Comparison of Grasping Performance of Tendon and Linkage Transmission Systems in an Electric-Powered Low-Cost Hand Prosthesis

Abstract

The popularization of fused deposition modeling (FDM) technology and open-source microcontrollers has permitted the explosion of electric hand prostheses that can be designed, shared, built, and operated at a low cost, under the Do It Yourself premise. Patients with limb reductions at the transcarpal or transradial level are best candidates to benefit from them. They manage the gross location with the remaining limb, while the built-in motors offer the possibility of controlling each finger independently. The number of mobile joints along the finger and the type of transmission can determine the quality of the grasp. Moreover, there is a need of objective procedures to assess the functionality of complete prototypes at reasonable effort. This work makes a critical review of the different transmission systems that can be found in most low-cost finger designs: linkage and tendon mechanisms. Mechanical performance has been analyzed using a standardized model of the index finger. Furthermore, robotic grasp quality metrics (GQM) have been used to evaluate by simulation the functionality of complete devices. Neither finger transmission design appeared clearly advantageous in the range of flexion studied. The evaluation of the complete devices gave slightly better quality grades for the linkage-driven model. Instead, tendon-driven model achieved a greater quantity of successful grasps. In the current state of art, some other aspects may have led to a dominant situation of the tendon-driven hands: fewer number of parts to be printed, easier assembly for a nonexpert user, advantageous in pursuit of lightweight devices.

Anthropomorphism Index of Mobility for Artificial Hands

“…Notwithstanding, some important aspects in the design of an artificial hand are not within the scope of the AIM: the orientation of the joint axes, the range of motion of the different hand joints, the dimension of the phalanges, the friction coefficient of the parts of the hand in contact with the objects, the grasping force exerted by the actuators, the efficiency of the driving linkages, the control system, etc. Some previous studies [33–35] have shown the relevance of these aspects. In this sense, the AIM, involving mainly the topological structure, the number of actuators, and the type of underactuation, can be considered as an index especially useful in the concept design stage.…”

Grasping Ability and Motion Synergies in Affordable Tendon-Driven Prosthetic Hands Controlled by Able-Bodied Subjects

“…Three of the most common 3D-printed electrical prosthetic hands for transradial amputees currently available online, with documented clinical usage, were chosen for the present study, namely (Andrés et al, 2019 ), the Dextrus v2.0, the InMoov, and the Limbitless hands. Together with the IMMA hand, designed by the authors (Llop-Harillo and Pérez-González, 2017b ), Table 1 summarizes each of the mechanical design characteristics as outlined by Controzzi et al ( 2014 ) and summarized in the previous section.…”

Application and use of quality metrics for the prediction of grasp success and evaluation of artificial hands

“…Also, the use of OpenHand and the methodologies described in this Chapter have been used to evaluate prosthetic hand designs in: Llop-Harillo et al, 2017;Cardín-Catalán et al, 2016;Llop-Harillo et al, 2018;Andrés et al, 2018.…”