Trajectory Generation Algorithm for Soft Quadcopter Landing on a Fixed Platform

This paper presents an algorithm for synthesizing the desired «flexible» kinematic trajectory, designed to ensure a «soft» landing of a quadcopter on a stationary horizontal landing platform. The algorithm is based on the integration of PID controllers with a dynamic mechanism for the formation of adaptive kinematic trajectories, which are adjusted at each iteration of the control cycle. Quantitative and qualitative requirements for the landing maneuver are formulated, including strict restrictions on the final values of vertical and horizontal speeds, as well as the orientation angles of the quadcopter. Control is based on feedback on the current state of the system, which ensures stable trajectory adaptation to changing flight conditions. The proposed algorithm is aimed at minimizing the vertical component of velocity at the moment of contact with the surface, which significantly reduces dynamic loads during landing. For realistic modeling of external disturbances, an adapted Dryden model was used, implemented through first-order aperiodic filters with parameters corresponding to lowaltitude flight conditions in an urban environment. The efficiency of the developed algorithm is confirmed by numerical modeling in conditions of severe atmospheric turbulence. The results obtained demonstrate the high accuracy of achieving the specified final motion parameters, which indicates the effectiveness of integrating «flexible» kinematic trajectories with classical controllers in the task of automatic «soft» landing of a quadcopter.