An integrated design and fabrication strategy for entirely soft, autonomous robots

Abstract

Soft robots possess many attributes that are difficult, if not impossible, to realize with conventional robots composed of rigid materials. Yet, despite recent advances, soft robots still remain tethered to hard robotic control systems and power sources. New strategies for creating completely soft robots, including soft analogs of these crucial components, are needed to realize their full potential. Here, we report the first untethered operation of a robot comprised solely of soft materials. The robot is controlled with microfluidic logic that autonomously regulates the catalytic decomposition of an on-board monopropellant fuel supply. Gas generated from fuel decomposition inflates fluidic networks downstream of the reaction sites, resulting in actuation. The robot’s body and microfluidic logic are fabricated by molding and soft lithography, respectively, while the pneumatic actuator networks, on-board fuel reservoirs and catalytic reaction chambers needed for movement are patterned within the body via a multi-material, embedded 3D printing technique. The relevant length scales of fluidic and elastomeric architectures required for function spanned several orders of magnitude. Our integrated design and rapid fabrication approach enables the programmable assembly of multiple materials within this architecture, laying the foundation for completely soft, autonomous robots.