Optical and mechanical characterization of microfabricated optical bend loss sensor for distributive pressure measurement

Abstract

The paper describes the development of a mesh waveguide sensor capable of measuring pressure force at the plantar interface. The uniqueness of the system is in its batch fabrication process, which involves a microfabrication molding technique with poly(dimethylsiloxane)(PDMS) as the optical medium. The pressure sensor consists of an array of optical waveguides lying in perpendicular rows and columns separated by elastomeric pads. A map of normal stress was constructed based on observed macro bending which causes intensity attenuation from the physical deformation of two adjacent perpendicular waveguides. In this paper, optical and mechanical analysis of the bend loss will be presented. We will also present the results using a two-layer neural network system for force and image construction of fourteen different shape patterns and its corresponding four different applied forces.

Review of fiber-optic pressure sensors for biomedical and biomechanical applications

“…To address some limitations of the previous configuration (e.g., low spatial resolution, consistent and accurate manufacturing of the sensor, cost and noise) a batch process to fabricate PDMS-based waveguide sensor, and a neural network technique to provide an accurate description of the force distribution, were proposed in further studies. 206,218,219 After successful bench tests, the same group has recently presented a full-scale foot pressure/shear sensor, capable of measuring normal forces ranging from 19.09 to 1000 kPa. 220 …”

Fiber optic intensity-modulated sensors: a review in biomechanics

“…The minimum detectable vertical and shear forces were 0.4 N and 2.2 N (at 60º pitch angle), respectively. To address some limitations of the previous configuration (e.g., low spatial resolution, consistent and accurate manufacturing of the sensor, cost and noise), a batch process to fabricate Poly (dimethylsiloxane) (PDMS) as the optical medium, and a neural network technique to provide an accurate description of the force distribution were proposed [134,136,137]. After successful bench tests, the same group recently presented a full-scale foot pressure/shear sensor, capable of measuring normal forces ranging from 19.09 kPa to 1000 kPa [138].…”