Piloted Simulation Handling Qualities Evaluation of a UAM-Scale Quadcopter with Hybrid RPM and Collective Pitch Control

Abstract

A real-time capable simulation model is developed for a 1200 lb quadcopter with hybrid variable-RPM and collective pitch control. Linear models and trim points are calculated using the Rensselaer Multicopter Analysis Code (RMAC), and controllers are designed to meet flying qualities specifications in hover and forward flight. Four control modes are flown by test pilots in a flight simulator. Three hybrid control configurations (Eco, Standard, and Sport modes) are evaluated, along with a baseline variable-RPM case. Five mission task elements (MTEs) are flown to test the handling qualities of each axis: Depart/Abort, Slalom, Hover Turn, Vertical Maneuver, and Precision Hover Task. Pilot feedback is collected in the form of handling qualities ratings (HQRs), as well as general comments. The baseline RPM control case is shown to be undesirable to pilots due to its increased delays, with the average HQR in the Level 2 region. Sport mode performs the best overall, with the average HQR being near the Level 1/2 boundary, though some pilot comments suggest that it may be over designed. The average HQR for Standard mode also falls on near the level 1/2 boundary, and pilots are generally satisfied with its performance. Eco mode is limited by its low pitch actuator margin, and has the lowest HQR due to its slow response and reduced magnitude of commands. Overall, it is shown that the hybrid control quadcopter is able to significantly outperform its variable-RPM counterpart in piloted simulation of MTEs.