A three-rotation-one-translation (3R1T) decoupled ankle rehabilitation robot. A robot body consists of a symmetrical hybrid mechanism. The hybrid mechanism comprises a base (6), a moving platform (4), a pedal plate (5), and three branches (1, 2, 3) for connecting the base and the moving platform. The first branch (1) of the three branches is a PRR branch. The second branch (2) and third branch (3) are both CPRR branches, and are symmetrically arranged with respect to the bottom of the base. The pedal plate and the moving platform are connected in series to form part of a branch. The mechanism as a whole is a 3R1T mechanism. A completely decoupled symmetrical two-rotation-one-translation parallel mechanism comprises a base (104), a moving platform (105), and three branches (101, 102, 103). The first branch (101) and the second branch (102) thereof are both PRR branches, and the third branch (103) is a CPU branch. The three branches are completely decoupled by means of motion pairs. The mechanism is a kinematically decoupled mechanism. Ankle movements are separately performed by controlling different branches. The mechanism is symmetrical, and has fewer branched-motion pairs, thereby improving the accuracy of control. The mechanism has a compact structure, and is stable.L'invention concerne un robot de rééducation de la cheville découplé à trois rotations et une translation (3R1T). Un corps de robot est constitué d'un mécanisme hybride symétrique. Le mécanisme hybride comprend une base (6), une plateforme mobile (4), une plaque de pédale (5) et trois branches (1, 2, 3) pour relier la base et la plateforme mobile. La première branche (1) des trois branches est une branche PRR. La deuxième branche (2) et la troisième branche (3) sont toutes deux des branches CPRR, et sont disposées symétriquement par rapport au fond de la base. La plaque de pédale et la plateforme mobile sont reliées en série pour former une partie d'une branche. Le mécanisme dans son ensemble est un mé
