Vision-based quadrotor stabilization using a pan and tilt camera

This paper proposes a nonlinear control architecture for the stabilization of a quadrotor vehicle based on image measurements of a set of landmarks obtained from a pan and tilt camera. The vehicle is stabilized vertically using an additional vertical position sensor and lateral-longitudinal stabilization is achieved with a nested saturation control law by feedback of image measurements, body attitude, and angular rate. Additionally, the pan and tilt camera is actively actuated to to keep the landmarks visible in the image sensor for most operating conditions. Simulation results are presented to assess the performance of the proposed control architecture.