Methods: A numerical simulation of a simplified three-dimensional, three degree-of-freedom system has been created to predict the motion of the kite under applied control of the tether. The simulation uses explicit numeric integration routines to approximate the solution of the set of coupled non-linear governing equations of motion. Control algorithms are initially tested using the simulation before testing on the experimental test bed.
Experimental validation is currently underway. A three axis load cell test bed is under construction and will provide the controller with the magnitude and direction of the tether tension. The encoder on the drive motor will determine tether length. Velocity feedback will be used to control the kite.
Results: Initial simulation shows that the kite tracks to a stable position while in the high tension state, which has also been validated by manual flight of the existing kites in extreme wind conditions. Manually flying the kite, and subsequent video analysis, has provided guidance in improving simulation parameters such as spin rate and direction.
Conclusions: The goal of this research is to achieve automated, sustained flight of a naturally unstable kite system and to better understand the system as a whole. This base knowledge can be built on to better understand, control, and design kite power systems. Experienced human flyers can expertly maneuver these kites with precision from hundreds of feet solely by changing the tension in the tether. The potential exists to produce a low cost, renewable energy source that can be implemented around the world.