Under-driven prosthetic hand with self-adaptive grasping function

An under-driven prosthetic hand with a self-adaptive grasping function, comprising a prosthetic hand body, a finger transmission module, an inter-finger transmission module, and a thumb driving module, wherein

• the prosthetic hand body comprises a palm and five fingers, and each of the fingers is respectively pulled to be bent by a first driving rope and pulled to be stretched by a second driving rope;
• the inter-finger transmission module is disposed inside the palm and comprises an inter-finger driving mechanism, an inter-finger transmission mechanism, and an inter-finger proportional transmission mechanism, wherein
• the inter-finger driving mechanism comprises a first motor and a first driving gear fixed onto an output shaft of the first motor, and the first motor is fixed onto the palm;
• the inter-finger transmission mechanism comprises a first inter-finger transmission mechanism and a second inter-finger transmission mechanism distributed on both sides of the first motor;
• the first inter-finger transmission mechanism comprises a first screw nut, a first polished rod, a first sliding block, and a first transmission gear, a first damping shaft, a first screw connector, and a first screw sequentially connected along a direction from a palm root to a metacarpophalangeal end;
• the first screw nut is disposed on the first screw, and the first sliding block is fixed onto the first screw nut and slides along the first polished rod;
• the second inter-finger transmission mechanism comprises a second screw nut, a second polished rod, a second sliding block, and a second transmission gear, a second damping shaft, a second screw connector, and a second screw sequentially connected along the direction from the palm root to the metacarpophalangeal end;
• the second screw nut is disposed on the second screw, and the second sliding block is fixed onto the second screw nut and slides along the second polished rod;
• the first screw, the second screw, the first polished rod, and the second polished rod are parallel to each other and are all fixed onto the palm;
• and
• the proportional transmission mechanism comprises a telescopic component and four third pulleys;
• the telescopic component is disposed with four fixed points arranged in a straight line, which one-to-one correspondingly fix the respective first driving ropes of remaining four fingers other than a thumb, or one-to-one correspondingly fix the respective second driving ropes of the remaining four fingers other than the thumb, and a distance between any two adjacent fixed points is telescopic;
• the telescopic component is pivotally connected to the first sliding block and the second sliding block respectively through two pins;
• the four third pulleys are disposed near the palm root and one-to-one correspond to the remaining four fingers other than the thumb;
• and after respective driving ropes of the remaining four fingers other than the thumb are wound around the corresponding third pulleys, the respective driving ropes are divided into the first driving ropes and the second driving ropes by the third pulleys;
• and
• the thumb is independently driven by the thumb driving module, the thumb driving module comprises a second motor fixed onto the palm and a thumb bending pulley fixed onto an output shaft of the second motor;
• and after a driving rope of the thumb is wound around the thumb bending pulley, the driving rope of the thumb is divided into the first drive rope and the second drive rope by the thumb bending pulley.