Tandem Tilt-Wing Control Design Based on Sensory Nonlinear Dynamic Inversion

Kurzfassung

Tandem tilt-wing eVTOL aircraft have become increasingly popular in the last decade due to their advantages of efficient wing-borne cruise flight and reduced reliance on ground- based infrastructure. However, this comes at the cost of a complex flight control task, which entails the handling of the different flight regimes and the transition between them. Dynamic inversion-based control methods, especially sensory nonlinear dynamic inversion (sensory NDI), have shown promise in addressing this challenge. This paper presents the design and implementation of a sensory NDI-based angular rate and velocity inversion integrated with an optimization-based control allocation scheme, which is cascaded with a parallel attitude and flight path controller. The parallel control loops are designed to facilitate a full transition while utilizing all available degrees of freedom and control effectors. This control law is demonstrated on a strip theory-based 6-DoF flight dynamic model of a tandem tilt-wing configuration. The results indicate that the control law can effectively invert the dynamics within a subset of the flight envelope. In fact, decoupling the pitch angle from the flight path and the outbound transition maneuver works smoothly, whereas maneuvering into the post-stall regime leads to instabilities and needs to be addressed in future work.