Trim strategy, control model, and flight dynamics characteristics of canard rotor/wing aircraft in transition mode

Abstract

The transition mode of canard rotor/wing (CRW) aircraft is complex and important. During the transition flight, components that generate lift are transferred from one to another, in addition, the redundancy of control system may induce control conflict even plane crash if they don't cooperate well. It is significant to investigate the trim strategy, redundant control, and flight dynamics characteristics of CRW during transition flight. First, aerodynamic forces and moments were calculated by combining the blade element theory, computational fluid dynamics (CFD) and engineering estimation, and the motion equations of CRW in transition mode are established. Next, by analyzing the principle of transition flight, a trim strategy is proposed, and the trim results are credible and reasonable. Then, a control model for solving redundant control is proposed, which can realize simple and effective control during the transition process. Finally, by analyzing the eigenvalues, it is found that the stability of most modes grows with the increase of forwarding flying speed in the transition process, whereas the variation of minority modes is complicated. The results demonstrate the complexity of dynamic characteristics of CRW in transition mode. The trim strategy and control model and the analysis of the dynamic characteristics in the paper can be used for the subsequent control system design and overall optimization design.