Robotic Materials

Rapid 3D Printing of Electrohydraulic (HASEL) Tentacle Actuators

2020

Article

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A comprehensive material system is introduced for the additive manufacturing of electrohydraulic (HASEL) tentacle actuators. This material system consists of a photo-curable, elastomeric silicone-urethane with relatively strong dielectric properties (εr ≈ 8.8 at 1 kHz) in combination with ionically-conductive hydrogel and silver paint electrodes that displace a vegetable-based liquid dielectric under the application of an electric field. The electronic properties of the silicone material as well as the mechanical properties of the constitutive silicone and hydrogel materials are investigated. The hydraulic pressure exerted on the dielectric working fluid in these capacitive actuators is measured in order to characterize their quasi-static behavior. Various design features enabled by 3D printing influence this behavior—decreasing the voltage at which actuation begins or increasing the force density in the system. Using a capacitance change of >35% across the actuators while powered, a demonstration of self-sensing inherent to HASELs is shown. Antagonistic pairs of the 3D printed actuators are shown to exert a blocked force of over 400 mN. An electrohydraulic tentacle actuator is then fabricated to demonstrate the use of this material and actuation system in a synthetic hydrostat. This tentacle actuator is shown to achieve motion in a multi-dimensional space.

Author(s): Maura R O’Neill and Eric Acome and Shannon Bakarich and Shane K Mitchell and Julia Timko and Christoph Keplinger and Robert F Shepherd
Journal: Advanced Functional Materials
Volume: 30
Number (issue): 40
Pages: 2005244
Year: 2020
Month: August
Department(s): Robotic Materials
Bibtex Type: Article (article)
Paper Type: Journal
DOI: 10.1002/adfm.202005244
URL: https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.202005244
Additional (custom) Fields:
acknowledgements: This work was supported in part by the National Science Foundation (NSF), under award No. 1830924 the Air Force Office of Scientific Research, under award No. FA9550-19-1-0290, the Defense Advanced Research Projects Agency (DARPA; Grant No. HR0011-19-C-0045), and an Army Research Laboratory Cooperative R&D Agreement. This work made use of the Cornell Center for Materials Research Facilities supported by the NSF MRSEC program (DMR-1719875) and the Cornell Biotechnology Resource Center under the National Institutes of Health award No. S10OD025049. C.K., E.A., and S.K.M. also acknowledge support from a Packard Fellowship from The David and Lucile Packard Foundation, and from the University of Colorado Boulder, as well as funding from the Army Research Office (Grant No. W911NF-18-1-0203), which was used to purchase laboratory equipment to characterize and fabricate actuators.

BibTex 

@article{Keplinger20-AFM-Rapid3D,
  title = {Rapid 3D Printing of Electrohydraulic (HASEL) Tentacle Actuators},
  author = {O'Neill, Maura R and Acome, Eric and Bakarich, Shannon and Mitchell, Shane K and Timko, Julia and Keplinger, Christoph and Shepherd, Robert F},
  journal = {Advanced Functional Materials},
  volume = {30},
  number = {40},
  pages = {2005244},
  month = aug,
  year = {2020},
  doi = {10.1002/adfm.202005244},
  url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.202005244},
  month_numeric = {8}
}