Pneumatic Coiling Actuator Inspired by the Awns of Erodium cicutarium

Abstract

This study examines the coiling and uncoiling motions of a soft pneumatic actuator inspired by the awn tissue of Erodium cicutarium. These tissues have embedded cellulose fibers distributed in a tilted helical pattern, which induces hygroscopic coiling and uncoiling in response to the daily changes in ambient humidity. Such sophisticated motions can eventually "drill" the seed at the tip of awn tissue into the soil: a drill bit in the plant kingdom. Through finite element simulation and experimental testing, this study examines a soft pneumatic actuator that has a similar reinforcing fiber layout to the Erodium plant tissue. This actuator, in essence, is a thin-walled elastomeric cylinder covered by tilted helical Kevlar fibers. Upon internal pressurization, it can exhibit a coiling motion by a combination of simultaneous twisting, bending, and extension. Parametric analyses show that the coiling motion characteristics are directly related to the geometry of tilted helical fibers. Notably, a moderate tilt in the reinforcing helical fiber leads to many coils of small radius, while a significant tilt gives fewer coils of larger radius. The results of this study can offer guidelines for constructing plant-inspired robotic manipulators that can achieve complicated motions with simple designs.

Morphological Computation in Plant Seeds for a New Generation of Self-Burial and Flying Soft Robots

“…Seed dispersal is an interesting area for ecology, plant diversity and adaptation, and climate change (Traveset et al, 2014;Johnson et al, 2019). More recently, seed functioning and dispersion abilities have attracted the interest also of material scientists and engineers (Elbaum et al, 2007;Armon et al, 2011;Yao and Ishii, 2019;Geer et al, 2020). The strategies of seed dispersal are in fact characterized by an interesting mass and energy efficiency, adaptability, robustness and the embodiment of remarkable forms of morphological intelligence (Pandolfi and Izzo, 2013).…”

The Bio-Engineering Approach for Plant Investigations and Growing Robots. A Mini-Review

“…Also robotics has contributed to this change in perspective by starting to mimic plants at both components and system level (Mazzolai et al, 2010(Mazzolai et al, , 2011Sadeghi et al, 2014Sadeghi et al, , 2020Hawkes et al, 2017;Nahar et al, 2017;Wooten and Walker, 2018;Must et al, 2019;Bolt et al, 2020;Geer et al, 2020).…”

“…New technologies, such as time-lapse recording, have demonstrated such abilities both above and below ground (Vincent et al, 2011 ; Silverberg et al, 2012 ; Vlad et al, 2014 ; Poppinga et al, 2015 ; Guerra et al, 2019 ; Rambaud-Lavigne and Hay, 2020 ). Also robotics has contributed to this change in perspective by starting to mimic plants at both components and system level (Mazzolai et al, 2010 , 2011 ; Sadeghi et al, 2014 , 2020 ; Hawkes et al, 2017 ; Nahar et al, 2017 ; Wooten and Walker, 2018 ; Must et al, 2019 ; Bolt et al, 2020 ; Geer et al, 2020 ).…”

E-seed

“…The actuation mechanism is inspired by the plant of the genus Erodium that deploys its seeds through a selfburial behavior [19]. Despite the previous attempts to build Erodium-inspired engineering systems [13,30,36], to our knowledge, a practical replica that resembles the architecture and function has yet to be developed. We hope this materialdriven system can be leveraged by other Human-Computer Interaction (HCI) researchers who are looking for suitable carriers for their sensors and interfaces that are arduous or resource-consuming to anchor.…”