Oscillator-based assistance of cyclical movements: model-based and model-free approaches

  • Renaud RonsseEmail author
  • Tommaso Lenzi
  • Nicola Vitiello
  • Bram Koopman
  • Edwin van Asseldonk
  • Stefano Marco Maria De Rossi
  • Jesse van den Kieboom
  • Herman van der Kooij
  • Maria Chiara Carrozza
  • Auke Jan Ijspeert
Special Issue - Original Article


In this article, we propose a new method for providing assistance during cyclical movements. This method is trajectory-free, in the sense that it provides user assistance irrespective of the performed movement, and requires no other sensing than the assisting robot’s own encoders. The approach is based on adaptive oscillators, i.e., mathematical tools that are capable of learning the high level features (frequency, envelope, etc.) of a periodic input signal. Here we present two experiments that we recently conducted to validate our approach: a simple sinusoidal movement of the elbow, that we designed as a proof-of-concept, and a walking experiment. In both cases, we collected evidence illustrating that our approach indeed assisted healthy subjects during movement execution. Owing to the intrinsic periodicity of daily life movements involving the lower-limbs, we postulate that our approach holds promise for the design of innovative rehabilitation and assistance protocols for the lower-limb, requiring little to no user-specific calibration.


Adaptive oscillator Assistance EMG Exoskeleton Metabolic cost Walking 



The authors were funded by the EU within the EVRYON Collaborative Project STREP (FP7-ICT-2007-3-231451).


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Copyright information

© International Federation for Medical and Biological Engineering 2011

Authors and Affiliations

  • Renaud Ronsse
    • 1
    • 2
    Email author
  • Tommaso Lenzi
    • 3
  • Nicola Vitiello
    • 3
  • Bram Koopman
    • 4
  • Edwin van Asseldonk
    • 4
  • Stefano Marco Maria De Rossi
    • 3
  • Jesse van den Kieboom
    • 1
  • Herman van der Kooij
    • 4
  • Maria Chiara Carrozza
    • 3
  • Auke Jan Ijspeert
    • 1
  1. 1.Biorobotics LaboratoryInstitute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
  2. 2.Centre for Research in Mechatronics (MCTR)Institute of Mechanics, Materials, and Civil Engineering, Université catholique de LouvainLouvain-la-NeuveBelgium
  3. 3.The BioRobotics Institute, Scuola Superiore Sant’AnnaPontederaItaly
  4. 4.Biomechanical Engineering LaboratoryInstitute for Biomedical Technology and Technical Medicine (MIRA), University of TwenteEA EnschedeThe Netherlands

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