Development of a high resolution plantar pressure monitoring pad based on fiber Bragg grating (FBG) sensors

Abstract

Background: High importance is given to plantar pressure monitoring in the field of biomedical engineering for the diagnosis of posture related ailments associated with diseases such as diabetes and gonarthrosis.

Objective: This paper presents the proof-of-concept development of a new high resolution plantar pressure monitoring pad based on fiber Bragg grating (FBG) sensors.

Methods: In the proposed configuration, the FBG sensors are embedded within layers of carbon composite material (CCM) in turn conforming to an arc shape. A total of four such arc shaped sensors are instrumented in the pad at the locations of the forefoot and the hind foot. As a test of the pad, static plantar pressure is monitored on normal subjects under various posture conditions. The pad is evaluated both as a standalone platform as well as a pad inserted inside a standard shoe.

Results: An average pressure sensitivity of 1.2 pm/kPa and a resolution of approximately 0.8 kPa is obtained in this special configuration. The pad is found to be suitable in both configurations- stand-alone pad as well as an insert inside a standard shoe.

Conclusion: The proposed set up offers a cost-effective high resolution and accurate plantar pressure measurement system suitable for clinical deployment. The novelty of the developed pressure pad lies in its ability to be used both as platform type as well as inserted in-sole type sensor system.

Keywords: Fibre-Bragg grating (FBG); diabetic foot; in-sole; plantar pressure; pressure; pressure monitoring pad.