Empirical Evaluation of Hexacopter Performance Post-Single Rotor Failure

Rotor failure is a potentially dangerous mode of failure in multirotors which may occur from structural or electrical damages. In scenarios where multirotors are used for urban air mobility, rotor failure may be catastrophic. Experimental in-situ observations were conducted using a subscale hexacopter. The hexacopter features a frame constructed primarily with carbon fiber and polylactic acid (PLA) with a maximum diameter of 2 feet and a propeller diameter of 12 inch by 4.7 inch pitch. Equal number of clockwise and counterclockwise rotors were featured in a cross (X) configuration with one rotor per arm. Configured with a shutoff circuit for a single rotor, constructed using an Arduino Due and 5V relay, gyroscope and accelerometer measurements for angular velocity and linear acceleration were collected using an inertial measurement unit (IMU) in a Pixhawk 6C flight controller. A microcontroller and relay circuit controls the rotor shutoff while the flight controller switches the multirotor to a quadcopter configuration post-rotor failure. Clockwise and counter-clockwise side-rotor failure were both evaluated to observe the multirotor’s deviance in pitch, yaw, and roll attitudes as well as the increase in rotor rotation speed required to maintain a hover. Experiments conducted in the field began with normal vertical takeoff with no rotor failure. After a preprogrammed time frame, the shutoff circuit stops the delivery of power to one of the six rotors, and the hexacopter then corrects for the failed rotor and assumes a hovering configuration. IMU measurements are taken during the entire flight from power-on to power-off. Strong foundational data on the performance of a hexacopter post-single rotor failure were collected and evaluated, providing a basis for future large-scale, UAM-sized tests and evaluations.