Tilting multicopter rotors for increased power efficiency and yaw authority

Abstract

We demonstrate that a simple mechanical modification increasing the yaw authority of a multicopter leads to a reduction in mechanical power consumption in flight. Increased yaw authority is achieved by tilting the propellers' thrust directions in the direction that increases their yaw torque. The power reduction is achieved in noisy environments, where the vehicle experiences external disturbances. This is due to the lower variance in motor forces required for yaw control, and the convex functional relationship between force and power consumed. We present a theoretical analysis motivating a reduction in power consumed to first order in increasing propeller tilt, in addition to increasing agility. Experiments validate the idea, where the measured electric power is used instead of the mechanical power consumption. Experiments are performed on two quadcopters of very different scales, with masses ranging from 45g to 1.15kg, with both showing a power improvement.