Dynamic obstacle avoidance planning for large-wingspan flapping-wing aircraft along a straight path under periodic equivalent attitude control

To addressing the dynamic obstacle avoidance challenge faced by large-span Flapping-wing flying robots (FWFRS) during straight-path flight, this paper introduces a dynamic programming approach integrated with periodic equivalent attitude control. The inherent characteristics of large-span FWFRS, including strong nonlinear aerodynamic forces, pronounced attitude oscillation, and complex dynamic coupling effects, pose unique hurdles for achieving rapid and stable obstacle avoidance in dynamic environments. This study commences by establishing a precise dynamic model that accounts for the influence of periodic flapping motion. Based on this model, a "Periodic Equivalent Attitude Control" (PEAC) strategy is proposed, which translates the intricate periodic wing flapping motion into controllable input commands for the aircraft’s attitude control system. Subsequently, a real-time dynamic obstacle avoidance planning algorithm is devised. By incorporating the aircraft’s dynamic characteristics under PEAC constraints, smooth trajectory correction commands that adhere to attitude dynamics constraints are generated online. This ensures that the aircraft maintains stable straight-path tracking capability and attitude safety while navigating around dynamic obstacles. Outdoor flight tests have demonstrated the effectiveness of the proposed method in addressing diverse dynamic obstacle scenarios, significantly enhancing the autonomous obstacle avoidance performance and flight reliability of large flapping-wing aircraft during straight-path flight missions.