scholarly journals Design and Qualitative Testing of a Prosthetic Foot With Rotational Ankle and Metatarsal Joints to Mimic Physiological Roll-Over Shape

2015 ◽  
Author(s):  
Kathryn M. Olesnavage ◽  
Amos G. Winter
Keyword(s):  
Design Concept ◽  
Preliminary Testing ◽  
Rigid Structure ◽  
Prosthetic Foot ◽  
Qualitative Feedback ◽  
Analysis Design ◽  
Prosthetic Feet ◽  
Optimal Stiffness ◽  
Further Development ◽  
Best Fit

This paper presents the analysis, design, and preliminary testing of a prototype prosthetic foot for use in India. A concept consisting of a rigid structure with rotational joints at the ankle and metatarsal with rotational stiffnesses provided by springs is discussed. Because literature suggests that prosthetic feet that exhibit roll-over shapes similar to that of physiological feet allow more symmetric gait, the joint stiffnesses were optimized to obtain the best fit between the roll-over shape of the prototype and of a physiological foot. Using a set of published gait data for a 56.7 kg subject, the optimal stiffness values for roll-over shape that also permit the motion required for natural gait were found to be 9.3 N·m/deg at the ankle and 2.0 N·m/deg at the metatarsal. The resulting roll-over shape has an R2 value of 0.81 when compared with the physiological roll-over shape. The prototype was built and tested in Jaipur, India. Preliminary qualitative feedback from testing was positive enough to warrant further development of this design concept.

scholarly journals Design and Preliminary Testing of a Prototype for Evaluating Lower Leg Trajectory Error as an Optimization Metric for Prosthetic Feet

2016 ◽  
Author(s):  
Kathryn M. Olesnavage ◽  
Amos G. Winter
Keyword(s):  
Lower Leg ◽  
Clinical Testing ◽  
Trajectory Error ◽  
Preliminary Testing ◽  
Rigid Structure ◽  
Prosthetic Foot ◽  
Constant Stiffness ◽  
Prosthetic Feet ◽  
Future Work ◽  
Novel Design

This work presents the design and preliminary testing of a prosthetic foot prototype intended for evaluating a novel design objective for passive prosthetic feet, the Lower Leg Trajectory Error (LLTE). Thus far, all work regarding LLTE has been purely theoretical. The next step is to perform extensive clinical testing. An initial prototype consisting of rotational ankle and metatarsal joints with constant rotational stiffness was optimized and built, but at 2 kg it proved too heavy to use in clinical testing. A new conceptual foot architecture intended to reduce the weight of the final prototype is presented and optimized for LLTE. This foot consists of a rotational ankle joint with constant stiffness of 6.1 N·m/deg, a rigid structure extending 0.08 m from the ankle-knee axis, and a cantilever beam forefoot with bending stiffness 5.4 N·m2. A prototype was built using machined delrin for the rigid structure, three parallel extension springs offset along a constant radius cam from a pin joint ankle, and machined nylon as the beam forefoot. In preliminary testing, it was determined that, despite efforts to minimize weight and size, this particular design was still too heavy and bulky as a result of the extension springs to be used in extensive clinical testing. Future work will focus on reducing the weight further by replacing linear extension springs with flexural elements before commencing with the clinical study.

scholarly journals Design and Testing of a Prosthetic Foot Prototype With Interchangeable Custom Rotational Springs to Adjust Ankle Stiffness for Evaluating Lower Leg Trajectory Error, an Optimization Metric for Prosthetic Feet

2017 ◽  
Author(s):  
Victor Prost ◽  
Kathryn M. Olesnavage ◽  
Amos G. Winter
Keyword(s):  
Optimization Method ◽  
Lower Leg ◽  
Trajectory Error ◽  
Preliminary Testing ◽  
Design Objective ◽  
Rigid Structure ◽  
Prosthetic Foot ◽  
Constant Stiffness ◽  
Ankle Stiffness ◽  
Prosthetic Feet

A prosthetic foot prototype intended for evaluating a novel design objective for passive prosthetic feet, the Lower Leg Trajectory Error (LLTE), is presented. This metric enables the optimization of prosthetic feet by modeling the trajectory of the lower leg segment throughout a step for a given prosthetic foot and selecting design variables to minimize the error between this trajectory and target physiological lower leg kinematics. Thus far, previous work on the LLTE has mainly focused on optimizing conceptual foot architectures. To further study this metric, extensive clinical testing on prototypes optimized using this method has to be performed. Initial prototypes replicating the LLTE-optimal designs in previous work were optimized and built, but at 1.3 to 2.1 kg they proved too heavy and bulky to be considered for testing. A new, fully-characterized foot design reducing the weight of the final prototype while enabling ankle stiffness to be varied is presented and optimized for LLTE. The novel merits of this foot are that it can replicate a similar quasi-stiffness and range of motion of a physiological ankle, and be tested with variable ankle stiffnesses to test their effect on LLTE. The foot consists of a rotational ankle joint with interchangeable U-shaped constant stiffness springs ranging from 1.5 Nm/deg to 16 Nm/deg, a rigid structure extending 0.093 m from the ankle-knee axis, and a cantilever beam forefoot with a bending stiffness of 16 Nm2. The prototype was built using machined acetal resin for the rigid structure, custom nylon springs for the ankle, and a nylon beam forefoot. In preliminary testing, this design performed as predicted and its modularity allowed us to rapidly change the springs to vary the ankle stiffness of the foot. Qualitative feedback from preliminary testing showed that this design is ready to be used in larger-scale studies. In future work, extensive clinical studies with testing different ankle stiffnesses will be conducted to validate the optimization method using the LLTE as a design objective.

Pengembangan Prototipe Piranti Lunak Sistem Informasi Manajemen Kegiatan Perekayasa Dengan Microsoft Excel

2014 ◽  
Vol 5 (2) ◽  
pp. 54-60
Author(s):  
Ivransa Zuhdi Pane
Keyword(s):  
Information System ◽  
Software Engineering ◽  
Management Information ◽  
Microsoft Excel ◽  
Development Stages ◽  
Engineering Activity ◽  
Engineering Information ◽  
Analysis Design ◽  
Index Terms ◽  
Further Development

Management of engineering activities based on information systems is expected to increase Engineer’s perfomances in executing the daily tasks. The software of such management information system should be built on the platform which is easy to use and adaptable to the dynamics of engineering activity management in the future. Software engineering, consisting of analysis, design and implementation, was carried out to realize a prototype which is ready to be applied in the further development stages. Index Terms - engineering activity, Engineering, information system, software engineering.

scholarly journals A Benchmark and Evaluation of Non-Rigid Structure from Motion

2020 ◽  
Author(s):  
Sebastian Hoppe Nesgaard Jensen ◽  
Mads Emil Brix Doest ◽  
Henrik Aanæs ◽  
Alessio Del Bue
Keyword(s):  
Computer Vision ◽  
Structure From Motion ◽  
State Of The Art ◽  
The State ◽  
Quality Data ◽  
Data Set ◽  
Rigid Structure ◽  
Public Data ◽  
3D Information ◽  
Further Development

AbstractNon-rigid structure from motion (nrsfm), is a long standing and central problem in computer vision and its solution is necessary for obtaining 3D information from multiple images when the scene is dynamic. A main issue regarding the further development of this important computer vision topic, is the lack of high quality data sets. We here address this issue by presenting a data set created for this purpose, which is made publicly available, and considerably larger than the previous state of the art. To validate the applicability of this data set, and provide an investigation into the state of the art of nrsfm, including potential directions forward, we here present a benchmark and a scrupulous evaluation using this data set. This benchmark evaluates 18 different methods with available code that reasonably spans the state of the art in sparse nrsfm. This new public data set and evaluation protocol will provide benchmark tools for further development in this challenging field.

scholarly journals Design and Implantation of a Voluntary Reading Mobile Application for People who are Visually Impaired

2018 ◽  
Vol 1 (1) ◽  
pp. 645-653
Author(s):  
Hanan Alateeq ◽  
Dalal Alzaid ◽  
Nadia Selim ◽  
Afnan Abouelwafa ◽  
Shiroq Al-Megren ◽  
...  
Keyword(s):  
Mobile Application ◽  
Visually Impaired ◽  
Preliminary Testing ◽  
Voluntary Reading ◽  
Reading Text ◽  
Phases Of Development ◽  
Analysis Design ◽  
Design And Testing

This paper proposed an application that supports visually impaired users in the community by providing voluntary audio support for readable content. The application, Basirah, allows visually impaired users to post audio request for reading text. Volunteers are able to view these requests and offer their response as recorded audio links. The application is developed for iOS devices and supports requests in English and allows for multi-lingual responses for volunteers. This paper presents Basirah and walks through the analysis, design, and testing phases of development. Preliminary testing was carried out on Basirah, where it has shown promising results and contribution.

Characterizing adaptations of prosthetic feet in the frontal plane

2020 ◽  
Vol 44 (4) ◽  
pp. 225-233
Author(s):  
Michael Ernst ◽  
Björn Altenburg ◽  
Thomas Schmalz
Keyword(s):  
Energy Storage ◽  
Theoretical Model ◽  
Ankle Joint ◽  
Frontal Plane ◽  
Measured Data ◽  
Limb Amputation ◽  
Clinical Parameters ◽  
Mechanical Adaptation ◽  
Prosthetic Foot ◽  
Prosthetic Feet

Background: Energy-storage and return feet incorporate various design features including split toes. As a potential improvement, an energy-storage and return foot with a dedicated ankle joint was recently introduced allowing for easily accessible inversion/eversion movement. However, the adaptability of energy-storage and return feet to uneven ground and the effects on biomechanical and clinical parameters have not been investigated in detail. Objectives: To investigate the design-related ability of prosthetic feet to adapt to cross slopes and derive a theoretical model. Study design: Mechanical testing and characterization. Methods: Mechanical adaptation to cross slopes was investigated for six prosthetic feet measured by a motion capture system. A theoretical model linking the measured data with adaptations is proposed. Results: The type and degree of adaptation depends on the foot design, for example, stiffness, split toe or continuous carbon forefoot, and additional ankle joint. The model used shows high correlations with the measured data for all feet. Conclusions: The ability of prosthetic feet to adapt to uneven ground is design-dependent. The split-toe feet adapted better to cross slopes than those with continuous carbon forefeet. Joints enhance this further by allowing for additional inversion and eversion. The influence on biomechanical and clinical parameters should be assessed in future studies. Clinical relevance Knowing foot-specific ability to adapt to uneven ground may help in selecting an appropriate prosthetic foot for persons with a lower limb amputation. Faster and more comprehensive adaptations to uneven ground may lower the need for compensations and therefore increase user safety.

Further Development and Preliminary Testing of the α-Prototype of an Ultra-Micro Gas Turbine for Portable Power Generation

2008 ◽  
Author(s):  
R. Capata ◽  
E. Sciubba
Keyword(s):  
Fluid Dynamic ◽  
Fem Analysis ◽  
Point Of View ◽  
Power Sources ◽  
Preliminary Testing ◽  
Micro Gas Turbine ◽  
Portable Power ◽  
Portable Electronics ◽  
Further Development ◽  
Physical Construction

The ever increasing development of portable electronics leads to a higher demand for compact and reliable power sources. Significant resources are being presently dedicated to the study of micro machined turbines, because of their remarkable power density that suggests that the generation of about 100–300 W with a total device weight of few hundreds grams and a fuel mass flow rate of few grams per second may be feasible in the short range. In this paper a possible configuration of such a nano-GT set is considered, which was defined on the basis of previous thermo-fluid dynamic analysis: the results of a preliminary design study, including some cold-run tests, are reported in this paper. The layout of the device was finalized on the basis of both a CFD and a FEM analysis that identified the “optimal” blade shape, shaft size and rotors arrangements under the point of view of the energy efficiency and of thermo-mechanical material stresses, Some of the problems deriving by the physical construction and preliminary testing of the prototype are analyzed and discussed.

The use of optimization techniques to model marine ecosystem dynamics at the JGOFS station at 47° N 20° W

1995 ◽  
Vol 348 (1324) ◽  
pp. 203-209 ◽  
Keyword(s):  
Primary Production ◽  
Mixed Layer ◽  
Marine Ecosystem ◽  
Optimization Technique ◽  
Compartment Model ◽  
Optimization Techniques ◽  
Ecosystem Dynamics ◽  
Data Sets ◽  
Further Development ◽  
Best Fit

A seven-compartment model of the mixed layer ecosystem was used to fit a time series of observations derived from data obtained during the 1989 JGOFS North Atlantic Bloom Experiment. A nonlinear optimization technique was used to obtain the best fit to the combined observation set. It was discovered that a solution which gave a good fit to primary production gave a bad fit to zooplankton and vice versa. The solution which fitted primary production also showed good agreement with a number of other independent data sets, but overestimated bacterial production. Further development is necessary to create a model capable of reproducing all the important features of the nitrogen flows within the mixed layer.

Parametric Evaluation of Hindfoot and Forefoot Properties and Their Effect on the Angular Stiffness of Prosthetic Feet

2012 ◽  
Author(s):  
Peter G. Adamczyk ◽  
Michelle Roland ◽  
Michael E. Hahn
Keyword(s):  
Stance Phase ◽  
Direct Calculation ◽  
Future Studies ◽  
Prosthetic Foot ◽  
Moment Arms ◽  
Walking Performance ◽  
Deformation Mechanics ◽  
Prosthetic Feet ◽  
Stiffness Characteristics ◽  
Parametric Adjustment

Prosthetic foot stiffness has been recognized as an important factor in optimizing the walking performance of amputees [1–3]. Commercial feet are available in a range of stiffness categories and geometries. The stiffness of linear displacements of the hindfoot and forefoot for several commercially available feet have been reported to be within a range of 27–68 N/mm [4] and 28–76 N/mm [5], respectively, but these values are most relevant only to the earliest and latest portions of stance phase, when linear compression or rebound naturally occur. In contrast, mid-stance kinetics are more related to the angular stiffness of the foot, which describes the ankle torque produced by angular progression of the lower limb over the foot during this phase. Little data is available regarding the angular stiffness of any commercially available feet. The variety of geometries between manufacturers and models of prosthetic feet makes a direct calculation of effective angular stiffness challenging due to changes in moment arms based on loading condition, intricacies of deformation mechanics of the structural components, and mechanical interaction between hindfoot and forefoot components. Thus, modeling the interaction between hindfoot stiffness, forefoot stiffness, and keel geometries and their combined effect on the angular stiffness of the foot may be a useful tool for correlating functional outcomes with stiffness characteristics of various feet. To understand how each of these factors affects angular stiffness, we developed a foot that can parametrically adjust each of these factors independently. The objective of this study was to mathematically model, design, and experimentally validate a prosthetic foot that has independent hindfoot and forefoot components, allowing for parametric adjustment of stiffness characteristics and keel geometry in future studies of amputee gait.

scholarly journals Perception and Interpretation: Points of Focus in Design Sketches

2012 ◽  
Author(s):  
Emma Sagan ◽  
Maria Yang
Keyword(s):  
Visual Perception ◽  
Surface Texture ◽  
Design Concept ◽  
Aesthetic Preference ◽  
Potential Customer ◽  
Texture Material ◽  
Further Development

During the design of a product, designers may show a potential customer or other stakeholder a drawing of a design concept in order to elicit feedback that can be used to inform further development of the design. Designers may desire feedback on specific aspects of a concept, such as its shape or size, but viewers may in fact focus on other elements of the drawing itself, such as color or surface texture. Viewers translate their visual perception of these representations into perceived understanding, but how can we know whether their interpretations are consistent with the designer’s intention? This paper evaluates the translation of four different product sketches by 163 participants. This study also considers how aesthetic preference and concrete information might influence a viewer’s opinion of an object. Results suggest that viewers were likely to recall physical aspects from a sketch of a product (material, shape) as well as its function. Findings also suggest that individuals preferred images that were overall more informative rather than aesthetically pleasing. Additionally, our research suggests that individuals were more likely to recall the texture, material or perceived efficiency of an object than recall the name of the object, its function, or its shape.

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