EXPLOITATION OF NONLINEAR DYNAMICS AND VIBRATIONAL STABILIZATION IN BIO-INSPIRED FLIGHT
DR. HAITHEM TAHA
Assistant Professor Department of Aerospace and Mechanical Engineering,
University of California, Irvine
Flapping-wing micro-air-vehicles (FWMAVs) represent complex multi-disciplinary systems whose analysis invokes the frontiers of the mechanical and aerospace engineering disciplines. From the aerodynamic point of view, a nonlinear, unsteady flow is created by the flapping motion. In addition, unconventional contributors, such as the leading edge vortex, to the aerodynamic loads become dominant in flight. On the other hand, the flight dynamics of a FWMAV constitutes a nonlinear, non-autonomous dynamical system; specifically a time-periodic system. Furthermore, the stringent weight and size constraints that are always imposed on FWMAVs invoke design with minimal actuation, which results in an under-actuated dynamical system.
In this presentation, I will show some of the above technical challenges and the approaches adopted to resolve them. In particular, I will show our exploitation of the saturation phenomenon in nonlinear dynamics to design an actuation mechanism that provides both kinematics for hovering and forward flight using only one actuator. I will also show a rigorous mathematical analysis that combines geometric control theory and averaging, which led to the discovery of a vibrational stabilization phenomenon. Finally, I will discuss formulation of airplane flight mechanics in a differential geometric control framework that results in recovery of nonlinear controllability when linear controllability is lost due to hydraulic loss of control surfaces. Moreover, novel nonlinear rolling mechanism is discovered, which has a significantly higher control authority near stall than the conventional linear rolling mechanism due to ailerons.
Haithem Taha is currently an assistant professor in the department of Mechanical and Aerospace Engineering at the University of California, Irvine. He received his PhD degree from the Engineering Science and Mechanics department at Virginia Tech simultaneously with an MSc degree in Interdisciplinary Mathematics in Dec 2013. He earned his BSc and MSc degrees in aerospace engineering from Cairo University, Egypt in 2005 and 2008, respectively, then, joined the German University in Cairo as an instructor for automatic control and then Virginia Tech in 2010 to start his PhD study. His PhD research has focused on aerodynamic modeling, flight dynamics and control of flapping wing micro-air vehicles. Mr. Taha has wide research interests that cover Geometric Nonlinear Control Theory and Unsteady Nonlinear Aerodynamics with application to Flight Dynamics of Flapping-Wing Micro-Air-Vehicles.