Output feedback observation and control for visual servoing of VTOL UAVs

This paper considers the question of stabilizing vertical take-off and landing (VTOL) unmanned aerial vehicles (UAVs) using a minimal and an inexpensive sensor suite. The sensor suite considered consists of rate gyros and a single embedded video camera system. The approach taken is based on the principles of dynamic image-based visual servo control and extends the authors' earlier work by removing dependence on additional sensors, such as accelerometers and magnetometers. The technique presented has potential for mini-UAVs evolving in urban areas where global positioning system signals may not be available. The control algorithms and coupled state observers are presented in details. The main result of the paper is synthesized in a theorem along with a rigorous stability analysis of the closed-loop system. An estimate of the basin of attraction for the closed-loop system is provided. Simulation results are performed to illustrate the performance of the proposed control. Copyright (C) 2010 John Wiley & Sons, Ltd.