Description and Preliminary Test Results of a Six Degrees of Freedom Rigid Wing Pumping System

Ampyx Power develops a pumping kite system with a rigid aircraft that is attached to the tether by a single attachment point. This unbridled configuration allows three degrees of freedom (DOF) for the aircraft attitude and three for the position. The total system can be described by these 6 DOF. Operating the pumping kite system requires a novel view on conventional flight control. A tether based reference frame is introduced that in effect decouples the longitudinal and lateral motion which can then be designed independently allowing the highly dynamic motion of the glider to be controlled through simple control schemes. Furthermore the longitudinal motion is constrained through the tether of which the tangential velocity is controlled by the generator providing an additional control input besides the elevator to control longitudinal motion. Flight tests demonstrate that using the tether based flight control system reasonably simple and commonly used control methods provide satisfactory flight performance. This paper gives an overview of the system components and control strategy and gives a brief overview of preliminary flight tests and performance.