Integrated flight/propulsion control of coaxial high-speed helicopter based on robust explicit model following control

Multiple flight modes and high maneuverability are typical characteristics of coaxial high-speed helicopters, making conventional separated flight/propulsion control strategies insufficient to satisfy high-performance control requirements. Meanwhile, the pronounced dynamic coupling across the entire flight envelope, together with strong external disturbances and time-varying flight characteristics, poses severe challenges to the robustness of control strategies. To address these issues, this paper proposes an integrated flight/propulsion control architecture based on Robust Explicit Model Following Control (REMFC). First, based on the torque-speed relationships between the rotor and the engine, an integrated flight/propulsion simulation model is established, incorporating the coaxial helicopter, turboshaft engine, and transmission system. Subsequently, by reconstructing the feedforward-feedback structure of explicit model following control and introducing an Extended State Observer (ESO), a robust explicit model following control strategy is developed. The proposed method achieves online estimation and compensation of unmodeled dynamics, aerodynamic disturbances, and parameter uncertainties, and the uniform boundedness of the closed-loop tracking error is theoretically guaranteed. Finally, based on the proposed REMFC strategy, an integrated flight/propulsion control law is designed to realize coordinated control and dynamic regulation of flight manipulation and engine speed. Multi-mission simulation results over the entire flight envelope demonstrate that the REMFC-based integrated control approach for coaxial high-speed helicopters outperforms conventional methods in reference command tracking, disturbance rejection, and rotor speed stabilization, significantly improving flight performance and robustness under complex flight conditions.