Tailless flapping wing micro air vehicles (FWMAVs) have
the potential of providing efficient flight at small scale,
with considerable agility. However, this agility also brings
significant control challenges, which are exacerbated by
the fact that the aerodynamics and dynamics of flapping
wing robots are still only partly understood.
In this article, we propose a novel, minimal dynamic
model that is not only validated with experimental data,
but also able to predict the consequences of various important
design changes. Specifically, the model captures
the flapping cycle averaged longitudinal dynamics of a
tailless flapping wing robot, taking into account the main
aerodynamic effects. The model is validated for airspeeds
up to 3.5 m/s (when the forward velocity starts to approximate
the wing velocities). It successfully predicts the effects
of changes to the center of mass and flight at different
pitch angles. Hence, the presented model forms an
important step in accelerating the control design of flapping
wing robots - which can now be done to a greater
extent in simulation. In order to illustrate this, we have
used the model to improve our control design, resulting in
a change of the maximal stable speed of the tailless DelFly
Transformer from 4 m/s to 7 m/s.