A novel under-actuated bionic hand and its grasping stability analysis

Abstract

This article presents a novel under-actuated robot hand, which has a thumb and two cooperative fingers. The thumb has two joints with 2 degrees of freedom driven by one motor. Each of the other two fingers has the same mechanism structure with the thumb and forms a cooperative mechanism, which is driven by only one motor with 4 degrees of freedom in total. All the under-actuated fingers are designed with the transmission mechanisms based on a kind of mechanism combined with the linkage mechanism and the passive elements. In this article, it is shown that under-actuated hand is able to reproduce most of the grasping behaviors of the human hand anthropomorphically and self-adaptively, without increasing the complexity of mechanism and control. The grasping stability analysis is given to help to understand the size range and load range of a stable grasp. Finally, the experiment results verify the high efficiency and stability of the novel mechanism.

Optimal Control and Grasping for a Robotic Hand with a Non-linked Double Tendon Arrangement

“…The articles [18], [20], [22], [23], [26], [29] exhibit a single degree of freedom and are unable to grasp objects with irregular shapes, a situation addressed in this article by employing the non-linked doubletendon arrangement. On the other hand, the articles [19], [27], [28], [30]- [32] feature a mechanical finger design with more than one degree of freedom, enabling them to grasp objects with irregular shapes. However, they lack a closed-loop control strategy, an aspect that is considered in the present article.…”

“…In [17] a hand controlled by various types of signals is presented, these are encephalographic, myoelectric, voice and gestures, the project provides a comprehensive explanation of the methods used to acquire the different signals; however, to move the hand, a control law is not used, that is, it is an open loop system. In [18], [19], it was also observed that they use myoelectric sensors as triggers of the control action. In [20]- [23], a hand prototype with five fingers divided into three parts (phalanges), joined by a small pulleys system is presented, in which, to perform the bending movement a direct current motor is used at the base, which acts on a wire (or cable) which runs through the inside of the finger and connects to the distal phalanx.…”

Advances in Finger and Partial Hand Prosthetic Mechanisms

“…The derived grasper can increase its robustness against external force perturbations. The UnderActuated UA finger [45] presented in the second row of Table 5 uses as the driving input the mechanical torque applied to link 1 (it does not have the interchangeability that characterizes the patent [43]). A and B are the MCP and PIP joints and once the link 3 is in contact with the object, the torsion spring 5 allows under actuation to be activated (in this case BE and ED are collinear).…”

A Systematic Approach to Stable Grasping of a Two-Finger Robotic Hand Activated by Jamming of Granular Media

“…Others adopted flexible fingers, fingers with flexible surfaces as an interface for grasping, or fingers with flexible joints [4][5][6][7][8][9][10]. Moreover, under-actuated mechanisms have also been employed to achieve safe and stable grasping [11][12][13][14][15][16][17][18]. While these approaches have proved effective, the levels of control and accuracy are still far from the biomimicry of natural grasping.…”