Design of a Lightweight Single-Actuator Multi-Grasp Prosthetic Hand with Force Magnification

2020 ◽  
pp. 1-33
Author(s):  
Huan Liu ◽  
Zhao Bin ◽  
Zenghui Liu ◽  
Kai Xu
Keyword(s):  
Energy Consumption ◽  
Clinical Evaluation ◽  
Adult Male ◽  
Myoelectric Control ◽  
Prosthetic Hand ◽  
Male Size ◽  
Differential Mechanism ◽  
Variable Transmission ◽  
Average Adult

Abstract Restoring human grasp functions by prosthesis is a long-standing challenge in robotics research. Aiming at prosthetic applications, this paper presents a novel anthropomorphic multigrasp hand design. The hand is driven by only one motor and several mechanisms were designed for enhanced functionality. First, a continuum differential mechanism (CDM) was used to generate differential finger motions and to simplify the transmission of the hand. Second, a Load Adaptive Variable Transmission (LAVT) was designed to magnify the grasp forces. Moreover, a prismatic clutch is embedded in the hand, to lower the motor's energy consumption. Myoelectric control was implemented using affordable control hardware and sensors. All the above components are integrated in the proposed prosthetic hand, which is an average adult male size and weighs 470g (including batteries). Experiments, including a preliminary clinical evaluation, were conducted to assess the effectiveness of the hand for prosthetic use. The results show that the hand can perform various grasp poses with adequate grasp forces.

scholarly journals Recent Advances in Myoelectric Control for Finger Prostheses for Multiple Finger Loss

2021 ◽  
Vol 11 (10) ◽  
pp. 4464
Author(s):  
Viritpon Srimaneepong ◽  
Artak Heboyan ◽  
Azeem Ul Yaqin Syed ◽  
Hai Anh Trinh ◽  
Pokpong Amornvit ◽  
...  
Keyword(s):  
Web Of Science ◽  
Myoelectric Control ◽  
Original Research ◽  
Prosthetic Hand ◽  
Precise Control ◽  
Prosthetic Hands ◽  
Prosthesis Retention ◽  
Finger Prosthesis ◽  
Artificial Hand

The loss of one or multiple fingers can lead to psychological problems as well as functional impairment. Various options exist for replacement and restoration after hand or finger loss. Prosthetic hand or finger prostheses improve esthetic outcomes and the quality of life for patients. Myoelectrically controlled hand prostheses have been used to attempt to produce different movements. The available articles (original research articles and review articles) on myoelectrically controlled finger/hand prostheses from January 1922 to February 2021 in English were reviewed using MEDLINE/PubMed, Web of Science, and ScienceDirect resources. The articles were searched using the keywords “finger/hand loss”, “finger prosthesis”, “myoelectric control”, and “prostheses” and relevant articles were selected. Myoelectric or electromyography (EMG) signals are read by myoelectrodes and the signals are amplified, from which the muscle’s naturally generated electricity can be measured. The control of the myoelectric (prosthetic) hands or fingers is important for artificial hand or finger movement; however, the precise control of prosthetic hands or fingers remains a problem. Rehabilitation after multiple finger loss is challenging. Implants in finger prostheses after multiple finger loss offer better finger prosthesis retention. This article presents an overview of myoelectric control regarding finger prosthesis for patients with finger implants following multiple finger loss.

Contact Stress Reduction Mechanisms for the CAM-Based Infinitely Variable Transmission

2007 ◽  
Author(s):  
Derek F. Lahr ◽  
Dennis W. Hong
Keyword(s):  
Contact Stress ◽  
Stress Reduction ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Speed Ratio ◽  
Cam Mechanism ◽  
Expected Performance ◽  
Differential Mechanism ◽  
Variable Transmission ◽  
Infinitely Variable Transmission

The Cam-based Infinitely Variable Transmission (IVT) is a new type of ratcheting IVT based on a three dimensional cam and follower system which provides unique characteristics such as generating specific functional speed ratio outputs including dwells, for a constant velocity input. This paper presents several mechanisms and design approaches used to improve the torque and speed capacity of this unique transmission. A compact, lightweight, and capable differential mechanism based on a cord and pulley system is developed to double the number of followers in contact with the cam at any time, thereby reducing the contact stress between the followers and the cam surface considerably. A kinematic model governing the motion of this differential is developed and a few experimental results from the prototype are presented, showing an overall increase in performance including a smooth output, a wide gear range, and the ability to shift under load. Plans for future improvements to the design, including an inverted external cam mechanism, is also presented along with the expected performance gains.

Modeling the Frictional Interaction in the Tendon-Pulley System of the Human Finger for Use in Robotics

2013 ◽  
Vol 19 (1) ◽  
pp. 149-169 ◽  
Author(s):  
Konstantinos Dermitzakis ◽  
Marco Roberto Morales ◽  
Andreas Schweizer
Keyword(s):  
Energy Consumption ◽  
High Load ◽  
Total Output ◽  
Prosthetic Hand ◽  
Pulley System ◽  
Output Force ◽  
Frictional Interaction ◽  
Reduction Of Energy Consumption ◽  
Human Finger

Physiological studies of the human finger indicate that friction in the tendon-pulley system accounts for a considerable fraction of the total output force (9–12%) in a high-load static posteccentric configuration. Such a phenomenon can be exploited for robotic and prosthetic applications, as it can result in (1) an increase of output force or (2) a reduction of energy consumption and actuator weight. In this study, a simple frictional, two-link, one-degree-of-freedom model of a human finger was created. The model is validated against in vitro human finger data, and its behavior is examined with respect to select physiological parameters. The results point to clear benefits of incorporating friction in tendon-driven robotic fingers for actuator mass and output force. If it is indeed the case that the majority of high-load hand grasps are posteccentric, there is a clear benefit of incorporating friction in tendon-driven prosthetic hand replacements.

Design and Myoelectric Control of an Anthropomorphic Prosthetic Hand

2017 ◽  
Vol 14 (1) ◽  
pp. 47-59 ◽  
Author(s):  
Nianfeng Wang ◽  
Kunyi Lao ◽  
Xianmin Zhang
Keyword(s):  
Myoelectric Control ◽  
Prosthetic Hand

Elastomeric passive transmission for autonomous force-velocity adaptation applied to 3D-printed prosthetics

2018 ◽  
Vol 3 (23) ◽  
pp. eaau5543 ◽  
Author(s):  
Kevin W. O’Brien ◽  
Patricia A. Xu ◽  
David J. Levine ◽  
Cameron A. Aubin ◽  
Ho-Jung Yang ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Cost Effective ◽  
Prosthetic Hand ◽  
Prosthetic Hands ◽  
Polyurethane Composite ◽  
Compact Size ◽  
Variable Transmission ◽  
3D Printed ◽  
Force Velocity ◽  
Projection Stereolithography

The force, speed, dexterity, and compact size required of prosthetic hands present extreme design challenges for engineers. Current prosthetics rely on high-quality motors to achieve adequate precision, force, and speed in a small enough form factor with the trade-off of high cost. We present a simple, compact, and cost-effective continuously variable transmission produced via projection stereolithography. Our transmission, which we call an elastomeric passive transmission (EPT), is a polyurethane composite cylinder that autonomously adjusts its radius based on the tension in a wire spooled around it. We integrated six of these EPTs into a three-dimensionally printed soft prosthetic hand with six active degrees of freedom. Our EPTs provided the prosthetic hand with about three times increase in grip force without compromising flexion speed. This increased performance leads to finger closing speeds of ~0.5 seconds (average radial velocity, ~180 degrees second−1) and maximum fingertip forces of ~32 newtons per finger.

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