A Method to Improve Prosthesis Leg Design Based on Pressure Analysis at the Socket-Residual Limb Interface

2016 ◽  
Author(s):  
Giorgio Colombo ◽  
Claudio Comotti ◽  
Davide Felice Redaelli ◽  
Daniele Regazzoni ◽  
Caterina Rizzi ◽  
...  
Keyword(s):  
Low Cost ◽  
Experimental Tests ◽  
Fe Model ◽  
Residual Limb ◽  
Pressure System ◽  
Pressure Distributions ◽  
Physical Prototype ◽  
Lower Limb Prosthesis ◽  
Loading Tests ◽  
Pressure Analysis

This paper presents a methodology and tools to improve the design of lower limb prosthesis through the measurement of pressure analysis at the interface residual limb-socket. The steps of the methodology and the design tools are presented using a case study focused on a transfemoral (amputation above knee) male amputee. The experimental setup based on F-Socket Tekscan pressure system is described as well the results of some static loading tests. Pressure data are visualized with a colour pressure map over the 3D model of the residual limb acquired using an optical low cost scanner, based on MS Kinect. Previous methodology is useful to evaluate a physical prototype; in order to improve also conceptual design, the Finite Element (FE) Analysis has been carried and results reached so far have been compared with experimental tests. Pressure distributions are comparable, even if some discrepancies have been highlighted due to sensors placements and implemented FE model. Future developments have been identified in order to improve the accuracy of the numerical simulations.

scholarly journals Friction and camber influences on the static stiffness properties of a racing tyre

2008 ◽  
Vol 222 (11) ◽  
pp. 1965-1976 ◽  
Author(s):  
P Gruber ◽  
R S Sharp ◽  
A D Crocombe
Keyword(s):  
Static Loading ◽  
Ground Surface ◽  
Fe Model ◽  
Static Stiffness ◽  
Softening Mechanism ◽  
Pressure Distributions ◽  
Road Friction ◽  
Loading Tests ◽  
Stiffness Characteristics ◽  
Extensive Experimental Data

Investigation of the stationary load—deflection behaviour of tyres reveals many details of the structure and the rubber-to-road friction properties. These characteristics are fundamental to the understanding of the behaviour of both the stationary and the rolling tyre. In connection with racing, tyre static stiffness characteristics are of interest as they reflect on the controllability of the vehicle to which they are fitted. In this paper, the construction of a finite element (FE) model capable of predicting the static tyre behaviour in great detail is presented. The model is validated against extensive experimental data, including contact pressure distributions and load—deflection characteristics. Static loading tests, which involve variations in the friction rules coupling tread rubber with the ground surface, and in wheel camber angle, are simulated with the tyre model. The results of the simulations reveal that a friction coefficient of 0.5 is sufficient to prevent sliding in static loading tests for this particular tyre. Lower levels of friction lead to tread sliding and reduced vertical tyre stiffness. Sliding is primarily lateral, leading to narrowing of the contact patch of the tyre. Narrowing also increases the local sidewall curvature, which is part of the softening mechanism for both upright and cambered tyres.

Developing an Optimized Low-Cost Transtibial Energy Storage and Release Prosthetic Foot Using Three-Dimensional Printing

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Hisham Kamel ◽  
Omar Harraz ◽  
Khaled Azab ◽  
Tamer Attia
Keyword(s):  
Energy Storage ◽  
Low Cost ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Healthy Person ◽  
Metabolic Energy ◽  
Normal Person ◽  
Fe Model ◽  
Prosthetic Foot ◽  
Human Foot

Abstract This paper presents the results of an investigative study on the development of an affordable and functional prosthetic foot for below knee amputees. A prototype was successfully manufactured using three-dimensional (3D) printing technology. This continuously evolving technology enables the rapid production of prosthetics that are individually customized for each patient. Our prototype was developed after conducting a topology optimization study that interestingly converged to the shape of the biological human foot. Afterward, a design was envisioned where a simple energy storage and release (ESAR) mechanism was implemented to replace the Achilles tendon, which minimizes the metabolic energy cost of walking. Our mechanism can successfully manage 70% of the energy compared to a normal person during each walking step. A finite element (FE) model of the prosthetic was developed and validated using experimental tests. Then, this FE model was used to confirm the safe operation of the prosthetic through simulating different loading scenarios according to the ISO standard. A prototype was successfully tested by a healthy person using an adapter that was designed and 3D printed for this purpose. Our study clearly showed that customizable prosthetics could be produced at a fraction 1/60 of the cost of the commercially sold ones.

scholarly journals Image processing based foot plantar pressure distribution analysis and modeling

2020 ◽  
Vol 17 (2) ◽  
pp. 594
Author(s):  
Ali Hussein Sabry ◽  
W. Z. Wan Hasan ◽  
Mohd Nazim Mohtar ◽  
Raja Mohd Kamil Raja Ahmad ◽  
Hafiz Rashidi Ramli ◽  
...  
Keyword(s):  
Mathematical Modelling ◽  
Plantar Pressure ◽  
Pressure Level ◽  
Diabetic Patients ◽  
Distribution Analysis ◽  
Foot Pressure ◽  
Pressure System ◽  
Pressure Distributions ◽  
Plantar Pressure Distribution ◽  
Pressure Analysis

<span lang="EN-GB">Although many equipments and techniques are available for plantar pressure analysis to study foot pressure distributions, there is still a need for mathematical modelling references to compare the acquired measurements. In order to derive formulas in this concern, this research proposes a measurement-based method which adopts the reference measured parameters such as; the weight of a subject, contact-area size, age, and the pressure level distribution over a plantar image captured by the EMED plantar pressure system. The proposed analysis and algorithm were verified by a group 79 volunteers through data collection with four various measurement conditions. Three mathematical modelling equations have been proposed that describe the relationships between the foot plantar pressure levels and the subject’s body mass, foot size, and age. The modelling of foot plantar pressure could be useful for various applications such as gait analysis, hospitals, clinics, custom shoe making, and early detection of ulceration in the case of diabetic patients.</span>

Research on Transmission Principle of Gearless Reducer

2013 ◽  
Vol 860-863 ◽  
pp. 1744-1747 ◽  
Author(s):  
Lin Wu ◽  
Ming Wang Dong
Keyword(s):  
Small Volume ◽  
High Efficiency ◽  
Raw Materials ◽  
Low Cost ◽  
Experimental Tests ◽  
Transmission Mechanism ◽  
Physical Prototype ◽  
First Time ◽  
Lateral Transmission ◽  
Prototype Design

Propose cylindrical cam lateral transmission mechanism for the first time, define the agency's three specific types. Design gearless reducer type A, B and C for construction elevator by the application of the agency to reducer industry. Conduct physical prototype processing manufacture based on cylindrical cam lateral transmission theory and virtual prototype design of gearless reducer. By contrast processing and experimental tests to determine that the theory of cylindrical cam lateral transmission mechanism is feasible. Gearless reducer have the advantage of high efficiency and energy saving, low cost, small volume, light weight, saving raw materials resources.

scholarly journals Innovative passive reinforcements for the gradual stabilization of a landslide according with the observational method

Landslides ◽  
2021 ◽  
Author(s):  
Lorenzo Brezzi ◽  
Alberto Bisson ◽  
Davide Pasa ◽  
Simonetta Cola
Keyword(s):  
Monitoring System ◽  
Low Cost ◽  
Economic Losses ◽  
Fe Model ◽  
Site Conditions ◽  
Observational Method ◽  
Rainy Period ◽  
Sustainable Solutions ◽  
Before And After ◽  
Set Up

AbstractA large number of landslides occur in North-Eastern Italy during every rainy period due to the particular hydrogeological conditions of this area. Even if there are no casualties, the economic losses are often significant, and municipalities frequently do not have sufficient financial resources to repair the damage and stabilize all the unstable slopes. In this regard, the research for more economically sustainable solutions is a crucial challenge. Floating composite anchors are an innovative and low-cost technique set up for slope stabilization: it consists in the use of passive sub-horizontal reinforcements, obtained by coupling a traditional self-drilling bar with some tendons cemented inside it. This work concerns the application of this technique according to the observational method described within the Italian and European technical codes and mainly recommended for the design of geotechnical works, especially when performed in highly uncertain site conditions. The observational method prescribes designing an intervention and, at the same time, using a monitoring system in order to correct and adapt the project during realization of the works on the basis of new data acquired while on site. The case study is the landslide of Cischele, a medium landslide which occurred in 2010 after an exceptional heavy rainy period. In 2015, some floating composite anchors were installed to slow down the movement, even if, due to a limited budget, they were not enough to ensure the complete stabilization of the slope. Thanks to a monitoring system installed in the meantime, it is now possible to have a comparison between the site conditions before and after the intervention. This allows the evaluation of benefits achieved with the reinforcements and, at the same time, the assessment of additional improvements. Two stabilization scenarios are studied through an FE model: the first includes the stabilization system built in 2015, while the second evaluates a new solution proposed to further increase the slope stability.

scholarly journals Numerical Analysis of the Perforated Steel Sheets Under Uni-Axial Tensile Force

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 632 ◽  
Author(s):  
Ahmed M. Sayed
Keyword(s):  
Load Capacity ◽  
Tensile Force ◽  
Three Dimensional ◽  
Tensile Load ◽  
Experimental Tests ◽  
Strain Engineering ◽  
Uniaxial Tensile ◽  
Fe Model ◽  
Stress Strain ◽  
Steel Sheets

The perforated steel sheets have many uses, so they should be studied under the influence of the uniaxial tensile load. The presence of these holes in the steel sheets certainly affects the mechanical properties. This paper aims at studying the behavior of the stress-strain engineering relationships of the perforated steel sheets. To achieve this, the three-dimensional finite element (FE) model is mainly designed to investigate the effect of this condition. Experimental tests were carried out on solid specimens to be used in the test of model accuracy of the FE simulation. Simulation testing shows that the FE modeling revealed the ability to calculate the stress-strain engineering relationships of perforated steel sheets. It can be concluded that the effect of a perforated rhombus shape is greater than the others, and perforated square shape has no effect on the stress-strain engineering relationships. The efficiency of the perforated staggered or linearly distribution shapes with the actual net area on the applied loads has the opposite effect, as it reduces the load capacity for all types of perforated shapes. Despite the decrease in load capacity, it improves the properties of the steel sheets.

Assessing Palmar and Pinch Forces in a Manufacturing Plant Using a Dynamic Pressure System

2005 ◽  
Vol 49 (14) ◽  
pp. 1395-1398 ◽  
Author(s):  
Karin N. Barsness ◽  
Nathan J. Anderson ◽  
Paul E. Cassidy ◽  
Holly S. Wick
Keyword(s):  
Dynamic Pressure ◽  
Pressure System ◽  
Task Effects ◽  
Work Tasks ◽  
System Use ◽  
Subjective Measurements ◽  
Hand Force ◽  
Analysis System ◽  
Internal And External Validity ◽  
Pressure Analysis

For work tasks requiring hand force and repetitive motions, risk increases directly proportional to an increase in force and repetition. Data on hand force exertion is generally collected by estimation of these forces by using subjective measurements, EMG recordings, or strain gauges. The objective of this study was to evaluate the use of a pressure pad system to quantify the ergonomic risk of a repetitive forceful manufacturing task. Effects of palmar and pinch forces and pressures associated with the current and proposed new work tasks were investigated by using a Novel Pliance dynamic pressure analysis system. Use of this system allowed the researchers to validate the reduction in forces associated with the tasks. This methodology has profound implications in that no compromise between internal and external validity is necessary, and allows quantification of ergonomic issues around forces, including tasks which requiring repetition and force exertions.

scholarly journals Experimental tests for foot pressure analysis during orthostatic position and gait

2017 ◽  
Vol 112 ◽  
pp. 08009
Author(s):  
Daniel Ganea ◽  
Elena Mereuta ◽  
Silvia Veresiu ◽  
Madalina Rus ◽  
Valentin Amortila
Keyword(s):  
Experimental Tests ◽  
Foot Pressure ◽  
Orthostatic Position ◽  
Pressure Analysis

scholarly journals Low-Cost Force Sensors Embedded in Physical Human–Machine Interfaces: Concept, Exemplary Realization on Upper-Body Exoskeleton, and Validation

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 505
Author(s):  
Niclas Hoffmann ◽  
Samet Ersoysal ◽  
Gilbert Prokop ◽  
Matthias Hoefer ◽  
Robert Weidner
Keyword(s):  
Low Cost ◽  
Testing Machine ◽  
Measurement Data ◽  
Upper Body ◽  
Testing Environment ◽  
Physical Support ◽  
Pressure Distributions ◽  
Human Machine Interfaces ◽  
Piezoresistive Pressure Sensor ◽  
Material Testing Machine

In modern times, the collaboration between humans and machines increasingly rises, combining their respective benefits. The direct physical support causes interaction forces in human–machine interfaces, whereas their form determines both the effectiveness and comfort of the collaboration. However, their correct detection requires various sensor characteristics and remains challenging. Thus, this paper presents a developed low-cost sensor pad working with a silicone capsule and a piezoresistive pressure sensor. Its measurement accuracy is validated in both an isolated testing environment and a laboratory study with four test subjects (gender-balanced), and an application integrated in interfaces of an active upper-body exoskeleton. In the material-testing machine, it becomes apparent that the sensor pad generally features the capability of reliably determining normal forces on its surface until a certain threshold. This is also proven in the real application, where the measurement data of three sensor pads spatially embedded in the exoskeletal interface are compared to the data of an installed multi-axis load cell and a high-resolution flexible pressure map. Here, the consideration of three sensor pads potentially enables detection of exoskeletal support on the upper arm as well as “poor” fit conditions such as uneven pressure distributions that recommend immediate system adjustments for ergonomic improvements.

scholarly journals Internet of things (IoT) based I-V curve tracer for photovoltaic monitoring systems

2019 ◽  
Vol 13 (3) ◽  
pp. 1022 ◽  
Author(s):  
H. B. Chi ◽  
M. F. N. Tajuddin ◽  
N. H. Ghazali ◽  
A. Azmi ◽  
M. U. Maaz
Keyword(s):  
Internet Of Things ◽  
Low Cost ◽  
Experimental Tests ◽  
Monitoring Systems ◽  
The Internet ◽  
Control Software ◽  
Curve Tracer ◽  
Current Voltage ◽  
The Internet Of Things

<span>This paper presents a low-cost PV current-voltage or <em>I-V</em> curve tracer that has the Internet of Things (IoT) capability. Single ended primary inductance converter (SEPIC) is used to develop the <em>I-V</em> tracer, which is able to cope with rapidly changing irradiation conditions. The <em>I-V</em> tracer control software also has the ability to automatically adapt to the varying irradiation conditions. The performance of the <em>I-V</em> curve tracer is evaluated and verified using simulation and experimental tests.</span>

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