Electrically-Driven Soft Fluidic Actuators Combining Stretchable Pumps With Thin McKibben Muscles.

Vito Cacucciolo,Hiroyuki Nabae,Koichi Suzumori,Herbert Shea

doi:10.3389/frobt.2019.00146

Vito Cacucciolo, Hiroyuki Nabae + Show 2 more

Open Access

https://doi.org/10.3389/frobt.2019.00146

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Abstract

Soft wearable robots could provide support for lower and upper limbs, increase weight lifting ability, decrease energy required for walking and running, and even provide haptic feedback. However, to date most of wearable robots are based on electromagnetic motors or fluidic actuators, the former being rigid and bulky, the latter requiring external pumps or compressors, greatly limiting integration and portability. Here we describe a new class of electrically-driven soft fluidic muscles combining thin, fiber-like McKibben actuators with fully Stretchable Pumps. These pumps rely on ElectroHydroDynamics, a solid-state pumping mechanism that directly accelerates liquid molecules by means of an electric field. Requiring no moving parts, these pumps are silent and can be bent and stretched while operating. Each electrically-driven fluidic muscle consists of one Stretchable Pump and one thin McKibben actuator, resulting in a slender soft device weighing 2 g. We characterized the response of these devices, obtaining a blocked force of 0.84 N and a maximum stroke of 4 mm. Future work will focus on decreasing the response time and increasing the energy efficiency. Modular and straightforward to integrate in textiles, these electrically-driven fluidic muscles will enable soft smart clothing with multi-functional capabilities for human assistance and augmentation.

Highlights

Soft wearables for human assistance and augmentation can provide muscle support for lower and upper limbs (Galiana et al, 2012; Asbeck et al, 2014; Natali et al, 2019), decrease the metabolic cost of running and walking (Kim et al, 2019), provide haptic feedback (Hinchet et al, 2018; Takahashi et al, 2019)
We describe the first integration of Stretchable Pumps with thin McKibben Muscles
The TMM (Thin McKibben Muscles) used in this study are a modified version of the devices developed by the authors in previous works (Kurumaya et al, 2017; Koizumi et al, 2018; Suzumori et al, 2018; Abe et al, 2019)

Summary

Introduction

Soft wearables for human assistance and augmentation can provide muscle support for lower and upper limbs (Galiana et al, 2012; Asbeck et al, 2014; Natali et al, 2019), decrease the metabolic cost of running and walking (Kim et al, 2019), provide haptic feedback (Hinchet et al, 2018; Takahashi et al, 2019). Of the different classes of soft actuators, soft fluidic actuators are the most widely adopted for wearables, due to their robustness, simple fabrication, and high energy density These actuators generally consist of a chamber inflated with a pressurized fluid. Examples include bellows-shaped pneumatic actuators (“pneu-nets”) (Mosadegh et al, 2014; Yap et al, 2015), fiber-reinforced fluidic actuators (Polygerinos et al, 2014; Cacucciolo et al, 2016), and McKibben actuators (Wehner et al, 2013)

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