Design of a Boundary Avoidance Tracking Controller for Air-to-Air Refueling

Abstract

Automation of air-to-air refueling is investigated, in order to reduce the mental workload on pilots. In this master’s thesis a boundary avoidance tracking controller is designed for air-to-air refueling. A nonlinear simulation containing a model of a F-16 aircraft and a probe and drogue refueling system is set up. Important effects such as the bow wave and the influence of the hose have been modeled by a potential-theoretic approach and a spring-damper-system respectively. A boundary avoidance tracking controller and a reference controller were developed and integrated in the simulation. A direct lift control system is implemented for the longitudinal controller in order to achieve fast reactions while avoiding stability issues. For the evaluation of the two controllers, simulation runs are carried out, while varying the initial position of the receiver. The simulation results are evaluated by use of introduced performance criteria and the controllers are compared. The resulting boundary avoidance tracking controller shows an unsatisfactory behavior and accomplishes successful contacts only for certain initial positions. The classical reference controller shows better behavior and is successful for a bigger range of initial positions.