Coordinated robust control for multi-wing airborne wind energy systems

• Applicant: Professor Dr.-Ing. Dieter Moormann
• Subject Area: Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 545539514

Airborne wind energy systems (AWES), pose great challenges to research projects, start-ups, and industry while potentially offering significant advantages in terms of wind accessibility, sustainability, and resource requirements. Within this field of airborne wind energy, multi-wing airborne wind energy systems (MW-AWES) emerged as a possible advantageous design concept. There, multiple airborne vehicles are coupled by tethers and are connected to a ground station. An advantage of such MW-AWES approaches is the higher efficiency of the system, as the total tether drag is reduced and the operational altitude is increased, offering favourable wind histograms. Furthermore, the required flight volume is smaller compared to single-wing systems due to much tighter flight radii. The MW-AWES technology holds numerous design options and challenges. Automated operations of such systems require a robust synchronization of all flight systems. Here, synchronization tasks are particularly challenging because they are both of homogeneous nature (e.g. coordination of vehicles per layer) as well as of heterogeneous nature (e.g. coordination of vehicles with a ground station winch, exerting a target force on the main tether). Thus, spatial deviations or deviations in the attitude of one flight system directly generate disturbances on all other flight systems. Moreover, these deviations propagate from the vehicles to the ground station winch, resulting in highly coupled, non-linear behaviour with respect to stationary operating points and dynamics. This requires a robust, failsafe, decentralized and at the same time synchronized control approach. Up until now, MW-AWES design and control approaches have only been conducted in idealized and simplified simulations, which mostly focus on the flight trajectories with respect to stability and energy optimization. In this project, we aim to develop a high-fidelity simulation framework for such multi-wing AWES that allows to analyse and identify the system’s flight mechanical and dynamical characteristics. Based on the developed models and simulation tools, a robust flight control and coordination concept will be developed, which shall be scalable to multi-layered MW-AWES. Finally, a control and coordination concept will be implemented for a single-layered MW-AWES demonstrator and validated through simulation studies and experimental flight tests. In this context, the overall research question to be answered is whether multi-wing airborne wind energy systems can be implemented practically and operated safely and in an efficient manner.

• DFG Programme: Research Grants