Compact Multilayer Extension Actuators for Reconfigurable Soft Robots.

Soft robotic pneumatic actuators generally excel in the specific application they were designed for but lack the versatility to be redeployed to other applications. This study presents a novel and versatile soft compact multilayer extension actuator (MEA) to overcome this limitation. We use the MEA linear output in different hybrid configurations to achieve this versatility. The unique design and fabrication of the MEA allow for a compact elastomeric actuator with innate tension, capable of reverting to its initial state without the need for external stimulus. The MEA is made from alternating elastomers with different Young's modulus, bestowing the MEA with high durability, force, and extension capabilities. In addition, the MEA is lightweight at 4 g, capable of a high force-to-weight ratio of 1000 and an extension ratio of 525%. We also explored varying the MEA parameters, such as its material and dimension, which further enhance its properties. Subsequently, we showed four different design configurations encompassing the MEA to produce four basic motions, that is, push, pull, bend, and twist. Finally, we demonstrated three possible hybrid configurations for manipulation, locomotion, and assistive applications that highlight the versatility, manipulability, and modularity of the MEA.