Ariel Walter, M. McKay, R. Niemiec, F. Gandhi, Christina M. Ivler
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引用次数: 1
Abstract
Fixed-pitch, variable-RPM quadcopters of increasing size are simulated in hover. Three aircraft sizes are considered, with rotor diameters of 4, 6, and 8 ft (1.2, 1.8, and 2.4 m) and gross weights of 300, 680, and 1200 lb (136, 308, and 544 kg) respectively. Control design is performed for each aircraft using CONDUIT®, first using standard ADS-33E-PRF handling qualities specifications. Froude scaling is then applied to the specifications in order to design more comparable, aggressive controllers for the two smaller aircraft. Piloted commands and gust inputs are simulated in the time domain in order to estimate the necessary motor current margins needed for adequate maneuverability local to hover. Of the maneuvers considered, a yaw rate step requires the highest current margin for the smallest aircraft, while the longitudinal velocity step requires the highest current margin for the others, regardless of the Froude scaling of the handling qualities metrics. Using the maximum current values from these simulations, the motor weight fraction is 8.3–10.6% for the 300-lb vehicle, 11.6–13.0% for the 680-lb vehicle, and 15.8% for the 1200 lb. Motor weight requirements can be reduced on the larger two aircraft by flying with the pitch and roll axes exclusively in the attitude command, attitude hold mode, rather than translational rate command. In this case, step commands in yaw rate are limiting for the 680-lb vehicle (10.7–11.8% motor weight fraction) and heave commands are limiting for the 1200-lb vehicle (13.6% motor weight fraction). Estimated motor weight requirements are also reduced by decreasing the rotor inertia and introducing additional filtering into the aircraft commands.
期刊介绍:
The Journal of the American Helicopter Society is a peer-reviewed technical journal published quarterly (January, April, July and October) by AHS — The Vertical Flight Society. It is the world''s only scientific journal dedicated to vertical flight technology and is available in print and online.
The Journal publishes original technical papers dealing with theory and practice of vertical flight. The Journal seeks to foster the exchange of significant new ideas and information about helicopters and V/STOL aircraft. The scope of the Journal covers the full range of research, analysis, design, manufacturing, test, operations, and support. A constantly growing list of specialty areas is included within that scope. These range from the classical specialties like aerodynamic, dynamics and structures to more recent priorities such as acoustics, materials and signature reduction and to operational issues such as design criteria, safety and reliability. (Note: semi- and nontechnical articles of more general interest reporting current events or experiences should be sent to the VFS magazine