Formation flight optimization using extremum seeking feedback

A comprehensive design procedure based on extremum seeking for minimum power demand formation flight is presented, the first with performance guarantees. The procedure involves the design of a new wake robust formation hold autopilot and transformation of the closed-loop aircraft dynamics to a form in which a newly available rigorous design procedure for extremum seeking is applicable. The design procedure is applied to a formation of Lockheed C-5s, extending the use of maximum performance formation flight to large transports. By the use of available experimental wake data of the C-5, a model of the aircraft in the wake is developed that models aerodynamic interference as feedback nonlinearities. Thus, this work is also the first to attain stable extremum seeking for a plant with nonlinear feedback. Optimal formation flight is attained by online minimization of an easily measurable objective, the pitch angle of the wingman.