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Stretchable e-skin and transformer enable high-resolution morphological reconstruction for soft robots

Nature Machine Intelligence volume 5, pages 261–272 (2023)Cite this article

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Abstract

Many robotic tasks require knowledge of the exact 3D robot geometry. However, this remains extremely challenging in soft robotics because of the infinite degrees of freedom of soft bodies deriving from their continuum characteristics. Previous studies have achieved only low proprioceptive geometry resolution (PGR), thus suffering from loss of geometric details (for example, local deformation and surface information) and limited applicability. Here we report an intelligent stretchable capacitive e-skin to endow soft robots with high PGR (3,900) bodily awareness. We demonstrate that the proposed e-skin can finely capture a wide range of complex 3D deformations across the entire soft body through multi-position capacitance measurements. The e-skin signals can be directly translated to high-density point clouds portraying the complete geometry via a deep architecture based on transformer. This high PGR proprioception system providing millimetre-scale, local and global geometry reconstruction (2.322 ± 0.687 mm error on a 20 × 20 × 200 mm soft manipulator) can assist in solving fundamental problems in soft robotics, such as precise closed-loop control and digital twin modelling.

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Fig. 1: Design of the SCAS and the pipeline for full-geometry, high PGR 3D deformation reconstruction of soft robots.
Fig. 2: High PGR 3D deformation reconstruction based on the virtual dataset.
Fig. 3: Characterization of the SCAS.
Fig. 4: Real-world high PGR proprioception.

Data availability

All data are publicly available in Edinburgh DataShare with the identifier https://doi.org/10.7488/ds/377345.

Code availability

Codes for the implementation of the C2DT are available in Edinburgh DataShare with the identifier https://doi.org/10.7488/ds/377345.

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Acknowledgements

Y.Y. and F.G.-S. acknowledge the support of the Data Driven Innovation Chancellor’s Fellowship at The University of Edinburgh. D.H. acknowledges the support of the studentship from the School of Engineering, The University of Edinburgh. S.Z. acknowledges the support of the Seed Funding for Strategic Interdisciplinary Research Scheme (SIRS) from The University of Hong Kong and the Germany/Hong Kong Joint Research Scheme (G-HKU707/22) from the Research Grants Council.

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Authors and Affiliations

  1. SMART Group, Institute for Digital Communications, School of Engineering, The University of Edinburgh, Edinburgh, UK

    Delin Hu & Yunjie Yang

  2. Institute for Integrated Micro and Nano Systems, School of Engineering, The University of Edinburgh, Edinburgh, UK

    Francesco Giorgio-Serchi

  3. Edinburgh Centre for Robotics, The Bayes Centre, The University of Edinburgh, Edinburgh, UK

    Francesco Giorgio-Serchi

  4. Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China

    Shiming Zhang

Authors
  1. Delin Hu
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  2. Francesco Giorgio-Serchi
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  3. Shiming Zhang
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  4. Yunjie Yang
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Contributions

Y.Y., F.G.-S., D.H. and S.Z. conceived the concept. Y.Y. and F.G.-S. supervised the project and acquired funding. D.H. and Y.Y. carried out the simulation, fabrication and experiments. S.Z. guided the material fabrication and characterization. Y.Y. designed the measurement electronics and software. D.H. designed the machine learning algorithm. D.H. and Y.Y. analysed the data. D.H., F.G.-S. and Y.Y. wrote the manuscript. All authors reviewed and revised the manuscript.

Corresponding author

Correspondence to Yunjie Yang.

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The authors declare that they have no competing interests.

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Nature Machine Intelligence thanks the anonymous reviewers for their contribution to the peer review of this work.

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Supplementary Information

Supplementary Figs. 1–11 and Tables 1–4.

Reporting Summary

Examples of high PGR geometry reconstruction on the virtual proprioception dataset.

Examples of high PGR geometry reconstruction on the real-world dataset.

Observation of examples of high PGR geometry reconstruction on the real-world dataset from multiple viewpoints.

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Hu, D., Giorgio-Serchi, F., Zhang, S. et al. Stretchable e-skin and transformer enable high-resolution morphological reconstruction for soft robots. Nat Mach Intell 5, 261–272 (2023). https://doi.org/10.1038/s42256-023-00622-8

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