1 August 2003 A flexible micromachined optical sensor for simultaneous measurement of pressure and shear force distribution on foot
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Lower limb complications associated with diabetes include the development of plantar ulcers that can lead to infection and subsequent amputation. While it is known from force plate analyses that there are medial/lateral and anterior/posterior shear components of the ground reaction force, there is little known about the actual distribution of this force during daily activities, nor about the role that shear plays in causing plantar ulceration. Furthermore, one critical reason why these data have not been obtained previously is the lack of a validated, widely used, commercially available shear sensor, in part because of the various technical issues associated with shear measurement. Here we have developed novel means of tranducing plantar shear and pressure stress via a new microfabricated optical system. The pressure/shear sensor consists of an array of optical waveguides lying in perpendicular rows and columns separated by elastomeric pads. A map of pressure and shear stress is constructed based on observed macro bending through the intensity attenuation from the physical deformation of two adjacent perpendicular optical waveguides. The uniqueness of the sensor is in its batch fabrication process, which involves injection molding and embossing techniques with Polydimethylsiloxane (PDMS) as the optical medium. Here we present the preliminary results of the prototype. The sensor has been shown to have low noise and responds linearly to applied loads. The smallest detectable force on each sensor element based on the current setup is ~0.1 N. The smallest area we have resolved in our mesh sensor is currently 950x950μm2
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Wei-Chih Wang, Wei-Chih Wang, Reynold R. Panergo, Reynold R. Panergo, Christopher M. Galvanin, Christopher M. Galvanin, William Ledoux, William Ledoux, Bruce Sangeorzan, Bruce Sangeorzan, Per G. Reinhall, Per G. Reinhall, } "A flexible micromachined optical sensor for simultaneous measurement of pressure and shear force distribution on foot", Proc. SPIE 5047, Smart Nondestructive Evaluation and Health Monitoring of Structural and Biological Systems II, (1 August 2003); doi: 10.1117/12.483932; https://doi.org/10.1117/12.483932

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