Force estimation in a piezoelectric cantilever using the Inverse-Dynamics-Based UIO technique.

International audienceThis paper presents the estimation of the force applied by a piezocantilever dedicated to micromanipulation/ microassembly. Relative to previous works, the presented method avoids the reliance on the force dynamics on the characteristics of the microobjects. Furthermore, the estimation is a closed-loop kind technique so that convergency can be ensured efficiently. To perform these, we consider the force at the tip of a piezocantilever as an unknown input and we use an Unknown Input Observation technique. We especially use the Inverse-Dynamics-Based UIO technique because it is well suited for a piezocantilever model. The experiments show that the performances of the observer are convenient for micromanipulation/ microassembly tasks

Estimation robuste par synthèse H2 de micro- et nanoforce à l'aide de ressorts magnétiques actifs.

National audienceThis article deals with the problematic of micro- and nanoforce measurement. The force is the unknown excitatory signal of a transducer whose only the output is measurable. This general problematic of an unknown input signal reconstruction from a noisy output signal is developed inside the H2 synthesis framework. The resulting methodology is implemented in a micro- and nanoforce sensor that uses a macroscopic seismic mass controlled by active magnetic springs. This methodology uses only a very basic knowledge on the force dynamic and thanks to H2 synthesis, ensures that the force estimation remains correct despite the transducer dynamic, the noise measurement, the uncertainty on the force dynamic and the sensor modeling errors

Etude et réalisation d'un prototype avancé de plateforme de mesure de micro et nanoforce par lévitation diamagnétique

La mesure de micro- et nano-force fait partie des mesures nécessaires à la caractérisation des interactionsou des propriétés mécaniques intervenant à l échelle micrométrique. Dans cette optique,nous avons poursuivi un travail de conception initié au Laboratoire d Automatique de Besançon en2002 pour développer un prototype avancé de capteur de micro- et nano-force par lévitation diamagnétique.Le transducteur force-déplacement de ce capteur est un microcapillaire rigide en verred une dizaine de centimètres. Ce microcapillaire est en lévitation passive stable dans l espace grâceà l action conjuguée de forces magnétiques et diamagnétiques créant ainsi un ressort magnétiquevirtuel. La mesure d une force externe appliquée à l extrémité du capillaire est rendue possible grâceà la connaissance de la mesure du déplacement du capillaire et de la raideur du ressort magnétique.La plage de mesure de ce capteur varie entre +-40 N avec une résolution de l ordre du nanonewton.Les avancées présentées dans ce manuscrit ont porté sur la détermination des efforts diamagnétiquesengendrés par l utilisation des plaques de graphite. Ce travail a permis une optimisation dudesign global du dispositif et son transfert à l entreprise STIL SA. De plus un processus d estimationpar déconvolution a été développé pour tenir compte du comportement dynamique du micro capillaireet des bruits de mesure du déplacement. Les domaines d applications potentiels de ce dispositifconcernent notamment la caractérisation des interactions mécaniques quasi-statiques pouvant intervenirentre deux micro-objets et la détermination de propriétés mécaniques propres à un micro-objet.The measurement of micro- and nano-force is necessary to characterize the mechanical propertiesand interactions occurring at micrometer scale. In this context, we work on an advanced design ofmicro- and nano-force sensor based on diamagnetic levitation initiated at Laboratoire d Automatiquede Besançon in 2002. The force-displacement transducer of this sensor is a ten centimeter long glassmicro capillary. This micro capillary levitates passively and stably thanks to the combined action ofmagnetic and diamagnetic forces which create a virtual magnetic spring. Measuring an external forceapplied to the end of the capillary is made possible through knowledge of the capillary displacementand the stiffness of magnetic spring. The measuring range of the sensor varies between +-40 N witha resolution about a nanonewton. Advances presented in this thesis focused on the determinationof the diamagnetic forces generated by the use of graphite plates. This work has allowed us tooptimize the overall design of the device and transfer it to our industrial partner STIL SA. Moreovera deconvolution estimation process was developed to take into account the dynamic behavior of themicro capillary and measurement noises. Potential fields of application of this device concern themechanical characterization of quasistatic interactions which may occur between two micro-objectsand the determination of intrinsic mechanical properties of a micro-objectBESANCON-Bib. Electronique (250560099) / SudocSudocFranceF

Piezoelectric systems for precise and high dynamic positioning: design, modeling, estimation and control

This HDR synthesizes the works I have carried out at the department of AS2M of the FEMTO-STInstitute as well as the different administrative, editorial and teaching activities. The research works(supervised, in collaboration, ...) deal with the: design, development, modeling, control and signalsmeasurement and estimation in piezoelectric based systems devoted to precise and highly dynamicpositioning applications. The systems behaviors include linear and nonlinear phenomena (hysteresisand creep) and badly damped vibrations which greatly compromise the performances of thepositioning tasks, and which pose great challenge in their control. The proposed control techniquesenclose feedforward and feedback schemes. In feedback schemes, mainly robust techniques arestudied: H-infinity techniques and interval control techniques. In the use of intervals, new theoreticalresults are also proposed and are applied to different applications: design, control, structuralanalysis. Innovative measurement techniques have also been proposed to estimate the signals inpiezoelectric systems by accounting for the limited space, the high dynamics and the high precisionrequirements. The last part of the HDR poses questions and wonders if these different developmentsand endeavors would not be profitable for the development of other applications than precise andhighly dynamic positioning