An Underactuated, Tendon-Driven, Wearable Exo-Glove With a Four-Output Differential Mechanism

Soft, underactuated, and wearable robotic exo-gloves have received an increased interest over the last years. These devices can be used to improve the capabilities of healthy individuals or to assist people that suffer from neurological and musculoskeletal diseases. Despite the significant progress in the field, most existing solutions are still heavy and expensive, they require an external power source to operate, and they are not wearable. In this paper, we focus on the development of an affordable, underactuated, tendon-driven, wearable exo-glove equipped with a novel four-output differential mechanism that provides grasping capabilities enhancement to the user. The device and the differential mechanism are experimentally tested and assessed using three different types of experiments: i) grasping tests that involve different everyday objects, ii) force exertion capability tests that assess the fingertip forces for different types of grasps, and iii) tendon tension tests that estimate the maximum tendon tension that can be obtained by employing the proposed differential. The device considerably improves the grasping capabilities of the user with a weight of 690 g and an operation autonomy of a whole day.