3D-Printed Hydraulic Fluidic Logic Circuitry for Soft Robots

Abstract

The confluence of soft robotics and fluidic logic have sparked innovations in integrated robots with superior flexibility and potential machine intelligence. However, current fluidically driven soft robots suffer from either a large number of input controlling devices, or limited driving power. Here, we propose a hydraulic fluidic logic circuitry for liquid driven soft robots, leveraging 3D printing technologies. The fundamental building blocks of the system are hydraulic normally-on and normally-off logic gates, namely NOT and AND, along with a multi-connected channel structure functioning as OR. Using minimal-input design principles, the XOR gate can be simplified to only two valves, and used to construct a sensor-free error detector. The design principle can also be extended to full adders, as well as amplifiers, which can greatly improve the flow efficiency of the system. Additionally, taking advantage of the incompressible nature of liquid and optimized logic circuitry using the minimal-input design principle, we present a quadruped soft robot integrated with combinational fluidic logic, realizing bidirectional turtle-like locomotion, controlled by only two inputs. The robot is capable of walking under heavy load and performing controllable underwater locomotion. This hydraulic fluidic soft robotic system utilizes a small number of inputs to control multiple distinct outputs, and alters the internal state of the circuit solely based on external inputs, holding significant promises for the development of microfluidics, fluidic logic, and intricate internal systems of untethered soft robots with machine intelligence.