A prosthesis for amputees of a lower limb, said prosthesis comprising a foot segment (10) and a tibial segment (12) articulated with each other by pivoting in an ankle joint (13), wherein the gait cycle of said prosthesis comprises a so-called swing phase, between the removal of the toe (22) and the support of the heel (21) of the foot and the so-called support phase, which comprises the support of the heel (21), the support of the sole (23) and the decoupling of the toe, where said ankle joint (13) comprises: - an actuator (70), in particular, a gear motor, - a microprocessor means (70 ') which is adapted to control the movement of the knee joint (13) by said actuator (70) to reproduce the natural gait cycle and define the relative position of the foot with respect to the tibia, - a position transducer ( 17a) on the axis of the knee joint (16) that it reproduces the movement of the tibia with respect to the foot, said position transducer (17a) measuring the rotation of the foot segment (10) in the knee and supplying an angular position signal； - a programming means residing in the microprocessor (70 '), said programming means calculating the angular velocity of the foot / tibia in accordance with said position signal； characterized in that: - said programming means is arranged to generate a plurality of n-dimensional curves that reproduce the gait cycle and because - said programming means makes said actuator (70) belong to one of said curves to characterize a predetermined gait or posture condition.Una prótesis para amputados de un miembro inferior, comprendiendo dicha prótesis un segmento de pie (10) y un segmento tibial (12) articulados entre sí mediante pivotamiento en una articulación del tobillo (13), en donde el ciclo de forma de andar de dicha prótesis comprende una así denominada fase de oscilación, entre la retirada de la punta del pie (22) y el apoyo del talón (21) del pie y la así denominada fase de apoyo, que comprende el apoyo del talón (21), el apoyo
