As a Master's student I spent a semester working at Carnegie Mellon University's Experimental Bio-Mechatronics Lab. where I worked on an assistive ankle orthoses. This was a new orthotic device that improves the walking efficiency of the wearer by actuating their ankle.

Ankle Orthoses

I designed the carbon fiber lateral brace supports that span from the knee to the ankle. When the orthoses drives the user's ankle the lateral supports transfer load from the foot to the lower leg. Thus, the supports had to withstand the large forces involved in helping push someone off the ground as they step. In addition, walking efficiency is adversely affected by additional mass on the legs, so the supports had to be as light as possible.

The evolution of the support. The final design can handle over twice the load of the initial design could and still weighs under 65 grams.

I went through a series of design iterations to improve the lateral brace support. I removed excess material while optimizing the geometry of the carbon fiber; I was able to reduce weight while still maintaining structural strength. I ran a series of FEA simulations for stress and displacement to guide my design decisions. By the end of the semester my design weighed just under 65 grams, but was still able to support a person as they walked.

Image Gallery

FEA simulations showing stress, exaggerated displacement, and factor of safety