Model and Validation of a Highly Extensible and Tough Actuator based on a Ballooning Membrane

Abstract

Soft robots are known for their ability to comply and having superior extensibility. However, one of the limitations of most of these robots is that they can stand only a limited amount of load before buckling, and they feature a non-negligible initial height. Hybrid soft-rigid actuators seem to offer a trade-off between compliance and the amount of load they can withstand, but only a few simple models have been proposed to describe the behavior of these actuators. In this paper, we propose a design, model and experimental validation of a Hyperelastic Ballooning Membrane actuator (HBMA) which shows an extensibility higher than 179%, as well as an ability to stand more than 20 times its own weight. Two models, giving the dynamic behavior of the HBMA in terms of displacement and pressure, have been derived from different hyperelastic models (Neo-Hookean and Mooney-Rivlin) and compared in terms of accuracy and robustness. Finally, an example of a hybrid soft-rigid continuum ballooning robot built with HBMAs is presented and characterized experimentally.

Hyperelastic Membrane Actuators: Analysis of Toroidal and Helical Multifunctional Configurations

“…We introduce the concept of stacked Hyperelastic Ballooning Membrane Actuators (HBMAs) [ 26 ] in orchestrated 3D expansions, which can be realized using two configurations: helical ( Figure 3(e) ) and toroidal ( Figure 4(e) ). Membrane ballooning has been extensively researched in material and mechanical engineering [ 27 – 29 ], mainly in regard to phenomenon modeling and actuation technologies.…”

“…The modules with radial expansion capabilities are referred to as Radial Actuation Chambers (RACs). The exoskeleton can be a flat substrate [ 26 ] or 3D structure, but in this work, we will cover the latter. Based on the concept of stacked HBMAs and the previously described requirements, we designed two multimodal actuators (M2H-HBMAs), which conceptual design we describe next.…”

“…The AAC chambers were also radially constrained by a sheet of PET, used as a representation of the structural scaffold and generic geometric constraint of the target tubular organ. The displacements of the AACs were measured using the experimental setup from [ 26 ] ( Figure 7(b) ). The experiments were repeated six times.…”

“…For simplification, only the TA is shown in the diagrams, but the conditions were identical for the HA. Please find a more detailed description of the setup used in this set of experiments in [ 26 ].…”

How the Environment Shapes Tactile Sensing: Understanding the Relationship Between Tactile Filters and Surrounding Environment

“…Soft robots and soft sensors are manufactured in a very wide range of materials and elastomers ( Lee et al, 2017) , making it challenging to generalize the possible advantages and disadvantages obtained by the material’s choice in relation to tactile sensing. However, a recent attempt at creating a more solid framework for the field ( Marechal et al, 2021) highlighted that the vast majority of soft robots nowadays are manufactured using two main silicone rubber series: Ecoflex ( Smooth-On ), mainly used for extreme deformations and induced mechanical instabilities such as ballooning ( Herzig et al, 2021 ; Costi et al, 2022a) , and Dragon Skin ( Smooth-On ), used to create more solid structures and slower controlled deformations ( Gao et al, 2021) .…”