This paper studies the effect of two aspects of multi-rotor drone models on the accuracy of simulations with respect to generated trajectories and energy consumption: rotor blade aerodynamics and rotor grouping. To examine these effects, an 18-rotor high performance drone carrying a 30 kg payload is used. In addition, an idealized motor efficiency curve is generated to be used when calculating the energy consumption of the flight trajectories to be analyzed. All trajectories analyzed in this paper are generated via open-loop simulations of the 18-rotor drone. The effect of the rotor blade aerodynamic model on trajectory simulation is examined by comparing trajectories resulting from simulations using blade element theory to model the rotor blade aerodynamics with trajectories resulting from simulations using a lumped blade model wherein the rotor blade aerodynamics are lumped into a single coefficient of lift and drag for the entire blade. Four simulations for roll, pitch, yaw, and vertical motions are completed using the same rotor speed inputs for each of the two aerodynamic models. The resulting trajectories show a 20% difference between the maximum roll and pitch angle achieved, a 58% difference in maximum altitude achieved, and a 91% percent difference in the maximum yaw angle achieved. These results indicate that the choice of aerodynamic model for the rotor blades has a significant effect on the resulting trajectories and then ultimately in the calculated energy consumption of those trajectories. The effect of rotor groupings on energy consumption is also examined. This is done by grouping the 18 rotors of the drone into two different groupings. The equivalent base inputs for each trajectory are found so that the total thrust for both groupings is the same by using a vertical trajectory. Then, three simulations for each grouping are completed for roll, pitch, and yaw motions. The inputs for these three trajectories are adjusted until the trajectories for both groupings are approximately the same. The resulting energy consumption for each of the 6 trajectories is calculated. The difference in energy consumption between the groupings for all three trajectories is 4-5% when no motor efficiency curve used and 8-9% when a motor efficiency curve is included in the power calculation. These results indicate that rotor grouping is important in over-actuated drones, such as the 18-rotor drone studied in this paper, for reducing the overall energy consumption of the drone, and thus increase its endurance. The importance of rotor grouping in reducing energy consumption may become especially important when closing the loop on the drone system by adding a control system.


Analysis of High Fidelity Modeling of Drone Dynamics and Aerodynamics for Reduced Energy Consumption

Division / Sponsors: 
Design Engineering Division and Computers & Information In Engineering Division


Paper Proceedings: https://asmedigitalcollection.asme.org/IDETC-CIE/IDETC-CIE2020/volume/83907

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