Considering the advantages of size and robustness in performing different kinds of task, many researches on tiny flying robots have been developed in recent years. Our main objective is to develop an autonomous and bio-inspired vibrating wing nano-air-vehicle of about 3cm in wingspan relying mainly on MEMS technologies. For this purpose, a vibrating-wing nano air vehicle (VWNAV) with resonant wings using indirect actuation and concise transmission to allow large and symmetrical bending angles as well as passive wing torsion is presented. This paper introduces an innovative energy modeling of such vehicle aiming at a better comprehension of the energy transmission from energy source to wings, thus allowing future optimization of the actuation efficiency. This work also includes a dynamic model used in a closed loop control for a vertical fly of VWNAV. The results nicely demonstrate the stabilization of the system at a desired position. Considering the multiphysics nature of the prototype, a Bond Graph approach has been chosen bringing thus a unique model for the whole system.