Formation Flight Test Results for UAV Research Aircraft Models

This paper presents experimental results for a research program using research UAVs built and developed at West Virginia University. The main objective of this effort was to provide a flight demonstration of a formation control scheme using three YF-22 research aircraft models. For several years formation flight research has been an important topic for the aerospace community. The benefits of formation flight and development of formation control problems have been investigated and well documented. A detailed mathematical model was obtained using parameter identification techniques from previously recorded flight data of the WVU YF-22 aircraft. From this data, a Simulink® based simulation environment was developed and used to test the formation control laws. Simulation results used this mathematical model to design and refine a set of control laws to maintain desired formation geometry during maneuvered flight. The formation control law consists of a set of inner and outer loop control schemes executed by an on-board computer system on the “Follower” aircraft. Performance of the “Follower” inner-loop control laws has been assessed through a series of flight tests. Flight-testing activities focusing on the formation control laws initially used a “virtual leader” scenario. Results of the “virtual leader” testing validated the overall design of the formation controller and confirmed the performance of the on-board computer system. Formation flight with two aircraft was then performed during the 2004 flight season. This paper will first describe the UAV models along with their customized electronic computer systems. Next, the aircraft mathematical model as well as the formation control schemes will be presented. The overall control design process, with emphasis on the controller implementation on the on-board computer, will also be described. Finally, the flight-testing operations and experimental results obtained to date will be presented and discussed.