimeters. These miniature positioning systems are cost effective solutions in many micro applications. This thesis presents the development of a miniature positioning system integrated with a non-contact long range displacement sensor. The uniqueness of the presented positioning system lies in its simple design with ability to perform micrometer to millimeter level strokes with pre-embedded auto guidance feature. Its design consists of a mobile part driven with four electromagnetic linear motors. Each motor consists of a fixed two phase current carrying planar electric drive coil and permanent magnet array that is realized with 14 permanent magnets arranged in north-south configuration. In order to achieve smooth motion a four point contact technique with hemispherical glass beads has been adapted to minimize the adherence effect. The overall design of the planar positioning system have been optimized to achieve a footprint size of 80 mm × 80 mm. The device can deliver motion within working range of 10 mm × 10 mm in xy-plane with sub micrometer level resolution at a speed of 12 mm/s. The device is capable to deliver a rotation motion of ±11° about the z axis in the xy-plane. Secondly, in order to measure the displacement performed by the mobile part, a non-contact long range linear displacement sensor has been designed. The overall dimensions of the sensor were optimized using a geometrical model. The fabrication of the sensor has been carried out via microfabrication in silicon material to achieve compact dimensions, so that it could be integrated in the mobile part of the positioning system. The sensor is able to provide 30.8 nm resolution with a linear measurement range of 12.5 mm. At the end, a novel cross structure has been designed and fabricated using microfabrication with the perspective to integrate the long range sensor.Moderne Positioniersysteme werden in vielen aufstrebenden Bereichen der Technik eingesetzt. Die Produkte stammen hierbei aus unterschiedlichen Technologiebereichen, die den Makro-, Mikro- und Nano- Maßstab abdecken. Diese Systeme bilden die Basis jeder Manipulationsaufgabe, in diesen Bereichen. In jüngster Zeit hat der Miniaturisierungstrend dazu geführt, dass in zahlreichen wissenschaftlichen Bereichen immer kleinere Versionen von Systemen realisiert wurden. Die typischen Abmessungen wurden dabei auf einige hundert Millimeter reduziert. Diese Miniatur Positioniersysteme sind kostengünstige Lösungen in vielen Mikro Anwendungen. Die vorliegende Arbeit stellt die Entwicklung eines Miniatur-Positioniersystems dar, in welches ein berührungsloser Wegsensor für lange Distanzen integriert wurde. Die Einzigartigkeit dieses Positionierungssystems liegt in der Einfachheit der Konstruktion in Kombination mit der Fähigkeit Bewegungen vom Mikrometer bis zum Millimeter Bereich mittels einer eingebetteten Autopilotfunktion auszuführen. Das Design besteht aus einem beweglichen Teil, welches mit vier elektrischen Linearmotoren angetrieben wird. Jeder Motor besteht aus zwei Teilen: Einem planaren elektrisch angetriebenen Schlitten und einer Anordnung von Permanentmagneten. Die Anordnung ist mit 14 Permanentenmagneten in Nord-Süd Ausrichtung realisiert. Um eine sanfte Bewegung zu erreichen wird eine Vierpunktauflage mit halbkugelförmigen Glasperlen verwendet. Hierdurch werden Adhäsionseffekte minimiert. Das Positionierungssystem kann Bewegungen im Arbeitsbereich von 10 mm × 10 mm in der xy-Ebene mit Submikrometer Auflösung und einer Geschwindigkeit von 12 mm/s ausführen. Das Gerät ist in der Lage eine Drehbewegung von ±11° um die z-Achse in der xy-Ebene auszuführen. Weiterhin wurde, um die Verschiebung des beweglichen Teils zu messen, ein kontak tloser Langstrecken-Wegsensor entworfen. Die Gesamtabmessungen des Sensors wurden mit einem geometrischen Modell optimiert. Die Herstellung des Sensors wurde mittels Mikrostrukturierung in Silizium ausgeführt um eine kompakte Abmessung zu erreichen, so dass es in den beweglichen Teil des Positionierungssystems integriert werden konnte. Der Sensor erreicht eine Auflösung von 30,8 nm in einem linearen Messbereich von 12.5 mm. Am Ende der Arbeit wurde eine neue Kreuz-Struktur konzipiert und hergestellt, gleichfalls mit Hilfe der Mikrostrukturierungstechnik. Hieraus ergibt sich die Perspektive den Langstrecken Wegsensor problemlos zu integrieren

Enabling Real-Time Terahertz Imaging With Advanced Optics and Computational Imaging

La bande des térahertz est une région particulière du spectre électromagnétique comprenant les fréquences entre 0.1 THz à 10 THz, pour des longueurs d’onde respectives de 3 mm à 30 um. Malgré tout l’intérêt que cette région a suscité au cours de la dernière décennie, de grands obstacles demeurent pour une application plus généralisée de la radiation THz dans les applications d’imagerie. Cette thèse aborde le problème du temps d’acquisition d’une image THz. Notre objectif principal sera de développer des technologies et techniques pour permettre l’imagerie THz en temps réel. Nous débutons cette thèse avec une revue de littérature approfondie sur le sujet de l’imagerie THz en temps réel. Cette revue commence par énumérer plusieurs sources et détecteurs THz qui peuvent immédiatement être utilisés en imagerie THz. Nous détaillons par la suite plusieurs modalités d’imagerie développés au cours des dernières années : 1) Imagerie THz en transmission, en réflexion et de conductivité, 2) imagerie THz pulsée, 3) imagerie THz par tomographie computationnelle et 4) imagerie THz en champ proche. Nous discutons par la suite plus en détail à propos de technologies habilitantes pour l’imagerie THz en temps réel. Pour cela, nous couvrons trois différents axes de recherche développés en littérature : 1)Imagerie en temps réel de spectroscopie THz dans le domaine du temps, 2) caméras THz et 3) imagerie en temps réel avec détecteur à pixel unique. Nous présentons ensuite le système d’imagerie que nous avons développé pour les démonstrations expérimentales de cette thèse. Ce système est basé sur la spectroscopie THz en temps réel et permet donc d’obtenir des images hyperspectrales en amplitude et en phase. Il utilise des antennes photoconductrices pour l’émission et la détection de la radiation THz. En outre, le détecteur est fibré, ce qui permet de le déplacer spatialement pour construire des images. Nous couvrons aussi brièvement plusieurs techniques de fabrication avancées que nous avons utilisées : impression 3D par filament, stéréolithographie, machinage CNC, gravure/découpe laser et transfert de métal par toner. Nous portons ensuite notre attention à l’objectif principal de cette thèse à travers trois démonstrations distinctes. Premièrement, nous concevons des composants THz à faibles pertes en utilisant des matériaux poreux. L’absence de détecteurs THz ultra-sensibles implique que les pertes encourues dans un système d’imagerie sont hautement indésirables. En effet, un moyennage temporel est généralement fait pour extraire de faibles signaux THz sévèrement enfouis sous le bruit technique. Ceci a pour impact de diminuer le nombre d’images à la seconde. ----------Abstract The terahertz band is a region of the electromagnetic spectrum comprising frequencies between 0.1 THz to 10 THz for respective wavelengths of 3 mm to 30 um. Despite all the interest and potential generated in the past decade for applications of this spectral band, there are still major hurdles impeding a wider use of THz radiation for imaging. This thesis addresses the problem of image acquisition time. Our main objective is to develop technologies and techniques to achieve real-time THz imaging. We start this thesis with a comprehensive review of the scientific literature on the topic of realtime THz imaging. This review begins by listing some off-the-shelf THz sources and detectors that could be readily used in THz imaging. We then detail some key imaging modalities developed in the past years: 1) THz transmission, reflection and conductivity imaging, 2) THz pulsed imaging, 3) THz computed tomography, and 4) THz near-field imaging. We then discuss practical enabling technologies for real-time THz imaging: 1) Real-time THz timedomain spectroscopy imaging, 2) THz cameras, and 3) real-time THz single-pixel imaging. We then present our fiber-coupled THz time-domain spectroscopy imaging setup. This system is used throughout the thesis for experimental demonstrations. We also briefly overview many advanced fabrication techniques that we have used, namely fused deposition modeling,stereolithography, CNC machining, laser cutting/engraving and metal transfer using toner. We then turn to the main objective of this thesis with three distinct demonstrations. First, we design low-loss THz components using porous media. The losses incurred in the imaging system are highly undesirable due to the lack of sensitive THz detectors. Indeed, time averaging is generally performed in order to retrieve THz signals severely buried under noise,which in return reduce the framerate. We propose to use low-refractive index subwavelength inclusions (air holes) in a solid dielectric material to build optical components. We show that these components have smaller losses than their all-solid counterparts with otherwise identical properties. We fabricate a planar porous lens and an orbital angular momentum phase plate, and we use our imaging system to characterize their effects on the THz beam. Second, we demonstrate a spectral encoding technique to significantly reduce the required number of measurements to reconstruct a THz image in a single-pixel detection scheme

Microrobotique et Micromécatronique pour la Réalisation de Tâches de Micro-Assemblage Complexes et Précises.

Ce document présente une synthèse de mes contributions scientifiques aux domaines de la microrobotique et de la micromécatronique ainsi que des transferts effectués, tant à destination de l’industrie que de l’enseignement. Les travaux conduits sont orientés vers la réalisation de tâches de micro-assemblage complexes, précises et automatisées par approche microrobotique et sont plus particulièrement appliqués aux MOEMS.L’échelle micrométrique considérée induit de nombreuses spécificités qui se traduisent par un déficit notable de connaissances du comportement des systèmes à cette échelle. Pour cela, une première partie des travaux est dédiée à l’étude et à la modélisation multiphysique des systèmes microrobotiques et micromécatroniques. Cette connaissance a conduit, dans une seconde partie des travaux, à la proposition de nouveaux principes de mesure et d’actionnement mais également au développement de microsystèmes complexes, instrumentés et intégrés (micro-banc-optique, micropince, plateformes compliantes). Enfin, des lois de commandes et des stratégies d’assemblage originales ont été proposées notamment une commande dynamique hybride force-position combinant une commande hybride externe et une commande en impédance. Celle-ci permet de maîtriser la dynamique des transitions contact/non-contact critique à l’échelle micrométrique mais également d’automatiser des processus de micro-assemblage complexes. L’ensemble de ces travaux ont fait l’objet de validations expérimentales permettant de quantifier précisément les performances obtenues (exactitude de positionnement, temps de cycle, robustesse…). Les perspectives de ces travaux portent sur la proposition de systèmes microrobotiques et micromécatroniques compacts et intégrés utiles au micro-assemblage haute dynamique ainsi qu’à l’assemblage de composants nanophotoniques

Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress

Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018