Production Engineering

, Volume 8, Issue 6, pp 755–764 | Cite as

Robot guided bolt tensioning tool with adaptive process control for the automated assembly of wind turbine rotor blade bearings

  • Rainer Müller
  • Leenhard Hörauf
  • Matthias Vette
  • Javier Lopez San Martin
  • Aitor Alzaga
  • Jörg Hohmann
  • Kaspar Althoefer
  • Helge Würdemann


The three rotor blade bearings of a wind turbine hub are mounted to the rotor by several hundred bolted joints. Within this assembly process, a specific preload force has to be applied to these bolts in order to achieve a defined clamping force between the bearing and the rotor. Despite high manual labour intensity and safety concerns (platforms need to be raised to reach bolted joint at a height of 4 m), workers use hydraulic bolt tensioning cylinders which need to be threaded on each bolt individually. In order to automate this recurring assembly process, a robot guided bolt tensioning tool has been developed, which is part of a self-adaptive assembly system. Hence, we are able to locate each bolted joint, mount the bolt tensioning tool and apply the preload to each bolt of the bearing sequentially. In order to be flexible for different product variants and compensate the tolerances of large product dimensions in the wind turbine assembly, an adaptive process has been created. Therefore, the relevant parameters describing the product and assembly process are identified which can be adapted depending on the rotor hub type. Furthermore, the tolerance chain is analysed and improved by integrating measurement techniques to the new tool and using these sensors in the adaptive process control.


Automation Assembly Joining technology Wind turbine Bolt tensioning 



The presented results are developed within the research projects COSMOS (Cost-driven Adaptive Factory based on Modular Self-Contained Factory Units) which is funded by the EU 7th Framework Programme (Grant Agreement No: 246371) and Autostretch which is funded by the ZIM-BMWI (Funding code: KF3010701AT2).


  1. 1.
    Weber T (2010) Am laufenden band (Continuously production). In: Neue energie. vol 4. pp 66–73Google Scholar
  2. 2.
    Hader M (2010) From Pioneer to Mainstream—Evolution of wind energy markets and implications for manufacturers and suppliers. Roland Berger StudyGoogle Scholar
  3. 3.
    Iken J, Thomas T (2011) Fließender Übergang (Fluid transition). In: Sonne, wind und wärme, vol 2Google Scholar
  4. 4.
    Hau E (2008) Windkraftanlagen—Grundlagen, Technik, Einsatz, Wirtschaftlichkeit (Wind turbines—basics, engineering, application, profitability). vol 4. SpringerGoogle Scholar
  5. 5.
    Monville JM (2005) Hydraulic bolt tensioners for accurate, safe and secure tightening. Evolution—the business and technology magazine from SKF, vol 3Google Scholar
  6. 6.
    C. Deters, H.A. Würdemann, L.D. Seneviratne, K. Althoefer (2012) Reconfigurable Assembly Approach for Wind Turbines using Multiple Intelligent Agents, ASME/IEEE International Conference on reconfigurable Mechanisms and RobotsGoogle Scholar
  7. 7.
    Deters C, Secco EL, Würdemann HA, Lam HK, Seneviratne LD, Althoefer K (2013) Model-free fuzzy tightening control for bolt/nut joint connections of wind turbine hubs, IEEE Int Conf Robot AutomGoogle Scholar
  8. 8.
    Lam HK, Li H, Deters C, Secco EL, Würdemann HA, Althoefer K (2013) Control design for interval Type-2 fuzzy systems under imperfect premise matching. IEEE Trans Ind Electron 61(2):956–968CrossRefGoogle Scholar
  9. 9.
    Deters C, Lam HK, Secco EL, Würdemann HA, Althoefer K (2014), Accurate bolt tightening using model-free fuzzy control for wind turbine hub bearing assembly. IEEE Trans Control Syst TechnolGoogle Scholar
  10. 10.
    Rothe Erde (2013) Slewing Bearings. CatalogueGoogle Scholar
  11. 11.
    Lewis TC (1998) Driving outage times down and improving joint integrity using bolt tensioning. Conference publication of power station maintance: profitability trough reliability. Conference publication of power station maintance: profitability trough reliability, vol 452. England, pp 154–156Google Scholar
  12. 12.
    SKF (2011) Bolt-tightening HandbookGoogle Scholar
  13. 13.
    Kirchner J, Göpfert U, Koop K (2008) Windenergieanlage mit einer Pitchdrehverbindung (Wind energy systems with pitch bearing ring controll). Patent No. EP 1959132 A2Google Scholar
  14. 14.
    ITH GmbH & Co KG (2014) Meschede, Germany. Accessed 06 Mar 2014
  15. 15.
    Müller R, Esser M, Janßen C, Vette M (2010) System identification of assembly cells—increased accuracy and demand-driven reconfiguration. In: Proceedings in manufacturing systems, vol 5, pp. 71–76Google Scholar
  16. 16.
    Müller R, Vette M, Hörauf L (2013) Adaptive Prozesssteuerung in der Montage (Adaptive process control in assembly). In: wt-online, vol 9, pp. 662–667Google Scholar
  17. 17.
    Hörauf L, Müller R, Bauer J, Neumann H, Vette M (2013) Development of an intelligent bolt tensioning system and adaptive process for the automated pitch bearing assembly of wind turbines. In: Advances in sustainable and competitive manufacturing systems. Springer, Berlin, pp 651–664Google Scholar

Copyright information

© German Academic Society for Production Engineering (WGP) 2014

Authors and Affiliations

  • Rainer Müller
    • 1
  • Leenhard Hörauf
    • 1
  • Matthias Vette
    • 1
  • Javier Lopez San Martin
    • 2
  • Aitor Alzaga
    • 3
  • Jörg Hohmann
    • 4
  • Kaspar Althoefer
    • 5
  • Helge Würdemann
    • 5
  1. 1.Centre for Mechatronics and Automatisation gGmbH (ZeMA)Group of Assembly Systems and Automatisation TechnologySaarbrückenGermany
  2. 2.Gamesa Innovation & Technology, AvdaSarrigurenSpain
  3. 3.IK4 TeknikerEibarSpain
  4. 4.ITH GmbH & Co. KGMeschedeGermany
  5. 5.Department of Informatics, Centre for Robotics Research (CoRe)King’s College LondonLondonUK

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