PalpAid: Multimodal Pneumatic Tactile Sensor for Tissue Palpation

TL;DR

PalpAid is a multimodal pneumatic tactile sensor designed to restore touch sensation in robot-assisted surgery by combining pressure and acoustic sensing for tissue characterization.

Contribution

It introduces a compact, easy-to-integrate tactile sensor that enhances sensory feedback in robotic surgery, addressing limitations of existing bulky sensors.

Findings

Successfully classified 3D-printed objects with different infills.

Demonstrated tissue identification with ex vivo tissues.

Proven robustness and compatibility with robotic systems.

Abstract

The tactile properties of tissue, such as elasticity and stiffness, often play an important role in surgical oncology when identifying tumors and pathological tissue boundaries. Though extremely valuable, robot-assisted surgery comes at the cost of reduced sensory information to the surgeon, with vision being the primary. Sensors proposed to overcome this sensory desert are often bulky, complex, and incompatible with the surgical workflow. We present PalpAid, a multimodal pneumatic tactile sensor to restore touch in robot-assisted surgery. PalpAid is equipped with a microphone and pressure sensor, converting contact force into an internal pressure differential. The pressure sensor acts as an event detector, while the acoustic signature assists in tissue identification. We show the design, fabrication, and assembly of sensory units with characterization tests for robustness to use, repetition cycles, and integration with a robotic system. Finally, we demonstrate the sensor's ability to classify 3D-printed hard objects with varying infills and soft ex vivo tissues. We envision PalpAid to be easily retrofitted with existing surgical/general robotic systems, allowing soft tissue palpation.