Swing Phase Simulation and Design of Above Knee Prostheses

1986 ◽  
Vol 108 (1) ◽  
pp. 65-72 ◽  
Author(s):  
C.-S. Tsai ◽  
J. M. Mansour
Keyword(s):  
System Performance ◽  
Current Practice ◽  
Walking Speed ◽  
Swing Phase ◽  
Design Parameters ◽  
Light Weight ◽  
Simple Design ◽  
Knee Prostheses ◽  
Constant Friction ◽  
Overall Performance

A detailed dynamic model of the stump-prosthesis system for an above knee amputee was developed. The model was used to examine the influence of controls and design parameters on the limb system performance during the swing phase of gait. The model duplicated the clinically known fact that hydraulic knee controllers allow the amputee to change walking speed while mechanical knee controllers limit the amputee to a single walking speed. Contrary to current practice, the simulations suggest that light weight prosthesis designs do not perform as well as heavier designs. A simple design based on a constant friction knee is shown to yield good overall performance.

Research on the Reliability of Box for Gear Test Bed

2011 ◽  
Vol 121-126 ◽  
pp. 1744-1748
Author(s):  
Xiang Yang Jin ◽  
Tie Feng Zhang ◽  
Li Li Zhao ◽  
He Teng Wang ◽  
Xiang Yi Guan
Keyword(s):  
Power Flow ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Design Parameters ◽  
The Finite Element Method ◽  
Test Bed ◽  
Kinematics Simulation ◽  
Beveloid Gears ◽  
Overall Performance

To determine the efficiency, load-bearing capacity and fatigue life of beveloid gears with intersecting axes, we design a mechanical gear test bed with closed power flow. To test the quality of its structure and predict its overall performance, we establish a three-dimensional solid model for various components based on the design parameters and adopt the technology of virtual prototyping simulation to conduct kinematics simulation on it. Then observe and verify the interactive kinematic situation of each component. Moreover, the finite element method is also utilized to carry out structural mechanics and dynamics analysis on some key components. The results indicate that the test bed can achieve the desired functionality, and the static and dynamic performance of some key components can also satisfy us.

scholarly journals Community Design Parameters and the Performance of Residential Cogeneration Systems

2007 ◽  
Vol 4 (2) ◽  
Author(s):  
Hazem Rashed-Ali
Keyword(s):  
System Performance ◽  
Design Parameters ◽  
Base Line ◽  
Line Model ◽  
Residential Communities ◽  
Mixed Use ◽  
Study Results ◽  
Cogeneration System ◽  
Design Characteristics ◽  
The Impact

The integration of cogeneration systems in residential and mixed-use communities has the potential of reducing their energy demand and harmful emissions and can thus play asignificant role in increasing their environmental sustainability. This study investigated the impact of selected planning and architectural design parameters on the environmental and economic performances of centralized cogeneration systems integrated into residential communities in U.S.cold climates. Parameters investigated include: 1) density, 2) use mix, 3) street configuration, 4) housing typology, 5) envelope and building systems’ efficiencies, and 6) passive solar energyutilization. The study integrated several simulation tools into a procedure to assess the impact of each design parameter on the cogeneration system performance. This assessment procedure included: developing a base-line model representing typical design characteristics of U.S. residential communities; assessing the cogeneration system’s performance within this model using three performance indicators: percentage of reduction in primary energy use, percentage of reduction in CO2 emissions; and internal rate of return; assessing the impact of each parameter on the system performance through developing 46 design variations of the base-line model representing potential changes in each parameter and calculating the three indicators for each variation; and finally, using a multi-attribute decision analysis methodology to evaluate the relative impact of each parameter on the cogeneration system performance. The study results show that planning parameters had a higher impact on the cogeneration system performance than architectural ones. Also, a significant correlation was found between design characteristics identified as favorable for the cogeneration system performance and those of sustainable residential communities. These include high densities, high use mix, interconnected street networks, and mixing of housing typologies. This indicates a higher potential for integrating cogeneration systems in sustainable communities.Keywords: cogeneration; residential & mixed use communities; energy efficiency; district heating

A Computer Model to Simulate the Swing Phase of a Transfemoral Prosthesis

2004 ◽  
Vol 20 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Brendan Burkett ◽  
James Smeathers ◽  
Timothy M. Barker
Keyword(s):  
Walking Speed ◽  
Swing Phase ◽  
Prosthetic Knee ◽  
Energy Demands ◽  
Swing Time ◽  
Significant Difference ◽  
Prosthetic Knee Joint ◽  
Transfemoral Prosthesis ◽  
Everyday Task ◽  
Phase Motion

For amputees to perform an everyday task, or to participate in physical exercise, it is crucial that they have an appropriately designed and functional prosthesis. Past studies of transfemoral amputee gait have identified several limitations in the performance of amputees and in their prosthesis when compared with able-bodied walking, such as asymmetrical gait, slower walking speed, and higher energy demands. In particular the different inertial characteristics of the prosthesis relative to the sound limb results in a longer swing time for the prosthesis. The aim of this study was to determine whether this longer swing time could be addressed by modifying the alignment of the prosthesis. The following hypothesis was tested: Can the inertial characteristics of the prosthesis be improved by lowering the prosthetic knee joint, thereby producing a faster swing time? To test this hypothesis, a simple 2-D mathematical model was developed to simulate the swing-phase motion of the prosthetic leg. The model applies forward dynamics to the measured hip moment of the amputee in conjunction with the inertial characteristics of prosthetic components to predict the swing-phase motion. To evaluate the model and measure any change in prosthetic function, we conducted a kinematic analysis on four Paralympic runners as they ran. When evaluated, there was no significant difference (p > 0.05) between predicted and measured swing time. Of particular interest was how swing time was affected by changes in the position of the prosthetic knee axis. The model suggested that lowering the axis of the prosthetic knee could reduce the longer swing time. This hypothesis was confirmed when tested on the amputee runners.

Design, Fabrication, and Characterization of a Soft Multi-Fingered Hand

2016 ◽  
Author(s):  
Lena Johnson ◽  
Hugh A. Bruck ◽  
Satyandra K. Gupta
Keyword(s):  
Geometric Model ◽  
Design Parameters ◽  
Experimental Setup ◽  
Robotic Hand ◽  
Iterative Design ◽  
Modeling Methods ◽  
Design And Manufacturing ◽  
Overall Performance ◽  
Fabrication And Characterization

This paper describes the design, fabrication, testing and modeling of the SUR Hand. The SUR Hand is a soft, under actuated robotic hand. Through an iterative design and manufacturing process, SUR Hand’s soft, actuating components have been adapted from the original PneuFlex, pneumatically actuated finger to be highly flexible and capable of actuating a precision force. This paper shows how altering the design parameters of the fingers altered their overall performance. Furthermore, it details the experimental setup for testing the components, as well as the modeling methods used. Finally, it shows the process for creating and validating a geometric model that characterizes proper grasping strategies, assuming a passive palm component.

Identifying predictors of players’ perception regarding sliding friendliness and the overall field performance of artificial turf systems for soccer

2016 ◽  
Vol 231 (2) ◽  
pp. 102-109
Author(s):  
Wilbert van den Eijnde ◽  
Renée Richters ◽  
Gert-Jan Kieft ◽  
Piet van Erp
Keyword(s):  
Skin Irritation ◽  
Field Performance ◽  
Statistical Analyses ◽  
Design Parameters ◽  
Artificial Turf ◽  
Shock Absorption ◽  
Overall Performance ◽  
Soccer Team

Due to different design parameters, there is a large variety of artificial turf configurations on the market for soccer. The ultimate aim for any player surface is to maximize the performance and to minimize injuries. The aim of this study is to develop and validate the Football Turf Performance Questionnaire which measures the performance of an artificial turf soccer pitch and to identify predictors for both the overall performance and sliding friendliness based on the players’ perceptions. Three types of artificial turf configurations were evaluated by an elite soccer team in five different trials. Statistical analyses were performed to check the reliability, the classification into factors and identification of predictors, respectively. The best predictors of the total judgement are the descriptors ‘hardness of the field during falling and during sprinting’ and ‘traction during stopping’ and the indicators ‘traction’ and ‘shock absorption’. For sliding friendliness solely, the best predictors are the descriptor ‘burning feeling of the skin after a sliding movement’ and the indicators ‘skin irritation’ and ‘traction’.

scholarly journals Bondgraph modelling and simulation of the dynamic behaviour of above-knee prostheses

1987 ◽  
Vol 11 (2) ◽  
pp. 65-70 ◽  
Author(s):  
P. G. Van De Veen ◽  
W. Van Der Tempel ◽  
J. De Vreiss
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Mass Distribution ◽  
Total Mass ◽  
Dynamic Behaviour ◽  
Step Length ◽  
Swing Phase ◽  
Knee Prostheses ◽  
Prosthetic Foot ◽  
Walking Velocity

A mathematical model was used to investigate the dynamic behaviour of an above-knee (AK) prosthesis in the swing phase and to analyse the influence of mass and mass distribution on the maximal stump load and the required energy. The model consists of a bondgraph model of the prosthesis and a “walking” model which predicts the walking velocity, step length and the femoral trajectory. Equipment was developed to measure the inertial properties of the components of the prosthesis. Through computer simulation, stickdiagrams of the swing phase and graphs of the variation with time of the hip and stump forces were obtained. It was found that for a normal AK prosthesis with a knee-lock mechanism the axial stump load is greatest at the beginning and at the end of the swing phase. At a walking velocity of 5 km/hr the maximum axial stump load amounts to 2.1 times the static weight of the prosthesis. The maximum axial stump force appeared to be almost directly proportional to the total mass of the prosthesis but independent of the mass distribution. The required energy also increased with the mass of the prosthesis but is' dependent on mass distribution. Because of their comparable weights the influence of the shoe is almost equal to the influence of the prosthetic foot. Thus lightweight shoes should be used with lightweight prosthetic feet in order to add to their advantages.

Analysis, simulation, and implementation of a human-inspired pole climbing robot

Robotica ◽  
2011 ◽  
Vol 30 (2) ◽  
pp. 279-287 ◽  
Author(s):  
A. Sadeghi ◽  
H. Moradi ◽  
M. Nili Ahmadabadi
Keyword(s):  
Static Analysis ◽  
Full Scale ◽  
The Other ◽  
Light Weight ◽  
Simple Design ◽  
Climbing Robot ◽  
Full Size ◽  
Control Light ◽  
The Stability ◽  
Novel Design

SUMMARYIn this paper, we present the design, static analysis, simulation, and implementation of a novel design for a naturally stable climbing robot that has been inspired from human pole/tree climbers. The other benefits of this robot, besides being naturally stable, are its simple design, ease of control, light weight, simple mechanism, and fast climbing speed. The robot consists of three wheels, two free and one active wheel, which enable the robot to climb or descend poles. The free wheels are almost frictionless, while the active wheel has enough friction to be able to apply force on the pole for stable climbing or descending. The wheels are designed in V-shape such that the robot can compensate for misplacements eliminating possible detachment from poles. Although the robot can operate with a single free wheel, however, an extra free wheel is added to increase the stability and safety of the robot. In this paper, the static analysis of the robot is presented and the robot is simulated. Furthermore, the robot is actually implemented and successfully tested in two sizes, a small size and a big/full size. The full-scale prototype has been equipped with washing and inspection tools and tested washing actual street lights. The results show the unique characteristics of this robot that make it more stable if more weight is carried.

scholarly journals Knee mechanisms for through-knee prostheses

1983 ◽  
Vol 7 (2) ◽  
pp. 107-112 ◽  
Author(s):  
K. Öberg
Keyword(s):  
Stance Phase ◽  
Stability Diagram ◽  
Phase Control ◽  
Swing Phase ◽  
Control Mechanisms ◽  
Knee Prostheses ◽  
Heavy Duty ◽  
Linkage Mechanism ◽  
The Stability

The most widely used knee mechanisms for through-knee amputees can be characterized as three principal types of design. These types are metal side bars with heavy duty joints, conventional knee mechanisms for above-knee amputees and special polycentric linkage mechanisms for through-knee amputees. An investigation in Sweden in 1979 showed that over 50% of the fittings were using the special polycentric linkage mechanisms for through-knee amputees. The stability diagram illustrates how voluntary and involuntary stability can be utilized by using different polycentric linkage mechanisms for through-knee amputees. The polycentric linkage mechanism can be designed for different stance phase characteristics as well as incorporation of different swing phase control mechanisms. The cosmesis of the available designs is acceptable but there is need for lighter and more compact designs especially for the young and small amputee.

Influence of the Different Design Parameters to the Centrifugal Compressor Tip Clearance Loss

2011 ◽  
Author(s):  
Teemu Turunen-Saaresti ◽  
Ahti Jaatinen
Keyword(s):  
Centrifugal Compressor ◽  
Tip Clearance ◽  
Design Parameters ◽  
Clear Correlation ◽  
Compressor Stage ◽  
Centrifugal Compressors ◽  
Blade Number ◽  
Overall Performance ◽  
Specific Speed

In this paper the effect of the tip clearance was studied with six different centrifugal compressors and data available in literature. The changes in the overall performance of the compressor stage were examined. The aim was to study the influence of the different design parameters to the tip clearance loss. It was evident by the previous studies that the sensitivity of the centrifugal compressor to the tip clearance loss varies with different designs. However, for the designer it is important to know the effect of the tip clearance loss in order to initially evaluate the quality of different designs. Analysis of the data demonstrated that no clear correlation between the sensitivity of the tip clearance loss and the specific speed, the diffusion ratio, the blade number and the ratio of blade heights exists.

Advanced Hydrodynamic Design of Vertical Diffuser Pumps Using Computational Fluid Dynamics

2002 ◽  
Author(s):  
Kristis V. Michaelides ◽  
Antonios Tourlidakis
Keyword(s):  
Development Process ◽  
Three Dimensional ◽  
Detailed Examination ◽  
Product Development Process ◽  
Design Parameters ◽  
Factors Affecting ◽  
Performance Predictions ◽  
Overall Performance ◽  
Industrial Use ◽  
Optimisation Procedure

The current paper describes an investigation into the industrial use of CFD and other computational technologies for the three-dimensional hydrodynamic design of vertical diffuser pumps and outlines the complete product development process. Detailed description of the complete design process is described and numerous CFD predictions of the flow are presented with detailed examination of the several factors affecting the hydrodynamics of impeller and diffuser and staging of the pump. Furthermore, variations of important geometrical design parameters based on the design optimisation procedure are discussed in accordance to the CFD results. The capabilities of the 3-D hydrodynamic design through CFD and the importance of the three dimensional blade geometry are demonstrated by the fact that two different pump impellers were designed based on strict design constraints affecting their basic dimensions. Finally, an overview of the functional prototypes development is described and comparisons are carried out between overall performance predictions and experimental results.

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