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Novel bio-inspired variable stiffness soft actuator via fiber-reinforced dielectric elastomer, inspired by Octopus bimaculoides

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Abstract

Compliant devices are used in a wide variety of applications like soft robots. Although soft robotics have played an important role in providing the desired compliance and reducing the safety concerns on robot–human interactions, the research community soon realized that for a soft robot, not only is the compliance quite important, but also the change in the compliance and its controllability is paramount. In this regard, this research proposes a novel bio-inspired variable stiffness fiber-reinforced dielectric elastomer actuator that performs similar to the tissues of the California two-spot octopus, scientifically known as Octopus bimaculoides. It is shown that by using an initially curved dielectric elastomer strip and by properly incorporating fibers, an interesting variable stiffness actuator can be created that lays the foundation for future bionic fingers and grippers. Using an experimentally validated numerical framework, different geometries of the proposed variable stiffness dielectric elastomer actuator (VSDEA) are simulated by the means of the finite element method. The main outputs of the simulations are the force–displacement curves for different configurations of the proposed VSDEA activated by different voltages ranging from 0 to 7.5 kV. The bending stiffness of the actuators that is the initial slope of the force–displacement curves is calculated and compared for different configurations. By analyzing the outcomes of the simulations, the paper introduces an optimum configuration that is capable of varying the stiffness of the structure up to 99.3% which is a good improvement compared with previous studies.

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Data availability

Data from all sections of the manuscript are available upon request.

Code availability

The FORTRAN code used in this manuscript is available upon request.

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Acknowledgements

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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Authors and Affiliations

  1. Research Laboratory of Passive Safety Systems, Faculty of Mechanical Engineering, K. N. Toosi University of Technology, P.O. Box 19395-1999, Tehran, Iran

    Alireza Ahmadi & Masoud Asgari

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  1. Alireza Ahmadi
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  2. Masoud Asgari
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Correspondence to Masoud Asgari.

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Ahmadi, A., Asgari, M. Novel bio-inspired variable stiffness soft actuator via fiber-reinforced dielectric elastomer, inspired by Octopus bimaculoides. Intel Serv Robotics 14, 691–705 (2021). https://doi.org/10.1007/s11370-021-00388-1

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