An FBG-based smart wearable ring fabricated using FDM for monitoring body joint motion

Abstract

This study proposed a new fiber Bragg grating-based smart ring for monitoring body joint postures occurred at elbow joint and knee joint positions. A single-mode fiber Bragg grating sensor was embedded into a 3D printed ring for sensing occurred deformation of the ring. The raw material used for fabricating the smart ring was polylactic acid, which was found to have the advantages of being flexible in nature and having ease of fabrication using fused deposition modeling method. The fabrication process of the fiber Bragg grating smart ring was characterized by the advantages of ease of handling, quick prototyping, high resolution, low cost, and time-saving. Bare fiber Bragg grating sensors were successfully embedded into hot printed polylactic acid material during the fused deposition modeling process, even the printing temperature of the printing nozzle exceeded 200℃. Two new smart wearable rings were fabricated and used to monitor systematic bend motion of elbow joint and knee joint. The measurement sensitivities of the two smart rings mounted at the elbow joint and knee joint were 0.0056 nm/° and 0.0276 nm/°, respectively. The corresponding maximum measurement angle within current calibration tests were 90° and 100°, respectively. The method of using both fiber Bragg grating and fused deposition modeling for sensor design can be extended for the fabrication of other sensors such as temperature sensors, strain sensors, pressure sensors, stress sensors, displacement sensors, and tilt sensors.

Fiber Bragg Gratings for Medical Applications and Future Challenges: A Review

“…For this reason, most of the studies for joint kinematics focused on the development and assessment of wearables based on FBGs [47]- [49] Usually, to improve their robustness and performances, FBGs have been housed into more flexible structures made of polymers such as Polyvinyl chloride -PVC [47]- [49], Dragon Skin™ silicone families [50], [51], polylactic acid -PLA [52], and Thermoplastic Polyurethane (TPU) [53]. Buttons, belts, Velcro® strips, and tapes have been used as bonding elements.…”

“…During jogging, the sensor mounted on the knee showed the highest values of strain and a signal amplitude reduction with speed. In this context, an innovative fabrication technique was proposed to develop a smart ring for knee and elbow joints in [52]. The FBGs were encapsulated in the system made of PLA during the printing process.…”

Sustainable Macromolecular Materials in Flexible Electronics

“…[ 176 ] On the other hand, PLA is preferred as the substrate or a protective material in sensor studies [ 203–205 ] due to its biodegradation feature. [ 206,207 ] This study examined only sensors that give electrical outputs. [ 208–210 ]…”

“…[176] On the other hand, PLA is preferred as the substrate or a protective material in sensor studies [203][204][205] due to its biodegradation feature. [206,207] This study examined only sensors that give electrical outputs. [208][209][210] Although PLA is not preferred as a transistor material, there are studies in the literature under the title of electrochemical organic transistors.…”

Curvature prediction of long‐period fibre grating based on random forest regression

“…During the bending process of the LPFG, the mode field distribution of the core fundamental and cladding modes change, subsequently changing the coupling coefficient between them. In recent years, many optical fibre curvature sensors based on different optical devices have been proposed, such as LPFG [10][11][12][13][14][15], FBG [16,17], multi-core fibre [18,19], photonic crystal fibre [20,21] and fibre tapers [22] etc. In terms of curvature measurement of LPFG, Zhang et al [10] designed an arch-shaped LPFG that detects vector bending in two orthogonal directions.…”