A Single-DOF Multi-Function Prosthetic Hand Mechanism With an Automatically Variable Speed Transmission

1992 ◽  
Author(s):  
Gongliang Guo ◽  
Xikang Qian ◽  
Willim A. Gruver
Keyword(s):  
Human Hand ◽  
Prosthetic Hand ◽  
Variable Speed ◽  
Prosthetic Device ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Flexion Extension ◽  
Robotic Applications ◽  
Fingertip Forces ◽  
Human Hands

Abstract This research concerns the design of a new three-fingered anthropomorphic hand mechanism for prosthetic and robotic applications. Based on the configuration and flexion/extension features of human hands, we develop a three-jointed finger mechanism using a gear-constrained planar five-bar linkage with a single degree of freedom (DOF). From an operational study of human hands, we also propose a multi-functional palm mechanism using a cam-groove submechanism. The hand can perform grasping, holding and pinching operations. To achieve the automatic shape adaptability of a human hand, a selfadaptable submechanism was designed within the palm based on the lever principle. An automatically variable speed transmission with selfadaptability was developed for this hand to achieve optimal flexing speed and optimal fingertip forces. This paper describes the mechanical structure and operational principles of this new prosthetic device.

The Influence of the Abduction Joints of Four Fingers to Grasp: Experimental and Simulated Verification

2021 ◽  
Vol 11 (24) ◽  
pp. 11960
Author(s):  
Yadong Yan ◽  
Chang Cheng ◽  
Mingjun Guan ◽  
Jianan Zhang ◽  
Yu Wang
Keyword(s):  
Success Rate ◽  
Hand Function ◽  
Great Influence ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Robotic Hand ◽  
Metacarpophalangeal Joints ◽  
Flexion Extension ◽  
Grasp Force ◽  
Grasp Quality

The thumb is the most important finger of the human hand and has a great influence on grasp manipulations. However, the extent to which joints other than the thumb joints affect the grasp, and thus, which joints should be included in a prosthetic hand, remains an open issue. In this paper, we focus on the metacarpophalangeal joints of the four fingers, except the thumb, which can generate flexion/extension and abduction/adduction motions. The contribution of these joints to grasping was evaluated in four aspects: grasp size, grasp force, grasp quality and grasp success rate. Six subjects participated in experiments with respect to the maximum grasp size and grasp force. The results show that possessing abduction mobility of the metacarpophalangeal joints can increase the grasp size by 4.67 ± 1.93 mm and the grasp force by 5.27 ± 4.25 N. Then, the grasping quality and success rate were tested in a simulation platform and using a robotic hand, respectively. The results show that grasp quality was promoted by 76.7% in the simulated environment with abduction mobility compared to without abduction mobility, whereas the grasp success rate was promoted by 68.3%. We believe that the results of this work can benefit the understanding of hand function and prosthetic hand design.

Biomechatronic design and control of an anthropomorphic artificial hand for prosthetic applications

Robotica ◽  
2015 ◽  
Vol 34 (10) ◽  
pp. 2291-2308 ◽  
Author(s):  
Ting Zhang ◽  
Xin Qing Wang ◽  
Li Jiang ◽  
Xinyu Wu ◽  
Wei Feng ◽  
...  
Keyword(s):  
Low Cost ◽  
Feedback System ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Natural Motion ◽  
Flexion Extension ◽  
Artificial Hand ◽  
Human Finger ◽  
Electrical Stimulator ◽  
And Control

SUMMARYIn this paper, we propose a biomechatronic design of an anthropomorphic artificial hand that is able to mimic the natural motion of human fingers. The prosthetic hand has 5 fingers and 15 joints, which are actuated by 5 embedded motors. Each finger has three phalanges that can fulfill flexion-extension movements independently. The thumb is specially designed to move along a cone surface when grasping, and the other four fingers are well developed based on the four-bar link mechanism to imitate the motion of the human finger. To accomplish the sophisticated control schemes, the fingers are equipped with numerous torque and position sensors. The mechanical parts, sensors, and motion control systems are integrated in the hand structure, and the motion of the hand can be controlled through electromyography (EMG) signals in real-time. A new concept for the sensory feedback system based on an electrical stimulator is also taken into account. The low-cost prosthetic hand is small in size (85% of the human hand), of low weight (420 g) and has a large grasp power (10 N on the fingertips), hence it has a dexterous and humanlike appearance. The performance of the prosthetic hand is validated in a clinical evaluation on transradial amputees.

Design and Integration of a Two-Digit Exoskeleton Glove

2017 ◽  
Author(s):  
Eric Refour ◽  
Bijo Sebastain ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Experimental Validation ◽  
Index Finger ◽  
Human Hand ◽  
Interaction Forces ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Coupling Relationship ◽  
Active Flexion ◽  
Normal Human ◽  
Flexion And Extension

This paper presents the design and integration of a two-digit exoskeleton glove. The proposed glove is designed to assist the user with grasping motions, such as the pincer grasp, while maintaining a natural coupling relationship among the finger and thumb joints, resembling that of a normal human hand. The design employs single degree of freedom linkage mechanisms to achieve active flexion and extension of the index finger and thumb. This greatly reduces the overall weight and size of the system making it ideal for prolonged usage. The paper describes the design, mathematical modeling of the proposed system, detailed electromechanical design, and software architecture of the integrated prototype. The prototype is capable of recording information about the index finger and thumb movements, interaction forces exerted by the finger/thumb on the exoskeleton, and can provide feedback through vibration. In addition, the glove can serve as a standalone device for rehabilitation purposes, such as assisting in achieving tip or pulp pinch. The paper concludes with an experimental validation of the proposed design by comparing the motion produced using the exoskeleton glove on a wooden mannequin with that of a natural human hand.

The influence of passive wrist joints on the functionality of prosthetic hands

2011 ◽  
Vol 36 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Peter J Kyberd
Keyword(s):  
Repeated Measures ◽  
Degree Of Freedom ◽  
Functional Score ◽  
Single Subject ◽  
Prosthetic Hand ◽  
Wrist Flexion ◽  
Single Degree Of Freedom ◽  
Prosthetic Hands ◽  
Single Degree ◽  
Wrist Flexor

Background: The addition of a passive wrist to a single degree of freedom prosthesis has an effect on its functionality. The amount of impact is undetermined.Objectives: To measure the grasping function of a commercial single degree of freedom hands with and without two forms of passive wrist flexor.Study Design: Form-board and timed tasks.Method: Repeated measures with a single subject using a validated assessment tool. The test measured the function of one conventional, single axis, powered hand controlled by the same myocontroller format. It was used in conjunction with a passive three position wrist flexor, a wrist with compliance in the flex/extend and radial/ulnar deviation and compared with a hand without these axes.Results: The overall functional score of the hand alone was 80 out of 100. The use of a wrist flexion unit resulted in a higher score (83) and the compliant wrist achieved a score of 79. The addition of a wrist allowed improved performance in Power, Lateral and Tips grips for both wrist designs, in addition the Extension grip was improved with the compliant wrist.Conclusion: Wrist flexion had a positive impact on the functional score. It enabled some tasks to be performed quicker and with less difficulty.Clinical relevanceThe majority of prosthetic hands have pro/supination yet there is little evidence about what impact this, or any other motion at the wrist, has on the overall functional capabilities of a prosthetic hand (i.e. grip). A commercial myoelectric prosthetic hand when used with and without two different wrist designs can potentially improve grip performance.

scholarly journals A cross-species neural integration of gravity for motor optimization

2021 ◽  
Vol 7 (15) ◽  
pp. eabf7800
Author(s):  
Jeremie Gaveau ◽  
Sidney Grospretre ◽  
Bastien Berret ◽  
Dora E. Angelaki ◽  
Charalambos Papaxanthis
Keyword(s):  
Optimization Strategy ◽  
Motor Patterns ◽  
Activation Patterns ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Neural Integration ◽  
Gravity Effects ◽  
Neural Signature ◽  
Experimental Findings ◽  
Muscular Activation

Recent kinematic results, combined with model simulations, have provided support for the hypothesis that the human brain shapes motor patterns that use gravity effects to minimize muscle effort. Because many different muscular activation patterns can give rise to the same trajectory, here, we specifically investigate gravity-related movement properties by analyzing muscular activation patterns during single-degree-of-freedom arm movements in various directions. Using a well-known decomposition method of tonic and phasic electromyographic activities, we demonstrate that phasic electromyograms (EMGs) present systematic negative phases. This negativity reveals the optimal motor plan’s neural signature, where the motor system harvests the mechanical effects of gravity to accelerate downward and decelerate upward movements, thereby saving muscle effort. We compare experimental findings in humans to monkeys, generalizing the Effort-optimization strategy across species.

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.

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