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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Design, Modeling, and Control of an Active Prosthetic Knee

Borjian, Roozbeh 26 September 2008 (has links)
The few microcontroller based active/semi-active prosthetic knee joints available commercially are extremely expensive and do not consider the uncertainties of inputs sensory information. Progressing in the controller of the current prosthetic devices and creating artificial lower limbs compatible with different users may lead to more effective and low-cost prostheses. This can affect the life style of lots of amputees specially the land-mine victims in developing war-torn countries who are unable to partake in the advancement of the current intelligent prosthetic knees. The purpose of the proposed Active Prosthetic Knee (APK) design is to investigate a new schema that allows the device to provide the full necessary torque at the knee joint based on echoing the state of the intact leg. This study involves the design features of the mechanical aspects, sensing system, communication, and knowledge-based controller to implement a cost-effective APK. The proposed microcontroller based prosthesis utilizes a ball screw system accompanied by a high-speed brushed servomotor to provide one degree of freedom for the fabricated prototype. Moreover, a modular test-bed is manufactured to mimic the lower limb motion which contributes investigating different controllers for the prototype. Thus, the test bed allows assessing the primary performance of the APK before testing on a human subject. Different types of sensing systems (electromyography and lower limb inclination angles) are investigated to extract signals from the user’s healthy leg and send the captured data to the APK controller. The methodology to measure each type of signal is described, and comparison analyses are provided. Wireless communication between the sensory part and actuator is established. A knowledge-based control mechanism is developed that takes advantage of an Adaptive-Network-based Fuzzy Inference System (ANFIS) to determine knee torque as a function of the echoing angular state of the able leg considering the uncertainty of inputs. Therefore, the developed controller can make the APK serviceable for different users. The fuzzy membership function’s parameters and rules define the knowledge-base of the system. This knowledge is based on existing experience and known facts about the walking cycle.
72

Design, Modeling, and Control of an Active Prosthetic Knee

Borjian, Roozbeh 26 September 2008 (has links)
The few microcontroller based active/semi-active prosthetic knee joints available commercially are extremely expensive and do not consider the uncertainties of inputs sensory information. Progressing in the controller of the current prosthetic devices and creating artificial lower limbs compatible with different users may lead to more effective and low-cost prostheses. This can affect the life style of lots of amputees specially the land-mine victims in developing war-torn countries who are unable to partake in the advancement of the current intelligent prosthetic knees. The purpose of the proposed Active Prosthetic Knee (APK) design is to investigate a new schema that allows the device to provide the full necessary torque at the knee joint based on echoing the state of the intact leg. This study involves the design features of the mechanical aspects, sensing system, communication, and knowledge-based controller to implement a cost-effective APK. The proposed microcontroller based prosthesis utilizes a ball screw system accompanied by a high-speed brushed servomotor to provide one degree of freedom for the fabricated prototype. Moreover, a modular test-bed is manufactured to mimic the lower limb motion which contributes investigating different controllers for the prototype. Thus, the test bed allows assessing the primary performance of the APK before testing on a human subject. Different types of sensing systems (electromyography and lower limb inclination angles) are investigated to extract signals from the user’s healthy leg and send the captured data to the APK controller. The methodology to measure each type of signal is described, and comparison analyses are provided. Wireless communication between the sensory part and actuator is established. A knowledge-based control mechanism is developed that takes advantage of an Adaptive-Network-based Fuzzy Inference System (ANFIS) to determine knee torque as a function of the echoing angular state of the able leg considering the uncertainty of inputs. Therefore, the developed controller can make the APK serviceable for different users. The fuzzy membership function’s parameters and rules define the knowledge-base of the system. This knowledge is based on existing experience and known facts about the walking cycle.
73

Optimization of transcranial direct current stimulation (tDCS) to modulate lower limb motor network in healthy humans

Soares Foerster, Aguida 30 August 2018 (has links)
No description available.
74

Caracterização da força de membros inferiores durante a execução do exercício foot work do método pilates / Characterization of lower limbs strength during the performance of the foot work exercise from pilates method

Machado, Carolina Neis 30 August 2013 (has links)
Made available in DSpace on 2016-12-06T17:06:57Z (GMT). No. of bitstreams: 1 Carolina Neis Machado.pdf: 2019539 bytes, checksum: 551e51b6d116d4ba06d2ac853f60e010 (MD5) Previous issue date: 2013-08-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Following exercise programs in vogue in recent years, one can observe the highlight of the Pilates method. Contrary to its popularity, there is a lack of quantitative information for prescription and progression of exercises of the method, which are important subsidies, particularly for rehabilitation. This study aims to characterize the strength of the lower limbs during the execution of an exercise often used in Pilates, the foot work. It is a quasi-experimental study, and a study of technological development. It was conducted in two phases: preliminary phase, corresponding to the construction of the instruments concerning to force measures (extensometric force plates), and application phase, in which occurred the data collection itself. The studied population consisted of 20 healthy adults, between 20 and 35 years old, familiar with the method. Data collection was carried out in a Pilates studio in the city of Florianópolis. For this purpose, the platforms developed for the study were secured to support the Reformer bar in order to enable the participant to perform the exercise without any changes in movement pattern. To collect data and force platforms we used the following instruments: digital scale, and stadiometer tape. Data was acquired and processed with the aid of ADS2002-IP and SAD32 systems. For the characterization of the vertical and horizontal components of force, descriptive statistics were used, identifying the mean and standard deviation. The analysis of the effect of different springs on the peak horizontal force component was performed using the paired Student T test, assuming a value of p <0.05, where a significant difference was found between the averages of peak of the horizontal component of the lower limbs reaction force in both collection situations. By verifying the effect of springs on the asymmetry of force in the right and left leg differences were only statistically significant against the resistance of blue springs. The practice time was an aspect that influenced the bilateral symmetry of the lower limbs. At the end of this work, other uses are visualized for the implementation of instrumented Reformer, as the evaluation of lateral asymmetries of the lower limbs, the diagnosis of bilateral deficit and its application in the context of hemiparetic. / Acompanhando programas de exercício em voga nos últimos anos, observa-se o destaque do método Pilates. Na contramão da sua popularidade, verifica-se falta de informações quantitativas para a prescrição e progressão dos exercícios do método, que são subsídios importantes, em especial, para a reabilitação. Este estudo tem por objetivo caracterizar a força de membros inferiores durante a execução de um exercício bastante utilizado no método Pilates, o foot work. Trata-se de um estudo quasi-experimental, bem como de um estudo de desenvolvimento tecnológico. Foi realizado em duas fases distintas: fase preliminar, correspondente à construção e adaptação dos instrumentos referentes às medidas dinamométricas (plataformas de força extensométricas), e fase de aplicação, em que se deu a coleta de dados propriamente dita. A população deste estudo foi composta por 20 adultos saudáveis, com idade entre 20 e 35 anos, familiarizados com o Pilates. A coleta de dados foi realizada nas dependências de um estúdio de Pilates, na cidade de Florianópolis. Para tal, as plataformas desenvolvidas para o estudo foram fixadas à barra de apoios do Reformer para possibilitar ao participante a execução do exercício sem que houvesse alterações no padrão de movimento. Para a coleta de dados, além das plataformas de força, foram utilizados um estadiômetro, uma balança antropométrica e uma fita métrica. Os dados foram adquiridos e processados com o auxílio dos sistemas ADS2002-IP e SAD32. Para a caracterização das componentes vertical e horizontal da força foi utilizada a estatística descritiva, com a identificação dos valores de média e desvio padrão. A análise do efeito das diferentes molas utilizadas no exercício sobre o pico da componente horizontal da força foi realizada através do teste T de Student para amostras dependentes, admitindo-se um valor de p<0,05, onde foi encontrada diferença significativa entre as médias dos picos da componente horizontal da força de membros inferiores nas duas situações de coleta. Ao verificar o efeito das molas sobre a assimetria da força de membro inferior direito e esquerdo, apenas foram encontradas diferenças estatisticamente significativas contra a resistência das molas azuis. O tempo de prática foi um aspecto que influenciou a simetria bilateral de membros inferiores. Ao fim desse trabalho, outras finalidades são visualizadas para a aplicação do Reformer instrumentado, como a avaliação de assimetrias laterais de membros inferiores, o diagnóstico do déficit bilateral e sua aplicação no contexto de pacientes hemiparéticos.
75

Cinemática e ação da musculatura do tornozelo em indivíduos com hemiparesia durante o andar para trás / Kinematics and muscle ankle action in individuals with hemiparesis during backwards walking

Azevedo, Alexandre Kretzer e Castro de 09 November 2015 (has links)
Made available in DSpace on 2016-12-06T17:07:07Z (GMT). No. of bitstreams: 1 Alexandre Azevedo.pdf: 1554836 bytes, checksum: 44119494437e2ee610d59d403183e1da (MD5) Previous issue date: 2015-11-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / One of the possible mechanisms that explain the increased speed forward walking (FW) after the training backward walking (BW) in people with hemiplegia could be an increased recruitment of ankle muscles during task BW. The goal of this study is compare the muscle activation (dorsi-flexors and plantarflexors) and the range of motion of the ankle during the tasks of FW and BW in subjects with hemiparesis after stroke and healthy control subjects. The study included 12 subjects (65 ± 9 years) with chronic hemiparesis (60 ± 40 months post-stroke) and mild to moderate impairment of lower limb (LL) (FMLL 25.0 ± 4.7 points). For the control group participated in 6 healthy subjects (62.2 ± 4.6 years). The range of motion (ROM) passive isokinetic torque of the ankle at 30º / sec and corresponding EMG activity in plantarflexor muscles (PF) - Medial gastrocnemius (MG) and soleus (SOL) and dorsiflexion (DF) - Tibialis anterior (TA ) and peroneus longus (PL) was compared between the legs with ANOVA oneway. They assessed the EMG activity of the muscles and the kinematics of the ankle during the AF and AT separately in each gait sub-phase: first double support (1DS), simple support (SS), second double support (2DS) and balance sheet (BL). Data were analyzed by ANOVA, taking as factors the direction (FW and BW) and LL paretic (LLP), non-paretic (LLNP) and control (CTL). The CTL group presented DF ROM greater than the LLNP and the LLP. The PF was greater torque in relation to LLNP and LLP and LLNP was greater than in the LLP. The DF torque was lower in the LLP compared to CTL and LLNP. The spatiotemporal variables stride length, stride length and walking speed were higher in AF and higher in CTL compared to LLNP and LLP. 1DS in stages, SS and 2DS ankle ROM was higher in CTL that LLNP and LLP. In 2DS and BL CTL showed higher ROM in the BW that in FW, and 2DS in the LLNP and LLP ROM in FW was higher. The CTL group showed higher EMG activity of DF (TA and PL) and PF (MG and SOL) for all sub-phases, and only in the BL RMS of all analyzed muscles was higher in FW compared to BW. In general the CTL group had higher amplitudes and higher EMG activity that the LLP and LLNP at all stages of the march. In 2DS and BL ankle ROM was higher in the BW in the CTL group, but not in LLNP and LLP. The swing phase the EMG activity of DF and PF was higher in FW compared to FL. Future studies should evaluate whether the lower ROM identified in kinematics is related to an ankle muscle co-activation in this population. / Um dos possíveis mecanismos que explicaria o aumento da velocidade do andar para frente (AF) após o treinamento do andar para trás (AT) em pessoas com hemiparesia poderia ser um maior recrutamento da musculatura do tornozelo durante a tarefa de AT. Pretendeu-se com esta pesquisa comparar a ativação muscular de dorsi e plantiflexores e a amplitude de movimento do tornozelo durante as tarefas de AF e AT entre sujeitos com hemiparesia pós-AVE e indivíduos controle saudáveis. Participaram do estudo 12 indivíduos (65±9 anos) com hemiparesia crônica (60±40 meses pós-AVE) e comprometimento leve a moderado de membro inferior (MI) (FMMI 25,0±4,7 pontos). Para o grupo controle participaram 6 indivíduos saudáveis (62,2±4,6 anos). A amplitude de movimento (ADM) passiva, o torque isocinético do tornozelo a 30º/s e a atividade EMG correspondente na musculatura plantiflexora (PF) (Gastrocnêmio Medial (GM) e Solear (SOL)) e dorsiflexora (DF) (Tibial Anterior (TA) e Fibular Longo (FL)) foram comparados entre os MI com a ANOVA de uma via. Foram avaliadas a atividade EMG da musculatura e a cinemática do tornozelo durante o AF e o AT separadamente em cada subfase da marcha: primeiro duplo apoio (1DA), apoio simples (AS), segundo duplo apoio (2DA) e balanço (BL). Os dados foram analisados através da ANOVA de duas vias, tendo como fatores a direção (AF e AT) e o MI (parético (MIP), não parético (MINP) e controle (CTL)). O grupo CTL apresentou ADM de DF maior que o MINP e que o MIP. O torque de PF foi maior no CTL em relação ao MINP e ao MIP e no MINP foi maior que no MIP. O torque de DF foi menor no MIP em relação ao CTL e MINP. As variáveis espaço-temporais comprimento da passada, comprimento do passo e velocidade de marcha foram maiores no AF em relação ao AT e maiores no CTL comparativamente ao MINP e MIP. Nas fases 1DA, AS e 2DA a ADM do tornozelo foi maior nos CTL que MINP e MIP. No 2DA e BL os CTL apresentaram maior ADM no AT que no AF, sendo que no 2DA o MINP e MIP a ADM no AF foi maior. O grupo CTL apresentou maior atividade EMG dos DF (TA e FL) e PF (GM e SOL) durante todas as subfases, sendo que apenas no BL a RMS de todos os músculos analisados foi maior no AF comparativamente ao AT. No 2DA e no BL a ADM do tornozelo foi maior no AT no grupo CTL, mas não nos MINP e MIP. O grupo CTL apresentou maiores amplitudes e maior atividade EMG que o MIP e MINP em todas as fases da marcha. Na fase de balanço a atividade EMG dos DF e PF foi maior no AF comparativamente ao AT.
76

Presence of Popliteal Artery Entrapment Syndrome in asymptomatic individuals during ultrasound examinations with plantar flexion

Wakter, Jacob January 2021 (has links)
Popliteal artery entrapment syndrome has been reported to be a rare disease typically found in athletic and otherwise healthy young adults. It manifests as a temporary lower limb pain that occurs in connection with physical exercise. It is caused by an anatomic anomaly, usually anaberrant head of the gastrocnemius muscle that compresses the popliteal artery on the backside of the knee joint. The popliteal artery is the main vessel supplying blood to the lower part of the leg and the condition, if left untreated, can lead to serious complications such as thrombosis or aneurysm. If detected in time and surgically corrected patients can expect full recovery within weeks.The purpose of this study was to examine a group of healthy asymptomatic individuals (n=50)using ultrasound and a series of provocation to see if there was a possibility of entrapment. A secondary objective was to find which maneuvers during the ultrasound would provide the best results. They were subjected to ultrasound examinations at rest, during plantar flexion without resistance, against a light resistance and against substantial resistance.The results showed that most of the test subjects could temporarily constrict blood flow greatly although ultrasound imagery alone was not enough to confirm diagnosis. It seems that detected occlusion of the artery in conjunction with other diagnostic data such as AnkleBrachial Index and symptomatology can be useful both in confirming or ruling out PAESwithout the use of more expensive and invasive methods.
77

Pevnostní analýza protézy dolní končetiny / Lower limb prosthetics FEM analysis

Omasta, Milan January 2009 (has links)
This masters´s thesis deals with computational modeling of transtibial lower-limb prosthesis. For assesment of loading character and geometrical configuration, the gait analysis of an amputee, including ground reaction force measurement, strain gauge analysis and motion analysis, was accomplished. Information on geometry was obtained using 3D optical scanning procedure. Material model was gathered using non-destructive mechanical testing and mimicked in a FEA software. For loading conditions the static structure analysys using FEM was accomplished. The critical poins in construction was found. Recognition of agreement about experimental and computational model was accomplished.
78

Deformačně-napěťová analýza protézy dolní končetiny / Stress-strain analysis of lower limb prosthetic

Musilová, Kateřina January 2010 (has links)
This master thesis deals with lower-limb prosthesis. The aim of the first part of this work is stress-strain analysis of trans-tibial prosthesis, which is understand without prosthetic socket and the foam prosthetic feet. Analysis is made using finite element method in ANSYS Workbench 12.0 software. For the purpose of setting up the computational model it is necessary to make few partial models. Model of geometry of the prosthesis is made in SolidWorks 2009. Based on the outputs of stress-strain analysis and the results evaluation, the critical component is chosen and this one is evaluated according to limite state for fatigue. The algorithm of evaluation of named component in the state of high cycle fatigue is discussed in the second part of this thesis.
79

Design protézy dolní končetiny pro děti / Design of Human Leg Prosthesis for Children

Malátková, Hana January 2016 (has links)
The topic of this master’s thesis is design of human leg prosthesis for children. The thesis concerns own design of transbinal prosthesis for children that meet the basic technical, ergonomical and social requi¬rements and also brings a new look and shape as solution to the main topic. The infant incubator is designed in regard to modern materials and technologies.
80

Vliv komplexního strečinku dolní končetiny na posturální stabilitu / Influence of a complex stretching exercise of lower limb on postural stability

Maier, Ludvík January 2016 (has links)
Title: Influence of a complex stretching exercise of lower limb on postural stability Objectives:: The main objective of this diploma these is to find out, using dynamic computerized posturography, whether the increased mobility of the lower limbs has a positive influence on postural stability. Another partial objective is to determine efficiency of the practised stretching exercises. Methods: This is a pilot study where in research participated five probands whose measurement results were evaluated qualitatively. The aged of probands at the time of the first measurement was from 13 to 18 years. All probands are male volleyball league players and during the last two years occurred to a marked grow by all of them. Given their tall stature, it was expected a decrease in the mobility of the lower limbs and muscle shortening. To the data acquisition was used clinical examination of active range of motion and shortened muscle testing according to Janda. Postural stability was measured using computerized dynamic posturography SMART EquiTest System from Neurocom. Measured data were processed using the program NeuroCom Balance Manager software. In the Framework of study were conducted two intrumental measurements in the range of two months. After the first measurement all probands were instructed how to...

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