Physics-Data-Hybrid Modeling of Tilt-Rotor Vertical Take-Off and Landing Aircraft

This paper presents a Physics-Data-Hybrid (PDH) approach to model the flight dynamics of tilt-rotor Vertical-TakeOff-and-Landing (VTOL) aircraft within the transition phase. The tilting rotors enable more agile flight by varying vectored thrusts; however, they render more complex aircraft dynamics and other challenges for modeling. The proposed PDH modeling approach starts from fundamental, nonlinear physical laws, and expresses them in a Linear Parameter-Varying (LPV) representation, which utilizes scheduling parameters to obtain kernels that encode the intrinsic nonlinearity. After that, flight data snapshots during the transition phase are used to determine the effective state space matrices, bypassing the laborious efforts to identify accurate flight coefficients. The proposed PDH approach is validated and its modeling accuracy is assessed via simulations on a tilt-rotor VTOL aircraft. The simulation first collects data snapshots by feeding a control input sequence to excite the aircraft dynamics and the PDH model is then derived. The state responses of the resulting PDH model are then compared against the true transition trajectory. The simulation results demonstrate the PDH model's excellent modeling accuracy.