High‐gain output feedback for a miniature UAV

Abstract

SUMMARY We consider the problem of output feedback robust stabilization of a ducted‐fan aerial vehicle in which high‐gain observers are used to overtake the knowledge of the linear and angular velocities of the vehicle in the control law. The proposed result is semiglobal in the attitude dynamics and in the estimation error, and global in the position variables. It is shown how the high‐gain control structure is effective notwithstanding the nonminimum‐phase behavior of the considered class of systems, provided that the airframe fulfills some geometric properties. The controller relies upon the use of nested saturations and high‐gain control laws. Although the theory is specified for a force‐torque generation mechanism of a ducted‐fan aerial vehicle, the results can be simply extended to the output feedback of many other under‐actuated rotorcrafts, such as helicopters. Experimental results are also proposed showing the effectiveness of the control law. Copyright © 2013 John Wiley & Sons, Ltd.