Researchers from the Autonomous Systems Lab at ETH Zurich, led by Professor Roland Siegwart, have developed a new framework for autonomous dynamic soaring with fixed-wing unmanned aerial vehicles (UAVs). This technique could potentially enable UAVs to fly indefinitely by harnessing energy from wind shear layers, reducing or even eliminating the need for internal energy sources.
Dynamic soaring is a flying technique that exploits the energy available in wind shear layers, which are areas where wind speed and direction change rapidly with altitude. By skillfully maneuvering through these layers, aircraft can gain energy, potentially allowing for extended or even unlimited flight times. The researchers have proposed a framework that enables fixed-wing UAVs to perform dynamic soaring autonomously.
The framework uses an explicit representation of the wind field and a classical approach for guidance and control of the UAV. To ensure robustness to wind field estimation errors, the researchers constructed point-wise robust reference paths for dynamic soaring and developed a robust path-following controller for the fixed-wing UAV. This means that the UAV can adjust its flight path in real-time to account for inaccuracies in wind field measurements or sudden changes in wind conditions.
The framework was evaluated in both simulation and real flight tests. In simulations, the researchers demonstrated robust dynamic soaring flight under varied wind conditions, estimation errors, and disturbances. Critical components of the framework, including energy predictions and path-following robustness, were also validated in real flights to ensure a small simulation-to-reality gap. The results strongly indicate the ability of the proposed framework to achieve autonomous dynamic soaring flight in wind shear.
For the energy sector, this research could have significant implications for the development of long-endurance UAVs for monitoring and inspection tasks, such as monitoring power lines, wind turbines, or pipelines. By reducing or eliminating the need for internal energy sources, these UAVs could operate for extended periods, reducing maintenance costs and improving safety. Additionally, the framework could be adapted for use in other applications where energy harvesting from wind is desirable, such as in the design of energy-efficient buildings or vehicles.
The research was published in the journal IEEE Transactions on Robotics, a leading publication in the field of robotics and automation. The paper is titled “Robust Optimization-based Autonomous Dynamic Soaring with a Fixed-Wing UAV” and is co-authored by Marvin Harms, Jaeyoung Lim, David Rohr, Friedrich Rockenbauer, Nicholas Lawrance, and Roland Siegwart.
This article is based on research available at arXiv.