Observation-Oriented design of a Monolithic Piezoelectric Microactuator with Optimally integrated Sensor.

International audienceThis paper presents an evolution in an optimization method, called FlexIn, developed for the optimal design of piezoelectric compliant smart structures. FlexIn is based on a flexible building block method that uses a genetic algorithm approach, to optimize a truss-like planar structure made of piezoelectric passive, active and, with the work reported in this paper, sensitive building blocks. The model of these blocks is established by means of a finite-element electromechanical formulation. The main contribution of this paper is to present a new observation-oriented criterion, along with a static electromechanical one, considered in the optimization procedure for the optimal placement of piezoactuating and piezosensing parts in the compliant micro-structure. In order to underline the interests of such a criterion, performances of three pseudo-optimal piezoelectric smart structures are drawn. Their analysis and comparison illustrate the role of the optimization method and the observation-oriented criterion, in the design of smart structures and in simplifying their control afterwards

Optimal Observability-based Modelling, Design and Characterization of Piezoelectric Microactuators.

International audienceThis paper deals with the optimal design of monolithic piezoelectric microactuators with integrated proprioceptive sensors. Dedicated to the microrobotic and micromechatronic fields, these works detail the modelling and the characterization of compliant structures with integrated actuating and sensing elements. The proposed optimal design procedure adresses not only static criteria but also dynamic ones. This leads to microdevices which are more performant with regards to mechanical (displacement, force...) and control (dynamics, stability, precision) characteristics. Efficient design of such devices is achieved using a flexible building block method. A topological optimization method combined with an evolutionary algorithm is used to optimize the design of truss-like planar structure. This method chooses the best location among the different piezoelectric elements. Different mechanical, actuation or sensing elements are accordingly chosen from a data bank. From the control point of view, optimisation criteria are considered to enforce the observability of the vibrational dominant modes of the structure. Therefore, control and observation Gramians are exploited in the optimal design to shape the open loop frequency response of both, actuation and sensing functions of the integrated device. In the last part of the paper, based on these results, the optimal design and manufacturing of an innovative piezoelectric flexible microgripper is proposed. The prototype is manufactured from a monolithic piezoelectric material (PIC 151). Its reduced size (15 mm x 18 mm) fits the requirement of both microrobotics and micromechatronics applications, which is suitable for micromanipulation tasks. The characterization and the performance of this integrated microactuator finally close the paper and the efficiency of the optimal design procedure for micromechatronics applications are shown

Optimal design and control simulation of a monolithic piezoelectric microactuator with integrated sensor.

International audienceThis paper presents an important evolution in an optimization method, called FlexIn, developed for the optimal design of piezoelectric compliant micromechanisms. It is based on a flexible building block method that uses an evolutionary approach, to optimize a truss-like planar structure made of piezoelectric passive, active and now sensitive building blocks. The model of these blocks is established by means of a finiteelement electromechanical formulation. The main contribution of this paper is to present an new control-observation-oriented criterion considered in the optimization procedure, among other conventional mechanical criteria, to optimize modal observability of the structure, for the placement of piezoactuating and piezosensing parts. In order to point out the underlying interests of this method for the design of smart structures with integrated actuators and sensors, a planar piezoelectric compliant smart micro-mechanism is optimally synthesized. Simulations of the device are finally performed illustrating the role of the observation-oriented criterion in simplifying the control of such smart structures

Méthode des blocs sensitifs pour la synthèse optimale de mécanismes flexibles à mesure piézoélectrique intégrée.

National audienceCet article présente une méthode de synthèse optimale pour la conception préliminaire de mécanismes flexibles monolithiques piézoélectriques. La construction d'un tel mécanisme, selon cette méthode baptisée FlexIn, est basée sur l'agencement de blocs flexibles piézoélectriques élémentaires qui peuvent être structurels, actionneurs et/ou capteurs, sélectionnés respectivement dans trois bibliothèques. Cet article décrit plus particulièrement l'approche utilisée pour établir le modèle aux éléments finis multi-physiques des blocs capteurs piézoélectriques, de type treillis de poutre, en vue de son intégration dans le logiciel de synthèse optimale. Les résultats obtenus présentent un écart de quelques pourcents avec ceux issus d'un code aux éléments finis commercial. A titre d'exemple, le modèle capteur est appliqué à une micropince monolithique existante ; le résultat de mesure est d'un ordre de grandeur satisfaisant. Ces résultats permettent de dresser les perspectives de la méthode de synthèse optimale proposée dans le cadre général de la conception de structures intelligentes pour la microrobotique

Modeling and control of a piezoelectric microactuator with proprioceptive sensing capabilities.

International audienceIn this paper, modeling and control strategies for a new observability-optimized piezoelectric microactuator are presented.The targeted applications concern mainly the design of microgripper for micromanipulation tasks. The device has been designed using a topological optimization method, which takes into account the optimal full integration of piezoelectric actuating and sensing elements within the device. It is achieved in link with modal controllability and observability considerations. The vibrational modes that govern the tip deflection of the monolithic compliant structure are proved to be fully observable by the integrated sensing area of the device. The proposed control strategy permits to simply reconstruct the deflection using electric charges measurement and modal state observer. Finally, the vibrations naturally induced by the flexible structure are successfully damped using robust and low order controller

Méthode des blocs sensitifs pour la synthèse optimale de mécanismes flexibles monolithiques à actionnement et mesure piézoélectriques intégrés

Cet article présente une méthode de synthèse optimale de mécanismes flexibles piézoélectriques monolithiques à actionneurs et capteurs intégrés. Il présente en particulier l’établissement du modèle aux éléments finis multiphysiques définissant les blocs capteurs piézoélectriques, et son utilisation au sein du logiciel d’optimisation. Les résultats du modèle sont validés en statique par un logiciel du commerce. Ils sont aussi validés dans le cas plus complet d’un système piézoélectrique intégré