Then, we review several typical multifingered dexterous hands from task scenarios, actuation mechanisms, and in-hand sensors points. First, we investigate the structure and principle of hand-centered visual sensing, tactile sensing, and motor control and related behavioral results. This article aims to give a brief overview of multifingered robotic manipulation from three aspects: a) the biological results, b) the structural evolvements, and c) the learning methods, and discuss potential future directions. The research dates back 30 years ago, yet, there remain great challenges to effectively design and control them due to their high dimensionality of configuration, frequently switched interaction modes, and various task generalization requirements. Multifingered robotic hands (usually referred to as dexterous hands) are designed to achieve human-level or human-like manipulations for robots or as prostheses for the disabled. Finally, we developed a prototype prosthetic hand based on the proposed design methods and demonstrated by experiment that it was able to perform human-like thumb opposition and to pass both precision and power grasp tests. The results show that, compared with the anthropomorphic trajectory measured from a human index, the proposed method improves the grasping ability by more than 10%.
On the basis of this metric, we optimized the geometry parameters of the thumb and index finger using the Monte Carlo method. Furthermore, we devised a new metric to evaluate the precision grasp quality based on the force conditions during grasp. We also developed a fully integrated fingertip tactile sensor with all components embedded in the distal phalanx designed to facilitate in-hand precision manipulation. In this study, we developed a novel thumb structure with coupled abduction–adduction and pronation–supination movement in the trapeziometacarpal joint. Moreover, linkage-driven prosthetic hands still lack quantitative precision grasp quality. Also, the thumb metacarpal length in comparison to all bones of the hand was significantly different from all long bones of the hand except the proximal phalanx of the middle finger (P = 1).īased on the morphology of the long bones of the hand and the high similarity between the thumb metacarpal and phalanges especially the proximal phalanx of the middle finger, it can be suggested that the current thumb metacarpal is a proximal phalanx of the thumb.Ĭurrent linkage-driven prosthetic hands still show limitations in aspects such as the thumb design and fingertip sensor. Our results showed that the length of the phalanges and the total length of the fingers are independent of the related metacarpal length (P < 0.001).
The correlation between all quantitative factors was done by Spearman Rank Correlation (Spearman's Rho) coefficient. Friedman Repeated Measures Analysis of Variance and Dunn’s post hoc test were carried out to compare the means of all variables.
The exploration targets were the length of all metacarpals (MC), proximal phalanges (PP), middle phalanges (MP), and distal phalanges (DP). We studied anterior–posterior X-ray images of the right hands of 80 individuals from 18 to 65 years old. So this anthropometric study was carried out by investigating the morphology of the long bones of the hand and correlations between the thumb metacarpal and other miniature long bones of the hand. But there are some old reports that few former scientists believed the thumb has three phalanges and it lacked a metacarpal, and the thumb metacarpal is a phalanx. For many years, it was thought that the thumb consists of just two phalanges that differentiate it from the other four medial triphalangeal fingers.
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