Abstract : This paper presents the design and implementation
of a nonlinear control scheme for multirotor helicopters that takes
first-order drag effects into account explicitly. A dynamic model
including the blade flapping and induced drag forces is provided
and a hierarchical nonlinear controller is presented. This controller
is designed for both high-precision flights as well as robustness
against model uncertainties and external disturbances.
This is achieved by using saturated integrators with fast desaturation
properties. The implementation of the controller on the flybox
hexacopter platform is described. The hardware and software architecture
of this UAV is discussed, and useful hints and insights
gained during its design process are presented. Finally, experimental
results and videos are reported to demonstrate the successful
implementation and the performance of the overall system.