Pilot-Assisted Conversion Flight Control for Tiltrotor Aircraft

Abstract

Transition maneuvers of tiltrotor aircraft require coordinated control of nacelle position while maintaining airspeed and altitude, resulting in high pilot workload. This paper proposes a pilot-assisted conversion control approach that accounts for the transitional aerodynamic characteristics of the rotor–wing system. A conversion path and corresponding nacelle rate distribution are derived by extracting phase-dependent lift characteristics from rotor and wing aerodynamic forces. Based on a stability and control augmentation system (SCAS), a pilot-assisted control architecture is developed by integrating scheduled pitch attitude and collective pitch with an altitude error compensator, establishing a coordinated transition framework that combines tilting rate with aerodynamic surface regulation. Simulation and flight test results showed that the proposed method reduces stick activity and pilot workload through coordinated regulation of altitude and speed. The transition exhibits small variations in altitude and pitch attitude, consistent with the underlying aerodynamic characteristics. By aligning configuration transition with lift–thrust variation and synchronizing nacelle tilt with aerodynamic control, the method improves flight state evolution and reduces pilot control effort.