Apr. 16 (Thursday) Allen Hurst (Cornell University)
Title: Morphing Aircraft in Perching Maneuvers
Abstract:
Over the last few decades, advances in embedded systems, lightweight actuators, and sensors - and a better understanding of the natural world - have precipitated an interest by engineers to develop systems and devices inspired by living organisms. Behaviors borrowed from animals have been applied to existing man-made systems to produce increased performance or new capabilities. This adaptation has been employed to design more natural means of sensing and locomotion and, in a broader sense, to utilize available forces and energies in the environment more efficiently. This presentation focuses on a novel bio-inspired aircraft capability called perching: the ability of an aircraft to make a planted landing using primarily aerodynamic forces in lieu of high thrust. Specifically, the modeling of the perching aircraft's aerodynamics and the problem of computing and optimizing a perching trajectory using this model are presented. The aerodynamic model discussed herein is designed using empirical and analytical methods in both separated and attached flow regimes, including nonlinear and time-varying effects such as flow separation and dynamic stall. This vehicle model is used to optimize the landing trajectory with respect to its spatial boundaries, e.g. the required starting distance from the landing site. Optimal solutions of varying thrust-to-weight ratio and center of gravity location are compared. Additionally, perching trajectories that compare morphing versus fixed-configuration aircraft are presented in order to demonstrate the effects of relaxed constraints on flight envelope and shape reconfiguration, respectively. The available control for disturbance rejection is distinguished between morphing and fixed-configuration aircraft. These results show that vehicle morphing increases the controllability of the aircraft throughout the maneuver as well as decreases the spatial requirements of the optimal perching trajectory.