Robotic ankle

An ankle prosthesis comprising:

• a main body, having a foot portion configured to rest on a walking surface;
• stump supporting means, configured to couple with a leg prosthetic element;
• linear actuation means, comprising a coupling between a screw element and a nut screw element having a friction coefficient lower than 0.16,
• wherein said stump supporting means, said screw element and said nut screw element are constrained to said main body according to a substantially four-bar linkage configuration, so that a relative rotation between said supporting means and said main body is allowed and so that said actuation means is configured to act as damping element along a damping direction (S) and is movable between an advanced position (Psup) and a rearward position (Pinf) with respect to said damping direction (S), wherein said foot portion comprises a first and a second contact position during a resting phase on the walking surface, wherein to said first and second contact position corresponds a respective opposite movement of said actuation means between said advanced position (Psup) and said rearward position (Pinf) during a damping condition of the loads transferred on said main body by the leg element.