Adaptive control for multi-rotor UAVs autonomous ship landing with mission planning

The autonomous ship landing control issue of multi-rotor Unmanned Aerial Vehicles (UAVs) is investigated. To achieve the ship landing operation efficiently and precisely, a novel mission planning consisting of an approaching stage and a landing stage is first proposed, where the desired altitude for the UAV is provided according to the requirements in each stage. Affected by rough sea wave, a feasible final landing condition is planned such that the UAV could land on the ship board in a safe environment. Then, the solution to the ship landing operation is transformed into the UAV trajectory tracking. Due to the under-actuated nature of the UAV, an adaptive robust hierarchical algorithm is developed such that the position tracking to the desired trajectory and the attitude tracking to the command attitude are achieved. In particular, an asymmetric saturated command force is designed by introducing a dynamic compensator to ensure the nonsingular attitude extraction, and a tracking error constrained applied torque is exploited to avoid the nature singularity of Euler angle in sequence. The asymptotic stability of the closed-loop system is analyzed in view of the hierarchical system stability theory. Simulations are performed to validate the proposed strategy.