M3D-skin: Multi-material 3D-printed Tactile Sensor with Hierarchical Infill Structures for Pressure Sensing

TL;DR

The paper addresses the need for accessible, easily fabricable tactile sensors suitable for integration in robots and wearables. It introduces M3D-skin, a multi-material FDM 3D-printed tactile sensor that uses hierarchical infill patterns to convert pressure into resistance change. The authors show how the sensor structure, layer count, and infill pattern tune sensitivity and dynamic range, validate a 4-tile and a 6-tile embodiment, and demonstrate applications on a robotic hand and a foot-sole. This approach enables low-cost, customizable tactile sensing with rapid prototyping and seamless integration, advancing practical deployment of tactile feedback in complex systems.

Abstract

Tactile sensors have a wide range of applications, from utilization in robotic grippers to human motion measurement. If tactile sensors could be fabricated and integrated more easily, their applicability would further expand. In this study, we propose a tactile sensor-M3D-skin-that can be easily fabricated with high versatility by leveraging the infill patterns of a multi-material fused deposition modeling (FDM) 3D printer as the sensing principle. This method employs conductive and non-conductive flexible filaments to create a hierarchical structure with a specific infill pattern. The flexible hierarchical structure deforms under pressure, leading to a change in electrical resistance, enabling the acquisition of tactile information. We measure the changes in characteristics of the proposed tactile sensor caused by modifications to the hierarchical structure. Additionally, we demonstrate the fabrication and use of a multi-tile sensor. Furthermore, as applications, we implement motion pattern measurement on the sole of a foot, integration with a robotic hand, and tactile-based robotic operations. Through these experiments, we validate the effectiveness of the proposed tactile sensor.

Figures (11)

• Figure 1: Overview of this study. The upper section illustrates the 3D-printed tactile sensor, M3D-skin, including its structure and internal infill pattern. The lower section presents application examples of the sensor.
• Figure 2: The structure of M3D-skin. The upper part of the sensor performs sensing through a layered structure composed of conductive and non-conductive filaments. The lower part of the sensor includes wiring layers, which connect to the circuit.
• Figure 3: The structure of the sensor layer: (A) The sparse infill sensing layer, and (B) The solid infill layers above and below the sensing layer. The sparse pattern structure utilizing infill in (A) is illustrated in the top-right of the figure, showing both the overall shape and the shape of each layer. The lower section presents the printed results of (A) and (B).
• Figure 4: The structure of the wiring layer. It connects the upper and lower infill layers of the sensor layer to the terminals. The resistance between the terminals is the sum of the resistance of the infill layers, wiring, and sensor layer. The lower section of the figure shows wiring examples for a single-tile sensor and a four-tile sensor.
• Figure 5: Illustration of the sensor principle, showing how the infill structure deforms under compression.