Image-based Visual Servoing for Vanishing Features and Ground Lines Tracking: Application to a Uav Automatic Landing

A unified modeling framework is defined and an image-based visual servoing scheme is introduced to evaluate the feasibility of a vision-based guidance for a UAV model during survey missions and for automatic landing. Relevant image features are selected to allow for the proposed objective, namely decoupling rotation and translation in the image, and allowing to respect the natural separation between the lateral and longitudinal motions of the aircraft. The controller design is adapted to include the aircraft dynamics and the vision output in an linear optimal control approach. Simulation results are presented in order to validate the proposed solution and allow for a critical evaluation. Index Terms Image-based visual servoing, Unmanned aerial vehicle (UAV), auto-landing, dynamic modeling, robust control Corresponding author. Email: [email protected] ha l-0 07 66 86 2, v er si on 1 19 D ec 2 01 2 Author manuscript, published in "International Journal of Optomechatronics 2 (2008) 275-295" DOI : 10.1080/15599610802303314 NOMENCLATURE ∆l,∆r,∆H left, right and horizon lines (δa, δe, δr, δT ) aileron, elevator, rudder and throttle deflections Ω = [p, q, r] angular velocity in body frame (φ, θ, ψ) Roll, pitch and yaw Euler angles (ρ, θ) polar representation of straight line in image plane A,B,C matrices of linear model K state feedback gain for controller L interaction matrix P = [N,E,D] aircraft position in earth frame (North, East, Down) Q,R matrices of LQR cost function r̄ 6D pose of camera w.r.t. earth frame S transformation matrix from earth to body frame s vector of visual signals TCT velocity screw Vt aircraft airspeed V = [u, v, w] inertial velocity in body frame (xH , yH) coordinates of vanishing point in image x,u,y, z state, input and output vectors of linear model X U state and input vector in dynamic model x = (x, y) projected point coordinates in image plane X = (X,Y, Z) point coordinates in image frame 2 ha l-0 07 66 86 2, v er si on 1 19 D ec 2 01 2