Spatial Sensitivity Equalization of ERT-Based Robotic Skin Through Gauge Factor Distribution Optimization

Abstract

Electrical Resistance Tomography (ERT) has emerged as a promising technology for large-area robotic skin due to its ability to reconstruct pressure distribution over extensive regions using a few sparsely distributed electrodes. Despite ERT's potential to reconstruct the external forces applied on 3D surfaces, the uneven distribution of spatial sensitivity leads to significant errors in identifying the physical quantities of contacts, inhibiting this technique from being an effective tactile sensor. To address this issue, this paper proposes a method to equalize the spatial sensitivity by modulating the conductivity of ERT sensors through topology optimization. In a simulation environment, the sensor's conductive domain was converted into a binary image and optimized to equalize spatial sensitivity and reduce disparities between low and highsensitivity areas. Additionally, we present a sensor fabrication method with a complex optimized conductive patch pattern from simulation by applying screen printing techniques. The effectiveness of the implemented spatial sensitivity equalization was validated by comparing it to a conventional ERT sensor in both simulations and real-world environments. The proposed sensitivity optimization method expands the use of ERT-based sensors for distributed tactile sensing in physical human-robot interaction scenarios.