CyberKite – an automated kite system

Controlling the powers of nature has always been a challenge of mankind.
In the context of the bionic learning network, Festo has faced this challenge with the CyberKite, a kite system with a cybernetic control unit, which was developed in cooperation with aeroix. The assignment of the engineers was to be able to control the wind as a unpredictable factor and to keep a ram air kite permanently in the air. With CyberKite, Festo and aeroix are presenting a biomechatronical design, which is able to autonomically steer and control a ram air wing of up to 24 square meters (258 square feet) without any external energy feed-in. The performance both of the electrical drives and the complete system is impressively demonstrated.

The intelligent control of the kite performance is carried out respectively dependent on wind conditions and the wing size used. Different operation modi and adapted flight path parameters guarantee an operation throughout a wide range of wind speeds. This makes CyberKite an exceptional endurer at arial heights. An automatic load limitation combined with a robust flight control allows a safe handling even of large wings. The performance of the kite is being controlled by a ground-based mechatronical
actuator unit provided by Festo

The bionic design of the wing originates from the Stingray® project, which was implemented for Festo in 1998 by the prospective concepts AG. The wing developed further here combines a large wing volume with a good lift to drag ratio and best possible selfstability. The wing keeps his position even at calm winds thanks to the bouyant lift. Thus changing and poor wind conditions have litlle effect on this hybrid wing-system.

Despite its flat and elegant design the wing flies without additional stabilizers. The adjustment of the wings is realized by a sterical rope transmission combined with the adaptive bridle-system. Thus, the wing is enabled to fly straight with extended wing ends and to bend the wings for spiralling (maneuvers), with sufficient lateral stability.

Because of the teathering the wing to the ground, undesired high forces can arise during strong and gusty winds. Electric drives and sensor technology by Festo react to the respective flight situation and keep the system stable. In the bridle, a passive, adaptive rope transmission system was developed, which, if required, effectively reduces the dynamic action of the wind force. For a controlled coiling and decoiling of the rope, a transfering axis, consisting of an electric linear drive, is assigned to each winch.

The controlling and steering of the CyberKite is based on a philosophy of intelligent resilience and not of one of rigid adherence. Here, the force of the wind is made utilizable by an energy efficient use of the drives. This makes it possible to feed back the breaking energy of the servo drives into the system and to make the surplus wind energy utilizable by the use of resilient winches, which are supplemented with most modern battery technology. In the "generator mode" the servo drives are being run periodically by the ropes, which are decoiled by the traction relayed by the kite. The regained electrical energy is stored in the batteries and reduces the energy demand of the system considerably. Future CyberKite systems can be operated energy-self-sufficiently at corresponding wind conditions thanks to the power of the wind.

The motivation...

for a corporate development of the CyberKite is based on the challenge of implementing a technology demonstrator with state of the art automation technology, that is capable of safely managing very complex contolling tasks. The best application field is nature with its imponderabilities. Here we find very sophisticated demands for automated control systems. From a mathematical point of view, wind is a variety of parametric fields with stochastic changes/, and it is a force of nature which accurately corresponds to these prerequisites. The assignment for Festo in cooperation with aeroix is to develop a kite system which remains in the air, unaffected by the wind direction. With regard to future man-machine-cooperations, the CyberKite serves as a prime example for the interaction of mechanical engineering with cross-section technologies like mechatronics and energy efficiency, in order to find solutions for complex challenges.


CyberKite at the Festo Bionic Learning Network

CyberKite - Project on "Kite energy and high altitude wind energy blog"