Post-ESC-Failure Performance of a UAM-Scale Hexacopter with Dual Three-Phase Motors

Dual three-phase motors are simulated on a 1200 lb hexacopter to examine its ability to tolerate any single electronic speed controller (ESC) failure. Redundancy is added, as each motor includes two sets of stator windings, powered by electrically independent ESCs, which drive a single motor shaft. Flight control laws are tuned on the healthy aircraft to meet standard flying-qualities specifications. Power constraints are embedded in the controller to enforce both instantaneous and continuous power limits for each ESC. With the proposed dual three-phase motor, the aircraft is shown to be capable of trimming in all single ESC failure cases, including the case of aft motor failure in forward flight. Time-domain simulations demonstrate the aircraft's ability to re-establish trim and recover from any single ESC failure in hover and forward flight. Flying-qualities specifications are re-evaluated for the post-failure aircraft, showing minor, but not debilitating, degradation in several flying-qualities metrics. The post-failure aircraft's ability to follow commands without violating power constraints is verified through time-domain simulations.