Robotic Materials

Miniaturized circuitry for capacitive self-sensing and closed-loop control of soft electrostatic transducers

2020

Article

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Soft robotics is a field of robotic system design characterized by materials and structures that exhibit large-scale deformation, high compliance, and rich multifunctionality. The incorporation of soft and deformable structures endows soft robotic systems with the compliance and resiliency that makes them well adapted for unstructured and dynamic environments. Although actuation mechanisms for soft robots vary widely, soft electrostatic transducers such as dielectric elastomer actuators (DEAs) and hydraulically amplified self-healing electrostatic (HASEL) actuators have demonstrated promise due to their muscle-like performance and capacitive self-sensing capabilities. Despite previous efforts to implement self-sensing in electrostatic transducers by overlaying sinusoidal low-voltage signals, these designs still require sensing high-voltage signals, requiring bulky components that prevent integration with miniature untethered soft robots. We present a circuit design that eliminates the need for any high-voltage sensing components, thereby facilitating the design of simple low cost circuits using off-the-shelf components. Using this circuit, we perform simultaneous sensing and actuation for a range of electrostatic transducers including circular DEAs and HASEL actuators and demonstrate accurate estimated displacements with errors <4%. We further develop this circuit into a compact and portable system that couples high voltage actuation, sensing, and computation as a prototype toward untethered multifunctional soft robotic systems. Finally, we demonstrate the capabilities of our self-sensing design through feedback control of a robotic arm powered by Peano-HASEL actuators.

Author(s): Khoi Ly and Nicholas Kellaris and Dade McMorris and Brian K Johnson and Eric Acome and Vani Sundaram and Mantas Naris and J Sean Humbert and Mark E Rentschler and Christoph Keplinger and Nikolaus Correll
Journal: Soft Robotics
Year: 2020
Month: October
Day: 1
Publisher: Mary Ann Liebert, Inc., publishers
Department(s): Robotic Materials
Bibtex Type: Article (article)
Paper Type: Journal
DOI: 10.1089/soro.2020.0048
URL: https://www.liebertpub.com/doi/full/10.1089/soro.2020.0048

BibTex 

@article{Keplinger20-SR-Miniaturized,
  title = {Miniaturized circuitry for capacitive self-sensing and closed-loop control of soft electrostatic transducers},
  author = {Ly, Khoi and Kellaris, Nicholas and McMorris, Dade and Johnson, Brian K and Acome, Eric and Sundaram, Vani and Naris, Mantas and Humbert, J Sean and Rentschler, Mark E and Keplinger, Christoph and Correll, Nikolaus},
  journal = {Soft Robotics},
  publisher = {Mary Ann Liebert, Inc., publishers},
  month = oct,
  year = {2020},
  doi = {10.1089/soro.2020.0048},
  url = {https://www.liebertpub.com/doi/full/10.1089/soro.2020.0048},
  month_numeric = {10}
}