P13002: Ankle-Foot Orthotic Un-Tethered, Mechanical


Project Summary Project Information

For an updated project description, click on the following link for the Project Readiness Package.

Foot drop, or the inability to dorsiflex the foot (i.e., point your toe upward) is a fairly common lasting side-effect of a stroke, affecting approximately 20% of stroke survivors (~1.3 million people each year). Foot drop can also occur as a side effect of ALS (Lou Gherig's Disease), Multiple Sclerosis, or injury to the peroneal nerve, increasing the number of people affected. Many current AFOs, particularly those used by people who need significant foot support, are either rigid or constrain the user's motion in ways that force unnatural gait. Commercially available AFOs are only capable of pointing the user’s foot up when off the ground. These passive devices do not allow users to safely move down inclines or stairs as the user’s foot will always be pointed upwards when off of the ground.

The development of an active AFO that utilizes a terrain sensing system has been produced by an MS student, Christopher Sullivan. This project intends to use the terrain sensing system in order to accommodate the user’s foot to upcoming terrain. This device will utilize an integrated micro-controller to interpret terrain data and a torque device to rotate the user’s foot to the desired position throughout the gait cycle.

Beginning in the fall of 2012, there will be 2 senior design teams developing Active AFOs that utilize the terrain sensing system. The scope of the Active Ankle-Foot Orthotic: Tethered team will be to design an active AFO equipped with air muscles as a foot actuation device. Because air muscles require high amounts of energy to contract, the system will be tethered to an air supply. Electrical power, and a connection to a computer for data processing will also be provided via the tethering device. The value of developing a tethered system would be to rehabilitate stroke patients just after incidents in which case they need help learning how to walk with a foot drop condition.

The scope of this project, the Active Ankle-Foot Orthotic: Untethered Non-Air Muscle, will be to design an active AFO in parallel to that of the tethered system. In order to make the device usable all day, a different torque mechanism will be required other than air muscles. The AFO device will utilize an onboard micro-controller to interpret sensor data. A battery will be used to power the sensors, micro-controller, and torque device, if necessary. This device will be useful for users with foot drop to wear on a day to day basis.

Future projects include Active Ankle-Foot Orthotic: Air Muscle Un-Tethered. This device will incorporate an un-tethered air muscle powered system that utilizes the onboard control system. Air power will be provided by a compressed air tank stored on the AFO unit. The Active Ankle-Foot Orthotic: device will use a non-rigid, form fitting structure that rotates the foot in the most natural way.

degree=90|Current AFO
Project Name
Ankle-Foot Orthotic Un-Tethered, Mechanical
Project Number
Project Family
Assistive devices
Start Term
End Term
Faculty Guide
Dr. DeBartolo, eademe@rit.edu
Primary Customer
Dr. DeBartolo, eademe@rit.edu
Sponsor (financial support)
National Science Foundation, Texas Instruments


Team Members

From Left: Dana, Rob, John, Sam, Shane, Pattie

From Left: Dana, Rob, John, Sam, Shane, Pattie

Member Role Major Contact
Patricia Schiotis Team Manager Mechanical Engineer pjs8419@rit.edu
Shane Reardon Lead Engineer Mechanical Engineer scr9488@rit.edu
Dana Kjolner Engineer Electrical Engineer dfk2645@rit.edu
Robert Ellsworth Engineer Electrical Engineer rxe8657@rit.edu
Sam Hosig Engineer Computer Engineer sgh1896@rit.edu
John Williams Engineer Computer Engineer jcw4429@rit.edu

Table of Contents


Planning & Execution

Systems Design

Detailed Design

Project Review

Photo Gallery

Planning & Execution

Build, Test, Document

Project Review

Photo Gallery

Final Presentation

Technical Paper



This material is based upon work supported by the National Science Foundation under Award No. BES-0527358. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.