Biomimetic Prosthetic Knee Using Antagonistic Muscle-Like Activation

2008 ◽  
Author(s):  
Ernesto C. Martinez-Villalpando ◽  
Jeff Weber ◽  
Grant Elliott ◽  
Hugh Herr
Keyword(s):  
Energy Consumption ◽  
Knee Prosthesis ◽  
Mechanical Work ◽  
Net Energy ◽  
Human Knee ◽  
Prosthetic Knee ◽  
Series Elasticity ◽  
Design And Implementation ◽  
Antagonistic Muscle ◽  
Prosthetic Knees

The majority of commercial prosthetic knees are passive in nature and therefore cannot replicate the positive mechanical work exhibited by the natural human knee in early and late stance. In contrast to traditional purely dissipative prosthetic knees, we propose a biomimetic active agonist-antagonist structure designed to reproduce both positive and negative work phases of the natural joint while using series elasticity to minimize net energy consumption. We present the design and implementation of the active knee prosthesis prototype.

Position and Weight Activated Passive Knee Mechanism

2015 ◽  
Author(s):  
Tyagi Ramakrishnan ◽  
Christina-Anne Lahiff ◽  
Asgard Kaleb Marroquin ◽  
Kyle B. Reed
Keyword(s):  
Human Gait ◽  
Low Friction ◽  
Human Knee ◽  
Prosthetic Knee ◽  
Normal Knee ◽  
Locking Mechanism ◽  
Angular Velocities ◽  
Normal Human ◽  
Prosthetic Knees ◽  
Simple Assembly

The human knee is a complex and robust system. It is the most important joint for human gait because of its immense load bearing ability. The loss of such an important joint often makes it difficult for a person to ambulate. Because of this and the resulting unnatural application of forces, many trans-femoral amputees develop an asymmetric gait that leads to future complications. Prosthetic knees are required to be well-designed to cope with all variabilities. There have been many prosthetic knee designs, some more complex than others. This paper describes the design and preliminary testing of a novel passive position and weight activated knee locking mechanism for use in lower limb prosthetics. This knee mechanism is designed to be a simple and economical alternative to existing knee mechanisms. The mechanism utilizes the dynamics of the user to lock the knee during stance and unlock during the swing phase. The presence of one moving component and a simple assembly makes this design a good base for customization. Results from testing the knee mechanism shows trends that are different from a normal human knee, which is to be expected. The prosthetic knee is designed to have low friction during swing of the shank and, hence, the flexion and extension angles and angular velocities are larger compared to a normal knee. The kinematics show a cyclic trend that is highly repeatable. Further refinement and testing can make this mechanism more efficient in mimicking a normal knee.

Influences of Antero-Posterior Tibial Slope on the Prosthetic Knee Contact Stresses

2016 ◽  
Vol 823 ◽  
pp. 137-142
Author(s):  
Dan Calafeteanu ◽  
Dan Tarnita ◽  
Marius Catana ◽  
Daniel Calin ◽  
Daniela Tarniţă
Keyword(s):  
Knee Prosthesis ◽  
Tibial Slope ◽  
Contact Stresses ◽  
Posterior Tibial Slope ◽  
Human Knee ◽  
Prosthetic Knee ◽  
Posterior Tibial ◽  
Human Knee Joint ◽  
Total Knee ◽  
3D Finite Element Method

In this paper, using 3D finite element method and starting from the virtual model of the human knee joint-prosthesis assembly, we investigate the effects of antero-posterior tibial slope on contact stresses in the three components of total knee prosthesis. Using AnsysWorkbench15.07 software, the stress and displacements maps are obtained for knee-prosthesis assemblies and for their components, considering two loading force: 800N and 2400N and two cases of prosthetic knee varus slope: 176o and b) 191o. For each prosthesis-knee assembly and for each considered force, two variants of antero-posterior tibial slope were considered: 00 and 50.

scholarly journals Temperature Effects on Electricity and Gas Consumption: Empirical Evidence from Mexico and Projections under Future Climate Conditions

2020 ◽  
Vol 13 (1) ◽  
pp. 305
Author(s):  
W.J. Wouter Botzen ◽  
Tim Nees ◽  
Francisco Estrada
Keyword(s):  
Climate Change ◽  
Energy Consumption ◽  
Fixed Effects ◽  
Electricity Consumption ◽  
Energy Transition ◽  
Net Energy ◽  
Economic Costs ◽  
Climate Conditions ◽  
Linear Relationships ◽  
Gas Consumption

Fixed effects panel models are used to estimate how the electricity and gas consumption of various sectors and residents relate to temperature in Mexico, while controlling for the effects of income, manufacturing output per capita, electricity and gas prices and household size. We find non-linear relationships between energy consumption and temperature, which are heterogeneous per state. Electricity consumption increases with temperature, and this effect is stronger in warm states. Liquified petroleum gas consumption declines with temperature, and this effect is slightly stronger in cold states. Extrapolations of electricity and gas consumption under a high warming scenario reveal that electricity consumption by the end of the century for Mexico increases by 12%, while gas consumption declines with 10%, resulting in substantial net economic costs of 43 billion pesos per year. The increase in net energy consumption implies greater efforts to comply with the mitigation commitments of Mexico and requires a much faster energy transition and substantial improvements in energy efficiency. The results suggest that challenges posed by climate change also provide important opportunities for advancing social sustainability goals and the 2030 Agenda for Sustainable Development. This study is part of Mexico’s Sixth National Communication to the United Nations Framework Convention on Climate Change.

Novel active magnetorheological knee prosthesis presents low energy consumption during ground walking

2021 ◽  
pp. 1045389X2098392
Author(s):  
Rafhael Milanezi de Andrade ◽  
Jordana Simões Ribeiro Martins ◽  
Marcos Pinotti ◽  
Antônio Bento Filho ◽  
Claysson Bruno Santos Vimieiro
Keyword(s):  
Energy Consumption ◽  
Stance Phase ◽  
Gait Cycle ◽  
Dynamic Models ◽  
Knee Prosthesis ◽  
Regenerative Braking ◽  
Harmonic Drive ◽  
Low Energy Consumption ◽  
Energetic Expenditure ◽  
Over Ground Walking

This study analyses the energy consumption of an active magnetorheological knee (AMRK) actuator that was designed for transfemoral prostheses. The system was developed as an operational motor unit (MU), which consists of an EC motor, a harmonic drive and a magnetorheological (MR) clutch, that operates in parallel with an MR brake. The dynamic models of the MR brake and MU were used to simulate the system’s energetic expenditure during over-ground walking under three different working conditions: using the complete AMRK; using just its motor-reducer, to operate as a common active knee prosthesis (CAKP), and using just the MR brake, to operate as a common semi-active knee prosthesis (CSAKP). The results are used to compare the MR devices power consumptions with that of the motor-reducer. As previously hypothesized, to use the MR brake in the swing phase is more energetically efficient than using the motor-reducer to drive the joint. Even if using the motor-reducer in regenerative braking mode during the stance phase, the differences in power consumption among the systems are remarkable. The AMRK expended 16.3 J during a gait cycle, which was 1.6 times less than the energy expenditure of the CAKP (26.6 J), whereas the CSAKP required just 6.0 J.

Effect of Diethylstilbestrol on Utilization of Energy by the Growing Chick

1958 ◽  
Vol 195 (3) ◽  
pp. 654-658 ◽  
Author(s):  
F. W. Hill ◽  
L. B. Carew ◽  
A. van Tienhoven
Keyword(s):  
Energy Consumption ◽  
Linear Function ◽  
Heat Production ◽  
Live Weight ◽  
Metabolizable Energy ◽  
Energy Yield ◽  
Net Energy ◽  
Lower Protein ◽  
Energy Gains ◽  
Total Tissue

Increased fat production in diethylstilbestrol-treated chicks was found to be due primarily to increased energy consumption and to a lesser extent to preferential synthesis of fat at the expense of protein tissue. This was shown in experiments comparing normal and estrogen-treated male chicks with respect to gains in live weight, fat and protein at two planes of nutrition, and the yield of metabolizable and productive (net) energy which they obtained from the diet. It was found that the fattening effect could not be due to increased digestibility, increased net energy yield from absorbed nutrients, or lowered heat production. Under the influence of estrogen, total tissue gain expressed in Calories was increased, and was composed of greater fat gain and lower protein gain. Tissue energy gains were a linear function of metabolizable energy consumption. This relationship predicted equal tissue energy gains under pair-feeding conditions, which was confirmed experimentally.

Reduced cortical brain activity with the use of microprocessor-controlled prosthetic knees during walking

2018 ◽  
Vol 43 (3) ◽  
pp. 257-265 ◽  
Author(s):  
Saffran Möller ◽  
David Rusaw ◽  
Kerstin Hagberg ◽  
Nerrolyn Ramstrand
Keyword(s):  
Cognitive Processes ◽  
Lower Limb ◽  
Brain Activity ◽  
Control Group ◽  
Healthy Controls ◽  
Prosthetic Knee ◽  
Level Walking ◽  
Lower Limb Prosthesis ◽  
Prosthetic Knees ◽  
Limb Prosthesis

Background: Individuals using a lower-limb prosthesis indicate that they need to concentrate on every step they take. Despite self-reports of increased cognitive demand, there is limited understanding of the link between cognitive processes and walking when using a lower-limb prosthesis. Objective: The objective was to assess cortical brain activity during level walking in individuals using different prosthetic knee components and compare them to healthy controls. It was hypothesized that the least activity would be observed in the healthy control group, followed by individuals using a microprocessor-controlled prosthetic knee and finally individuals using a non-microprocessor-controlled prosthetic knee. Study design: Cross-sectional study. Methods: An optical brain imaging system was used to measure relative changes in concentration of oxygenated and de-oxygenated haemoglobin in the frontal and motor cortices during level walking. The number of steps and time to walk 10 m was also recorded. The 6-min walk test was assessed as a measure of functional capacity. Results: Individuals with a transfemoral or knee-disarticulation amputation, using non-microprocessor-controlled prosthetic knee ( n = 14) or microprocessor-controlled prosthetic knee ( n = 15) joints and healthy controls ( n = 16) participated in the study. A significant increase was observed in cortical brain activity of individuals walking with a non-microprocessor-controlled prosthetic knee when compared to healthy controls ( p < 0.05) and individuals walking with an microprocessor-controlled prosthetic knee joint ( p < 0.05). Conclusion: Individuals walking with a non-microprocessor-controlled prosthetic knee demonstrated an increase in cortical brain activity compared to healthy individuals. Use of a microprocessor-controlled prosthetic knee was associated with less cortical brain activity than use of a non-microprocessor-controlled prosthetic knee. Clinical relevance Increased understanding of cognitive processes underlying walking when using different types of prosthetic knees can help to optimize selection of prosthetic components and provide an opportunity to enhance functioning with a prosthesis.

scholarly journals Is Energy a Requirement for, or a Consequence of Economic Growth in Mauritius?

2020 ◽  
Author(s):  
HArris Neeliah ◽  
Boopen SEETANAH
Keyword(s):  
Economic Growth ◽  
Energy Consumption ◽  
Voluntary Contraction ◽  
Net Energy ◽  
Omitted Variables ◽  
Production Models ◽  
Long Run ◽  
Short Run ◽  
Growth Production ◽  
Dynamic Time

Abstract The non-reproducible nature of energy, coupled to its essentiality either as a direct or an intermediary input, makes it a crucial factor of production. We posit that it is, a complement to capital and labor and should be included in growth production models. Mauritius is a net energy importer, hence information about the nexus between energy consumption and economic growth is central to policy-making. This paper attempts to analyze this relationship for Mauritius within a multivariate framework over the period 1961 to 2019. The work adopts a dynamic time series framework (VECM approach) to account for dynamism, causality, endogeneity and omitted variables. Empirical results reveal long-run and short-run elasticities of energy consumption on economics growth of 0.33 and 0.17 respectively, thus giving credence to the thesis that energy is an important growth determinant in Mauritius. We also uncovered bi-directional causality between energy consumption and economic growth in both the long-run and the short-run. Therefore, unexpected and/ or voluntary contraction in either economic growth or energy consumption could result in a ‘feedback effect’ and dent either.JEL: Q4, O1

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