Final Post

Hello everyone,

It has been a great summer, but sadly it now has come to an end. Going into my project summary, the purpose was to create a hydraulic powered Ankle-Foot Orthosis (AFO) that would be able to emulate any passive AFO. This would allow the practitioner to prescribe the correct passive AFO to a patient within one clinical visit. At the final stages of the project, my role was to make sure the hydraulic AFO would indeed emulate any passive AFO with a range of [0-4 Nm/degree]. To accomplish this, I used various Data acquisition hardware and software along with a Bi-articular Reciprocating Universal Compliance Estimator (BRUCE) to test the apparatus. BRUCE uses a force sensor located on a metal segment that would represent a leg, an angle sensor is also located within a metal segment that would represent an ankle. The data inputted to the computer is the torque applied on the "foot", and the angle displacement. The data gathered was then analyzed through a Matlab script that outputted an averaged stiffness coefficient for each set of data. The problem encountered was that there was a huge variance between the measured and input stiffness. This was due to the elasticity of the bottom shoe platform used within the hydraulic AFO. To compensate for this a variance equation was acquired by creating a linear relationship between the calculated error and the input stiffness. A linear equation for this relationship was acquired, and was added to the command script in the Arduino software, which was the software used to control the system. From here a 65 trial test was performed on the hydraulic AFO and an average error of 2.84% was calculated. This falls within the [0-5%] range needed to consider the hydraulic AFO successful. The next step in this project would be to test it on human subjects and make any minor adjustments to maximize comfort. Also, the next step would be to modify the system and implement an algorithm that would help come up with the most effective passive AFO design according to its application. Altogether this was a great project, and I will be leaving with increased knowledge on hydrolic systems and their applications on bio-medical devices. My advice to any REU entering the research environment is to have as much communication as they can with their adviser and their grad student. They are the ones whom you will learn the most from, but also try things on your own, don't rely on them to solve most of your problems. 

Have a great day guys! It was awesome getting to know you all this summer!