scholarly journals Design of a Robotic Hand With a Biologically-Inspired Parallel Actuation System for Prosthetic Applications

2010 ◽  
Author(s):  
Anthony L. Crawford ◽  
Alba Perez-Gracia
Keyword(s):  
Flexor Digitorum Profundus ◽  
Human Hand ◽  
Robotic Hand ◽  
Direct Relation ◽  
Task Execution ◽  
Biologically Inspired ◽  
Prosthetic Hands ◽  
Actuation System ◽  
Flexor Digitorum ◽  
Behavior Strength

This paper presents the design of a robotic hand for prosthetic applications. The main characteristic of this robotic hand is its biologically-inspired parallel actuation system, which is based on the behavior/strength space of the Flexor Digitorum Profundus (FDP) and the Flexor Digitorum Superficialis (FDS) muscles. The design separates the strength space of the FDS and FDP muscles into a lighter strength region where finer manipulation and general approach tasks are executed, and a higher strength region where the more robust grasps are achieved. Two parallel actuator types and kinematic structures are designed to complement the requirements of both strength space regions. This unique structure is intended to be driven by electromyographical (EMG) signals captured at the surface of the skin. The direct relation between signal and actuation system lends itself well to interpreting the EMG signals from the FDP and FDS muscles into effective task execution, with the goal of helping the user to achieve a good approximation of the full capabilities associated with the human hand, without compromising strength, dexterity, appearance, or weight; which are common issues associated with prosthetic hands.

scholarly journals Activation of individual extrinsic thumb muscles and compartments of extrinsic finger muscles

2013 ◽  
Vol 110 (6) ◽  
pp. 1385-1392 ◽  
Author(s):  
J. Alexander Birdwell ◽  
Levi J. Hargrove ◽  
Todd A. Kuiken ◽  
Richard F. ff. Weir
Keyword(s):  
Neural Control ◽  
Muscular Activity ◽  
Middle Finger ◽  
The Other ◽  
Flexor Digitorum Profundus ◽  
Human Hand ◽  
Activity Levels ◽  
Extensor Pollicis Longus ◽  
Flexor Digitorum ◽  
Different Levels

Mechanical and neurological couplings exist between musculotendon units of the human hand and digits. Studies have begun to understand how these muscles interact when accomplishing everyday tasks, but there are still unanswered questions regarding the control limitations of individual muscles. Using intramuscular electromyographic (EMG) electrodes, this study examined subjects' ability to individually initiate and sustain three levels of normalized muscular activity in the index and middle finger muscle compartments of extensor digitorum communis (EDC), flexor digitorum profundus (FDP), and flexor digitorum superficialis (FDS), as well as the extrinsic thumb muscles abductor pollicis longus (APL), extensor pollicis brevis (EPB), extensor pollicis longus (EPL), and flexor pollicis longus (FPL). The index and middle finger compartments each sustained activations with significantly different levels of coactivity from the other finger muscle compartments. The middle finger compartment of EDC was the exception. Only two extrinsic thumb muscles, EPL and FPL, were capable of sustaining individual activations from the other thumb muscles, at all tested activity levels. Activation of APL was achieved at 20 and 30% MVC activity levels with significantly different levels of coactivity. Activation of EPB elicited coactivity levels from EPL and APL that were not significantly different. These results suggest that most finger muscle compartments receive unique motor commands, but of the four thumb muscles, only EPL and FPL were capable of individually activating. This work is encouraging for the neural control of prosthetic limbs because these muscles and compartments may potentially serve as additional user inputs to command prostheses.

Motor-Unit Synchrony Within and Across Compartments of the Human Flexor Digitorum Superficialis

2007 ◽  
Vol 97 (1) ◽  
pp. 550-556 ◽  
Author(s):  
Tara L. McIsaac ◽  
Andrew J. Fuglevand
Keyword(s):  
Motor Unit ◽  
Motor Neurons ◽  
Motor Units ◽  
Flexor Digitorum Profundus ◽  
Human Hand ◽  
Flexor Digitorum Superficialis ◽  
Short Term ◽  
Synaptic Inputs ◽  
Muscles Of The Hand ◽  
Flexor Digitorum

An interesting feature of the muscular organization of the human hand is that the main flexors and extensors of the fingers are compartmentalized and give rise to multiple parallel tendons that insert onto all the fingers. Previous studies of motor-unit synchrony in extensor digitorum and flexor digitorum profundus indicated that synaptic input to motor neurons supplying these multitendoned muscles is not uniformly distributed across the entire pool of motor neurons but instead appears to be partially segregated to supply subsets of motor neurons that innervate different muscular compartments. Little is known, however, about the organization of the synaptic inputs to the motor neurons supplying another multitendoned finger muscle, the flexor digitorum superficialis (FDS). Therefore in this study, we estimated the extent of divergence of last-order inputs to FDS motor neurons by measuring the degree of short-term synchrony among motor units within and across compartments of FDS. The degree of synchrony for motor-unit pairs within the same digit compartment was nearly twofold that of pairs of motor units in adjacent compartments and more than fourfold that of pairs in nonadjacent compartments. Therefore like other multitendoned muscles of the hand, last-order synaptic inputs to motor neurons supplying the FDS appear to primarily supply subsets of motor neurons innervating specific finger compartments. Such an organization presumably enables differential activation of separate compartments to facilitate independent movements of the fingers.

scholarly journals Flexor Digitorum Superficialis and Flexor Digitorum Profundus with separated sheaths

2015 ◽  
pp. 199-201
Author(s):  
Seyed Mokhtar Esmaeilnejd Ganji ◽  
Behnam Baghianimoghadam
Keyword(s):  
Clinical Relevance ◽  
Proximal Phalanx ◽  
Clinical Findings ◽  
Flexor Digitorum Profundus ◽  
Human Hand ◽  
Normal Variation ◽  
Case Description ◽  
Flexor Digitorum Superficialis ◽  
Zone Ii ◽  
Flexor Digitorum

Case description: A 25 years old man presented with a laceration on radial side of proximal phalanx of 4th finger (zone II flexor) which was due to cut with glass. Clinical findings: The sheaths of Tendons of flexor digitorum sperficialis and profundus were not the same and each tendon had a separate sheath. Treatment and outcome: The tendons were reconstructed by modified Kessler sutures, after 15 months the patient had a 30 degrees of extension lag even after physiotherapy courses. Clinical relevance: This is the first reported of such normal variation in human hand tendon anatomy.

A simplified model of a multi-jointed mechanical finger calibrated with experimental data by vision system

2021 ◽  
Vol 235 (1) ◽  
pp. 164-175
Author(s):  
C Cosenza ◽  
V Niola ◽  
S Savino
Keyword(s):  
Experimental Data ◽  
Vision System ◽  
Control Strategies ◽  
Image Correlation ◽  
Robotic Hand ◽  
Prosthetic Device ◽  
Prosthetic Hands ◽  
Mechanical Hand ◽  
Free Mode ◽  
Mechanical Finger

The development of suitable models for mechanical fingers, whether they are part of prosthetic device or of a robotic hand, is a powerful tool to predict the behaviour of their components since the early stages of design, especially for underactuated mechanisms. Experimental data can improve the reliability of such models and promote their application to build proper control strategies especially for prosthetic hands. Here, we have developed a multi-jointed model of a mechanical finger. The finger is part of the Federica hand: an underactuated mechanical hand that was conceived for prosthetic purpose. The model accounts for friction phenomena in the finger and it is tuned with experimental data acquired through a digital image correlation device. The model allowed us to write kinematics relations of the phalanges and evaluate finger configurations in relation to the closure velocity. Moreover, it was possible to estimate the tendon force and the work analysis occurring during the closure tasks, both in free mode and in presence of objects.

scholarly journals The effect of tissue culture on suture holding strength and degradation in canine tendon

2009 ◽  
Vol 34 (5) ◽  
pp. 643-650 ◽  
Author(s):  
H. OMAE ◽  
C. ZHAO ◽  
Y.-L. SUN ◽  
M. E. ZOBITZ ◽  
S. L. MORAN ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Tensile Load ◽  
Flexor Digitorum Profundus ◽  
Tendon Suture ◽  
Pull Out ◽  
Culture Model ◽  
Static Tensile ◽  
Tissue Culture Model ◽  
Flexor Digitorum ◽  
Pull Out Strength

The purpose of this study was to assess tendon metabolism and suture pull-out strength after simple tendon suture in a tissue culture model. One hundred and twelve flexor digitorum profundus tendons from 28 dogs were cultured for 7, 14, or 21 days with or without a static tensile load. In both groups increased levels of matrix metalloproteinase (MMP) mRNA was noted. Suture pull-out strength did not decrease during tissue culture. While the presence of a static load had no effect on the pull-out strength, it did affect MMP mRNA expression. This tissue culture model could be useful in studying the effect of factors on the tendon-suture interface.

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