Miniature Pneumatic Actuators for Soft Robots by High-Resolution Multimaterial 3D Printing

Miniature soft robots offer excellent safety and deformability, which are highly desirable in applications such as navigation in confined areas or the manipulation of microscale objects. However, it is difficult to manufacture such robots using traditional processes due to the complexity of their design. While rapidly advancing 3D printing technologies offer manufacturing flexibility, it is still challenging to fabricate soft pneumatic robots on millimeter scales due to the difficulty in making microscale voids and channels, which are essential for pneumatic actuation. A generic process flow for systematic and efficient tailoring of the material formulation and key processing parameters for digital light processing-based 3D printing of miniature pneumatic actuators for soft robots is presented. The process flow includes selection of photoabsorber and material performance characterization to determine the appropriate material formulation and characterizations for curing depth and XY fidelity to identify the combination of exposure time and sliced layer thickness. By applying the tailored results to a self-built multimaterial 3D printing system, an assortment of miniature soft pneumatic robots with various structures and morphing modes are printed. Furthermore, potential applications of printed miniature actuators are exemplified by a soft debris remover that navigates in a confined space and collects small objects in a hard-to-reach position.