Interaction Forces of Soft Fiber Reinforced Bending Actuators

Zheng Wang, Panagiotis Polygerinos, Johannes T.B. Overvelde, Kevin C. Galloway, Katia Bertoldi, Conor J. Walsh

    Research output: Contribution to journalArticlepeer-review

    127 Scopus citations


    Soft-bending actuators are inherently compliant, compact, and lightweight. They are preferable candidates over rigid actuators for robotic applications ranging from physical human interaction to delicate object manipulation. However, characterizing and predicting their behaviors are challenging due to the material nonlinearities and the complex motions they can produce. This paper investigates a soft-bending actuator design that uses a single air chamber and fiber reinforcements. Additionally, the actuator design incorporates a sensing layer to enable real-time bending angle measurement for analysis and control. In order to study the bending and force exertion characteristics when interacting with the environment, a quasi-static analytical model is developed based on the bending moments generated from the applied internal pressure and stretches of the soft materials. Comparatively, a finite-element method model is created for the same actuator design. Both the analytical model and the finite-element model are used in the fiber reinforcement analysis and the validation experiments with fabricated actuators. The experimental results demonstrate that the analytical model captures the relationships of supplied air pressure, actuator bending angle, and interaction force at the actuator tip. Moreover, it is shown that an off-the-shelf bend angle sensor integrated to the actuator in this study could provide real-time force estimation, thus eliminating the need for a force sensor.

    Original languageEnglish (US)
    Article number7781665
    Pages (from-to)717-727
    Number of pages11
    JournalIEEE/ASME Transactions on Mechatronics
    Issue number2
    StatePublished - Apr 2017


    • Bending
    • fluidic actuator
    • interaction force
    • modeling
    • soft robot

    ASJC Scopus subject areas

    • Control and Systems Engineering
    • Computer Science Applications
    • Electrical and Electronic Engineering


    Dive into the research topics of 'Interaction Forces of Soft Fiber Reinforced Bending Actuators'. Together they form a unique fingerprint.

    Cite this