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1.
Sensors (Basel) ; 21(19)2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34640956

RESUMO

Stumbling during gait is commonly encountered in patients who suffer from mild to serious walking problems, e.g., after stroke, in osteoarthritis, or amputees using a lower leg prosthesis. Instead of self-reporting, an objective assessment of the number of stumbles in daily life would inform clinicians more accurately and enable the evaluation of treatments that aim to achieve a safer walking pattern. An easy-to-use wearable might fulfill this need. The goal of the present study was to investigate whether a single inertial measurement unit (IMU) placed at the shank and machine learning algorithms could be used to detect and classify stumbling events in a dataset comprising of a wide variety of daily movements. Ten healthy test subjects were deliberately tripped by an unexpected and unseen obstacle while walking on a treadmill. The subjects stumbled a total of 276 times, both using an elevating recovery strategy and a lowering recovery strategy. Subjects also performed multiple Activities of Daily Living. During data processing, an event-defined window segmentation technique was used to trace high peaks in acceleration that could potentially be stumbles. In the reduced dataset, time windows were labelled with the aid of video annotation. Subsequently, discriminative features were extracted and fed to train seven different types of machine learning algorithms. Trained machine learning algorithms were validated using leave-one-subject-out cross-validation. Support Vector Machine (SVM) algorithms were most successful, and could detect and classify stumbles with 100% sensitivity, 100% specificity, and 96.7% accuracy in the independent testing dataset. The SVM algorithms were implemented in a user-friendly, freely available, stumble detection app named Stumblemeter. This work shows that stumble detection and classification based on SVM is accurate and ready to apply in clinical practice.


Assuntos
Atividades Cotidianas , Membros Artificiais , Marcha , Humanos , Máquina de Vetores de Suporte , Caminhada
2.
PLoS One ; 16(6): e0252870, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34138903

RESUMO

The Delft Self-Grasping Hand is an adjustable passive prosthesis operated using the concept of tenodesis (where opening and closing of the hand is mechanically linked to the flexion and extension of the wrist). As a purely mechanical device that does not require harnessing, the Self-Grasping Hand offers a promising alternative to current prostheses. However, the contralateral hand is almost always required to operate the mechanism to release a grasp and is sometimes also used to help form the grasp; hence limiting the time it is available for other purposes. In this study we quantified the amount of time the contralateral hand was occupied with operating the Self-Grasping Hand, classified as either direct or indirect interaction, and investigated how these periods changed with practice. We studied 10 anatomically intact participants learning to use the Self-Grasping Hand fitted to a prosthesis simulator. The learning process involved 10 repeats of a feasible subset of the tasks in the Southampton Hand Assessment Procedure (SHAP). Video footage was analysed, and the time that the contralateral hand was engaged in grasping or releasing was calculated. Functionality scores increased for all participants, plateauing at an Index of Functionality of 33.5 after 5 SHAP attempts. Contralateral hand involvement reduced significantly from 6.47 (first 3 attempts) to 4.68 seconds (last three attempts), but as a proportion of total task time remained relatively steady (increasing from 29% to 32%). For 9/10 participants most of this time was supporting the initiation of grasps rather than releases. The reliance on direct or indirect interactions between the contralateral hand and the prosthesis varied between participants but appeared to remain relatively unchanged with practice. Future studies should consider evaluating the impact of reliance on the contralateral limb in day-to-day life and development of suitable training methods.


Assuntos
Lateralidade Funcional/fisiologia , Força da Mão/fisiologia , Aprendizagem/fisiologia , Membros Artificiais , Simulação por Computador , Feminino , Voluntários Saudáveis , Humanos , Masculino , Fatores de Tempo , Gravação em Vídeo
3.
Prosthet Orthot Int ; 45(1): 54-61, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33834745

RESUMO

BACKGROUND: Current body-powered hands have very low acceptance rates. They also require high activation forces. In the past, a high acceptance rate was reported for the then-available Hüfner hand, a hand which could be controlled by relatively low activation forces. OBJECTIVE: The aim of this study was to measure and quantify the mechanical performance of the Hüfner hand. STUDY DESIGN: Mechanical evaluation. METHODS: Two versions of the Hüfner hand were tested using a mechanical test bench. Forces and displacements were measured under four different glove conditions (no glove, leather, polyvinyl chloride (PVC), silicone). The measured results were compared to data from currently available voluntary-closing hands. RESULTS: The Hüfner hand required 132-170 Nmm of work and 78-104 N cable force to pinch 15 N. The overall mechanical performance of the Hüfner hands is better than currently available body-powered hands. CONCLUSION: The mechanical performance of the Hüfner hand was measured and quantified. Mechanical testing results show that the Hüfner hand has better mechanical performance than current body-powered hands. This may have contributed to its reported high acceptance rates. The design of the Hüfner hand, combined with data presented in this study, can serve as guidelines for the design of a new generation of body-powered hands.


Assuntos
Membros Artificiais , Mãos , Força da Mão , Humanos , Fenômenos Mecânicos , Desenho de Prótese
4.
Med Eng Phys ; 89: 22-32, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33608122

RESUMO

Positioning and stabilizing a catheter at the required location inside a vessel or the heart is a complicated task in interventional cardiology. In this review we provide a structured classification of catheter stabilization mechanisms to systematically assess their challenges during cardiac interventions. Commercially available, patented, and experimental prototypes of catheters were classified with respect to their stabilizing mechanisms. Subsequently, the classification was used to define requirements for future cardiac catheters and persisting challenges in catheter stabilization. The classification showed that there are two main stabilization mechanisms: surface-based and volume-based. Surface-based mechanisms apply attachment through surface anchoring, while volume-based mechanisms make use of locking through shape or force against the vessel or cardiac wall. The classification provides insight into existing catheter stabilization mechanisms and can possibly be used as a tool for future design of catheter stabilization mechanisms to keep the catheter at a specific location during an intervention. Additionally, insight into the requirements and challenges for catheter stabilization inside the heart and vasculature can lead to the development of more dedicated systems in the future, allowing for intervention- and patient-specific instrument manipulation.


Assuntos
Sistema Cardiovascular , Cateteres , Desenho de Equipamento , Humanos , Fenômenos Mecânicos
5.
Proc Inst Mech Eng H ; 235(3): 336-345, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33292076

RESUMO

Various upper-limb prostheses have been designed for 3D printing but only a few of them are based on bio-inspired design principles and many anatomical details are not typically incorporated even though 3D printing offers advantages that facilitate the application of such design principles. We therefore aimed to apply a bio-inspired approach to the design and fabrication of articulated fingers for a new type of 3D printed hand prosthesis that is body-powered and complies with basic user requirements. We first studied the biological structure of human fingers and their movement control mechanisms in order to devise the transmission and actuation system. A number of working principles were established and various simplifications were made to fabricate the hand prosthesis using a fused deposition modelling (FDM) 3D printer with dual material extrusion. We then evaluated the mechanical performance of the prosthetic device by measuring its ability to exert pinch forces and the energy dissipated during each operational cycle. We fabricated our prototypes using three polymeric materials including PLA, TPU, and Nylon. The total weight of the prosthesis was 92 g with a total material cost of 12 US dollars. The energy dissipated during each cycle was 0.380 Nm with a pinch force of ≈16 N corresponding to an input force of 100 N. The hand is actuated by a conventional pulling cable used in BP prostheses. It is connected to a shoulder strap at one end and to the coupling of the whiffle tree mechanism at the other end. The whiffle tree mechanism distributes the force to the four tendons, which bend all fingers simultaneously when pulled. The design described in this manuscript demonstrates several bio-inspired design features and is capable of performing different grasping patterns due to the adaptive grasping provided by the articulated fingers. The pinch force obtained is superior to other fully 3D printed body-powered hand prostheses, but still below that of conventional body powered hand prostheses. We present a 3D printed bio-inspired prosthetic hand that is body-powered and includes all of the following characteristics: adaptive grasping, articulated fingers, and minimized post-printing assembly. Additionally, the low cost and low weight make this prosthetic hand a worthy option mainly in locations where state-of-the-art prosthetic workshops are absent.


Assuntos
Membros Artificiais , Mãos , Dedos , Humanos , Impressão Tridimensional , Desenho de Prótese
6.
Prosthet Orthot Int ; : 309364620952900, 2020 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-32907487

RESUMO

BACKGROUND: Current body-powered hands have very low acceptance rates. They also require high activation forces. In the past, a high acceptance rate was reported for the then-available Hüfner hand, a hand which could be controlled by relatively low activation forces. OBJECTIVE: The aim of this study was to measure and quantify the mechanical performance of the Hüfner hand. STUDY DESIGN: Mechanical evaluation. METHODS: Two versions of the Hüfner hand were tested using a mechanical test bench. Forces and displacements were measured under four different glove conditions (no glove, leather, polyvinyl chloride (PVC), silicone). The measured results were compared to data from currently available voluntary-closing hands. RESULTS: The Hüfner hand required 132-170 Nmm of work and 78-104 N cable force to pinch 15 N. The overall mechanical performance of the Hüfner hands is better than currently available body-powered hands. CONCLUSION: The mechanical performance of the Hüfner hand was measured and quantified. Mechanical testing results show that the Hüfner hand has better mechanical performance than current body-powered hands. This may have contributed to its reported high acceptance rates. The design of the Hüfner hand, combined with data presented in this study, can serve as guidelines for the design of a new generation of body-powered hands.

7.
Front Robot AI ; 7: 596185, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33585573

RESUMO

Wearable robots assist individuals with sensorimotor impairment in daily life, or support industrial workers in physically demanding tasks. In such scenarios, low mass and compact design are crucial factors for device acceptance. Remote actuation systems (RAS) have emerged as a popular approach in wearable robots to reduce perceived weight and increase usability. Different RAS have been presented in the literature to accommodate for a wide range of applications and related design requirements. The push toward use of wearable robotics in out-of-the-lab applications in clinics, home environments, or industry created a shift in requirements for RAS. In this context, high durability, ergonomics, and simple maintenance gain in importance. However, these are only rarely considered and evaluated in research publications, despite being drivers for device abandonment by end-users. In this paper, we summarize existing approaches of RAS for wearable assistive technology in a literature review and compare advantages and disadvantages, focusing on specific evaluation criteria for out-of-the-lab applications to provide guidelines for the selection of RAS. Based on the gained insights, we present the development, optimization, and evaluation of a cable-based RAS for out-of-the-lab applications in a wearable assistive soft hand exoskeleton. The presented RAS features full wearability, high durability, high efficiency, and appealing design while fulfilling ergonomic criteria such as low mass and high wearing comfort. This work aims to support the transfer of RAS for wearable robotics from controlled lab environments to out-of-the-lab applications.

8.
Proc Inst Mech Eng H ; 233(11): 1122-1131, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31597553

RESUMO

In developing countries, the access of amputees to prosthetic devices is very limited. In a way to increase accessibility of prosthetic hands, we have recently developed a new approach for the design and 3D printing of non-assembly active hand prostheses using inexpensive 3D printers working on the basis of material extrusion technology. This article describes the design of our novel 3D-printed hand prosthesis and also shows the mechanical and functional evaluation in view of its future use in developing countries. We have fabricated a hand prosthesis using 3D printing technology and a non-assembly design approach that reaches certain level of functionality. The mechanical resistance of critical parts, the mechanical performance, and the functionality of a non-assembly 3D-printed hand prosthesis were assessed. The mechanical configuration used in the hand prosthesis is able to withstand typical actuation forces delivered by prosthetic users. Moreover, the activation forces and the energy required for a closing cycle are considerably lower as compared to other body-powered prostheses. The non-assembly design achieved a comparable level of functionality with respect to other body-powered alternatives. We consider this prosthetic hand a valuable option for people with arm defects in developing countries.


Assuntos
Membros Artificiais , Mãos , Impressão Tridimensional , Humanos , Fenômenos Mecânicos , Desenho de Prótese
9.
Proc Inst Mech Eng H ; 233(11): 1141-1150, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31526098

RESUMO

One of the most prominent drivers in the development of surgical procedures is the will to reduce their invasiveness, attested by minimally invasive surgery being the gold standards in many surgical procedures and natural orifices transluminal endoscopic surgery gaining acceptance. A logical next step in this pursuit is the introduction of hyper-redundant instruments that can insert themselves along multi-curved paths referred to as Follow-the-Leader motion. In the current state of the art, two different types of Follow-the-Leader instruments can be distinguished. One type of instrument is robotized; the movements of the shaft are controlled from outside the patient by actuators, for example, electric motors, and a controller storing a virtual track of the desired path. The other type of instrument is more mechanical; the movements of the shaft are controlled from inside the patient by a physical track that guides the shaft along the desired path. While in the robotized approach all degrees of freedom of the shaft require an individual actuator, the mechanical approach makes the number of degrees of freedom independent from the number of actuators. A desirable feature as an increasing number of actuators will inevitably drive up costs and increase the footprint of an instrument. Building the physical track inside the body does, however, impede miniaturization of the shaft's diameter. This article introduces a new fully mechanical approach for Follow-the-Leader motion using a pre-determined physical track that is placed outside the body. This new approach was validated with a prototype called MemoFlex, which supports a Ø5 mm shaft (standard size in minimally invasive surgery) that contains 28-degrees-of-freedom and utilizes a simple steel rod as its physical track. Even though the performance of the MemoFlex leaves room for improvement, especially when following multiple curves, it does validate the proposed concept for Follow-the-Leader motion in three-dimensional space.


Assuntos
Desenho de Equipamento , Fenômenos Mecânicos , Procedimentos Cirúrgicos Minimamente Invasivos/instrumentação , Movimento (Física)
10.
Proc Inst Mech Eng H ; 232(9): 962-971, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30114955

RESUMO

In developing countries, prosthetic workshops are limited, difficult to reach, or even non-existent. Especially, fabrication of active, multi-articulated, and personalized hand prosthetic devices is often seen as a time-consuming and demanding process. An active prosthetic hand made through the fused deposition modelling technology and fully assembled right after the end of the 3D printing process will increase accessibility of prosthetic devices by reducing or bypassing the current manufacturing and post-processing steps. In this study, an approach for producing active hand prosthesis that could be fabricated fully assembled by fused deposition modelling technology is developed. By presenting a successful case of non-assembly 3D printing, this article defines a list of design considerations that should be followed in order to achieve fully functional non-assembly devices. Ten design considerations for additive manufacturing of non-assembly mechanisms have been proposed and a design case has been successfully addressed resulting in a fully functional prosthetic hand. The hand prosthesis can be 3D printed with an inexpensive fused deposition modelling machine and is capable of performing different types of grasping. The activation force required to start a pinch grasp, the energy required for closing, and the overall mass are significantly lower than body-powered commercial prosthetic hands. The results suggest that this non-assembly design may be a good alternative for amputees in developing countries.


Assuntos
Membros Artificiais , Guias como Assunto , Mãos , Impressão Tridimensional , Desenho de Prótese/métodos , Humanos , Fenômenos Mecânicos
11.
Prosthet Orthot Int ; 42(1): 66-74, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28190380

RESUMO

BACKGROUND: The group of passive prostheses consists of prosthetic hands and prosthetic tools. These can either be static or adjustable. Limited research and development on passive prostheses has been performed although many people use these prosthesis types. Although some publications describe passive prostheses, no recent review of the peer-reviewed literature on passive prostheses is available. OBJECTIVE: Review the peer-reviewed literature on passive prostheses for replacement of the hand. STUDY DESIGN: Literature review. METHODS: Four electronic databases were searched using a Boolean combination of relevant keywords. English-language articles relevant to the objective were selected. RESULTS: In all, 38 papers were included in the review. Publications on passive prosthetic hands describe their users, usage, functionality, and problems in activities of daily living. Publications on prosthetic tools mostly focus on sport, recreation, and vehicle driving. CONCLUSION: Passive hand prostheses receive little attention in prosthetic research and literature. Yet one out of three people with a limb deficiency uses this type of prosthesis. Literature indicates that passive prostheses can be improved on pulling and grasping functions. In the literature, ambiguous names are used for different types of passive prostheses. This causes confusion. We present a new and clear classification of passive prostheses. Clinical relevance This review provides information on the users of passive prosthetic hands and tools, their usage and the functionality. Passive prostheses receive very little attention and low appreciation in literature. Passive prosthetic hands and tools show to be useful to many unilateral amputees and should receive more attention and higher acceptance.


Assuntos
Atividades Cotidianas , Membros Artificiais , Mãos , Desenho de Prótese , Humanos
12.
Proc Inst Mech Eng H ; 231(12): 1213-1223, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29125034

RESUMO

Follow-the-leader propagation allows for the insertion of flexible surgical instruments along curved paths, reducing the access required for natural orifice transluminal endoscopic surgery. Currently, the most promising follow-the-leader instruments use the alternating memory method containing two mechanical memory-banks for controlling the motion of the flexible shaft, which reduces the number of actuators to a minimum. These instruments do, however, require concentric structures inside the shaft, limiting its miniaturization. The goal of this research was, therefore, to develop a mechanism conforming the principles of the alternating memory method that could be located at the controller-side instead of inside the shaft of the instrument, which is positioned outside the patient and is therefore less restricted in size. First, the three-dimensional motion of the shaft was decoupled into movement in a horizontal and vertical plane, which allowed for a relatively simple planar alternating memory mechanism design for controlling planar follow-the-leader motion. Next, the planar movement of the alternating memory mechanism was discretized, increasing its resilience to errors. The resulting alternating memory mechanism was incorporated and tested in a proof-of-concept prototype called the Memo Slide. This prototype does not include a flexible shaft, but was fully focused on proving the function of the alternating memory mechanism. Evaluation of the Memo Slide shows the mechanism to work very well, being able to transfer any planar path that lays within its physical boundaries along the body of the mechanism without accumulating errors.


Assuntos
Fenômenos Mecânicos , Procedimentos Cirúrgicos Minimamente Invasivos/instrumentação , Biomimética , Desenho de Equipamento , Miniaturização , Movimento (Física)
13.
IEEE Int Conf Rehabil Robot ; 2017: 1197-1202, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28813984

RESUMO

State of art upper limb prostheses lack several degrees of freedom (DoF) and force the individuals to compensate for them by changing the motions of their arms and body. Such movements often yield to articulation injuries, nonetheless these could be prevented by adding DoFs, for instance, an articulated passive wrist. Available stiff or compliant wrists with passive flexion/extension and/or radial/ulnar deviation are sub-optimal solutions. Indeed, stiff wrists induce the individuals wearing them to perform exaggerated compensatory movements during the reaching phase while compliant wrists proved to be unpractical while manipulating heavy objects. Here we present a wrist capable of combining the benefits of stiff and compliant wrists. It is provided with two switchable levels of passive compliance that are automatically selected. The prototype was integrated in a body-powered hydraulic hand prosthesis and actuated using the same hydraulic circuit of the hand. Detailed analysis of the parameters that affect the compliance, the critical load and the performance of the prosthesis are presented.


Assuntos
Membros Artificiais , Força da Mão/fisiologia , Desenho de Prótese/métodos , Punho/fisiologia , Humanos , Amplitude de Movimento Articular/fisiologia
14.
Disabil Rehabil Assist Technol ; 12(3): 300-314, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28152642

RESUMO

GOAL: This paper aims to provide an overview with quantitative information of existing 3D-printed upper limb prostheses. We will identify the benefits and drawbacks of 3D-printed devices to enable improvement of current devices based on the demands of prostheses users. METHODS: A review was performed using Scopus, Web of Science and websites related to 3D-printing. Quantitative information on the mechanical and kinematic specifications and 3D-printing technology used was extracted from the papers and websites. RESULTS: The overview (58 devices) provides the general specifications, the mechanical and kinematic specifications of the devices and information regarding the 3D-printing technology used for hands. The overview shows prostheses for all different upper limb amputation levels with different types of control and a maximum material cost of $500. CONCLUSION: A large range of various prostheses have been 3D-printed, of which the majority are used by children. Evidence with respect to the user acceptance, functionality and durability of the 3D-printed hands is lacking. Contrary to what is often claimed, 3D-printing is not necessarily cheap, e.g., injection moulding can be cheaper. Conversely, 3D-printing provides a promising possibility for individualization, e.g., personalized socket, colour, shape and size, without the need for adjusting the production machine. Implications for rehabilitation Upper limb deficiency is a condition in which a part of the upper limb is missing as a result of a congenital limb deficiency of as a result of an amputation. A prosthetic hand can restore some of the functions of a missing limb and help the user in performing activities of daily living. Using 3D-printing technology is one of the solutions to manufacture hand prostheses. This overview provides information about the general, mechanical and kinematic specifications of all the devices and it provides the information about the 3D-printing technology used to print the hands.


Assuntos
Membros Artificiais , Mãos/fisiologia , Impressão Tridimensional/instrumentação , Atividades Cotidianas , Humanos , Impressão Tridimensional/economia , Extremidade Superior
15.
Prosthet Orthot Int ; 40(1): 109-16, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25336050

RESUMO

BACKGROUND: The functional performance of currently available body-powered prostheses is unknown. OBJECTIVE: The goal of this study was to objectively assess and compare the functional performance of three commonly used body-powered upper limb terminal devices. STUDY DESIGN: Experimental trial. METHODS: A total of 21 able-bodied subjects (n = 21, age = 22 ± 2) tested three different terminal devices: TRS voluntary closing Hook Grip 2S, Otto Bock voluntary opening hand and Hosmer Model 5XA hook, using a prosthesis simulator. All subjects used each terminal device nine times in two functional tests: the Nine-Hole Peg Test and the Box and Blocks Test. RESULTS: Significant differences were found between the different terminal devices and their scores on the Nine-Hole Peg Test and the Box and Blocks Test. The Hosmer hook scored best in both tests. The TRS Hook Grip 2S scored second best. The Otto Bock hand showed the lowest scores. CONCLUSION: This study is a first step in the comparison of functional performances of body-powered prostheses. The data can be used as a reference value, to assess the performance of a terminal device or an amputee. CLINICAL RELEVANCE: The measured scores enable the comparison of the performance of a prosthesis user and his or her terminal device relative to standard scores.


Assuntos
Membros Artificiais , Força da Mão/fisiologia , Terapia Ocupacional/instrumentação , Desenho de Prótese/métodos , Análise de Variância , Engenharia Biomédica , Simulação por Computador , Feminino , Mãos/fisiologia , Voluntários Saudáveis , Humanos , Masculino , Países Baixos , Jogos e Brinquedos , Ajuste de Prótese , Amostragem , Análise e Desempenho de Tarefas , Extremidade Superior/fisiologia , Adulto Jovem
16.
IEEE Trans Neural Syst Rehabil Eng ; 23(3): 431-40, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25122837

RESUMO

Rejection rates of upper limb prostheses are high (23%-45%). Amputees indicate that the highest design priority should be reduction of the mass of the prosthetic device. Despite all efforts, the mass of the new prosthetic hands is 35%-73% higher than that of older hands. Furthermore, current hands are thicker than a human hand, they operate slower and do not provide proprioceptive force and position feedback. This study presents the Delft Cylinder Hand, a body powered prosthetic hand which mass is 55%-68% lower than that of the lightest current prosthetic hands, operates faster, has an anthropomorphic shape, and provides proprioceptive force and position feedback. The hand has articulating fingers, actuated by miniature hydraulic cylinders. The articulating fingers adapt to the shape of the grasped object. Its functional scores are similar to that of current prosthetic devices. The hand has a higher mechanical performance than current body-powered hands. It requires 49%-162% less energy from the user and it can deliver a higher maximum pinch force (30-60 N).


Assuntos
Mãos , Próteses e Implantes , Desenho de Prótese , Adulto , Amputados , Fenômenos Biomecânicos , Meio Ambiente , Retroalimentação Fisiológica , Feminino , Dedos , Humanos , Masculino , Fenômenos Mecânicos , Propriocepção
17.
Prosthet Orthot Int ; 38(2): 96-102, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23690287

RESUMO

BACKGROUND: Cosmetic gloves that cover a prosthetic hand have a parasitic positive stiffness that counteracts the flexion of a finger joint. OBJECTIVES: Reducing the required input torque to move a finger of a prosthetic hand by compensating the parasitic stiffness of the cosmetic glove. STUDY DESIGN: Experimental, test bench. METHODS: The parasitic positive stiffness and the required input torques of a polyvinyl chloride glove and a silicone glove were measured when flexing a metacarpophalangeal finger joint for 90°. To compensate this positive stiffness, an adjustable compensation mechanism with a negative stiffness was designed and built. A MATLAB model was created to predict the optimal settings of the mechanism, based on the measured stiffness, in order to minimize the required input torque of the total system. The mechanism was tested in its optimal setting with an applied glove. RESULTS: The mechanism reduced the required input torque by 58% for the polyvinyl chloride glove and by 52% for the silicone glove. The total energy dissipation of the joint did not change significantly. CONCLUSIONS: This study shows that the undesired positive stiffness in the joint can be compensated with a relatively simple negative stiffness mechanism, which fits inside a finger of a standard cosmetic glove. Clinical relevance This study presents a mechanism that compensates the undesired stiffness of cosmetic gloves on prosthetic hands. As a result, it requires less input force, torque and energy to move the fingers. Application of this mechanism in body-powered hands will reduce the control effort of the user.


Assuntos
Articulação da Mão , Mãos , Próteses e Implantes , Desenho de Prótese , Amplitude de Movimento Articular , Fenômenos Biomecânicos , Cosméticos , Luvas Protetoras , Humanos , Cloreto de Polivinila , Silicones , Torque
18.
J Rehabil Res Dev ; 50(5): 723-32, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24013919

RESUMO

Current articulating electric and body-powered hands have a lower pinch force (15-34 N) than electric hands with stiff fingers (55-100 N). The cosmetic glove, which covers a hand prosthesis, negatively affects the mechanical efficiency of a prosthesis. The goal of this study is to mechanically compare polyvinylchloride (PVC) and silicone cosmetic gloves and quantify the stiffness of the finger joints, the required actuation energy, and the energy dissipation during joint articulation. Six cosmetic gloves, identical in size but made from different materials, were mechanically tested: three PVC and three silicone. The silicone gloves required less work and dissipated less energy during flexing. They also had a lower joint stiffness and required a lower maximum joint torque. Based on energy requirements, joint stiffness, and required joint torque, the tested silicone glove is most suitable for application on an articulating hand prosthesis.


Assuntos
Membros Artificiais , Mãos , Fenômenos Mecânicos , Cloreto de Polivinila , Silicones , Elasticidade , Feminino , Humanos , Masculino , Teste de Materiais , Maleabilidade , Torque
19.
J Rehabil Res Dev ; 50(9): 1253-66, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24458965

RESUMO

The goal of this study was to find an efficient method of energy transmission for application in an anthropomorphic underactuated body-powered (BP) prosthetic hand. A pulley-cable finger and a hydraulic cylinder finger were designed and tested to compare the pulley-cable transmission principle with the hydraulic cylinder transmission principle. Both fingers had identical dimensions and a low mass. The only thing that differed between the fingers was the transmission principle. The input energy was measured for a number of tasks. The pulley-cable finger required more input energy than the hydraulic cylinder finger to perform the tasks. This was especially the case in tasks that required high pinch forces. The hydraulic cylinder transmission is therefore the more efficient transmission for application in BP prosthetic fingers.


Assuntos
Amputados , Membros Artificiais , Dedos , Mãos , Desenho de Prótese , Amputados/reabilitação , Eficiência , Dedos/fisiologia , Mãos/fisiologia , Humanos , Teste de Materiais , Força de Pinça , Análise e Desempenho de Tarefas , Torque
20.
J Rehabil Res Dev ; 49(4): 523-34, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22773256

RESUMO

Quantitative data on the mechanical performance of upper-limb prostheses are very important in prostheses development and selection. The primary goal of this study was to objectively evaluate the mechanical performance of adult-size voluntary opening (VO) prosthetic terminal devices and select the best tested device. A second goal was to see whether VO devices have improved in the last two decades. Nine devices (four hooks and five hands) were quantitatively tested (Hosmer model 5XA hook, Hosmer Sierra 2 Load VO hook, RSL Steeper Carbon Gripper, Otto Bock model 10A60 hook, Becker Imperial hand, Hosmer Sierra VO hand, Hosmer Soft VO hand, RSL Steeper VO hand, Otto Bock VO hand). We measured the pinch forces, activation forces, cable displacements, mass, and opening span and calculated the work and hysteresis. We compared the results with data from 1987. Hooks required lower activation forces and delivered higher pinch forces than hands. The activation forces of several devices were very high. The pinch forces of all tested hands were too low. The Hosmer model 5XA hook with three bands was the best tested hook. The Hosmer Sierra VO hand was the best tested hand. We found no improvements in VO devices compared with the data from 1987.


Assuntos
Amputação/reabilitação , Membros Artificiais , Mãos/fisiologia , Desenho de Prótese/tendências , Adulto , Eficiência , Força da Mão/fisiologia , Humanos
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