Design of a 3D-printable, robust anthropomorphic robot hand including intermetacarpal joints

Artificial-Hand Technology—Current State of Knowledge in Designing and Forecasting Changes

“…Most artificial hands are human-based, which means that there are four palm fingers (index-little) and a thumb [38,[70][71][72][73]. However, some research groups found solutions with three [74][75][76][77][78][79][80][81] or four [23,40,[82][83][84][85][86][87][88][89][90] fingers applied ( Figure 3). While the former group mainly contains optimized grasp algorithm testing platforms, the latter consists of more versatile devices.…”

“…3 clearly shows no dependencies or a trend of an increasing number of constructions with fewer than five fingers, and the ratio of these mechanisms is dropping. The appearance of such devices could simply be explained by both construct simplification and restricted space [40,88].…”

“…Another example is the Robonaut hand [20,118] that also included the opposition of the little and ring fingers. For the same purpose, having better adhesion, [40] utilized three CMC joints (palm fingers) that each had a single degree of motion.…”

“…The authors of [116] used a miniature Pololu with a 35:1 reduction that allowed to rotate joints with a speed of 20 deg/s. RCH1 Hand [45] with Maxon RE-maxl7 motors and separate gears (64:1) achieved 2750 deg/s in the DIP joint with a total grasping force of 30 N. These and other examples [40,75,77,79,94,136,137] showed that a free-standing motor, regardless if it is brushed or brushless, is not able to drive such mechanisms like a robotic hand.…”

“…Whole actuators lead to the possibility of installing more of them in the palm or forehand, therefore increasing the number of degrees of freedom (DOF) [36][37][38]. According to the material and fabrication techniques, 3D printing is indisputably the most important innovation, as it makes prototyping and replacing parts much faster and cheaper [39,40].…”