Automatic Control of Pumping Cycles for the SkySails Prototype in Airborne Wind Energy

  • Michael Erhard
  • Hans Strauch
Part of the Green Energy and Technology book series (GREEN)


The efficient and economic operation of tethered kites for accessing highaltitude winds as a renewable source of energy requires fully automated setups. During the last decade the SkySails kite systems have been developed for applications in marine propulsion and energy generation. In this chapter we give a descriptive overview of the flight control of the tethered kite and of the control of the tether reeling speed leading to pumping cycles for energy generation. This chapter focuses on the discussion and justification of the overall design choices, functional dependencies and the presentation of the complete system in a self-contained way. For details of the mathematical modeling and control theoretical aspects references for further reading are provided. After an introduction, the dynamical model for the tethered dynamics is briefly summarized. Subsequently, the estimation and sensor system is presented. Then, the control approach is discussed and the parts of the control system are reviewed in detail. Finally the implemented system is briefly compared to other control approaches.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.



Michael Erhard gratefully acknowledges funding from ERC ST HIGH-WIND (259166) and valuable discussions within this collaboration.


  1. 1.
    Baayen, J. H., Ockels, W. J.: Tracking control with adaption of kites. IET Control Theory and Applications 6(2), 182–191 (2012).
  2. 2.
    De Lellis, M., Saraiva, R., Trofino, A.: Turning angle control of power kites for wind energy. In: Proceedings of the 52nd Annual Conference on Decision and Control (CDC), pp. 3493–3498, Firenze, Italy, 10–13 Dec 2013.
  3. 3.
    Diehl, M.: Real-time optimization for large scale nonlinear processes. Ph.D. Thesis, University of Heidelberg, 2001.
  4. 4.
    Erhard, M., Horn, G., Diehl, M.: A quaternion-based model for optimal control of the Sky-Sails airborne wind energy system. ZAMM – Journal of Applied Mathematics and Mechanics (2016). arXiv:1508.05494 [math.OC]
  5. 5.
    Erhard, M., Strauch, H.: Theory and Experimental Validation of a Simple Comprehensible Model of Tethered Kite Dynamics Used for Controller Design. In: Ahrens, U., Diehl, M., Schmehl, R. (eds.) Airborne Wind Energy, Green Energy and Technology, Chap. 8, pp. 141–165. Springer, Berlin Heidelberg (2013).
  6. 6.
    Erhard, M., Strauch, H.: Control of Towing Kites for Seagoing Vessels. IEEE Transactions on Control Systems Technology 21(5), 1629–1640 (2013).
  7. 7.
    Erhard, M., Strauch, H.: Flight control of tethered kites in autonomous pumping cycles for airborne wind energy. Control Engineering Practice 40, 13–26 (2015).
  8. 8.
    Erhard, M., Strauch, H.: Sensors and Navigation Algorithms for Flight Control of Tethered Kites. In: Proceedings of the European Control Conference (ECC13), Zurich, Switzerland, 17–19 July 2013. arXiv:1304.2233 [cs.SY]
  9. 9.
    Erhard, M., Strauch, H., Diehl, M.: Automatic Control of Optimal Pumping Cycles in Airborne Wind Energy. In: Schmehl, R. (ed.). Book of Abstracts of the International Airborne Wind Energy Conference 2015, p. 55, Delft, The Netherlands, 15–16 June 2015. Presentation video recording available from:
  10. 10.
    Fagiano, L., Milanese, M., Piga, D.: Optimization of airborne wind energy generators. International Journal of Robust and Nonlinear Control 22(18), 2055–2083 (2011).
  11. 11.
    Fagiano, L., Zgraggen, A. U., Morari, M., Khammash, M.: Automatic crosswind flight of tethered wings for airborne wind energy:modeling, control design and experimental results. IEEE Transactions on Control System Technology 22(4), 1433–1447 (2014).
  12. 12.
    Ilzhöfer, A., Houska, B., Diehl, M.: Nonlinear MPC of kites under varying wind conditions for a new class of large-scale wind power generators. International Journal of Robust and Nonlinear Control 17(17), 1590–1599 (2007).
  13. 13.
    Jehle, C.: Automatic Flight Control of Tethered Kites for Power Generation. M.Sc.Thesis, Technical University of Munich, Germany, 2012.
  14. 14.
    Jehle, C., Schmehl, R.: Applied Tracking Control for Kite Power Systems. AIAA Journal of Guidance, Control, and Dynamics 37(4), 1211–1222 (2014).
  15. 15.
    Loyd, M. L.: Crosswind kite power. Journal of Energy 4(3), 106–111 (1980).
  16. 16.
    Luchsinger, R. H.: Pumping Cycle Kite Power. In: Ahrens, U., Diehl, M., Schmehl, R. (eds.) Airborne Wind Energy, Green Energy and Technology, Chap. 3, pp. 47–64. Springer, Berlin Heidelberg (2013).
  17. 17.
    Maaß, J., Erhard, M.: Software System Architecture for Control of Tethered Kites. In: Ahrens, U., Diehl, M., Schmehl, R. (eds.) Airborne Wind Energy, Green Energy and Technology,Chap. 35, pp. 599–611. Springer, Berlin Heidelberg (2013).
  18. 18.
    Ruth, M., Lebsock, K., Dennehy, C.: What’s new is what’s old: use of Bode’s integral theorem (circa 1945) to provide insight for 21st century spacecraft attitude control system design tuning. AIAA Paper 2010-8428. In: AIAA Guidance, Navigation, and Control Conference, p. 8428, Toronto, ON, Canada, 2–5 Aug 2010.

Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  1. 1.SkySails GmbHHamburgGermany
  2. 2.Systems Control and Optimization Laboratory, Department of Microsystems Engineering (IMTEK)University of FreiburgFreiburgGermany

Personalised recommendations