A Novel Fiber Bragg Grating Three-Dimensional Force Sensor for Medical Robotics

Abstract

This article introduces a novel Fiber Bragg Grating (FBG) 3-D force sensor designed for the end-effectors of medical robots. The sensor incorporates a specially designed layered elastic structure, achieving miniaturization, structural self-decoupling, and high-sensitivity 3-D force measurement through a cleverly compact spatial design and a reasoned layout of 5 FBGs. The construction of the theoretical model successfully decouples temperature and force. Simulation experiments determine the sensor's operational frequency range to be 0–403.6 Hz, validated through rapid prototype verification using 3-D printing technology. Static experiments reveal that the sensor's maximum measurement range and minimum resolution are <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula>5 N and 4.95 mN, respectively. The maximum sensitivity and minimum interaxis coupling are determined to be 201.86 pm/N, 0.01%F.S.(Fy–Fz), respectively. In dynamic experiments, The minimum tracking error is 3.89% F.S and successfully adapts to the end-effector of a robotic arm. Remarkably, the sensor excels in force detection during medical palpation and acupuncture procedures, validating its effectiveness and practicality in real-world applications. This study presents a reliable and high-performance end-effector force-sensing solution for the field of medical robotics.