JJAP Conference Proceedings

JJAP Conf. Proc. 4, 011611 (2016) doi:10.7567/JJAPCP.4.011611

Stiffness control of a robotic arm using robust fixed point transformations

Teréz A. Várkonyi1, József K. Tar1, Imre J. Rudas2

  1. 1Antal Bejczy Center for Intelligent Robotics, Óbuda University, Budapest H-1032 Hungary
  2. 2University Research and Innovation Center, Óbuda University, Budapest H-1032 Hungary
  • Received September 27, 2015
  • PDF (942 KB) |


Nowadays, energy consumption of electronic systems is a very important question. Much money and time can be saved with a well-designed system, where the depletion is minimal. In this paper, the power usage of the arm of a NAO Next Gen robot is optimized by controlling dynamically the stiffness of its motor. The control strategy is based on Robust Fixed Point Transformations (RFPT). The results show that the proposed control method can reduce the power usage significantly, and as a surprise, it can reduce the inaccuracy of the tracking caused by the unpunctual sensors of the robot.

Creative Commons License Content from this work may be used under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.


  1. 1 Datasheet for the NAO Next Gen robot [http://www.istec.org/wp-content/uploads/2013/11/Datasheet_H25_NAO_Next_Gen_EN.pdf].
  2. 2 NAO robot for education and research [https://www.aldebaran.com/en/solutions/education-research].
  3. 3 E. Elibol, J. Calderon, and A. Weitzenfeld, RoboCup 2013: Robot World Cup XVII (Springer, Berlin/Heidelberg, 2014) p. 492.
  4. 4 J. M. Calderon, E. Elibol, W. Moreno, and A. Weitzenfeld, Proc. 8th Workshop on Human Soccer Robots, 13th IEEE_RAS International Conference on Humanoid Robots, Atlanta, GA, 2013.
  5. 5 N. Shafii, N. Lau, and L. P. Reis, RoboCup 2014: Robot World Cup XVIII (Springer, International Publishing, 2015) p. 583.
  6. 6 J. K. Tar, J. F. Bitó, L. Nádai, and J. A. Tenreiro Machado, Acta Polytechnica Hungarica 6, 21 (2009).
  7. 7 Web [https://www.aldebaran.com/en/cool-robots/nao/find-out-more-about-nao].