Muscle-fiber array inspired, multiple-mode, pneumatic artificial muscles through planar design and one-step rolling fabrication

Abstract

Although the advances in artificial muscles enable creating soft robots with biological dexterity and self-adaption in unstructured environments, producing scalable artificial muscles with multiple-mode actuations is still elusive. Inspired by muscle-fiber arrays in muscular hydrostats, we present a class of versatile artificial muscles, called MAIPAMs (Muscle-fiber Array Inspired Pneumatic Artificial Muscles), capable of multiple-mode actuations (such as parallel elongation-bending-spiraling actuations, parallel 10 bending actuations, and cascaded elongation-bending-spiraling actuations). Our MAIPAMs mainly consist of active 3D elastomer-balloon arrays reinforced by a passive elastomer membrane, which is achieved through a planar design and one-step rolling fabrication approach. We introduce the prototypical designs of MAIPAMs and demonstrate their muscle-mimic structures and versatility, as well as their scalable ability to integrate flexible while un-stretchable layers for contraction and twisting actuations and compliant electrodes for self-sensing. We further demonstrate that this class of artificial muscles shows promising potentials for versatile robotic applications, such as carrying a camera for recording videos, gripping and manipulating objects, and climbing a pipe-line.

Soft and lightweight fabric enables powerful and high-range pneumatic actuation

“…Unlike conventional silicone-based pneumatic actuators with hard-to-compress, thick structures, the fabric chambers can be readily compressed into a flat sheet, making it possible to laminate multiple chambers with different motion modes layer by layer. In this way, rapid reconfiguration can be achieved through one actuator by selecting different chambers to inflate, which, in conventional actuators, typically requires radially spacing multiple actuators or manual assistance (22)(23)(24). Multi-df dexterous motion and reconfiguration have long been highly desirable features for soft robots.…”

“…Among many actuation methods (e.g., electrical, thermal, optical, and magnetic) (12)(13)(14)(15)(16)(17)(18)(19), pneumatic-driven soft actuators have garnered considerable attention for their simple and safe operation features, low cost, and ease of fabrication. These actuators comprise a cephalopod-liked structure entirely constructed from elastomeric materials (e.g., silicone rubber) and come equipped with pneumatic channels that provide various deformation modes upon pressure (20)(21)(22)(23)(24). Although these modes of deformation are dexterous and safe for interaction, their load-bearing and load-carrying capabilities are seriously compromised by the intrinsic stretchability of the rubbery materials.…”

Fabrication and Functionality Integration Technologies for Small‐Scale Soft Robots

“…[35,103,104] Inextensible parts (papers or fibers) are also frequently adopted in casting to restrain extension in certain directions, thereby leading to the stretching, bending, and curling of soft robots. [43,[105][106][107] For soft robots that have complex inner structures, detachable modular molds are suggested for the convenience of demolding. [108] With supplementary techniques such as lamination casting, retractable pin casting, and lost wax casting, [109] casting enables the fabricating of most of soft robots.…”

Bioinspired helical-artificial fibrous muscle structured tubular soft actuators

“…Looking into natural tubular actuators for inspiration in addressing this challenge, we noticed that the 3D fibrous architectures of trunks of elephants, the entirely soft tubular actuators without the assistance of bones and joints featuring a closely packed 3D array of muscle fibers can well define their DOF (well known as muscle hydrostats; Fig. 1A) ( 16 ), which enables remarkably diverse, complex, and highly controlled shape transformations ( 17 , 18 ). For elephant trunks, muscle fibers are directionally arranged and winded around the trunk’s long axis to form the tubular muscle layer (Fig.…”