Optical Fiber Tactile Sensor Based on a Biocompatible Whisker- Inspired Transducer

Abstract

Bioinspired whisker transducers establish tactile sensing through elongated probes connected to base mechanoreceptors, providing minimally invasive access in robotic navigation environments and textural surveillance. However, the available electronic and optical transducers rely on the intricate processing of multiple measurement channels to decode the bending magnitude and direction from whisker arrays. Therefore, this article introduces a biocompatible, agar gel-made, vibrissa-like device with an optical fiber specklegram sensor embedded in its base. The hydrogel’s biodegradability, softness, and tailorable viscoelastic properties support its feasibility for biomedical applications. Furthermore, speckle pattern analysis performs fiber quasi-distributed assessment by evaluating the correlation coefficient regarding reference images acquired by a camera. Experiments reveal practical resolutions of ~0.7 mm and ~13° for displacement magnitude and direction, respectively, allowing for interrogating two vibrissae connected to a single fiber. Moreover, dynamic tests highlight the optical signal changes due to shape and textural effects. Such a biocompatible whisker enhanced by a sensitive and straightforward interrogation approach motivates future developments toward biomedical probes for intrabody surveillance and soft robotics.