Prótese em fibra de carbono para pé com integração de sensores ópticos FBG

Abstract

The sensors based on optical fibers Bragg gratings have significant applications in the area of biomechanics, due to its characteristics of high sensitivity to mechanical stresses, lightness, ease of multiplexing of sensors, and immunity to electromagnetic interference. The sensor also has high integration with composites of epoxy polymer matrix. The prospect of fabrication of carbon fiber prostheses with this sensor can enable real-time monitoring of prosthesis user. This system can favor the best fit the prosthesis to body, anticipating dysfunctions and preventing future injuries, especially in hips and spine. This work describes the constructive aspects, and the analyzes of the characterization study of a foot carbon fiber prosthesis instrumented with commercial FBG sensors. It is analyzed 9 sensors arranged in the form of a 3 x 3 matrix in the coronal and sagittal planes. In this way the sensors mesh comprises the anterior to posterior region and the medial to lateral region. Responses of the sensors to the gait are presented at speeds of 1.5 km/h and 3.5 km/h, with adaptation for non-amputated user. The relationship between the response of the sensors and the phases of the gait during the entire support phase is discussed and demonstrated. Thermal tests are also described for the analysis of FBG's chirp formation during the curing process of the composite material, which showed a maximum enlargement of 20% and a mean of 15% of the spectrum. This work validates the concept of FBG sensors application in carbon fiber foot prostheses, allowing new approaches in studies applied to the improvement of prostheses with detections of gait inadequacy outside clinic environments.