This dissertation presents two novel 6-axis magnetic-levitation (maglev) stages that are capable of nanoscale positioning. These stages have very simple and compact structure that is advantageous to meet requirements in the next-generation nanomanufacturing. The 6-axis motion generation is accomplished by the minimum number of actuators and sensors. The first-generation maglev stage is capable of generating translation of 300 ??m in x, y and z, and rotation of 3 mrad about the three orthogonal axes. The stage demonstrates position resolution better than 5 nm rms and position noise less than 2 nm rms. It has a light moving-part mass of 0.2126 kg. The total power consumption by all the actuators is only around a watt. Experimental results show that the stage can carry, orient, and precisely position an additional payload as heavy as 0.3 kg. The second-generation maglev stage is capable of positioning at the resolution of a few nanometers over a planar travel range of several millimeters. A novel actuation scheme was developed for the compact design of this stage that enables 6-axis force generation with just 3permanent-magnet pieces. Electromagnetic forces were calculated and experimentally verified. The complete design and construction of the second-generation maglev stage was performed. All the mechanical part and assembly fixtures were designed and fabricated at the mechanical engineering machine shop. The single moving part is modeled as a pure mass due to the negligible effect of the magnetic spring and damping. Classical as well as advanced controllers were designed and implemented for closed-loop feedback control. A nonlinear model of the force was developed and applied to cancel the nonlinearity of the actuators over the large travel range. Various experiments were conducted to test positioning, loading, and vibration-isolation capabilities. This maglev stage has a moving-part mass of 0.267 kg. Its position resolution is 4 nm over a travel range of 5 ?? 5 mm in the x-y plane. Its actuators are designed to carry and precisely position an additional payload of 2 kg. Its potential applications include semiconductor manufacturing, micro-fabrication and assembly, nanoscale profiling, and nano-indentation.

This dissertation presents two novel 6-axis magnetic-levitation (maglev) stages that are capable of nanoscale positioning. These stages have very simple and compact structure that is advantageous to meet requirements in the next-generation nanomanufacturing. The 6-axis motion generation is accomplished by the minimum number of actuators and sensors. The first-generation maglev stage is capable of generating translation of 300 ??m in x, y and z, and rotation of 3 mrad about the three orthogonal axes. The stage demonstrates position resolution better than 5 nm rms and position noise less than 2 nm rms. It has a light moving-part mass of 0.2126 kg. The total power consumption by all the actuators is only around a watt. Experimental results show that the stage can carry, orient, and precisely position an additional payload as heavy as 0.3 kg. The second-generation maglev stage is capable of positioning at the resolution of a few nanometers over a planar travel range of several millimeters. A novel actuation scheme was developed for the compact design of this stage that enables 6-axis force generation with just 3permanent-magnet pieces. Electromagnetic forces were calculated and experimentally verified. The complete design and construction of the second-generation maglev stage was performed. All the mechanical part and assembly fixtures were designed and fabricated at the mechanical engineering machine shop. The single moving part is modeled as a pure mass due to the negligible effect of the magnetic spring and damping. Classical as well as advanced controllers were designed and implemented for closed-loop feedback control. A nonlinear model of the force was developed and applied to cancel the nonlinearity of the actuators over the large travel range. Various experiments were conducted to test positioning, loading, and vibration-isolation capabilities. This maglev stage has a moving-part mass of 0.267 kg. Its position resolution is 4 nm over a travel range of 5 ?? 5 mm in the x-y plane. Its actuators are designed to carry and precisely position an additional payload of 2 kg. Its potential applications include semiconductor manufacturing, micro-fabrication and assembly, nanoscale profiling, and nano-indentation.

This thesis presents the design and fabrication of a novel magnetically levitated (maglev) device with six-degree-of-freedom motion capability at nanometer precision. The applications of this device are manufacture of nanoscale structures, assembly of microparts, vibration isolation of delicate instrumentation, and telerobotics. In this thesis, a single-moving stage is levitated by six maglev actuators. The total mass of the moving stage is 0.2126 kg. Three laser interferometers and three capacitance sensors are used to gather the position information. User interface and real-time control routines are implemented digitally on a VME PC and a digital-signal-processor (DSP) board. The underlying mechanical design and fabrication, electrical system setup, control system design, noise analysis, and test results are presented in this thesis. Test results show a quick step response in all six axes and a resolution of 2.5 nm rms in horizontal motion and 25 nm rms in vertical motion.

This thesis presents the design and fabrication of a novel magnetically levitated (maglev) device with six-degree-of-freedom motion capability at nanometer precision. The applications of this device are manufacture of nanoscale structures, assembly of microparts, vibration isolation of delicate instrumentation, and telerobotics. In this thesis, a single-moving stage is levitated by six maglev actuators. The total mass of the moving stage is 0.2126 kg. Three laser interferometers and three capacitance sensors are used to gather the position information. User interface and real-time control routines are implemented digitally on a VME PC and a digital-signal-processor (DSP) board. The underlying mechanical design and fabrication, electrical system setup, control system design, noise analysis, and test results are presented in this thesis. Test results show a quick step response in all six axes and a resolution of 2.5 nm rms in horizontal motion and 25 nm rms in vertical motion.

This dissertation demonstrates that a magnetic-levitation (maglev) stage has the capabilities to control movements and reject vibration simultaneously. The mathematical model and vibration control scheme with a 6-degree-of-freedom (6-DOF) maglev stage for nanoscale positioning are developed for disturbance rejection. The derived full nonlinear dynamic equation of motions (EOMs) of the maglev stage include translational and rotational motions with differential kinematics. The derived EOMs and the magnetic forces are linearized to design a multivariable controller, a Linear Quadratic Gaussian with Loop Transfer Recovery (LQG/LTR), for vibration disturbance rejection in a multi-input multi-output (MIMO) system. For a more accurate model, the dynamics of an optical table with a pneumatic passive isolation system is also considered. The model of the maglev stage with the optical table is validated by experiments. Dual-loop controllers are designed to minimize the influence of the vibration disturbance between the moving platen and the optical table in the x-, y-, and z-axes motions. The inner-loop compensator regulates the velocity to reject vibration disturbance and the outer-loop compensator tracks positioning commands. When the vibration disturbances of 10 to 100 Hz are applied, the vibration-reduction ratios are about 30 to 65 percent in horizontal motion and 20 to 45 percent in vertical motion. In addition, the vibration disturbances of 45.45 Hz are attenuated by about 4 to 40 percent in angular motions. The vibration control schemes are effective in not only translational but rotational motions. In step responses, the vibration control schemes reduce the wandering range in the travel from the origin to another location. Positioning and tracking accuracies with the vibration controller are better than those without the vibration controller. In summary, these dual-loop control schemes with velocity feedback control improved the nanopositioning and vibration/disturbance rejection capabilities of a maglev system.

L'objectif de la thèse est l'élaboration de lois de commande de haute performance et leur validation en temps réel sur une plateforme expérimentale 3D de nano-positionnement à base de courant à effet tunnel, développée au laboratoire GIPSA-lab. Elle s'inscrit donc dans le cadre des systèmes micro-/nano-mécatronique (MEMS), et de la commande. Plus précisément, le principal enjeu considéré est de positionner la pointe métallique à effet tunnel (comme en microscopie à effet tunnel STM) contre la surface métallique en utilisant des actionneurs piézoélectriques en X, Y et Z et un micro-levier (comme en microscopie à force atomique AFM) actionné électrostatiquement en Z avec une grande précision et une bande passante élevée. Cependant, la présence de différents effets indésirables apparaissant à cette petite échelle (comme le bruit de mesure, des non-linéarités de natures différentes, les couplages, les vibrations) affectent fortement la performance globale du système 3D. En conséquence, une commande de haute performance est nécessaire. Pour cela, un nouveau modèle 3D du système a été développé et des méthodes de contrôle appropriées pour un tel système ont été élaborées. Tout d'abord l'accent est mis sur de positionnement selon les axes X et Y. Les effets d'hystérésis et de fluage non linéaires présents dans les actionneurs piézoélectriques ont été compensés et une comparaison entre les différentes méthodes de compensation est effectuée. Des techniques modernes de commande robuste SISO et MIMO sont ensuite utilisées pour réduire les effets des vibrations piézoélectriques et des couplages entre les axes X et Y. Le mouvement horizontal est alors combiné avec le mouvement vertical (Axe Z) et une commande du courant tunnel et du micro-levier. Des résultats expérimentaux illustrent le nano positionnement 3D de la pointe, et des résultats de simulation pour la reconstruction de la topographie de la surface ainsi que le positionnement du micro-levier à base d'un modèle multi-modes. / The objective of this thesis was to elaborate high performance control strategies and their real-time validation on a tunneling current-based 3D nanopositioning system developed in GIPSA-lab. The thesis lies in the domain of micro-/nano mechatronic systems (MEMS) focused on applications of fast and precise positioning and scanning tunneling microscopy (STM). More precisely, the aim is to position the metallic tunneling tip (like in STM) over the metallic surface using piezoelectric actuators in X, Y and Z directions and actuated micro-cantilever (like in Atomic Force Microscope AFM), electrostatically driven in Z direction, with high precision, over possibly high bandwidth. However, the presence of different adverse effects appearing at such small scale (e.g. measurement noise, nonlinearities of different nature, cross-couplings, vibrations) strongly affect the overall performance of the 3D system. Therefore a high performance control is needed. To that end, a novel 3D model of the system has been developed and appropriate control methods for such a system have been elaborated. First the focus is on horizontal X and Y directions. The nonlinear hysteresis and creep effects exhibited by piezoelectric actuators have been compensated and a comparison between different compensation methods is provided. Modern SISO and MIMO robust control methods are next used to reduce high frequency effects of piezo vibration and cross-couplings between X and Y axes. Next, the horizontal motion is combined with the vertical one (Z axis) with tunneling current and micro-cantilever control. Illustrative experimental results for 3D nanopositioning of tunneling tip, as well as simulation results for surface topography reconstruction and multi-mode cantilever positioning, are finally given.

Avec les dernières avancées en matière de nanotechnologies, il est devenu possible de concevoir, avec une grande efficacité, de nouveaux dispositifs et systèmes nanométriques. Il en résulte la nécessité de développer des méthodes de pointe fiables pour la nano manipulation et la nano caractérisation. La d´étection directe par l’homme n’ étant pas une option envisageable à cette échelle, les tâches sont habituellement effectuées par un opérateur humain expert `a l’aide de microscope électronique à balayage équipé de dispositifs micro nano robotiques. Toutefois, en raison de l’absence de méthodes efficaces, ces tâches sont toujours difficiles et souvent fastidieuses à réaliser. Grâce à ce travail, nous montrons que ce problème peut être résolu efficacement jusqu’ à une certaine mesure en utilisant les informations extraites des images. Le travail porte sur l’utilisation des images électroniques pour développer des méthodes automatiques fiables permettant d’effectuer des tâches de nano manipulation et nano caractérisation précises et efficaces. En premier lieu, puisque l’imagerie électronique à balayage est affectée par les instabilités de la colonne électronique, des méthodes fonctionnant en temps réel pour surveiller la qualité des images et compenser leur distorsion dynamique ont été développées. Ensuite des lois d’asservissement visuel ont été développées pour résoudre deux problèmes. La mise au point automatique utilisant l’asservissement visuel, développée, assure une netteté constante tout au long des processus. Elle a permis d’estimer la profondeur inter-objet, habituellement très difficile à calculer dans un microscope électronique à balayage. Deux schémas d’asservissement visuel ont été développés pour le problème du nano positionnement dans un microscope électronique. Ils sont fondés sur l’utilisation directe des intensités des pixels et l’information spectrale, respectivement. Les précisions obtenues par les deux méthodes dans diff érentes conditions expérimentales ont été satisfaisantes. Le travail réalisé ouvre la voie à la réalisation d’applications précises et fiables telles que l’analyse topographique,le sondage de nanostructures ou l’extraction d’ échantillons pour microscope électronique en transmission. / With the latest advances in nanotechnology, it became possible to design novel nanoscale devicesand systems with increasing efficiency. The consequence of this fact is an increase in the need for developing reliable and cutting edge processes for nanomanipulation and nanocharacterization. Since the human direct sensing is not a feasible option at this particular scale, the tasks are usually performedby an expert human operator using a scanning electron microscope (SEM) equipped withmicro-nanorobotic devices. However, due to the lack of effective processes, these tasks are always challenging and often tiresome to perform. Through this work we show that, this problem can be tackle deffectively up to an extent using the microscopic vision information. It is concerned about using the SEM vision to develop reliable automated methods in order to perform accurate and efficient nanomanipulation and nano characterization. Since, SEM imaging is affected by the non-linearities and instabilities present in the electron column, real time methods to monitor the imaging quality and to compensate the time varying distortion were developed. Later, these images were used in the development of visual servoing control laws. The developed visual servoing-based autofocusing method ensures a constant focus throughout the process and was used for estimating the inter-object depth that is highly challenging to compute using a SEM. Two visual servoing schemes were developed toperform accurate nanopositioning using a nanorobotic station positioned inside SEM. They are basedon the direct use of global pixel intensities and Fourier spectral information respectively. The positioning accuracies achieved by both the methods at different experimental conditions were satisfactory.The achieved results facilitate in developing accurate and reliable applications such as topographic analysis, nanoprobing and sample lift-out using SEM.

A conventional large aperture telescope required for binary star research is typically cost prohibitive. A prototype active optics system was created and fitted to a telescope frame using relatively low cost components. The active optics system was capable of tipping, tilting, and elevating the mirrors to align reflected star light. The low cost mirror position actuators have a resolution of 31 nm, repeatable to within 16 nm. This is accurate enough to perform speckle analysis for the visible light spectrum. The mirrors used in testing were not supported with a whiffletree and produced trefoil-like aberrations which made phasing two mirrors difficult. The active optics system was able to successfully focus and align the mirrors through manual adjustment. Interference patterns could not be found due to having no method of measuring the mirror surfaces, preventing proper mirror alignment and phasing. Interference from air turbulence and trefoil-like aberrations further complicated this task. With some future project additions, this system has the potential to be completely automated. The success of the active optics actuators makes for a significant step towards a fully automated sparse aperture telescope.

Este trabalho apresenta o projeto de pesquisa desenvolvido para a obtenção do título de Mestre em Engenharia Elétrica, na área de concentração de engenharia de sistemas, da Escola Politécnica da Universidade de São Paulo. O principal objetivo deste trabalho foi o desenvolvimento de um sistema de acionamento (driver) para os atuadores piezoelétricos do interferômetro de Fabry-Pérot do espectrômetro BTFI (Brazilian Tunable Filter Imager), um instrumento visitante do telescópio SOAR (Southern Astrophysical Research Telescope), no Chile. O Fabry-Pérot é um instrumento óptico composto de duas superfícies paralelas altamente reflexivas (espelhos), cuja distância é controlada por um sistema de nanoposicionamento composto de três atuadores piezoelétricos (piezos) do tipo APA® (Amplified Piezoelectric Actuators) e um sistema de medida capacitivo. O principal requisito técnico de desempenho do sistema de nanoposicionamento do Fabry-Pérot é tal que o ruído de posicionamento dos espelhos deve ser limitado a 3 . No entanto, os fenômenos não lineares de histerese e escorregamento (creep) dos piezos limitam a precisão de posicionamento do sistema de controle, razão pela qual foi desenvolvido um sistema de acionamento por carga e tensão para os piezos, com o intuito de atenuar suas não linearidades e, consequentemente, melhorar o desempenho do sistema de controle em malha fechada, em termos de ruído de posicionamento. A primeira etapa deste trabalho consistiu da caracterização do modelo e da instrumentação do sistema de nanoposicionamento do Fabry-Pérot, composto de sensores capacitivos, conversores de sinal, atuadores piezoelétricos e sistema de aquisição de dados. Após a caracterização dos componentes do sistema, sua especificação técnica de desempenho de 3 foi traduzida em requisitos de engenharia para o projeto do sistema eletrônico de acionamento dos piezos por carga e tensão, notadamente em termos de ruído, tempo de resposta, banda de resposta em frequência, ganho, corrente e tensão elétricas e dissipação de potência. Uma vez concluído o projeto do driver, um protótipo foi implementado e testado com o sistema real, a fim de se verificar experimentalmente a atenuação dos efeitos não lineares. Finalmente, foram realizados alguns experimentos com o driver e o sistema de nanoposicionamento em malha fechada, controlado por um compensador PI, a fim de se verificar a influência da atenuação das não linearidades dos piezos nesta configuração. Após a análise dos resultados experimentais obtidos, verificou-se que o ruído de posicionamento do sistema, em malha fechada, é significativamente menor quando os fenômenos não linearidades dos piezos são atenuados. / This work represents the research project to obtain the degree of Master of Sciences in Electrical Engineering, specializing in Systems Engineering, at the Escola Politécnica da Universidade de São Paulo, in São Paulo, Brazil. The main objective of this project was to design an electronic power driver for the piezoelectric actuators of the Fabry-Pérot interferometer of the BTFI spectrometer, a visitor instrument of the SOAR telescope, in Chile. Fabry-Pérot is an optical instrument composed by two high reflexive parallel surfaces (mirrors), which distance is controlled by a nanopositioning system composed by three piezoelectric actuators (piezos) of the class APA® (Amplified Piezoelectric Actuators) and a capacitive measurement system. The main performance specification of the Fabry-Pérots nanopositioning system is such that the positioning noise must be limited to 3 . However, the nonlinear behaviors (hysteresis and creep) of the piezos limit the positioning precision of the control system, for which reason a charge and voltage actuation system was developed for the piezos, in order to mitigate its nonlinearities and, consequently, improve the performance of the control system in closed loop, in terms of positioning noise. The first step in this work consisted on the characterization of the Fabry-Pérot nanopositioning systems model and instrumentation, which are composed by capacitive sensors, signal converters, piezoelectric actuators and a data acquisition board. After the characterization of the components of the nanopositioning system, the 3 specification was interpreted to low level engineering requirements for the design of the charge and voltage driver, especially in terms of noise, response time, frequency bandwidth, gain, electrical current, voltage and power dissipation. Once concluded the design of the driver, a prototype was implemented and tested in the real system, in order to verify the attenuation of the nonlinear effects. Finally, some experiments with the driver and the nanopositioning system were performed in closed loop, controlled by a PI compensator, in order to verify the influence of the attenuation of the nonlinearities of the piezos in such configuration. The analysis of the obtained experiment results showed that the nanopositioning systems noise, in closed loop, is significantly reduced when the nonlinear effects of the pizeos are attenuated.

Este trabalho apresenta o projeto de pesquisa desenvolvido para a obtenção do título de Mestre em Engenharia Elétrica, na área de concentração de engenharia de sistemas, da Escola Politécnica da Universidade de São Paulo. O principal objetivo deste trabalho foi o desenvolvimento de um sistema de acionamento (driver) para os atuadores piezoelétricos do interferômetro de Fabry-Pérot do espectrômetro BTFI (Brazilian Tunable Filter Imager), um instrumento visitante do telescópio SOAR (Southern Astrophysical Research Telescope), no Chile. O Fabry-Pérot é um instrumento óptico composto de duas superfícies paralelas altamente reflexivas (espelhos), cuja distância é controlada por um sistema de nanoposicionamento composto de três atuadores piezoelétricos (piezos) do tipo APA® (Amplified Piezoelectric Actuators) e um sistema de medida capacitivo. O principal requisito técnico de desempenho do sistema de nanoposicionamento do Fabry-Pérot é tal que o ruído de posicionamento dos espelhos deve ser limitado a 3 . No entanto, os fenômenos não lineares de histerese e escorregamento (creep) dos piezos limitam a precisão de posicionamento do sistema de controle, razão pela qual foi desenvolvido um sistema de acionamento por carga e tensão para os piezos, com o intuito de atenuar suas não linearidades e, consequentemente, melhorar o desempenho do sistema de controle em malha fechada, em termos de ruído de posicionamento. A primeira etapa deste trabalho consistiu da caracterização do modelo e da instrumentação do sistema de nanoposicionamento do Fabry-Pérot, composto de sensores capacitivos, conversores de sinal, atuadores piezoelétricos e sistema de aquisição de dados. Após a caracterização dos componentes do sistema, sua especificação técnica de desempenho de 3 foi traduzida em requisitos de engenharia para o projeto do sistema eletrônico de acionamento dos piezos por carga e tensão, notadamente em termos de ruído, tempo de resposta, banda de resposta em frequência, ganho, corrente e tensão elétricas e dissipação de potência. Uma vez concluído o projeto do driver, um protótipo foi implementado e testado com o sistema real, a fim de se verificar experimentalmente a atenuação dos efeitos não lineares. Finalmente, foram realizados alguns experimentos com o driver e o sistema de nanoposicionamento em malha fechada, controlado por um compensador PI, a fim de se verificar a influência da atenuação das não linearidades dos piezos nesta configuração. Após a análise dos resultados experimentais obtidos, verificou-se que o ruído de posicionamento do sistema, em malha fechada, é significativamente menor quando os fenômenos não linearidades dos piezos são atenuados. / This work represents the research project to obtain the degree of Master of Sciences in Electrical Engineering, specializing in Systems Engineering, at the Escola Politécnica da Universidade de São Paulo, in São Paulo, Brazil. The main objective of this project was to design an electronic power driver for the piezoelectric actuators of the Fabry-Pérot interferometer of the BTFI spectrometer, a visitor instrument of the SOAR telescope, in Chile. Fabry-Pérot is an optical instrument composed by two high reflexive parallel surfaces (mirrors), which distance is controlled by a nanopositioning system composed by three piezoelectric actuators (piezos) of the class APA® (Amplified Piezoelectric Actuators) and a capacitive measurement system. The main performance specification of the Fabry-Pérots nanopositioning system is such that the positioning noise must be limited to 3 . However, the nonlinear behaviors (hysteresis and creep) of the piezos limit the positioning precision of the control system, for which reason a charge and voltage actuation system was developed for the piezos, in order to mitigate its nonlinearities and, consequently, improve the performance of the control system in closed loop, in terms of positioning noise. The first step in this work consisted on the characterization of the Fabry-Pérot nanopositioning systems model and instrumentation, which are composed by capacitive sensors, signal converters, piezoelectric actuators and a data acquisition board. After the characterization of the components of the nanopositioning system, the 3 specification was interpreted to low level engineering requirements for the design of the charge and voltage driver, especially in terms of noise, response time, frequency bandwidth, gain, electrical current, voltage and power dissipation. Once concluded the design of the driver, a prototype was implemented and tested in the real system, in order to verify the attenuation of the nonlinear effects. Finally, some experiments with the driver and the nanopositioning system were performed in closed loop, controlled by a PI compensator, in order to verify the influence of the attenuation of the nonlinearities of the piezos in such configuration. The analysis of the obtained experiment results showed that the nanopositioning systems noise, in closed loop, is significantly reduced when the nonlinear effects of the pizeos are attenuated.