A skin-like conformal sensor for real-time shape mapping

2026-05-01

AI Summary

Existing vision-based methods struggle to achieve reliable, real-time 3D deformation sensing due to line-of-sight occlusions and spatial constraints. This work proposes a skin-inspired flexible sensor that embeds a two-dimensional mirror-stacked array of oxidized eutectic gallium–indium (o-EGaIn) strain gauges within an elastomeric membrane. By integrating off-neutral-axis strain measurement, a mechanics-guided observation model, and a fast optimization algorithm, the system enables high-precision, real-time 3D shape reconstruction without requiring line-of-sight and conforming to arbitrary curved surfaces. A 5×5 sensor array with 12 mm spacing achieves an average reconstruction error of only 0.62 mm and a latency of 0.1 s across diverse deformations. The approach has been successfully demonstrated in applications including gesture recognition, tactile interaction, and intraoperative monitoring, overcoming longstanding limitations of conventional sensing in occluded and spatially confined environments.

Abstract

Reliable real-time 3D shape sensing is essential for robust control and interpretation of deformable systems during motion. Existing vision-based approaches require line-of-sight and complex instrumentation, limiting operation in occluded and space-constrained settings. Here, we introduce a scalable, skin-like sensor that reconstructs its continuous 3D deformation in real time from distributed strain measurements. The device embeds a 2D array of mirror-stacked, printed oxidized eutectic gallium-indium (o-EGaIn) strain gauges within an elastomeric film to measure off-neutral-axis strains. Combined with a mechanics-informed observation model and a fast optimization routine, the system estimates local curvature, elongation, offset, and orientation under concurrent stretching, bending, and indentation, enabling reconstruction of complex surfaces. A 5-by-5 array with a 12 mm pitch achieves a mean surface reconstruction error of 0.62 mm with 0.1s latency across all tested scenarios. When conforming to complex surfaces, the sensor provides fast 3D shape mapping of the underlying geometry. Demonstrations involving palm gesturing, finger indentation, and contact-induced balloon deformation highlight utility for epidermal motion tracking, haptic interaction, and intraoperative monitoring.

Problem

• 3D shape sensing
• deformable systems
• real-time sensing
• occluded environments
• space-constrained settings

Innovation

• conformal sensor
• real-time 3D shape sensing
• strain gauge array
• mechanics-informed modeling
• soft electronics