Multi-Layer LDPE Pouch Robots Enabled by Inkjet-Printed Masking Layers

Abstract

Inflatable pouches are attractive as actuators and structural links in soft robots due to their low deflated profile and high deformation ratio. However, current pouch robot fabrication methods have relatively large minimum feature sizes and multi-layer fabrication challenges, limiting the integration of mechanisms with many independent degrees of freedom (DoF). A new monolithic prototype fabrication method utilizes inkjet printing of a masking ink layer, which prevents film bonding and thus defines inflatable regions. Multi-layer inflatable pouches of any planar geometry can be created using thermal fusing, with inter-layer connections and a minimum feature resolution of 0.3 mm. The multi-layer fabrication process enables the integration of pouches for bending actuation and structure, pneumatic channels, and external port connections. This high level of integration enables the fabrication of pouch robots with many independent DoFs. Specific examples using four layers of 38 micrometer thick Low-density polyethylene (LDPE) include 1) a 38 mm-wide 4-fingered robot hand with 8 independent DoFs which rotates a cube within its palm and 2) a 138 mm-long planar continuum manipulator with 10 independent DoFs for pick-and-place of a cylinder. These example designs demonstrate the capability of ink-patterned masking to achieve new levels of functionality for thin-film pouch robots.