Adaptive Underactuated Finger With Active Rolling Surface

Abstract

This paper presents the design, prototype and kinematic model of a new adaptive underactuated finger with an articulated skin/surface that is able to bend and, at the same time, provides active rolling motion along its central axis while keeping the finger configuration. The design is based on a planar chain of overlapping spherical phalanxes that are tendon-driven. The finger has an articulated surface made of an external chain of hollow universal joints that can rotate via its central axis on the surface of the internal structure. The outer surface provides a second active Degree of Freedom (DoF). The two actuators, driving the bending and/or rolling motion, can be used independently. A set of experiments have been included to validate and measure the performance of the prototype for the grasping and rolling actions. The proposed finger can be built with a different number of phalanxes and sizes. A number of these fingers can be arranged along a palm structure resulting in a multi-finger robotic grasper for applications that require adaptation and in-hand manipulation capabilities such as pHRI.

Vision-Based In-Hand Manipulation for Variously Shaped and Sized Objects by a Robotic Gripper With Active Surfaces

“…The fingertips, made of soft polyurethane, can deform so that the contact region between the surfaces of the object and the fingertips is increased. A hand with both rolling and passively bending underactuated fingers was presented by J. M. Gómez-de-Gabriel and H. A. Wurdemann [27]. Also, the two-fingered hand advanced by Tincani et al [28] consists of an underactuated gripper with conveyor belts.…”

“…To achieve high manipulation capability, robotic hands with active surfaces have been proposed. Active surfaces [5] refer to the movable components such as belts [21]- [23], [28]- [32] or rollers [24]- [27] on a finger, which can continuously rotate or translate the grasped object. While the objects with simple shapes like cubes or cylinders can be easily manipulated through a large range of motion by active surfaces, it is difficult to deal with various shapes of the objects.…”

In-Hand Manipulation With a Simple Belted Parallel-Jaw Gripper

“…Placing belts parallel to the fingers allows for objects to be pulled further into a grasp or rolled around an axis perpendicular to the belts [21][22][23][24][25]. Gómez-de Gabriel and Wurdemann [26] and Rahman et al [27] rotate the active surfaces by 90 degrees, creating a gripper where the active surface moves perpendicular to the fingers. Yuan et al [28,29] drive motion through coordinating the orientation of three cylinders or spheres.…”