Innovation of robotic hand with two thumbs

Abstract

Patients with hand or little finger amputation suffer from manual skill loss and both aesthetic and psychological aspects. In this research we aim to enhance the grasping abilities by adding an additional thumb, involving multiple iterations of the palm’s design. Congenital anomalies, such as polydactyly show people that hold extra fingers have advantage in manual dexterity. There are studies where a sixth finger added to the hand (a thumb) improves manual skills. Salvietti [35], propose a solution to compensate the grip abilities in patients with stroke, adding a sixth adjustable robotic finger. Among its results the extra finger acts as a motivational assistance device. Segura [36] indicate that extra artificial limbs, offer the possibility of increasing the workspace, dexterity, resistance and reduce user fatigue. Starting from existing robotic hands models like Inmoov and Parloma, are analyzed convergence patterns of design, morphology of the palms of the hands, the degree of freedom for two thumbs, manufacturing costs, assembly, and 3D printing patterns to generate remixes. In this work a mechatronic design methodology is used. Through the convergence patterns and the use of 3D printing, Inmoov and Parloma remixes were assembled, both compared, and we got four additional remixes. The approximate cost of manufacturing is above US$530.00 and required more than 120 hours of printing. In later studies, each link and join hand will be acted with intelligent material and force sensors attached to each fingertip to compare grasping and dexterity behaviors of a normal hand to an enhanced one.