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

Renaud Ronsse, 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

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)1173-1185
Number of pages13
JournalMedical and Biological Engineering and Computing
Issue number10
Publication statusPublished - Oct 2011


  • Adaptive oscillator
  • Assistance
  • EMG
  • Exoskeleton
  • Metabolic cost
  • Walking

ASJC Scopus subject areas

  • Biomedical Engineering
  • Computer Science Applications
  • Medicine(all)


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