A fiber Bragg grating based sensing platform fabricated by fused deposition modeling process for plantar pressure measurement

Fused deposition modeling (FDM) is an important technology for 3D printing and can be used for rapidly production of functional parts. This paper presents a fiber Bragg grating (FBG) based sensing platform fabricated using FDM method. This sensing platform include a number of pressure sensing components fabricated by layering of extruded Polylactic Acid (PLA) materials. FBG sensors were fixed at center of each sensing component for pressure measurement. Performance of the sensing system was calibrated by applying step by step load on FBG pressure sensors. After calibration, this sensing platform was used to monitor plantar pressure distribution arise from weight gaining and losing processes of a female subject. It is found that plantar pressure of heel is almost twice the pressure magnitudes of both the first and second metatarsus (fore-foot), while there is limited pressure at the mid-foot position during weight gaining process. Pressures of the two metatarsus areas are around 50% (pressure ratio) of heel position and decrease continuously as the increase of subject weight, but weight losing process has very limited influence on this pressure ratio. Center of gravity of this female subject was also found to shift backward substantially during weighting gaining process. Therefore, protection of the heel position is highly important during both weight gaining and losing processes due to the presence of significant pressure concentration.