Flight Dynamics, Control, and Testing of a Coaxial Helicopter UAV with Folding Rotor Blades

Abstract

Air launched effects refer to unmanned aerial vehicles deployed from another aircraft. These unmanned aircraft can perform intelligence gathering, surveillance, and reconnaissance in contested areas in place of or prior to the arrival of manned aircraft. A potential air launched effects candidate is the Unmanned Generic Coaxial Rotorcraft which has a cylindrical fuselage, folding rotor blades, and the capability to hover. A series of flight tests were conducted to collect test data for system identification. A bare-airframe flight dynamics model of the vehicle was identified using frequency domain methods and verified in the time domain with doublets. The existing vehicle's PX4 inner-loop flight control system was modeled in Simulink®, combined with the identified hover model, and validated against flight test data. The analysis model was then used to perform multi-objective optimization of the flight control system gains using a comprehensive set of specifications. The optimized control system is shown to have improved tracking and disturbance rejection performance over the baseline in simulation while meeting all desired specifications.