Automatic helicopter flight based on wind-induced threat identification in urban environments

Aimed at the safety of helicopter flight in the highly dynamic wind field of urban low-altitude environment, a wind field simulation and reconstruction method based on unsteady Reynolds-Averaged Navier-Stokes (RANS) and Snapshot Proper Orthogonal Decomposition (Snapshot POD) is proposed in this paper. A comprehensive flight simulation platform is developed, integrating the simulated wind field, a helicopter flight dynamic model, an explicit Model-Following Control System (MFCS), and a simplified precision pilot model. Focusing on the issue of airflow disturbances from nearby obstacles in urban environments, a spatiotemporal, dual-source wind-induced threat identification model is established, which fuses turbulence threat and operational exceedance threat, and is incorporated into the construction of safety maps used for trajectory planning. The neighborhood search strategy of the A* algorithm is improved to enhance the trajectory’s environmental adaptability, forming an automatic helicopter flight simulation method for complex urban wind environments, integrating wind field prediction, trajectory planning, and flight simulation. Applied to real-world environment flight simulation, the Improved Safety Map-based A* method (I-SM-A*) can reduce the number of path nodes and approach the target faster compared with the Traditional A* method (Trad-A*). The designed trajectory can effectively isolate the wind-induced threat caused by the building airflow. This results in a reduction in pilot workload, as evidenced by decreases of 10.6% and 8.0% in the time and frequency domains, respectively. The flight simulation platform can accurately track the designed trajectory and achieve reliable automatic flight planning in complex urban windy environments.