Optimal Flight Pattern Debate for Airborne Wind Energy Systems: Circular or Figure-of-eight?

Abstract. The computational study compares the performance of circular and figure-of-eight flight patterns for fixed-wing ground-generation airborne wind energy (AWE) systems using a PID-based basic controller that effectively controls the kite during each patterns pumping cycle in a Matlab^® Simulink^® environment. A simple, adjustable control framework enables a steady analysis within consistent operational parameters, allowing for fair comparisons of power output, power quality, ground surface area requirements, and structural load impacts. The simulation results reveal that using the 150 m² MegAWES reference kite at 15 ms⁻¹ the circular flight pattern achieves the highest cycle-averaged power output, providing 1.85 MW at a power density of 2.94 MWkm⁻², making it advantageous for maximizing energy within limited spatial constraints. Conversely, the figure-of-eight down-loop pattern demonstrates superior power quality with lower power peaks (a peak-to-average-power ratio of 3.85) and lower expected structural fatigue due to a reduced load frequency of 0.034 Hz, supporting greater operational stability and system longevity. The up-loop variation performed the worst on all metrics considered in this work. This study offers insights into the trade-offs between energy output, efficiency, and structural demands associated with each flight path, providing a foundation for future AWE flight path selection and control strategy optimizations.