Liquid Manipulator with Printed Electrode Patterns for Soft Robotic Systems

Abstract Soft robots are able to safely operate in a dynamically evolving or highly unstructured environment by virtue of their inherited compliance. Among the available actuation methods for soft robotics, fluid‐driven is frequently preferred due to holistic design considerations that enable multipurpose yet straightforward mechanical solutions to complicated issues. The motion of a soft fluid‐driven robotic system usually relies on the flow of its internal fluid, however, existing fluid pumps only enable a single linear flow, which severely hinders the integrated multifunctional design of soft robots. Herein, a class of liquid manipulator is proposed based on electrohydrodynamic (EHD) effect, which consists of a flexible substrate with a printed planar electrode pattern. By streamlining the electric field distribution via electrode pattern, the liquid manipulator can manipulate the fluid flow, allowing fluid to perform multiple movement behaviors, including tangential, radial, and linear motions. These liquid manipulators are fabricated by printing planar electrode patterns onto flexible substrates using the digital printing method, in which both the printed electrodes and substrate are flexible and bendable. These liquid manipulators are flexible, fast‐response, thin, lightweight, and scalable, which can be easily embedded into soft fluidic systems with insignificant footprint and weight and actuate their rapid movements. Three liquid manipulators are embedded into a continuously rotating motor, focus‐tunable liquid lens, and soft linear actuator to achieve their multiple motions, i.e., continuous rotation, radial motion, and linear motion, illustrating broad potential of liquid manipulators in soft robotic systems.