Share Email Print

Proceedings Paper

Foot angle determination using conductive polymer sensors
Author(s): L. M. Castano; A. E. Winkelmann; A. B. Flatau
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

A study was carried out to assess the possibility of monitoring of joint angles, foot posture and foot motion through the use of conductive polymer sensors. The sensors are composed of a carbon polymer coating on an elastic fabric and they behave like strain gauges. A mechanically driven hinge was used to simulate joint motion by generating an angle change between its wings. A sensor strip was clamped longitudinally across the hinge in order for it to stretch when the angle between the wings increases. An electrogoniometer was used to monitor the angle spanned by the two wings of the hinge. Series of simultaneous measurements of angle and resistance were conducted at different speeds. Results indicate that a unique rate of change of voltage can be assigned to a specific angular velocity. This idea allows the tabulation of a database of voltages and time derivatives of voltages with corresponding angles and angular velocities. Angular velocity information was obtained by computing the derivatives of sensor output voltages in real time and comparing both voltage and their time derivatives to values in the database, with linear interpolation used as necessary. Angular displacement was then obtained by numerically integrating velocity information. Three carbon sensors were then applied on socks and were placed on different locations of maximum strain on the foot. Wireless data transmission was added in order to enable unhindered foot motion for future applications.

Paper Details

Date Published: 31 March 2010
PDF: 12 pages
Proc. SPIE 7647, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010, 76470Z (31 March 2010); doi: 10.1117/12.847679
Show Author Affiliations
L. M. Castano, Univ. of Maryland, College Park (United States)
A. E. Winkelmann, Univ. of Maryland, College Park (United States)
A. B. Flatau, Univ. of Maryland, College Park (United States)

Published in SPIE Proceedings Vol. 7647:
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010
Masayoshi Tomizuka, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?