Path Planning and Trajectory Tracking Control of Quadrotor Dragging System in Marine Environment

Compared to traditional vessels used for recovering and transporting floating objects on the water surface, deploying unmanned aerial vehicles to perform the task of dragging floating objects has many advantages in saving time, cost and flexibility. This paper presents a method of modeling, control, and obstacle avoidance for a novel quadrotor dragging system, addressing the effective recovery of floating objects on the water surface with dispersed obstacles and external disturbances, especially in a marine environment. Firstly, an 8-degree-of-freedom coupled mathematical model is established for the quadrotor dragging system using a combination method of the Newton-Euler equation and Lagrange equation, which facilitates a better analysis of the position coupling relationship between the quadrotor and the dragged floating payload. Secondly, a path planning scheme is presented based on the idea of transforming the floating payload’s desired obstacle avoidance trajectory into the quadrotor’s desired flight trajectory. Applying the artificial potential field algorithm to generate the floating payload’s desired obstacle avoidance trajectory and capturing the floating payload through binocular vision, then the quadrotor’s desired flight trajectory is further obtained by utilizing the position coupling relationship between the quadrotor and the floating payload. Thirdly, a cascaded sliding mode control scheme with hyperbolic tangent function is designed to enhance the tracking performance and anti-interference ability of the quadrotor dragging system. Finally, simulation results verify the effectiveness of the designed path planning scheme and control scheme.