A study on plant root apex morphology as a model for soft robots moving in soil

PLoS One. 2018 Jun 6;13(6):e0197411. doi: 10.1371/journal.pone.0197411. eCollection 2018.

Abstract

Plants use many strategies to move efficiently in soil, such as growth from the tip, tropic movements, and morphological changes. In this paper, we propose a method to translate morphological features of Zea mays roots into a new design of soft robots that will be able to move in soil. The method relies on image processing and curve fitting techniques to extract the profile of Z. mays primary root. We implemented an analytic translation of the root profile in a 3D model (CAD) to fabricate root-like probes by means of 3D printing technology. Then, we carried out a comparative analysis among the artificial root-like probe and probes with different tip shapes (cylindrical, conical, elliptical, and parabolic) and diameters (11, 9, 7, 5, and 3 mm). The results showed that the energy consumption and the penetration force of the bioinspired probe are better with respect to the other shapes for all the diameters of the developed probes. For 100 mm of penetration depth and 7 mm of probe diameter, the energy consumption of the bioinspired probe is 89% lesser with respect to the cylindrical probe and 26% lesser with respect to the conical probe. The penetration performance of the considered tip shapes was evaluated also by means of numerical simulations, obtaining a good agreement with the experimental results. Additional investigations on plant root morphology, movement strategies, and material properties can allow the development of innovative bioinspired solutions exploitable in challenging environments. This research can bring to breakthrough scenarios in different fields, such as exploration tasks, environmental monitoring, geotechnical studies, and medical applications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Environmental Monitoring
  • Humans
  • Movement / physiology*
  • Plant Roots / anatomy & histology
  • Plant Roots / growth & development*
  • Robotics*
  • Soil
  • Zea mays / anatomy & histology
  • Zea mays / growth & development*

Substances

  • Soil

Grants and funding

RG is supported by Bonfiglioli Riduttori SpA. NMP is supported by the European Commission H2020 under the Graphene Flagship Core 2 No. 785219 (WP14 “Polymer Composites”) and FET Proactive “Neurofibres” grant No. 732344. BM is supported by the European Comission under the FLAG-ERA Joint Transnational Call (JTC) 2016, RoboCom++. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.