scholarly journals Development of an Anthropomorphic Prosthetic Hand with Underactuated Mechanism

2020 ◽  
Vol 10 (12) ◽  
pp. 4384
Author(s):  
Wooseok Ryu ◽  
Youngjin Choi ◽  
Yong Je Choi ◽  
Yeong Geol Lee ◽  
Sungon Lee
Keyword(s):  
Degrees Of Freedom ◽  
Power Transmission ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Underactuated Mechanism ◽  
Hand Size ◽  
Distal Interphalangeal ◽  
Compact Design ◽  
Constant Velocity Joints ◽  
Self Adaptive

An anthropomorphic prosthetic hand for wrist or forearm amputees is developed herein. The prosthetic hand was designed with an underactuated mechanism, which makes self-adaptive grasping possible, as well as natural motions such as flexion and extension. The finger and thumb modules were designed with four degrees of freedom by motions of the distal interphalangeal, proximal interphalangeal, and metacarpophalangeal joints. In this research, we pursued several novel trials in prosthetic hand design. By using two four-bar linkages composed of a combination of linkages and gears for coupling joints at each finger, it was possible to make a compact design, and the linkage has advantages such as accurate positioning, uniform power transmission, and high payload. Also, by using constant-velocity joints, torque is transferred to finger modules regardless of adduction/abduction motions. In addition, adduction/abduction and self-adaptive grasping motions are passively realized using torsional springs. The developed prosthetic hand was fabricated with a weight of 475 g and a human hand size of 175 mm. Experiments with diverse objects showed its good functionality.

scholarly journals Human Hand Anatomy-Based Prosthetic Hand

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 137
Author(s):  
Larisa Dunai ◽  
Martin Novak ◽  
Carmen García Espert
Keyword(s):  
3D Printing ◽  
Degrees Of Freedom ◽  
Use Of Force ◽  
Hand Movements ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Object Surface ◽  
Hand Phalanges ◽  
High Level

The present paper describes the development of a prosthetic hand based on human hand anatomy. The hand phalanges are printed with 3D printing with Polylactic Acid material. One of the main contributions is the investigation on the prosthetic hand joins; the proposed design enables one to create personalized joins that provide the prosthetic hand a high level of movement by increasing the degrees of freedom of the fingers. Moreover, the driven wire tendons show a progressive grasping movement, being the friction of the tendons with the phalanges very low. Another important point is the use of force sensitive resistors (FSR) for simulating the hand touch pressure. These are used for the grasping stop simulating touch pressure of the fingers. Surface Electromyogram (EMG) sensors allow the user to control the prosthetic hand-grasping start. Their use may provide the prosthetic hand the possibility of the classification of the hand movements. The practical results included in the paper prove the importance of the soft joins for the object manipulation and to get adapted to the object surface. Finally, the force sensitive sensors allow the prosthesis to actuate more naturally by adding conditions and classifications to the Electromyogram sensor.

Novel Design of a 3D Printed Anthropomorphic Soft Prosthetic Hand

2020 ◽  
Author(s):  
Esme Abbot ◽  
Amanda de Oliveira Barros ◽  
James Yang
Keyword(s):  
Degrees Of Freedom ◽  
Fused Deposition Modeling ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Fused Deposition ◽  
Versatile Tool ◽  
3D Printed ◽  
External Covering ◽  
Almost All ◽  
Precision Grasping

Abstract Human hands play a key role in almost all activities of daily living (ADLs) because it is an incredibly versatile tool capable of complex motion. For individuals who have had a complete loss of the hand, the ability to perform ADLs is impaired. Effective prosthetics accurately simulate the movements of a human hand by providing a high number of degrees of freedom, an efficient control system, and an anthropomorphic appearance. In this paper, the design and construction process of a highly anthropomorphic soft robotic prosthetic hand is outlined. The design specifications of the hand are based on feedback from current and former prosthetic users. The hand endoskeleton was 3D printed using fused deposition modeling techniques and was enclosed in a silicone coating modeled, after a real human hand. The hand presents anthropomorphic design in its realistic bone shapes and in its external covering that is like skin in texture and mechanical properties. The hand utilizes the flexibility of silicone instead of antagonistic tendons which would otherwise add complexity and weight to the prosthetic design. The prototype also includes adduction/abduction of the fingers, which is a common omitted movement in other prosthetics. Testing showed that the hand is capable of effective power and precision grasping.

scholarly journals Human Hand Anatomy Based Prosthetic Hand

2020 ◽  
Author(s):  
Larisa Dunai ◽  
Martin Novak ◽  
Carmen García Espert
Keyword(s):  
Degrees Of Freedom ◽  
Use Of Force ◽  
Hand Movements ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Object Surface ◽  
Hand Phalanges ◽  
3D Printed ◽  
High Level

The present paper describes the development of a prosthetic hand based on the human hand anatomy. The hand phalanges are printed by using 3D printed with Polylactic Acid material. One of the main contributions is the investigation on the prosthetic hand joins; the proposed design enables to create personalized joins that allow the prosthetic hand a high level of movement by increasing the degrees of freedom of the fingers. Moreover, the driven wire tendons show a progressive grasping movement, being the friction of the tendons with the phalanges very low. Another important point is the use of force sensitive resistors for simulating the hand touch pressure. These are used for the grasping stop simulating touch pressure of the fingers. Surface Electromyogram (EMG) sensors allow the user to control the prosthetic hand grasping start. Their use may provide the prosthetic hand the possibility of classification of the hand movements. The practical results included in the paper prove the importance of the soft joins for the object manipulation and to get adapted to the object surface. Finally, the force sensitive sensors allow the prosthesis to actuate with more naturalness by adding conditions and classifications to the Electromyogram sensor.

Investigation into reducing anthropomorphic hand degrees of freedom while maintaining human hand grasping functions

2019 ◽  
Vol 233 (2) ◽  
pp. 279-292 ◽  
Author(s):  
Mohamed Zarzoura ◽  
Pablo del Moral ◽  
Mohammed I Awad ◽  
Farid A Tolbah
Keyword(s):  
Degrees Of Freedom ◽  
Hierarchical Cluster ◽  
Human Hand ◽  
Coupling Scheme ◽  
Joint Movement ◽  
Joint Coupling ◽  
Minimum Number ◽  
Distal Interphalangeal ◽  
Anthropomorphic Hands ◽  
High Degree

Underactuation is widely used when designing anthropomorphic hand, which involves fewer degrees of actuation than degrees of freedom. However, the similarities between coordinated joint movements and movement variances across different grasp tasks have not been suitably examined. This work suggests a systematic approach to identify the actuation strategy with the minimum number for degrees of actuation for anthropomorphic hands. This work evaluates the correlations of coordinated movements in human hands during 23 grasp tasks to suggest actuation strategies for anthropomorphic hands. Our approach proceeds as follows: first, we find the best description for each coordinated joint movement in each grasp task by using multiple linear regression; then, based on the similarities between joint movements, we classify hand joints into groups by using hierarchical cluster analysis; finally, we reduce the dimensionality of each group of joints by employing principal components analysis. The metacarpophalangeal joints and proximal interphalangeal joints have the best and most consistent description of their coordinated movements across all grasp tasks. The thumb metacarpophalangeal and abduction/adduction between the ring and little fingers exhibit relatively high independence of movement. The distal interphalangeal joints show a high degree of independent movement but not for all grasp tasks. Analysis of the results indicates that for the distal interphalangeal joints, their coordinated movements are better explained when all fingers wrap around the object. Our approach fails to provide more information for the other joints. We conclude that 19 degrees of freedom for an anthropomorphic hand can be reduced to 13 degrees of actuation distributed between six groups of joints. The number of degrees of actuation can be further reduced to six by relaxing the dimensionality reduction criteria. Other resolutions are as follows: (a) the joint coupling scheme should be joint-based rather than finger-based and (b) hand designs may need to include finger abduction/adduction movements.

scholarly journals NTU Hand: A New Design of Dexterous Hands

1998 ◽  
Vol 120 (2) ◽  
pp. 282-292 ◽  
Author(s):  
Li-Ren Lin ◽  
Han-Pang Huang
Keyword(s):  
Degrees Of Freedom ◽  
Industrial Robot ◽  
Point Of View ◽  
Human Hand ◽  
Three Dimension ◽  
Robot Arm ◽  
Specific Point ◽  
Mechanical Parts ◽  
Compact Design ◽  
The Relationship

A new five-finger robot hand (NTU hand) with seventeen degrees of freedom (DOF) is developed in this paper. In contrast to traditional tendon-driven robots, the NTU hand has an uncoupled configuration that each finger and joint are all individually driven. Since all actuators, mechanical parts and sensors are packed on the hand, the size of NTU hand is almost the same as a human hand. Such compact design makes the hand easily adapt to the industrial robot arm and the prosthetic applications. Based on the mechanical structure of the NTU hand, the direct and inverse kinematics are developed. In addition, computer simulation with three-dimension graphics is built to evaluate the manipulable range of the NTU hand. From the simulation, the relationship between the hand and the grasped object in a specific point of view can be obtained.

scholarly journals A Single-Actuated, Cable-Driven, and Self-Contained Robotic Hand Designed for Adaptive Grasps

Robotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 109
Author(s):  
Negin Nikafrooz ◽  
Alexander Leonessa
Keyword(s):  
Degrees Of Freedom ◽  
Power Transmission ◽  
Transmission System ◽  
Human Hand ◽  
Robotic Hand ◽  
Power Transmission System ◽  
Wide Range ◽  
3D Printed ◽  
Design Characteristics ◽  
And Control

Developing a dexterous robotic hand that mimics natural human hand movements is challenging due to complicated hand anatomy. Such a practical design should address several requirements, which are often conflicting and force the designer to prioritize the main design characteristics for a given application. Therefore, in the existing designs the requirements are only partially satisfied, leading to complicated and bulky solutions. To address this gap, a novel single-actuated, cable-driven, and self-contained robotic hand is presented in this work. This five-fingered robotic hand supports 19 degrees of freedom (DOFs) and can perform a wide range of precision and power grasps. The external structure of fingers and the thumb is inspired by Pisa/IIT SoftHand, while major modifications are implemented to significantly decrease the number of parts and the effect of friction. The cable configuration is inspired by the tendon structure of the hand anatomy. Furthermore, a novel power transmission system is presented in this work. This mechanism addresses compactness and underactuation, while ensuring proper force distribution through the fingers and the thumb. Moreover, this power transmission system can achieve adaptive grasps of objects with unknown geometries, which significantly simplifies the sensory and control systems. A 3D-printed prototype of the proposed design is fabricated and its base functionality is evaluated through simulations and experiments.

scholarly journals Development and Evaluation of an Adaptive Multi-DOF Finger with Mechanical-Sensor Integrated for Prosthetic Hand

Micromachines ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 33
Author(s):  
Changcheng Wu ◽  
Tianci Song ◽  
Zilong Wu ◽  
Qingqing Cao ◽  
Fei Fei ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Joint Angle ◽  
Angle Measurement ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Finger Joints ◽  
Adaptive Motion ◽  
Distal Interphalangeal ◽  
Measurement Principle ◽  
Mechanical Sensor

To realize the adaptive grasping of objects with diverse shapes and to capture the joint angles of the finger, a multi degree of freedom (DOF) adaptive finger for prosthetic hand is proposed in this paper. The fingers are designed with three joints. The maximum rotation angle of the finger joints is 90°. The angle at which the finger joints bend can be captured. Firstly, the prototype design, forward kinematics and force analysis of phalanges are described in detail. In order to achieve an adaptive motion pattern similar to that of the human hand, this paper investigates the optimization of the torsion spring stiffness coefficient so that the metacarpophalangeal (MCP) joints, proximal interphalangeal (PIP) joints, and distal interphalangeal (DIP) joints of the bionic finger meet a motion ratio of approximately 3:3:1. Then, in order to realize the joint angle measurement in the process of grasping an object, the mechanical-sensor integrated finger joint is designed, and the composition, angle measurement principle and measurement circuit are introduced in detail. Finally, joint angle measurement, movement law evaluation and object grasping experiments are performed to verify the validity of the designed finger. The experimental results show that the root-mean-square (RMS) of the DIP, PIP and MCP angle measurement errors are 0.36°, 0.59° and 0.32°, respectively. The designed finger is able to grasp objects with different shapes stably.

scholarly journals Soft Exoskeletons: Development, Requirements, and Challenges of the Last Decade

Actuators ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 166
Author(s):  
Alan Francisco Pérez Vidal ◽  
Jesse Yoe Rumbo Morales ◽  
Gerardo Ortiz Torres ◽  
Felipe de Jesús Sorcia Vázquez ◽  
Alan Cruz Rojas ◽  
...  
Keyword(s):  
Control Systems ◽  
Degrees Of Freedom ◽  
Power Transmission ◽  
Structural Characteristics ◽  
Current Trend

In this article, various investigations on soft exoskeletons are presented and their functional and structural characteristics are analyzed. The present work is oriented to the studies of the last decade and covers the upper and lower joints, specifically the shoulder, elbow, wrist, hand, hip, knee, and ankle. Its functionality, applicability, and main characteristics are exposed, such as degrees of freedom, force, actuators, power transmission methods, control systems, and sensors. The purpose of this work is to show the current trend in the development of soft exoskeletons, in addition to specifying the essential characteristics that must be considered in its design and the challenges that its construction implies.

scholarly journals Design and multichannel electromyography system-based neural network control of a low-cost myoelectric prosthesis hand

2021 ◽  
Vol 12 (1) ◽  
pp. 69-83
Author(s):  
Saygin Siddiq Ahmed ◽  
Ahmed R. J. Almusawi ◽  
Bülent Yilmaz ◽  
Nuran Dogru
Keyword(s):  
Neural Network ◽  
Control Method ◽  
Low Cost ◽  
Hand Movement ◽  
Cost Effective ◽  
Network Control ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Myoelectric Prosthesis ◽  
System File

Abstract. This study introduces a new control method for electromyography (EMG) in a prosthetic hand application with a practical design of the whole system. The hand is controlled by a motor (which regulates a significant part of the hand movement) and a microcontroller board, which is responsible for receiving and analyzing signals acquired by a Myoware muscle device. The Myoware device accepts muscle signals and sends them to the controller. The controller interprets the received signals based on the designed artificial neural network. In this design, the muscle signals are read and saved in a MATLAB system file. After neural network program processing by MATLAB, they are then applied online to the prosthetic hand. The obtained signal, i.e., electromyogram, is programmed to control the motion of the prosthetic hand with similar behavior to a real human hand. The designed system is tested on seven individuals at Gaziantep University. Due to the sufficient signal of the Mayo armband compared to Myoware sensors, Mayo armband muscle is applied in the proposed system. The discussed results have been shown to be satisfactory in the final proposed system. This system was a feasible, useful, and cost-effective solution for the handless or amputated individuals. They have used the system in their day-to-day activities that allowed them to move freely, easily, and comfortably.

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