May 2, 2026 · physics.app-phJ/K move · Enter open · S save
Kaiping Yin, Sooik Im, Chaorui Qiu, Yun Bai+4
Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA. · Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA · Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA. · Department of Biostatistics and Bioinformatics, Duke University, Durham, NC 27710, USA. · Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA.
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.