Gone with the Wind: Nonlinear Guidance for Small Fixed-Wing Aircrafts in Arbitrarily Strong Windfields

TL;DR

This paper introduces a nonlinear guidance strategy enabling small fixed-wing UAVs to operate safely and effectively in arbitrarily strong windfields, addressing a critical challenge for autonomous flight in adverse environmental conditions.

Contribution

It presents a novel nonlinear guidance method for non-holonomic vehicles in strong flowfields, ensuring stability and path tracking despite wind speeds exceeding vehicle airspeed.

Findings

Guidance strategy guarantees convergence to safe configurations.

Successful real-world flight tests in very windy conditions.

Simulation results confirm robustness and effectiveness.

Abstract

The recent years have witnessed increased development of small, autonomous fixed-wing Unmanned Aerial Vehicles (UAVs). In order to unlock widespread applicability of these platforms, they need to be capable of operating under a variety of environmental conditions. Due to their small size, low weight, and low speeds, they require the capability of coping with wind speeds that are approaching or even faster than the nominal airspeed. In this paper we present a principled nonlinear guidance strategy, addressing this problem. More broadly, we propose a methodology for the high-level control of non-holonomic unicycle-like vehicles in the presence of strong flowfields (e.g. winds, underwater currents) which may outreach the maximum vehicle speed. The proposed strategy guarantees convergence to a safe and stable vehicle configuration with respect to the flowfield, while preserving some tracking performance with respect to the target path. Evaluations in simulations and a challenging real-world flight experiment in very windy conditions confirm the feasibility of the proposed guidance approach.