Using Fiber Optic Bundles to Miniaturize Vision-Based Tactile Sensors

TL;DR

This paper introduces a miniaturized vision-based tactile sensor using fiber optic bundles, achieving high spatial resolution and force sensitivity in a small form factor suitable for robotic palpation tasks.

Contribution

The paper presents a novel fiber optic bundle design for tactile sensors, enabling a compact size of 15 mm diameter with high resolution and remote electronics, suitable for medical and robotic applications.

Findings

Sensor achieves 0.22 mm spatial resolution

Force resolution of 5 mN for normal and shear forces

Demonstrated effective prostate tissue palpation and discrimination

Abstract

Vision-based tactile sensors have recently become popular due to their combination of low cost, very high spatial resolution, and ease of integration using widely available miniature cameras. The associated field of view and focal length, however, are difficult to package in a human-sized finger. In this paper we employ optical fiber bundles to achieve a form factor that, at 15 mm diameter, is smaller than an average human fingertip. The electronics and camera are also located remotely, further reducing package size. The sensor achieves a spatial resolution of 0.22 mm and a minimum force resolution 5 mN for normal and shear contact forces. With these attributes, the DIGIT Pinki sensor is suitable for applications such as robotic and teleoperated digital palpation. We demonstrate its utility for palpation of the prostate gland and show that it can achieve clinically relevant discrimination of prostate stiffness for phantom and ex vivo tissue.