A Compact McKibben Muscle Based Bending Actuator for Close-to-Body Application in Assistive Wearable Robots

Martin Tschiersky*, Edsko E.G. Hekman, Dannis M. Brouwer, Just Herder, Koichi Suzumori

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

28 Citations (Scopus)
176 Downloads (Pure)


In this paper we demonstrate a pneumatic bending actuator for upper-limb assistive wearable robots which uses thin McKibben muscles in combination with a flexure strip. The actuator features both active soft actuation and passive gravity support, and in terms of force transmission bridges the gap between the classic rigid type actuators and the emerging soft actuator technologies. Its flexure strip leverages the high-force low-displacement properties of McKibben muscles towards a large rotational range of motion and reduces localized forces at the attachments. We explain the synthesis method by which these actuators can be obtained and optimized for high specific moment output. Physical specimens of three optimized actuator designs are built and tested on a dedicated experimental setup, verifying the computational models. Furthermore, a proof-of-concept upper-limb assistive wearable robot is presented to illustrate a practical application of this actuator and its potential for close-to-body alignment. We found that based on our currently available components actuators can be built which, given a width of 80 mm, are able to produce a moment exceeding 4 Nm at an arm elevation of 90 deg.
Original languageEnglish
Pages (from-to)3042-3049
Number of pages8
JournalIEEE Robotics and automation letters
Issue number2
Early online date21 Feb 2020
Publication statusPublished - Apr 2020
EventInternational Conference on Robotics and Automation, ICRA 2020 - Virtual Conference, Paris, France
Duration: 31 May 202031 Aug 2020


  • Hydraulic/pneumatic actuators
  • Physically assistive devices
  • Prosthetics and exoskeletons
  • Upper-limb
  • Wearable robots


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