Reconfigurable Auxetic Devices (RADs) for Robotic Surface Manipulation

2025-11-24

AI Summary

Conventional robotic surface materials—exhibiting positive Poisson’s ratios—suffer from poor adaptability and inability to achieve multi-directional cooperative deformation. To address this, we propose a reconfigurable auxetic lattice structure incorporating a backlash-coupled mechanism with intentional gaps, enabling active, controllable bidirectional deformation (contraction and expansion) while preserving structural compliance. Our approach integrates embedded servo actuation, underactuated control strategies, and unit-level dynamic modeling, augmented by activation functions that emulate cellular-like responsive behavior. Experimental results demonstrate versatile multimodal surface deformation, with strong agreement between model predictions and physical measurements. This work overcomes key limitations of conventional auxetic materials in adaptive interfaces—namely, limited deformability control and single-mode responsiveness—establishing a new paradigm for intelligent robotic surfaces that simultaneously offers programmability, local tunability, and high conformability.

Technology Category

• Intelligent Robots: Manipulation
• Natural Language Processing: Safety and Robustness
• Cognitive Modeling & Cognitive Systems: Adaptive Behavior

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems

Abstract

Robotic surfaces traditionally use materials with a positive Poisson's ratio to push and pull on a manipulation interface. Auxetic materials with a negative Poisson's ratio may expand in multiple directions when stretched and enable conformable interfaces. Here we demonstrate reconfigurable auxetic lattices for robotic surface manipulation. Our approach enables shape control through reconfigurable locking or embedded servos that underactuate an auxetic lattice structure. Variable expansion of local lattice areas is enabled by backlash between unit cells. Demonstrations of variable surface conformity are presented with characterization metrics. Experimental results are validated against a simplified model of the system, which uses an activation function to model intercell coupling with backlash. Reconfigurable auxetic structures are shown to achieve manipulation via variable surface contraction and expansion. This structure maintains compliance with backlash in contrast with previous work on auxetics, opening new opportunities in adaptive robotic structures for surface manipulation tasks.

Problem

• Develop reconfigurable auxetic lattices for robotic surface manipulation.
• Enable shape control via underactuated structures with unit cell backlash.
• Achieve variable surface conformity through adjustable contraction and expansion.

Innovation

• Reconfigurable auxetic lattices enable shape control
• Variable expansion via backlash between unit cells
• Underactuated structure with reconfigurable locking or servos