scholarly journals Design of 3D-printed Cable Driven Humanoid Hand Based on Bidirectional Elastomeric Passive Transmission

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Teru Chen ◽  
Xingwei Zhao ◽  
Guocai Ma ◽  
Bo Tao ◽  
Zhouping Yin
Keyword(s):  
Human Hand ◽  
Good Balance ◽  
Dynamical Simulation ◽  
Complex Part ◽  
Grasping Force ◽  
3D Printed ◽  
And Performance ◽  
Human Finger ◽  
The Cost ◽  
Humanoid Hand

AbstractMotion control of the human hand is the most complex part of the human body. It has always been a challenge for a good balance between the cost, weight, responding speed, grasping force, finger extension, and dexterity of prosthetic hand. To solve these issues, a 3D-printed cable driven humanoid hand based on bidirectional elastomeric passive transmission (BEPT) is designed in this paper. A semi-static model of BEPT is investigated based on energy conservation law to analyze the mechanical properties of BEPT and a dynamical simulation of finger grasping is conducted. For a good imitation of human hand and an excellent grasping performance, specific BEPT is selected according to human finger grasping experiments. The advantage of BEPT based humanoid hand is that a good balance between the price and performance of the humanoid hand is achieved. Experiments proved that the designed prosthetic hand’s single fingertip force can reach 33 N and the fastest fingertip grasping speed realized 0.6 s/180°. It also has a good force compliance effect with only 430g’s weight. It can not only grab fragile objects like raw eggs and paper cup, but also achieve strong grasping force to damage metal cans. This humanoid hand has considerable application prospects in artificial prosthesis, human-computer interaction, and robot operation.

scholarly journals Design of 3D-Printed Cable Driven Humanoid Hand Based on Bidirectional Elastomeric Passive Transmission

2020 ◽  
Author(s):  
Te-Ru Chen ◽  
Xing-Wei Zhao ◽  
Guo-Cai Ma ◽  
Bo Tao ◽  
Zhou-Ping Yin
Keyword(s):  
Human Hand ◽  
Control Effect ◽  
Good Balance ◽  
Complex Part ◽  
Grasping Force ◽  
3D Printed ◽  
And Performance ◽  
Human Finger ◽  
The Cost ◽  
Humanoid Hand

Abstract Motion control of the human hand is the most complex part of the human body. It has always been a challenge for a good balance between the cost, weight, responding speed, grasping force, finger extension, and dexterity of prosthetic hand. In order to research and imitate the movement of the human hand, a 3D-printed cable driven humanoid hand based on bidirectional elastomeric passive transmission (BEPT) is designed in this paper. A semi-static model of BEPT is investigated based on energy conservation law to analyze the mechanical properties of BEPT. Then a simulation of dynamics of finger grasping is conducted. For a better imitation of human hand and a better grasping performance, specific BEPT is selected according to human finger grasping experiments. The advantage of BEPT based humanoid hand is that a good balance between the price and performance of the humanoid hand is achieved. Experiments proved that designed humanoid hand’s excellent grasping performance can be realized through BEPT. The designed prosthetic hand’s single fingertip force can reach 33N and has a good force control effect with 430g’s weight. It can not only grab fragile objects like raw eggs and paper cup, but also achieve strong grasping force to damage metal cans.

scholarly journals Suitability of the Openly Accessible 3D Printed Prosthetic Hands for War-Wounded Children

2021 ◽  
Vol 7 ◽  
Author(s):  
John-John Cabibihan ◽  
Farah Alkhatib ◽  
Mohammed Mudassir ◽  
Laurent A. Lambert ◽  
Osama S. Al-Kwifi ◽  
...  
Keyword(s):  
Credit Card ◽  
Cost Model ◽  
Low Cost ◽  
Human Hand ◽  
Prosthetic Hands ◽  
Grasping Force ◽  
3D Printers ◽  
3D Printed ◽  
The Cost

The field of rehabilitation and assistive devices is being disrupted by innovations in desktop 3D printers and open-source designs. For upper limb prosthetics, those technologies have demonstrated a strong potential to aid those with missing hands. However, there are basic interfacing issues that need to be addressed for long term usage. The functionality, durability, and the price need to be considered especially for those in difficult living conditions. We evaluated the most popular designs of body-powered, 3D printed prosthetic hands. We selected a representative sample and evaluated its suitability for its grasping postures, durability, and cost. The prosthetic hand can perform three grasping postures out of the 33 grasps that a human hand can do. This corresponds to grasping objects similar to a coin, a golf ball, and a credit card. Results showed that the material used in the hand and the cables can withstand a 22 N normal grasping force, which is acceptable based on standards for accessibility design. The cost model showed that a 3D printed hand could be produced for as low as $19. For the benefit of children with congenital missing limbs and for the war-wounded, the results can serve as a baseline study to advance the development of prosthetic hands that are functional yet low-cost.

3-D Printed Orthotic Hand With Wrist Mechanism Using Twisted and Coiled Polymeric Muscles

2017 ◽  
Author(s):  
Ashvath Sharma ◽  
Lokesh Saharan ◽  
Yonas Tadesse
Keyword(s):  
Metacarpophalangeal Joint ◽  
Proximal Interphalangeal Joint ◽  
Interphalangeal Joint ◽  
Human Hand ◽  
Custom Made ◽  
Normal Hand ◽  
3D Printed ◽  
And Performance ◽  
Electrical Motors ◽  
Human Finger

Most stroke victims undergo muscular disorders leading to weakening of muscles and inability to perform normal hand activities. An exoskeleton device is therefore needed to aid in performing basic hand movements to improve the quality of life of the victims. Most of the available devices in literature are controlled using electrical motors with a rigid structure and complex design. This paper discusses the design and performance of an inexpensive and lightweight 3D printed orthotic device featuring a wrist mechanism. The design is simple and utilizes twisted and coiled polymeric (TCP) muscles which are easy to fabricate using a silver coated nylon 6, 6 threads. The device facilitates the movement of all the three joints of the human finger namely, distal interphalangeal joint (DIP), proximal interphalangeal joint (PIP) and the metacarpophalangeal joint (MCP). Experiments were performed using a custom-made hand which was 3D printed and casted using silicone rubber with a shore hardness 10 (Ecoflex® 010) to resemble an actual human hand. The results showed the range of motion achieved with the device, grasping and pinching of various objects with assistive efforts using TCP muscles and demonstrated the capability of the device to achieve flexion and extension of the fingers mimicking the human finger movements.

Android Hands: A State-of-the-Art Report

2014 ◽  
Author(s):  
Evgenios Vlachos ◽  
Henrik Schärfe
Keyword(s):  
Literature Review ◽  
State Of The Art ◽  
Structure Functions ◽  
Social Robot ◽  
The State ◽  
Human Hand ◽  
Prosthetic Hands ◽  
Available Technology ◽  
And Performance ◽  
Humanoid Hand

Humans have adjusted their space, their actions, and their performed tasks according to their morphology, abilities, and limitations. Thus, the properties of a social robot should fit within these predetermined boundaries when, and if it is beneficial for the user, and the notion of the task. On such occasions, android and humanoid hand models should have similar structure, functions, and performance as the human hand. In this paper we present the anatomy, and the key functionalities of the human hand followed by a literature review on android/humanoid hands for grasping and manipulating objects, as well as prosthetic hands, in order to inform roboticists about the latest available technology, and assist their efforts to describe the state-of-the-art in this field.

Return on Invesment (ROI) of Software Product: A Systematic Literature Review

2015 ◽  
Vol 6 (1) ◽  
pp. 50-57
Author(s):  
Rizqa Raaiqa Bintana ◽  
Putri Aisyiyah Rakhma Devi ◽  
Umi Laili Yuhana
Keyword(s):  
Return On Investment ◽  
Assessment Criteria ◽  
Software Product ◽  
And Performance ◽  
Rational Consideration ◽  
Actual Return ◽  
The Cost ◽  
Investment Models ◽  
The Impact

The quality of the software can be measured by its return on investment. Factors which may affect the return on investment (ROI) is the tangible factors (such as the cost) dan intangible factors (such as the impact of software to the users or stakeholder). The factor of the software itself are assessed through reviewing, testing, process audit, and performance of software. This paper discusses the consideration of return on investment (ROI) assessment criteria derived from the software and its users. These criteria indicate that the approach may support a rational consideration of all relevant criteria when evaluating software, and shows examples of actual return on investment models. Conducted an analysis of the assessment criteria that affect the return on investment if these criteria have a disproportionate effort that resulted in a return on investment of a software decreased. Index Terms - Assessment criteria, Quality assurance, Return on Investment, Software product

scholarly journals A Knitted Sensing Glove for Human Hand Postures Pattern Recognition

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1364
Author(s):  
Seulah Lee ◽  
Yuna Choi ◽  
Minchang Sung ◽  
Jihyun Bae ◽  
Youngjin Choi
Keyword(s):  
Pattern Recognition ◽  
Confusion Matrix ◽  
Strain Sensors ◽  
Mixed Data ◽  
Human Hand ◽  
Flexible Sensors ◽  
Target Hand ◽  
The Cost ◽  
Grasp Posture ◽  
Conductive Yarn

In recent years, flexible sensors for data gloves have been developed that aim to achieve excellent wearability, but they are associated with difficulties due to the complicated manufacturing and embedding into the glove. This study proposes a knitted glove integrated with strain sensors for pattern recognition of hand postures. The proposed sensing glove is fabricated at all once by a knitting technique without sewing and bonding, which is composed of strain sensors knitted with conductive yarn and a glove body with non-conductive yarn. To verify the performance of the developed glove, electrical resistance variations were measured according to the flexed angle and speed. These data showed different values depending on the speed or angle of movements. We carried out experiments on hand postures pattern recognition for the practicability verification of the knitted sensing glove. For this purpose, 10 able-bodied subjects participated in the recognition experiments on 10 target hand postures. The average classification accuracy of 10 subjects reached 94.17% when their own data were used. The accuracy of up to 97.1% was achieved in the case of grasp posture among 10 target postures. When all mixed data from 10 subjects were utilized for pattern recognition, the average classification expressed by the confusion matrix arrived at 89.5%. Therefore, the comprehensive experimental results demonstrated the effectiveness of the knitted sensing gloves. In addition, it is expected to reduce the cost through a simple manufacturing process of the knitted sensing glove.

scholarly journals Preparation and Performance Evaluation of Duotone 3D-Printed Polyetheretherketone as Oral Prosthetic Materials: A Proof-of-Concept Study

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1949
Author(s):  
Ling Ding ◽  
Wei Lu ◽  
Jiaqi Zhang ◽  
Chuncheng Yang ◽  
Guofeng Wu
Keyword(s):  
Titanium Dioxide ◽  
Performance Evaluation ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Flexural Properties ◽  
Proof Of Concept ◽  
Tooth Color ◽  
Dental Application ◽  
3D Printed ◽  
And Performance

Literature has reported the successful use of 3D printed polyetheretherketone (PEEK) to fabricate human body implants and oral prostheses. However, the current 3D printed PEEK (brown color) cannot mimic the vivid color of oral tissues and thus cannot meet the esthetical need for dental application. Therefore, titanium dioxide (TiO2) and ferric oxide (Fe2O3) were incorporated into PEEK to prepare a series of tooth-color and gingival-color PEEK composites in this study. Through color measurements and mechanical tests, the color value and mechanical performance of the 3D printed PEEK composites were evaluated. In addition, duotone PEEK specimens were printed by a double nozzle with an interface between tooth-color and gingival-color parts. The mechanical performance of duotone PEEK with two different interfaces (horizontal and vertical) was investigated. With the addition of TiO2 and Fe2O3, the colors of 3D printed PEEK composites become closer to that of dental shade guides. 3D printed PEEK composites generally demonstrated superior tensile and flexural properties and hence have great potential in the dental application. In addition, duotone 3D printed PEEK with a horizontal interfacial orientation presented better mechanical performance than that with a vertical one.

3D PRINTED HEXAPOD ROBOT ACTUATED BY SHAPE MEMORY ALLOY SPRINGS: DESIGN AND PERFORMANCE ANALYSIS

2021 ◽  
Author(s):  
Edilberto Alves de Abrantes Júnior ◽  
Augusto Figueiredo ◽  
Carlos Jose de Araujo ◽  
Raimundo Duarte
Keyword(s):  
Performance Analysis ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Hexapod Robot ◽  
3D Printed ◽  
And Performance

Characterisation of Static Strip Seal Flow

2007 ◽  
Author(s):  
Arash Farahani ◽  
Peter Childs
Keyword(s):  
Gas Flow ◽  
Pressure Ratio ◽  
Flow Characteristics ◽  
Main Stream ◽  
Cfd Modelling ◽  
Height Range ◽  
And Performance ◽  
Nozzle Guide ◽  
The Cost ◽  
Cooling Air

Strip seals are used in gas turbine engines between two static elements or between components which do not move relative to each other, such as Nozzle Guide Vanes (NGVs). The key role of a strip seal between NGV segments is sealing between the flow through the main stream annulus and the internal air system, a further purpose is to limit the inter-segmental movements. In general the shape of the strip seal is a rectangular strip that fits into two slots in adjacent components. The minimum clearance required for static strip seals must be found by accounting for thermal expansion, misalignment, and application, to allow correct fitment of the strip seals. Any increase in leakage raises the cost due to an increase in the cooling air use, which is linked to specific fuel consumption, and it can also alter gas flow paths and performance. The narrow path within the seal assembly, especially the height has the most significant affect on leakage. The height range of the narrow path studied in this paper is 0.01–0.06 mm. The behaviour of the flow passing through the narrow path has been studied using CFD modelling and measurements in a bespoke rig. The CFD and experimental results show that normalized leakage flow increases with pressure ratio before reaching a maximum. The main aim of this paper is to provide new experimental data to verify the CFD modelling for static strip seals. The typical flow characteristics validated by CFD modelling and experiments can be used to predict the flow behaviour for future static strip seal designs.

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