EIT-Pneumatic Hybrid Robotic Skin for Practical and Accurate Force Map Reconstruction

2026-05-27

AI Summary

This study addresses the challenges of non-uniform sensitivity and low force reconstruction accuracy in conventional electrical impedance tomography (EIT) for large-area tactile sensing. To overcome these limitations, the authors propose a novel hybrid robotic skin that integrates EIT with pneumatic tactile sensing, fabricated via 3D printing and spray coating to ensure low cost and scalability. By combining Tikhonov regularization-based inverse reconstruction with a single-pad pneumatic calibration strategy, the method significantly reduces sensitivity non-uniformity—evidenced by a decrease in the coefficient of variation from 0.31 to 0.14—and enables consistent, high-fidelity force distribution reconstruction across the entire sensing area. The system’s robust multi-contact perception capability is validated on a humanoid robot’s chest plate, demonstrating its potential as a practical and scalable tactile solution for full-body somatosensory robotics.

Abstract

We present a hybrid robotic skin that combines electrical impedance tomography (EIT) with pneumatic tactile sensing to improve force reconstruction capability. The developed robotic skin is fabricated entirely by 3D printing and spray coating, making it affordable and easy to build. A Tikhonov-regularized inverse reconstruction, paired with per-pad pneumatic calibration, enables accurate large-area tactile sensing with a simple measurement scheme. For validation, we conducted load-cell indentation experiments; the results showed consistent force reconstruction across locations within a pad. Compared with an EIT-only baseline, sensitivity non-uniformity was also reduced, with the coefficient of variation decreasing from 0.31 to 0.14, indicating that the proposed approach addresses a longstanding limitation of EIT. We further demonstrated chest-mounted integration on a humanoid robot and found that the pneumatic signals remained reliable across diverse contact scenarios, including multiple simultaneous contacts on the same sensing pad. These results indicate a practical path toward accurate, scalable whole-body tactile sensing in real robotic systems.

Problem

• force reconstruction
• electrical impedance tomography
• tactile sensing
• sensitivity non-uniformity
• robotic skin

Innovation

• EIT-pneumatic hybrid
• force map reconstruction
• 3D-printed robotic skin
• Tikhonov regularization
• whole-body tactile sensing