  Over the last few decades, multicopters have become significantly popular
because of their various applications. However, multicopters suffer from poor
endurance performance as compared to other aircraft configurations with lifting
surfaces. In this paper, a co-design approach for the multicopter structure and
propulsive system is presented with the objective of improving the energetic
efficiency of the vehicle, while respecting dynamic performance requirements.
For this purpose, the approach uses a bi-level formulation to optimize
concurrently the design and the control. The methodology offers the possibility
to activate or not a passive fault tolerant strategy in the controller
synthesis to be tolerant to single rotor failure. In contrast to conventional
design approaches that sequentially design each part, the co-design approach
leads to a better optimal solution due to the consideration of the interactions
and couplings between design and control. With the proposed co-design approach,
the results show the soundness of the proposed design methodology and a
significant reduction in the consumed energy compared to a reference
non-optimal design, while maintaining the same requirements in terms of dynamic
performance.
