Robust Wind-Aware Path Optimization Onboard Small Fixed-wing UAVs
Thomas Bucher, Thomas Stastny, Sebastian L. Verling, Roland Siegwart · AIAA SCITECH 2023 Forum · 2023
View Video Presentation: https://doi.org/10.2514/6.2023-2640.vid Small, fixed-wing Uncrewed Aerial Vehicles (UAVs) flying in high winds often suffer from large path following deviations, especially on curved segments. Autopilots generally rely on the path following controller to attenuate such disturbances in a feedback manner. This work instead approaches this problem preemptively by incorporating the wind estimate at the path planning stage. Trochoids and “shifted” clothoids are utilized to find the time-optimal path between an initial and final pose, outputting the ground relative trajectory the aircraft must fly. As geometric path following controllers require a solution for the closest point to the aircraft on a respective path, and trochoids and clothoids do not have a closed-form solution to this problem, we propose a computationally lightweight path sampling algorithm to approximate the solution and enable direct integration with existing path following guidance laws. The path sampling and path following algorithms are implemented on open-source autopilot firmware and demonstrated in several relevant software-in-the-loop simulations. The results show that incorporating knowledge of the wind and vehicle dynamics in the planning stage leads to a more repeatable and predictable UAV path following behavior.