Design of a novel three degrees of freedom ankle prosthesis inspired by human anatomy

Although the potential advantages of a powered ankle-foot prosthesis have been well investigated, no research has developed foot anatomy such as tendon, Tiabialis anterior, and Gastrocnemius in detail. One of the main barriers that prohibit such a development is the challenge of building an ankle-foot prosthesis that matches the size, weight, and anatomy of the intact ankle, but still provides a sufficiently large instantaneous power output and torque to propel an amputee. In this paper, a powered cable driven ankle-foot prosthesis is presented that overcomes these design challenges. The prosthesis comprises one active degree of freedom, which provides dorsiflexion and plantarflexion motion by transmitting power through cables. Moreover, the prosthesis possesses two passive joints of toe and inversion and eversion maneuver. With this architecture, the ankle-foot prosthesis matches the size, weight, and anatomy of the human ankle, and is shown to be satisfying the restrictive design specifications dictated by normal human ankle walking biomechanics.