Control law for the automatic docking procedure during aerial refueling

Control systems


Obolensky Y. G.1*, Pohvalensky V. L.2, Cheglakov D. I.2**

1. Russian Aircraft Corporation MiG, 2, Leningradskoe shosse, Moscow, 125171, Russia
2. MIG corporation, 6, Leningraskoe shosse, Moscow, 125171, Russia



Automatic in-flight refueling of unmanned aerial vehicle (UAV).
This paper addresses the fly-by-wire system automatic control algorithm design for the in-flight refueling procedure of high maneuverable aircraft.
The main goal is to navigate and control UAV (during the docking phase of in-flight refueling procedure) so that probe will link up with the drogue mounted on the flexible hose trailing behind the aircraft-tanker. Practical probe and drogue autonomous in-flight refueling requires a robust relative navigation and control algorithm to be designed.
The design process of the control algorithm can be divided into three main parts. The first one includes linearization of UAV equations of motion for the typical values of airspeed and altitude when in-flight refueling. This can be carried out by commonly used linearization technique. The second part consists of linear analysis and design of the inner loop (angular velocity stabilization) control algorithm. The design process is based on the L1 adaptive control theory. In the third part, the linear observers and other components of outer control loop are developed. Feasibility and performance of the total system were demonstrated by simulation of unmanned refueling aircraft docking maneuvers with the non-stationary drogue of an unmanned tanker.
Results presented in the paper showed that the controller can enable precise in-flight refueling thanks to the new algorithm, allowing for real measurement errors, plant modeling errors, and disturbance.
Presented in this paper control algorithm may be used in a fly-by-wire systems of modern manned and unmanned aerial vehicles.


fly-by-wire system, aerial refueling, docking procedure, wake vortex, observer


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