Pneumatic feedback for wearable lower limb exoskeletons further explored

Heidi Muijzer-Witteveen, Francisco Guerra, Victor Sluiter, Herman Van Der Kooij

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review


For optimal control of wearable lower limb exoskeletons the sensory information flow should also be (partly) restored, especially when the users are Spinal Cord Injury subjects. Several methods, like electrotactile or electromechanical vibrotactile stimulation, to provide artificial sensory feedback have been studied thoroughly and showed promising results. Pneumatic tactile stimulation might be an alternative to these methods, because the stimulation amplitudes can be larger and in cases of force feedback, the modality of stimulation and sensing can be matched. In this study we have developed a setup that can provide pneumatic feedback with four feedback levels via three stimulation modalities: (1) amplitude modulation, (2) position modulation and (3) frequency modulation. The differences in subject stimulus perception between these three stimulation modalities were evaluated through a magnitude estimation task performed with 10 healthy subjects. Percentages correctly identified feedback levels were significantly higher for frequency modulation than the other two stimulation modalities. Also through questionnaires the subjects indicated that feedback through frequency modulation was the most intuitive and the only method where addition of an extra feedback level was indicated as possible. The results of this study show that pneumatic feedback is feasible, can provide high percentages of feedback level discrimination that are at least comparable to vibrotactile stimulation and therefore encourages further research to optimize the pneumatic setup.

Original languageEnglish
Title of host publicationHaptics: Perception, Devices, Control and Applications
Subtitle of host publicationProceedings of the 10th International Conference Eurohaptics 2016 - Part 1
EditorsF. Bello, H. Kajimoto, Y. Visell
Place of PublicationBerlin, Germany
ISBN (Print)9783319423203
Publication statusPublished - 2016
Event10th International Conference on Haptics: Perception, Devices, Control, and Applications, EuroHaptics 2016 - London, United Kingdom
Duration: 4 Jul 20167 Jul 2016

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)03029743
ISSN (Electronic)16113349


Conference10th International Conference on Haptics: Perception, Devices, Control, and Applications, EuroHaptics 2016
CountryUnited Kingdom


  • Pneumatic feedback
  • Stimulus modulation
  • Wearable exoskeleton

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