OVMI Project

The motive of the OVMI (French for Flying Object Mimicking the Insect) project is to design a robust, autonomous and efficient flapping-wing nano-air-vehicle (FWNAV) relying on MEMS technologies. Key features of our design is its bio-inspiration, its innovative actuation concept including resonance phenomenon and passive torsion as well as its fabrication method. Thus various prototypes can be micromachined and tested with typically a wingspan of 3cm and weighting only 20mg as shown below.

Nano Air Vehicle

Being a multidisciplinary project and in order to improve our design and carry out an airborne prototype, new scientific methods and technical skills are developed in three main areas: the development of an efficient actuation, an optimization of the motion transmission and finally the comprehension of aeroelastic phenomena on our wings. Each time, the aim is to develop novel concept towards a more efficient, compact, and lighter prototype.

  • Actuation

    Figure 1 : Three kinds of actuation employed by insects (with the red parts denoting muscles).

    In each muscle¬†organisation, the wing motion is correled to the tergum one. The actuation concept is based on this connection. The MMMS (micro-magneto-mechanical system) is sticked to the tergum, its vibrating motion reproduce insect’s tergum one. The actuation is a wide research area, the MMMS is constantly upgraded to increase its efficiency and the power delivered.

    The Electro-Active Polymer is another solution to emulate insect muscles that presents important advantages in fabrication and mechanical performances.

  • Structure

    Prototype on a silicon wafer

    The structure is made of an epoxy-based negative photoresist SU-8, which presents several advantages in both the fabrication and mechanical areas. Furthermore the SU-8 mimicks properly the insect wing material properties. Prototypes are realized by batch using photolithography on a silicon wafer. To insure the motion transmisision from the actuator to the wings, differents joints solution has been investigated aiming at increasing the overall wing displacement.

  • Aerodynamic

    Developing a FWNAV is an ambitious and arduous tasks relying currently mostly on trial and error method. In order to assist these developments, a preliminary design tool evaluating the aeroelastic performance of a flapping wing is also investigated. Our approach is to couple a structural finite element solver to a quasi-steady aerodynamic model of the insect flight. Linked with an optimizer, this tool can perform investigations for ‘optimized’ wing geometry interesting from an aerodynamic and energetic point of view.

    Aeroelastic simulation

    Results recently obtained are very encouraging