A Pillbug-Inspired Morphing Mechanism Covered with Sliding Shells

2025-06-05

AI Summary

Inspired by the hygroscopic curling behavior of pillbugs, this paper addresses the challenge of simultaneously achieving multimodal locomotion and structural protection in deployable robots. We propose a single-degree-of-freedom reconfigurable mechanism design that integrates a slider-crank with scissor-linkage actuation to enable autonomous, bidirectional switching between curling-rolling (downhill) and planar-straight (wheel-like) locomotion modes. For the first time, the pillbug’s morphological transition is abstracted into a three-segment continuous curve model, and a shell–mechanism co-design framework is established, incorporating a 3D curved sliding exoskeleton to concurrently ensure motion adaptability and physical shielding. Prototype validation demonstrates full-cycle morphological reversibility, single-actuator integrated mode transformation, and robust locomotion performance across both modalities. This work establishes a novel bioinspired paradigm for reconfigurable, multifunctional soft–rigid hybrid robots.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Machine Learning: Bio-inspired Learning
• Planning, Routing, and Scheduling: Replanning and Plan Repair

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Search and Retrieval-Augmented AI: Multilingual and cross-lingual Web search
• Web Mining and Content Analysis: Mining multimedia, multimodal, multilingual, cross-lingual Web data

Abstract

This research proposes a novel morphing structure with shells inspired by the movement of pillbugs. Instead of the pillbug body, a loopcoupled mechanism based on slider-crank mechanisms is utilized to achieve the rolling up and spreading motion. This mechanism precisely imitates three distinct curves that mimic the shape morphing of a pillbug. To decrease the degree-of-freedom (DOF) of the mechanism to one, scissor mechanisms are added. 3D curved shells are then attached to the tracer points of the morphing mechanism to safeguard it from attacks while allowing it to roll. Through type and dimensional synthesis, a complete system that includes shells and an underlying morphing mechanism is developed. A 3D model is created and tested to demonstrate the proposed system's shape-changing capability. Lastly, a robot with two modes is developed based on the proposed mechanism, which can curl up to roll down hills and can spread to move in a straight line via wheels.

Problem

• Design a pillbug-inspired morphing mechanism with sliding shells
• Reduce mechanism's DOF to one using scissor mechanisms
• Develop a robot with rolling and straight-line movement modes

Innovation

• Loop-coupled slider-crank mechanism for morphing
• Scissor mechanisms reduce DOF to one
• 3D curved shells protect and enable rolling