Underactuated robotic hand

An anthropomorphic robotic hand, comprising:

• a palm (00) and a metacarpus (10) configured to rotate with respect to said palm around an axis of rotation (180);
• four fingers substantially aligned and constrained to said palm and a fifth finger opposing to the four aligned fingers, each one of said four aligned fingers comprising at least a proximal phalanx (21, 31, 41, 51), a middle phalanx (22, 32, 42, 52) and a distal phalanx (23, 33, 43, 53), and said fifth finger comprising a proximal phalanx (11) and a distal phalanx (13), the proximal phalanges (21, 31, 41, 51) of each one of said four aligned fingers being hinged to said palm (00) in respective axes of rotation (240, 340, 440, 540) and the proximal phalanx (11) of said fifth finger being hinged to said metacarpus (10) in a respective axis of rotation (140);
• a motor (100);
• a plurality of bevel gear differential stages which transmit motion from said motor (100) to said aligned fingers and to said opposable finger, characterized in that said motor (100) is configured to directly drive only a first planet carrier of a first differential stage;
• said plurality of differential stages comprises a first differential stage having a first planet carrier moved by said motor (100) and sun gears moving a second planet carrier of a second differential stage and a fifth planet carrier of a fifth differential stage, sun gears of said second differential stage being integral to a third planet carrier of a third differential stage and a fourth planet carrier of a fourth differential stage,
• sun gears of said third and fourth differential stages being configured so that they respectively engage with four gears (210, 310, 410, 510) having axes coincident with said respective axes of rotation (240, 340, 440, 540) between proximal phalanges (21, 31, 41, 51) of said aligned four fingers and said palm (00), and sun gears of a fifth differential stage being configured to respectively rotate said metacarpus (10) and a gear (110) having an axis coincident with said respective axis of rotation (140) between the proximal phalanx (11) of said fifth finger and said metacarpus (10).