ZipFold: Modular Actuators for Scaleable Adaptive Robots

2026-04-06

AI Summary

This work addresses the limitations of existing morphing robots, which often rely on custom mechanisms that hinder modularity, scalability, and cross-task reusability. The authors propose a compact actuator based on flexible 3D-printed plastic strips that uniquely integrates folding and zipper-like deployment mechanisms, enabling continuous and reversible transitions between a compliant contracted state and a quasi-rigid expanded state. This design facilitates concurrent control over both stiffness and scale while supporting modular integration. The mechanical performance of the actuator is experimentally characterized, and a four-module adaptive walking robot prototype is developed to demonstrate effective morphological reconfiguration and stiffness modulation. The approach establishes a new paradigm for building versatile, reconfigurable soft robotic systems.

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.

Problem

• shape-changing robots
• modular actuators
• scalability
• reconfigurability
• adaptive robotics

Innovation

• modular actuator
• deployable structure
• stiffness adaptation
• zip-fold mechanism
• 3D-printed robotics