Sujet de Doctorats 2013 - IEMN

place un modèle aéro-élastique d’aile, adapté au prototype envisagé. Cette modélisation permettra deconcevoir une structure en accord avec les lois de l'aérodynamique et les non-linéarités liées aux grandsdéplacements; elle contribuera à mimer la cinématique de vol le plus fidèlement possible. Ce modèledevra subir encore quelques étapes de validation et devra permettre de fournir des formes d’aile simplessusceptibles de produire un maximum de portance. Ce modèle sera complété par des validationsexpérimentales à l’aide de dispositifs de mesure (caméra rapide, visualisation par injection de fumée etmicrobalances).Abstract :The flapping wing-flight allows obtaining a quasi-stationary flight (as opposed to fixed wing objects).This capability is very useful in the case of the realization of micro-nano-drones, because they have tomeet high requirements in terms of maneuverability and stability. In addition, an object with flappingwings at small scale can be more efficient for stabilization and propulsion than an object with fixed (jettype) or rotating wing (helicopter type) since it can take advantage of air patterns. The interest inproducing a nano-drone with flapping wings would also bring acoustic and visual discretion.The objective of this PHD thesis is the optimization of a Flying Object Mimicking Insect (OVMI) atscale 1. This project is at the interface of several disciplines such as aeroelasticity, microtechnology,automation and energy and involves collaboration between two scientific laboratories: ONERA foraeroelastic wing aspects, and IEMN for the structure optimization part and integration ofmicroactuators. As a starting point, the student should work on existing prototypes (mass 20mg) madeby IEMN for which the effects of lift have already been demonstrated (approximately 13mg measuredusing a microbalance). These prototypes consist of an electromagnetic actuator inserted on a flexiblestructure made using microsystems technology and which allows the movement of the wings in bothbending and torsion.The work will then be structured around two main parts:On the first part, the expected results at the end of the PHD thesis is an optimization of thephotosensitive polymer structure constituting the body and wings of the artificial insect. In particular,goals are to minimize its mass, to improve the flexibility of wings, and to increase their bending andtwisting amplitude. In addition, the student will be responsible for the integration of additionalelectronic components such as an inertial device. The active polymer will be assessed to replace theelectromagnetic actuator used currently and thus divide the mass of the actuator by 5. On these aspects,the student will benefit from the micro-and nanotechnology means of design, fabrication andcharacterization of IEMN.At the second part, the student should understand the aeroelastic phenomena when working at scalesinvolving very low Reynolds numbers. ONERA has already developed a model of aero-elastic wing,which is suitable for the considered prototype. This modeling will allow designing a structure inaccordance with the laws of aerodynamics and nonlinearities associated with large displacements andwill contribute to mimic the kinematics of flight as closely as possible. This model will undergo a fewvalidation steps and will help to provide simple wing shapes capable of producing a maximum lift. Thismodel will be complemented by experimental validation using measuring devices (speed camera,visualization by injecting smoke and microbalances).41