Flight Simulation and Control of a Helicopter Undergoing Rotor Chord Extension Morphing

The current study focuses on flight simulation and control of a helicopter undergoing rotor chord morphing. A model-following dynamic inversion controller with inner and outer loop control laws (CLAWS) is implemented and chord extension is introduced as an additional feedforward component to the inner loop CLAW. Simulation results based on a chord-morphing variant of the UH-60A Black Hawk helicopter at 20,000 lbs gross weight are presented. From the baseline rotor blade, the chord is increased from 63% to 83% of the rotor span by means of a trailing-edge plate (TEP) extension at a deployment angle of 2 degrees. Chord morphing at sea-level and hot-and-high conditions are considered. The controller is shown to regulate the operating state of the aircraft well over the nominal morphing duration of 60 seconds and also for reduced durations down to 15 seconds. Differences between baseline and morphed states are discussed. In addition, the performance of the controller with respect to rate of morphing is evaluated and the effect of asynchronous morphing is also considered.