Soft machines display shape adaptation to external circumstances due to their intrinsic compliance. To achieve increasingly more responsive behaviors upon interactions without relying on centralized computation, embodying memory directly in the machines' structure is crucial. Here, we harness the bistability of elastic shells to alter the fluidic properties of an enclosed cavity, thereby switching between stable frequency states of a locomoting self-oscillating machine. To program these memory states upon interactions, we develop fluidic circuits surrounding the bistable shell, with soft tubes that kink and unkink when externally touched. We implement circuits for both long-term and short-term memory in a soft machine that switches behaviors in response to a human user and that autonomously changes direction after detecting a wall. By harnessing only geometry and elasticity, embodying memory allows physical structures without a central brain to exhibit autonomous feats that are typically reserved for computer-based robotic systems.

The current fabrication and assembly of fluidic circuits for soft robots relies heavily on manual processes; as the complexity of fluidic circuits increases, manual assembly becomes increasingly arduous, error-prone, and timeconsuming. We introduce a software tool that generates printable fluidic networks automatically. We provide a library of fluidic logic elements that are easily 3D printed from thermoplastic polyurethanes using Fused Deposition Modeling only. Our software tool and component library allow the development of arbitrary soft digital circuits. We demonstrate a variable frequency ring oscillator and a full adder. The simplicity of our approach using FDM printers only, democratizes fluidic circuit implementation beyond specialized laboratories. Our software is available on GitHub (https://github.com/roboticmaterialsgroup/FluidLogic).

Abstract--Soft underwater robots typically explore bioinspired designs at the expense of power efficiency when compared to traditional underwater robots, which limits their practical use in real-world applications. A soft hydrostatic pressure sensor is configured as a bangbang controller actuating a swim bladder made from silicone balloons. Due to its simple design, low cost, and ease of fabrication using FDM printing and soft lithography, it serves as a starting point for the exploration of non-electronic underwater soft robots. A. Traditional Underwater Gliders Over the last several decades, underwater gliders have gained popularity among autonomous underwater vehicles (AUVs) [1], [2]. Compared to other AUVs, underwater gliders can achieve greater traveling distances, lower power consumption, and improved cost effectiveness.

Engineers have created an inflatable robot so nimble it can beat the classic Nintendo game Super Mario Bros. The machine, pioneered by Ryan Sochol, an assistant professor of mechanical engineering, and other researchers at the University of Maryland, resembles a three-fingered hand and uses an emerging technology called soft robotics to manipulate objects. Its movements are pressure controlled, powered by air and water instead of electricity, and are so precise that the robots can be modified to fit an array of prosthetics and biomedical devices. Typically constructed with malleable materials like rubber or silicone, soft robots have been used by hospitals and in manufacturing for years. Most look more like an octopus than a stiff android covered in wires, like C-3PO from Star Wars.