Developing a Prosthesis Design using A Gearbox to Replicate the Human Hand Mechanism

Prosthetic is an artificial tool that replaces a member of the human frame that is absent because of ailment, damage, or distortion. The current research activities in Iraq draw interest to the upper limb discipline because of the growth in the number of amputees. Thus, it becomes necessary to increase researches in this subject to help in reducing the struggling patients. This paper describes the design and development of a prosthesis for people able and wear them from persons who have amputation in the hands. This design is composed of a hand with five fingers moving by means of a gearbox ism mechanism. The design of this artificial hand has 5 degrees of freedom. This artificial hand works based on the principle of under actuated system. The used motor is 6V Polulu high-power carbon brush micro metal gearmotor with gear ratio equal to 50:1. The motor was chosen due to its compactness and cheapness. The hand manufacturing process was done using a 3D printer and using polylactic acid material. Numbers of experiments were accomplished using the designed hand for gripping objects. Initially, the electromyography signal (EMG) was recorded when the muscle contracted in one second, two seconds, three seconds. The synthetic hand was able to produce a range of gestures and grasping for objects.

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Design of Multiple Wearable Robotic Extra Fingers for Human Hand Augmentation

Robotics ◽

10.3390/robotics8040102 ◽

2019 ◽

Vol 8 (4) ◽

pp. 102 ◽

Cited By ~ 2

Author(s):

Monica Malvezzi ◽

Zubair Iqbal ◽

Maria Cristina Valigi ◽

Maria Pozzi ◽

Domenico Prattichizzo ◽

...

Keyword(s):

Upper Limb ◽

Manufacturing Process ◽

Research Topic ◽

Human Hand ◽

Mechanical Resistance ◽

External Disturbances ◽

Passive Element ◽

Single Finger ◽

Differential Mechanism ◽

Potential Applications

Augmenting the human hand with robotic extra fingers is a cutting-edge research topic and has many potential applications, in particular as a compensatory and rehabilitation tool for patients with upper limb impairments. Devices composed of two extra fingers are preferred with respect to single finger devices when reliable grasps, resistance to external disturbances, and higher payloads are required. Underactuation and compliance are design choices that can reduce the device complexity and weight, maintaining the adaptability to different grasped objects. When only one motor is adopted to actuate multiple fingers, a differential mechanism is necessary to decouple finger movements and distribute forces. In this paper, the main features of a wearable device composed of two robotic extra fingers are described and analyzed in terms of kinematics, statics, and mechanical resistance. Each finger is composed of modular phalanges and is actuated with a single tendon. Interphalangeal joints include a passive elastic element that allows restoring the initial reference configuration when the tendon is released. The stiffness of each passive element can be customized in the manufacturing process and can be chosen according to a desired closure movement of the fingers. Another key aspect of the device is the differential system connecting the actuator to the fingers.

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EXPRO: exoskeleton for rehabilitation of upper limb

Visión electrónica ◽

10.14483/22484728.18381 ◽

2018 ◽

Vol 1 (2) ◽

pp. 227-233

Author(s):

Javier Fernando Garnica-Molina ◽

Juan Nicolás Bustos-Ramírez ◽

Jessica Zuleima Parrado-Agudelo ◽

Cristian Mauricio Casallas-Contreras ◽

Luis Miguel Méndez-Moreno

Keyword(s):

Finite Elements ◽

Polylactic Acid ◽

Upper Limb ◽

Degrees Of Freedom ◽

Raspberry Pi ◽

Upper Limb Rehabilitation ◽

Power And Control ◽

3D Software ◽

Limb Rehabilitation ◽

And Control

In the upper limb rehabilitation field, assisting to various patients per day, in different kinds of therapies is an exhausting task which can be achieved in a semiautomated or automated manner. The ExPro is an exoskeleton of 3 degrees of freedom designed and created to support rehabilitation treatments for patients with little or no mobility in their arms. The device consists in a machine able to move forearm and wrist according to prone-supination, ulnar and radial deflection and flex-extension of wrist movements. The proposed prototype was designed to assist therapists in the first step of rehabilitation treatments, thus, passive therapies. Each mechanical component was designed in the Inventor 3D software and printed on PLA materials (polylactic acid). The controlling step is a Raspberry Pi 3 that receives information, interprets and connects power, and control PCBs. The design and calculations were tasted with the finite elements tool of inventor software. The work result presents an exoskeleton prototype easy to operate and transport, safe for the patient and able to carry out several preprogramed movements.

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Low-Cost Prosthesis for People with Transradial Amputations

Al-Nahrain Journal for Engineering Sciences ◽

10.29194/njes.23020167 ◽

2020 ◽

Vol 23 (2) ◽

pp. 167-177

Author(s):

Hneen Mahdi Jaber ◽

Mohammed A. Mohammed ◽

Nabel Kadhim Abd al-Sahib

Keyword(s):

3D Printing ◽

Degrees Of Freedom ◽

Low Cost ◽

Gear Ratio ◽

Ansys Software ◽

Maximum Deformation ◽

Emg Signal ◽

Actuation System ◽

Knn Classification ◽

Artificial Hand

Prosthetic is an artificial tool that replaces part of the human frame absent because of ailment, damage, or distortion. The current activities in Iraq draw interest to the upper limb discipline because of the growth in variety of amputees and. It is necessary to do extensive researches in this subject to help lessen the struggling of patients. This paper describes the design and development of low-cost prosthesis for people with transradial amputations. The presented design involves a hand with five fingers moving by means of a gear box mechanism. The design of this artificial hand allows five degrees of freedom(5DOF), one degree of freedom for each finger. The artificial hand works by an actuation system (6V) Polou motor with gear ratio equal to 50:1 due to its compactness and cheapness. The designed hand was manufactured by a 3D printing process using polylacticacid material (PLA). Some experimental were accomplished using the designed hand for gripping objects. Initially the EMG signal was recorded when the muscle contracted in one second, two seconds, three seconds. The synthetic hand was able to produce range of gesture and grasping moves separately just like the actual hand by using KNN classification which are complete hand Pinch, fist, and jack chuck. The simulation of the fingers movements was achieved using ANSYS software to analysis the movement (pinch, fist, and jack chuck), obtain bested of stress influencer at each finger, and maximum deformation at each movement.

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COMPARING DIFFERENT MATERIALS OF I-JOIST: WOODEN COMPOSITE AND POLYLACTIC ACID 3D PRINTER PLASTIC

European Journal of Technical and Natural Sciences ◽

10.29013/ejtns-20-4-43-49 ◽

2020 ◽

pp. 43-49

Author(s):

M. Saranov ◽

H. Yingcheng

Keyword(s):

Polylactic Acid ◽

3D Printer

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A 4-DOF Upper Limb Exoskeleton for Physical Assistance: Design, Modeling, Control and Performance Evaluation

Applied Sciences ◽

10.3390/app11135865 ◽

2021 ◽

Vol 11 (13) ◽

pp. 5865

Author(s):

Muhammad Ahsan Gull ◽

Mikkel Thoegersen ◽

Stefan Hein Bengtson ◽

Mostafa Mohammadi ◽

Lotte N. S. Andreasen Struijk ◽

...

Keyword(s):

Upper Limb ◽

Tracking Control ◽

Degrees Of Freedom ◽

Control Method ◽

Mechanical Design ◽

Trajectory Tracking Control ◽

Upper Limb Exoskeleton ◽

And Performance ◽

Physically Disabled People ◽

Human Upper Limb

Wheelchair mounted upper limb exoskeletons offer an alternative way to support disabled individuals in their activities of daily living (ADL). Key challenges in exoskeleton technology include innovative mechanical design and implementation of a control method that can assure a safe and comfortable interaction between the human upper limb and exoskeleton. In this article, we present a mechanical design of a four degrees of freedom (DOF) wheelchair mounted upper limb exoskeleton. The design takes advantage of non-backdrivable mechanism that can hold the output position without energy consumption and provide assistance to the completely paralyzed users. Moreover, a PD-based trajectory tracking control is implemented to enhance the performance of human exoskeleton system for two different tasks. Preliminary results are provided to show the effectiveness and reliability of using the proposed design for physically disabled people.

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Dzyaloshinskii–Moriya interaction in noncentrosymmetric superlattices

npj Computational Materials ◽

10.1038/s41524-021-00592-8 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Woo Seung Ham ◽

Abdul-Muizz Pradipto ◽

Kay Yakushiji ◽

Kwangsu Kim ◽

Sonny H. Rhim ◽

...

Keyword(s):

Heavy Metal ◽

Degrees Of Freedom ◽

Orbit Coupling ◽

Inversion Symmetry ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Band Formation ◽

Research Activities ◽

Moriya Interaction

AbstractDzyaloshinskii–Moriya interaction (DMI) is considered as one of the most important energies for specific chiral textures such as magnetic skyrmions. The keys of generating DMI are the absence of structural inversion symmetry and exchange energy with spin–orbit coupling. Therefore, a vast majority of research activities about DMI are mainly limited to heavy metal/ferromagnet bilayer systems, only focusing on their interfaces. Here, we report an asymmetric band formation in a superlattices (SL) which arises from inversion symmetry breaking in stacking order of atomic layers, implying the role of bulk-like contribution. Such bulk DMI is more than 300% larger than simple sum of interfacial contribution. Moreover, the asymmetric band is largely affected by strong spin–orbit coupling, showing crucial role of a heavy metal even in the non-interfacial origin of DMI. Our work provides more degrees of freedom to design chiral magnets for spintronics applications.

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Human Hand Anatomy-Based Prosthetic Hand

Sensors ◽

10.3390/s21010137 ◽

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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Supercritical Impregnation of PLA Filaments with Mango Leaf Extract to Manufacture Functionalized Biomedical Devices by 3D Printing

Polymers ◽

10.3390/polym13132125 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2125

Author(s):

José María Rosales ◽

Cristina Cejudo ◽

Lidia Verano ◽

Lourdes Casas ◽

Casimiro Mantell ◽

...

Keyword(s):

Antioxidant Activity ◽

3D Printing ◽

Polylactic Acid ◽

Leaf Extract ◽

Three Dimensional ◽

3D Printer ◽

Pharmacological Properties ◽

Bioactive Properties ◽

Supercritical Impregnation ◽

Mango Leaves

Polylactic Acid (PLA) filaments impregnated with ethanolic mango leaves extract (MLE) with pharmacological properties were obtained by supercritical impregnation. The effects of pressure, temperature and amount of extract on the response variables, i.e., swelling, extract loading and bioactivity of the PLA filaments, were determined. The analysis of the filaments biocapacities revealed that impregnated PLA filaments showed 11.07% antidenaturant capacity and 88.13% antioxidant activity, which after a 9-day incubation shifted to 30.10% and 9.90%, respectively. Subsequently, the same tests were conducted on printed samples. Before their incubation, the printed samples showed 79.09% antioxidant activity and no antidenaturant capacity was detected. However, after their incubation, the antioxidant activity went down to only 2.50%, while the antidenaturant capacity raised up to 23.50%. The persistence of the bioactive properties after printing opens the possibility of using the functionalized PLA filaments as the feed for a three-dimensional (3D) printer.

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Thermal, structural, and mechanical effects of nanofibrillated cellulose in polylactic acid filaments for additive manufacturing

BioResources ◽

10.15376/biores.15.4.7954-7964 ◽

2020 ◽

Vol 15 (4) ◽

pp. 7954-7964

Author(s):

Diego Gomez-Maldonado ◽

Maria Soledad Peresin ◽

Christina Verdi ◽

Guillermo Velarde ◽

Daniel Saloni

Keyword(s):

Tensile Strength ◽

Additive Manufacturing ◽

3D Printing ◽

Polylactic Acid ◽

Modulus Of Elasticity ◽

Manufacturing Process ◽

Thermal Characterization ◽

Nanofibrillated Cellulose ◽

Small Decrease ◽

The Matrix

As the additive manufacturing process gains worldwide importance, the need for bio-based materials, especially for in-home polymeric use, also increases. This work aims to develop a composite of polylactic acid (PLA) and nanofibrillated cellulose (NFC) as a sustainable approach to reinforce the currently commercially available PLA. The studied materials were composites with 5 and 10% NFC that were blended and extruded. Mechanical, structural, and thermal characterization was made before its use for 3D printing. It was found that the inclusion of 10% NFC increased the modulus of elasticity in the filaments from 2.92 to 3.36 GPa. However, a small decrease in tensile strength was observed from 55.7 to 50.8 MPa, which was possibly due to the formation of NFC aggregates in the matrix. This work shows the potential of using PLA mixed with NFC for additive manufacturing.

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Postural Synergy-Based Exoskeleton Reproducing Natural Human Movements to Improve Upper Limb Motor Control after Stroke

10.21203/rs.3.rs-104427/v1 ◽

2020 ◽

Author(s):

Chang He ◽

Cai-Hua Xiong ◽

Ze-Jian Chen ◽

Wei Fan ◽

Xiao-Lin Huang

Keyword(s):

Motor Control ◽

Upper Limb ◽

Degrees Of Freedom ◽

Response Rate ◽

Human Movement ◽

Interaction Force ◽

Human Anatomy ◽

Clinical Trial Registration ◽

Upper Limb Exoskeleton ◽

Human Movements

Abstract Background: Upper limb exoskeletons have drawn significant attention in neurorehabilitation because of anthropomorphic mechanical structure analogous to human anatomy. Whereas, the training movements are typically underorganized because most exoskeletons only control the movement of the hand in space, without considering rehabilitation of joint motion, particularly inter-joint postural synergy. The purposes of this study were to explore the application of a postural synergy-based exoskeleton (Armule) reproducing natural human movements for robot-assisted neurorehabilitation and to preliminarily assess its effect on patients' upper limb motor control after stroke. Methods: We developed a novel upper limb exoskeleton based on the concept of postural synergy, which provided five degrees of freedom (DOF) , natural human movements of the upper limb. Eight participants with hemiplegia due to a first-ever, unilateral stroke were recruited and included. They participated in exoskeleton therapy sessions 45 minutes/day, 5 days/week for 4 weeks, with passive/active training under anthropomorphic trajectories and postures. The primary outcome was the Fugl-Meyer Assessment for Upper Extremities (FMA-UE). The secondary outcomes were the Action Research Arm Test(ARAT), modified Barthel Index (mBI) , and exoskeleton kinematic as well as interaction force metrics: motion smoothness in the joint space, postural synergy error, interaction force smoothness, and the intent response rate. Results: After the 4-weeks intervention, all subjects showed significant improvements in the following clinical measures: the FMA-UE ( p =0.02), the ARAT ( p =0.003), and the mBI score ( p <0.001). Besides, all subjects showed significant improvements in motion smoothness ( p =0.004), postural synergy error ( p =0.014), interaction force smoothness ( p =0.004), and the intent response rate ( p =0.008). Conclusions: The subjects were well adapted to our device that assisted in completing functional movements with natural human movement characteristics. The results of the preliminary clinical intervention indicate that the Armule exoskeleton improves individuals’ motor control and activities of daily living (ADL) function after stroke, which might be associated with kinematic and interaction force optimization and postural synergy modification during functional tasks. Clinical trial registration: ChiCTR, ChiCTR1900026656; Date of registration: October 17, 2019. http://www.chictr.org.cn/showproj.aspx?proj=44420

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