Performance Analysis of the Underactuated Finger for Adam’s Hand

The purpose of prosthetic hands is to replicate the functional capabilities of the human hand, allowing users to perform daily tasks effectively. The mechanical design of artificial fingers is a key factor in determining the overall performance of these prostheses. A novel solution in this field is the Adam Hand by BionIT Labs, which belongs to the family of underactuated, multiarticulated myoelectric prostheses. This paper presents a kinetostatic analysis of the Adam’s Hand finger, which utilizes a gear train as an underactuated transmission mechanism. A test bench is also introduced to experimentally measure the grasping force when the finger spans its entire working range, defined by a 90° rotation of the proximal and distal phalanx joints. The experimental results demonstrate good agreement with the theoretical predictions, yielding mean percentage errors of less than 4%, with maximum error of about 6%. The analytical and experimental results obtained from Adam’s hand are also compared with those of an alternative prosthesis, namely Bebionic, that is fully actuated.