ESM emeritus faculty member Leonard Meirovitch, University Distinguished Professor Emeritus, and Ilhan Tuzcu, his former Ph.D. student and Postdoctoral Research Associate (and currently Assistant Professor, University of Alabama), have achieved a significant breakthrough in aeronautics. In particular, they have developed a unified theory capable of simulating the flight of flexible aircraft.
BLACKSBURG, Va., Dec. 13, 2004 – Their new theory is expected to open a new area in aeronautics research and aid the development of a new generation of aircraft, namely, autonomous unmanned aerial vehicles (UAVs). These aircraft must execute critical maneuvers while being controlled by autopilots. Their novel theory is described in three recent papers in AIAA Journal and Journal of Guidance, Control, and Dynamics.
According to Professor Meirovitch, problems of aircraft dynamics have traditionally been investigated within the confines of two separate disciplines -- flight dynamics and aeroelasticity. The first is concerned primarily with the stability of maneuvering rigid aircraft and the second with the divergence and flutter of flexible cantilevered wings. The theory developed by Meirovitch and Tuzcu recognizes the obvious facts that all aircraft possess some degree of flexibility and carry out various maneuvers. Based on fundamental principles, for which ESM is renowned, and using a global or "system concept" the theory integrates material from four different disciplines, namely analytical dynamics, structural dynamics and aerodynamics, and controls into a single mathematical formulation.
The Meirovitch-Tuzcu concept automatically includes all six rigid body degrees of freedom of the aircraft (three translations and three rotations) and the elastic deformations of all flexible aircraft components, as well as all the forces acting on the aircraft, such as aerodynamic, gravitational and control forces, and forces of an external nature (e.g., due to gusts). Considering the manner in which aircraft are flown, and using a perturbation approach, the state equations of motion are separated into a nonlinear problem for the large motions of the aircraft flying on a given path as if it were rigid and a linear, generally time-varying problem for the elastic variables and small perturbations in the rigid-body variables. Feedback control forces are then designed to drive the elastic vibration and the perturbations in the rigid-body variables to zero, thus ensuring that the aircraft flies on the intended path.