Robust Control and Visual Servoing of an Uav

The purpose of this paper is to show that a combination of a nonlinear controller for an UAV of quadrotor type and visual servoing for trajectories generation leads to better stability results in a perturbed environment. The quadrotor is an underactuated system and highly nonlinear, which induces some difficulties in the design of the controller and in particular the application of visual servoing. The dynamic model of the quadrotor has been established by taking into account the gyroscopic effects of the rotors. The state-space representation of the system has been chosen in such a way that it enables to derive a backstepping controller. To generate the trajectories, three types of visual servoing have been investigated, 2D, 3D and 2D1/2, in order to draw the advantages and the drawbacks of each approach. Numerical simulations have been performed and have confirmed the validity of the theoretical results, besides the backstepping controller has shown the ability to control the quadrotor in the presence of relatively high perturbation conditions. Copyright © 2008 IFAC.