Assessing Multi-rotor UAV Controllability in Low Altitude Fine-Scale Wind Fields

Abstract

This study presents a means of assessing unmanned aerial vehicle (UAV) control in various environments using control margin. The metric gives an instantaneous measure of control authority and is defined by dividing required torque by maximum available torque. Required torque is the sum total of torque developed by a vehicle's rotors and residual terms representing the torque required to compensate for any remaining disturbances. The metric was demonstrated on a representative small quad-rotor UAV in real world and laboratory environments. Utilizing only rotor revolutions per second and inertial measurement unit information, the metric indicates degraded control in conditions consistent with loss of control. This metric may ultimately be useful in understanding the low level wind environment, for certification of vehicles, or for real-time monitoring of control authority.