A Novel Experimental Model and a Drag-optimal Allocation Method for Variable-Pitch Propellers in Multirotors

International audienceThis paper proposes a new mathematical model to map the rotational speed and angle ofattack (pitch) of small-size propellers typically used in multirotors and the aerodynamic thrust force anddrag moment produced by the propeller itself. The new model is inspired by standard models using theblade-element and momentum theories, which have been suitably modified in order to allow for explicit fastcomputation of the direct and inverse map (useful for high-frequency control) and obtain a better adherence toexperimental data. The new model allows and captures all the main nonlinear characteristics of the thrust/draggeneration. An extensive experimental comparison shows that the prediction capability of the proposedmodel outperforms the most commonly used models at date. In the second part of the paper, two optimizationmethods are proposed in order to exploit the redundancy of the inputs of variable-pitch propellers to decreasethe power consumption due to the drag dissipation. The first method deals with the optimal allocation forthrust generation on a single propeller, while the second method is aimed at solving the optimal allocation ofthe rotational speed and pitch of all the propellers in a multi-rotor with any number of propellers. Simulationsresults show the viability and effectiveness of the proposed method