ZipFold: Modular Actuators for Scaleable Adaptive Robots

TL;DR

This paper presents ZipFold, a modular, scalable actuator using folding and zipping of 3D-printed plastic strips to enable reversible shape and stiffness changes for adaptive robots.

Contribution

Introduction of a simple, scalable, and reconfigurable actuator mechanism based on folding and zipping for shape-changing robotic applications.

Findings

Achieves reversible scale and stiffness transformations.

Enables smooth transitions between flexible and rigid states.

Demonstrated in a four-module adaptive walking robot.

Abstract

There is a growing need for robots that can change their shape, size and mechanical properties to adapt to evolving tasks and environments. However, current shape-changing systems generally utilize bespoke, system-specific mechanisms that can be difficult to scale, reconfigure or translate from one application to another. This paper introduces a compact, easy-to-fabricate deployable actuator that achieves reversible scale and stiffness transformations through compound folding and zipping of flexible 3D-printed plastic strips into square-section deployable beams. The simple actuation method allows for smooth, continuous transitions between compact (flexible) and expanded (quasi-rigid) states, facilitating diverse shape and stiffness transformations when modules are combined into larger assemblies. The actuator's mechanical performance is characterized and an integrated system involving a four-module adaptive walking robot is demonstrated.