A Homography-Based Visual Servo Control Approach for an Underactuated Unmanned Aerial Vehicle in GPS-Denied Environments

Abstract

This paper proposes a homography-based visual servo control approach for the stabilization of underactuated unmanned aerial vehicles in GPS-denied environments. A virtual homography matrix is proposed, and a new visual error vector is defined to obtain the passivity-like visual error equation. In addition, a homography-based online translation velocity estimator and a nonlinear backstepping visual servo control approach are addressed to promote fast maneuvering without linear velocity feedback. Unlike conventional homography-based visual servo control solutions that only guarantee the local stability in the equilibrium, the proposed control scheme can get the global stability in large offset. Simulation and experimental tests with a realistic quadrotor subject to the measurement noise are carried out to verify the robustness and performance of the control approach. In addition, the autonomous tracking experiment when the target speed is unpredictable are also reported.