Most people do not question walking, or how exactly the body functions to accomplish daily movements, but amputees cope with the struggles of walking and the use of prosthetic limbs everyday.

Xiangrong Shen, assistant professor of mechanical engineering, is working to develop better ankle technology in prosthetic limbs, as the ankle produces more energy needed for walking that both the knee and hip joints.

After receiving a grant of $564,000 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Shen teamed up with fellow researchers at Vanderbilt and the Georgia Institute of Technology to begin working on the ankle.

Shen and his team, including John Baker, a mechanical engineering professor, and Samit Roy, the William D. Jordan professor of aerospace engineering, work with graduate as well as some UA undergraduate students in their advanced research.

Although there is already a previous device used in above-the-knee limb replacements, no technologies have been created to address ankle problems.

“Right now there is a lag in robotic engineering,” Shen said. “I think that the people with limb issues can absolutely benefit from robotic technologies, especially with newly constructed limbs.”

The ankle prosthesis Shen is working on mechanically powers the ankle joint without forcing the amputee to use more unnecessary energy. The two key components of this development are the liquid fuel called monopropellant, an energy storing medium that allows the prosthesis to store energy for everyday use.

The other necessity is the sleeve muscle actuator, an artificial muscle that replaces the motor movements, developed to resemble the natural human skeletal muscle. The researchers will use their multi-camera motion capturing system to monitor the subject’s movements with the prosthesis.

The select undergraduate students involved with Shen work in his lab developing exoskeleton robotic legs that can help people with lower limb weaknesses.

“It is gratifying to help amputees, especially veterans of war in need. This is a useful application of my work. Aerospace is one aspect of what I do, but this work will benefit others,” Roy said. “I don’t see myself only working with aerospace technology; I want to use my work wherever it is needed.”

While hard at work on this project, Shen and his team have had to explore ways to artificially create the natural approaches of fuel management, storage, as well as thermal insulation and heat management.

The main goal is to create something that closely resembles the human body and its natural motor functions for those who lack such abilities.

“This is a relatively new system,” Shen said. “There are some problems in putting the prosthesis into clinical use because the components of the prosthesis are still being developed. In our research, the long-term goal is to develop powered prostheses with comparable appearance and functionality of human limbs.”

Shen and his associates hope to have this project ready for medical use by 2016.