Optical Micro/Nanofiber Enabled Multiaxial Force Sensor for Tactile Visualization and Human–Machine Interface

Abstract

Abstract Tactile sensors with capability of multiaxial force perception play a vital role in robotics and human–machine interfaces. Flexible optical waveguide sensors have been an emerging paradigm in tactile sensing due to their high sensitivity, fast response, and antielectromagnetic interference. Herein, a flexible multiaxial force sensor enabled by U‐shaped optical micro/nanofibers (MNFs) is reported. The MNF is embedded within an elastomer film topped with a dome‐shaped protrusion. When the protrusion is subjected to vector forces, the embedded MNF undergoes anisotropic deformations, yielding time‐resolved variations in light transmission. Detection of both normal and shear forces is achieved with sensitivities reaching 50.7 dB N−1 (14% kPa−1) and 82.2 dB N−1 (21% kPa−1), respectively. Notably, the structural asymmetry of the MNF induces asymmetrical optical modes, granting the sensor directional responses to four‐directional shear forces. As proof‐of‐concept applications, tactile visualizations for texture and relief pattern recognition are realized with a spatial resolution of 160 µm. Moreover, a dual U‐shaped MNF configuration is demonstrated as a human–machine interface for cursor manipulation. This work represents a step towards advanced multiaxial tactile sensing.

Keywords

• directional response
• human–machine interface
• micro/nanofiber (MNF)
• multiaxial force
• optical sensor
• tactile visualization