Design method for an anthropomorphic hand able to gesture and grasp

This paper presents a numerical method to conceive and design the kinematic model of an anthropomorphic robotic hand used for gesturing and grasping. In literature, there are few numerical methods for the finger placement of human-inspired robotic hands. In particular, there are no numerical methods, for the thumb placement, that aim to improve the hand dexterity and grasping capabilities by keeping the hand design close to the human one. While existing models are usually the result of successive parameter adjustments, the proposed method determines the fingers placements by mean of empirical tests. Moreover, a surgery test and the workspace analysis of the whole hand are used to find the best thumb position and orientation according to the hand kinematics and structure. The result is validated through simulation where it is checked that the hand looks well balanced and that it meets our constraints and needs. The presented method provides a numerical tool which allows the easy computation of finger and thumb geometries and base placements for a human-like dexterous robotic hand.Comment: IEEE International Conference on Robotics and Automation, May 2015, Seattle, United States. IEEE, 2015, Proceeding IEEE International Conference on Robotics and Automatio

Progettazione e sviluppo di una mano robotica sotto-attuata per robot umanoide bipede

Lo scopo di questo lavoro è la progettazione e lo sviluppo di una mano robotica antropomorfa che possa essere integrata sul robot bipede SABIAN. L'esame dello stato dell'arte verte sulle mani robotiche per robot umanoidi presenti nella letteratura scientifica, con particolare attenzione ai meccanismi di trasmissione. L'obiettivo è quello di progettare una mano facilmente controllabile con un ridotto numero di attuatori che sia in grado di realizzare operazioni di presa anche in ambiente non strutturato e gestualità avanzata. Un'accurata analisi della trasmissione sotto-attuata e l'individuazione di indici globali di performance ha permesso di strutturare una procedura di ottimizzazione volta alla prevenzione dei fenomeni di instabilità della presa. Il dimensionamento del sistema di estensione passivo segue sulla base del Know-How dell'ARTS-lab, che unitamente al controllo, si prefigge lo scopo di replicare la dinamica del dito umano nella fase di chiusura prima della presa. Il lavoro si è concluso con la progettazione della mano e dell'unità di attuazione, puntando l'attenzione all'integrazione dei sensori nella struttura e la realizzazione delle dita

Performance of modified jatropha oil in combination with hexagonal boron nitride particles as a bio-based lubricant for green machining

This study evaluates the machining performance of newly developed modified jatropha oils (MJO1, MJO3 and MJO5), both with and without hexagonal boron nitride (hBN) particles (ranging between 0.05 and 0.5 wt%) during turning of AISI 1045 using minimum quantity lubrication (MQL). The experimental results indicated that, viscosity improved with the increase in MJOs molar ratio and hBN concentration. Excellent tribological behaviours is found to correlated with a better machining performance were achieved by MJO5a with 0.05 wt%. The MJO5a sample showed the lowest values of cutting force, cutting temperature and surface roughness, with a prolonged tool life and less tool wear, qualifying itself to be a potential alternative to the synthetic ester, with regard to the environmental concern

Analysis and optimization of underactuated finger for CMSysLab robotic hand

In this paper is presented mathematical analysis of 3-DOF underactuated robotic finger with linkage driven mechanism. The optimization procedure is described for obtaining optimal parameters of four bar mechanism. As results, the adaptability of the finger is improved and the grasping forces maximized within the working area limits

Four-bar linkage mechanism optimization for linkage driven underactuated robotic finger

When designing linkage driven underactuated robotic finger, many parameters needs to be satisfied in order to produce robust robotic hand capable of withstanding industrial environment and capable of fulfilling all needs of robotic assembly in terms of precision and dexterity. For this study, four-bar linkage mechanisms are used to drive underactuated robotic finger and design parameter that will be addressed is transmission performance. Optimization method used for obtaining length of links of four-bar mechanism, based on transmission performance is shown. Freundenstein’s analytic method for four-bar linkage function generation, is chosen, and calculated link lengths are to be used for acquiring parameter called transmission defect, parameter that is objective function to be minimized in this optimization process. Maximizing transmission performance, leads to increase of the transmitted torque from the actuated joints to the underactuated joints through transmission mechanism. This paper presents design and kinematic analysis of three degrees of freedom (3-DoF) underactuated robotic finger with linkage driven mechanism for CMSysLab robotic hand

The Mechanism Analysis of Underactuated Robotic Finger for Optimum Grasping Using Gradient Descent Method

This study was devoted in investigating the optimum geometric parameters for underactuated linkage three phalanges robotic finger. New kinematic and kinetic equations of grasping were derived in this research taking into account the angle for the ternary solid links of the four-bar linkages. To obtain the target of optimization, a gradient descent method was used which consists of three stages to find the optimal geometric parameters with high accuracy. Five criteria were selected to find the optimal solution by using multi objectives function algorithm, these are percentage of the grasping stability, the grasp forces, squeezing force, Mimic function for grasping task, and transmission angle for grasping operation. Gradient descent method starts by detecting the optimal geometric parameters for each criterion and choosing the best geometric parameters from the five criteria functions. At the optimum solution, the underactuated robotic finger prototype was built from hard Polylactic acid (PLA) plastic using rapid prototyping and was tested performance by grasping objects. Finally, the results have been shown that the robotic finger adapts to the wanted configurations