FBG-FT-IMU: Multimodal Measurement System for Acupuncture Manipulation

The quantification of acupuncture manipulation relies heavily on kinematic and dynamic parameters, crucial for the advancement of acupuncture intelligence. Therefore, this article proposes a novel multimodal measurement system tailored for acupuncture manipulation. This system integrates fiber Bragg grating (FBG)-based force/torque sensors with an intelligent posture glove equipped with an inertial measurement unit (IMU), named FBG-FT-IMU. The force/torque measurement component utilizes three FBGs and achieves miniaturization (diameter: 5 mm), lightweight (0.7 g), and high precision (resolution: 0.019 N/0.009 N $\cdot $ mm) through clever elastic body design, mechanical modeling, finite-element analysis, and 3-D printing technology. Additionally, the accuracy of sensor creep and temperature compensation are 0.1% F.S. and 8% F.S., respectively. The intelligent posture glove, by analyzing the finger movement patterns of acupuncture manipulation, installs IMU sensors at corresponding joints to measure XYZ-axis angles, velocities, and accelerations during needling. The system can simultaneously collect 11 data points and has been tested on both simulated and real human skin, covering four conventional techniques. Furthermore, the system underwent classification testing of manipulation categories on multiple benchmark neural network models, demonstrating excellent accuracy. The highest accuracy of FBG-FT-IMU reached 0.9519, significantly surpassing the cases of using FBG-FT (0.7513) or IMU (0.9314) individually. These results underscore the effectiveness and superiority of the data collection system, emphasizing its significance in comprehensively quantifying the acupuncture manipulation employed by acupuncture practitioners.