Intelligent Terrain Adaptive Ankle Prosthesis

Intelligent Terrain Adaptive Ankle Prostheses – Uses semi-active damping as a mechanism to provide active slope adaptation.

The goal of this research is to develop an intelligent ankle prosthesis for transtibial amputees, which will have the capability to detect changes in the terrain and modulate its passive dynamics on a continuous basis, providing a more stable and safer step.

There is much motivation for this project.  Lower limb prostheses have been around for a very long time however until recently there has been little progress in the development of this technology.  The most widely prescribed ankle/foot prosthesis is still made out of wood (the SACH foot, or Solid Ankle Cushioned Heel).  There are more advanced passive prostheses than the SACH foot however they all lack the ability to adapt to changes in the terrain intelligently via onboard embedded systems allowing the capability of continuously modulating the passive dynamics with a very small power source.  The lack of intelligent adaptability is assumed to be a large contributing factor to the falling rate in the amputee community, exceeding that of the institutionalized elderly.

Another source of motivation is the growing size of the amputee population in need of such technology.  Approximately 1 out of 500 people in the US have had major lower limb amputations, and this is expected to double by the year 2050 due to the aging population and the prevalence of diabetes and other dysvascular diseases.

Elderly amputees as well as those who have lost their lower extremities due to health reasons are the most in need of self stabilizing intelligent prostheses, since they aren’t as agile as generally healthy people who have lost their limbs due to traumatic injuries.  It is hoped however that this newly developed technology will benefit the entire amputee population, restoring their ambulation capabilities close to that of able bodied persons, leading to a safer and overall better life.


A.K. LaPré and F. Sup, “A Semi-Active Damper Design for use in a Terrain Adaptive Ankle Prosthesis,” Proc. of the ASME Int. Mech. Eng. Congress and Exposition, IMECE2011-65533, 2011.

A.K. LaPré and F. Sup, “Simulation of a Slope Adapting Ankle Prosthesis Provided by Semi-Active Damping,” 33rd Int. Conf. of the IEEE Engineering in Medicine and Biology Society, p. 587-90, 2011.