Tiltrotor Conversion System Design and Flight Dynamics Simulation for VTOL Aircraft

The growing demand for Urban Air Mobility (UAM) has created a promising outlook for the development of VTOL aircraft, which are anticipated to bring about a revolutionary transformation in urban transportation. Tilt-rotor aircraft, as a representative of high-performance VTOL aircraft, combine the characteristics of airplanes and helicopters. This is achieved by relying on the rotation of two or more nacelles through a conversion system that includes actuators and tilting mechanisms. The smooth and flexible transition maneuvers of the aircraft depend on the reliability of the conversion system design and the servo control strategy. In this paper, we analyze the typical external loads encountered by the tilting mechanisms, propose two feasible design schemes for the tilting system, and assess their characteristics through rigid-flexible coupling co-simulation. To further examine the impact of the actuation system's characteristics on the overall aircraft performance, we employ a multi-body method to model the nonlinear dynamics using the XV-15 as the subject of study. The modeling process considers various physical effects and disturbances to ensure a realistic representation of the system, making it suitable for practical design implementation. The high-fidelity dynamics model of the VTOL aircraft serves as a platform for investigating the coupling effects between the flight controller and actuation system.