Wearable macro-bend optical fiber sensor for biomechanical motion evaluation.

• Wearable Optical Fiber Sensor based macro-bending loss for Biomechanical Motion Evaluation. • A U-shaped fiber sensor has been integrated into elbow and knee joint phantoms and measuring its response to various elbow and knee joint movements in the range of 0°-90°. • The recorded sensing data revealed an extra sensitivity of −0.457 nm/° with linear regression coefficients of more than 98.7 % for elbow flexion angle and a 0.506 nm/° sensitivity with a high linear regression coefficient of ∼ 99.6 % for knee flexion angle. • The proposed sensor exhibits a high sensitivity which it significantly improves the optical sensing signal to more than 5.5 times in correspondence with many previous published works. The biocompatibility and other unique physical properties of optical fibers reflect their potential for use in biomechanical motion sensing. In this paper, a wearable macro-bending structure fiber sensor has been fabricated and its potential is demonstrated for observing key motions during physical therapy for patients with joint stiffness. The sensor's performance has been evaluated by integrating it into elbow and knee joint phantoms and measuring its response to various elbow and knee joint movements in the range of 0°-90°. The recorded sensing data revealed the extra sensitivity of −0.457 nm/° with linear regression coefficients (R2) of more than 98.7 % for elbow flexion angle and a 0.506 nm/° sensitivity with a high linear regression coefficient (R2) of ∼ 99.6 % for knee flexion angle. Additionally, good reproducibility and swift response facility were demonstrated during the experiment, indicating that the designed sensor possesses enormous potential in terms of different body motion monitoring applications, even subtle ones. The results show that the sensor's high sensitivity leads to a very good correlation between the sensor's output and the actual elbow joint movement. [ABSTRACT FROM AUTHOR]