Matching Items (9)

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Optimal Prosthetic Development for the Good of all Amputees

Description

This paper emphasizes how vital prosthetic devices are as tools for both congenital and acquired amputees in order to maximize this population's level of societal productivity, but several issues exist with the current technological focus of development by the prosthetic

This paper emphasizes how vital prosthetic devices are as tools for both congenital and acquired amputees in order to maximize this population's level of societal productivity, but several issues exist with the current technological focus of development by the prosthetic industry that creates unnecessary hurdles that amputees must surpass in order to truly benefit from these tools. The first major issue is that these devices are not readily available to all amputees. The astronomical cost of most prosthetic devices is a variable that restricts low income amputee populations from obtaining these vital tools regardless of their level of need, thus highlighting the fact that amputees who are not financially stable are not supported in a fashion that is conducive to their success. Also, cost greatly affects children who suffer from a missing appendage due to the fact that they are in constant need of prosthetic replacement because of physical growth and development. Another issue with the current focus of the prosthetic industry is that it focuses on acquired amputees because this population is much larger in comparison to congenital amputees and thus more lucrative. Congenital amputees' particular needs are often entirely ignored in terms of prosthetic innovation. Finally, low daily utilization is a major issue amongst the amputee population. Several variables exist with the use of prosthetic devices that cause many amputees to decide against the utilization of these tools, like difficulty of use and lack of comfort. This paper will provide solutions to cost, discrimination, issues in development, and daily utilization by emphasizing on how lowering the cost through alternative designs and materials, transitioning the focus of technological development onto the entire amputee population rather than targeting the most lucrative group, and advancing the design in a fashion to which promotes daily utilization will provide the largest level of societal support, so that the amputee population as a whole can maximize their level of productivity in a manner that will allow this group to conquer the hardships that are introduced into their lives due to a missing appendage.

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Date Created
2018-05

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The Effect of El Niño Southern Oscillation Phase on Arizona Severe Weather

Description

The El Niño Southern Oscillation (ENSO) consists of a linkage between changes in sea-surface temperatures and atmospheric pressure across the Tropical Pacific. ENSO encompasses three phases: neutral events, warm/El Niño events in which sea-surface temperatures are warmer-than-normal and the pressure

The El Niño Southern Oscillation (ENSO) consists of a linkage between changes in sea-surface temperatures and atmospheric pressure across the Tropical Pacific. ENSO encompasses three phases: neutral events, warm/El Niño events in which sea-surface temperatures are warmer-than-normal and the pressure gradient decreases across the Equatorial Pacific, and cold/La Niña events in which Tropical Pacific sea-surface temperatures are cooler-than-normal and the pressure gradient increases. Previous studies have determined a connection between variations in ENSO phase and weather patterns across the globe, focusing particularly on surface temperature and precipitation patterns in the United States. However, little research exists that attempts to link changes in ENSO phase with severe weather in Arizona. Therefore, in this study, I analyzed how variations in ENSO phase affect the frequency, intensity, and spatial distribution of four types of severe weather from 1959 to 2016 in Arizona, including a) tornado events, b) severe thunderstorm wind events, c) hail events, and d) heavy rain and flash flood events. I collected data on the Oceanic Niño Index (ONI), a measure of ENSO, as well as storm reports for each severe weather phenomenon dating back to 1959. Then, I analyzed the frequency of each Arizona severe weather event type within each of the twelve annual months and over the entire study period. I also analyzed mean intensity values (Fujita/Enhanced Fujita Scale rating, path width, and path length for tornadoes; hail diameter in millimeters for hail; and wind gust speed for severe thunderstorm wind events) for each severe weather phenomenon, excluding the heavy rain and flash flood events. Finally, I used the Mean Center and Directional Distribution tools in ArcGIS to determine variations in the spatial distribution and mean centers between each ENSO phase for each severe weather event type. I found that ENSO phase, particularly La Niña, does impact the frequency and intensity of tornadoes, hail, thunderstorm wind, and heavy rain/flash flood events in Arizona. However, it appears that ENSO does not affect the spatial distribution of these Arizona severe weather phenomena. These findings attempt to fill in the gap in the literature and could help meteorologists better forecast changes in Arizona severe weather, in turn allowing Arizonans to better prepare for and mitigate the effects of severe weather across the state.

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Date Created
2018-05

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Design, Characterization, and Evaluation of a Dynamic Soft Robotic Prosthetic Socket Interface

Description

Prosthetic sockets are a static interface for dynamic residual limbs. As the user's activity level increases, the volume of the residual limb decreases by up to 11% and increases by as much as 7% after activity. Currently, volume fluctuation is

Prosthetic sockets are a static interface for dynamic residual limbs. As the user's activity level increases, the volume of the residual limb decreases by up to 11% and increases by as much as 7% after activity. Currently, volume fluctuation is addressed by adding/removing prosthetic socks to change the profile of the residual limb. However, this is time consuming. These painful/functional issues demand a prosthetic socket with an adjustable interface that can adapt to the user's needs. This thesis presents a prototype design for a dynamic soft robotic interface which addresses this need. The actuators are adjustable depending on the user's activity level, and their structure provides targeted compression to the soft tissue which helps to limit movement of the bone relative to the socket. The engineering process was used to create this design by defining system level requirements, exploring the design space, selecting a design, and then using testing/analysis to optimize that design. The final design for the soft robotic interface meets the applicable requirements, while other requirements for the electronics/controls will be completed as future work. Testing of the prototype demonstrated promising potential for the design with further refinement. Work on this project should be continued in future research/thesis projects in order to create a viable consumer product which can improve lower limb amputee's quality of life.

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2018-05

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The Development of a Comfortable Myoelectric Prosthetic Socket \u2014 Fishbone

Description

This paper proposes a new socket design to complement Project Fishbone, a design project focused on creating a lightweight transradial prosthetic device. The socket has a simple concept of introducing perforations on the surface of the socket using cost effective,

This paper proposes a new socket design to complement Project Fishbone, a design project focused on creating a lightweight transradial prosthetic device. The socket has a simple concept of introducing perforations on the surface of the socket using cost effective, and rapid manufacturing methods such as vacuum thermoforming and drilling. The perforations on the socket allows for greater air ventilation to the prosthetic user's residual skin thus reducing the temperature within the socket. There were nine primary design iterations that were tested: 0.125, 0,187, 0.25-inch-thick designs, and 3/16, 15/64, 17/64-inch perforation sizes, and 12, 18 and 24 count of perforations. Initial test was done using the sockets of different thickness without any perforations to check for uniformity in design and manufacturing method using a regression test. It was found that an increase in thickness directly related to an increase in temperature cooling time. The temperature cooling test was run using a three-factor DOE method and no clear interaction between the factors was observed, thus the Kruskal-Wallis statistical test along with the post hoc Mann-Whitney test to check for significance among the factors as well as significance of groups within the factors. Statistical significance (p<0.05) was found in the socket thickness and size of perforations. Additionally, significance (p<0.02) was found in the 0.125 and 0.187-inch thickness and the 3/16-inch size perforations. Based on the significance between each group, the best combination for increased cooling time reduction was thus found to be with the 0.125-inch thick HDPE sheet and 3/16-inch sized perforation while the number of perforations did not make much difference. These results proved the concept of this new socket design that could be implemented into existing upper limb prosthetic systems.

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Date Created
2017-05

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Development of a Wearable Haptic Feedback System for Use in Lower-Limb Prosthetics: Proof of Concept and Verification

Description

Skin and muscle receptors in the leg and foot provide able-bodied humans with force and position information that is crucial for balance and movement control. In lower-limb amputees however, this vital information is either missing or incomplete. Amputees typically compensate

Skin and muscle receptors in the leg and foot provide able-bodied humans with force and position information that is crucial for balance and movement control. In lower-limb amputees however, this vital information is either missing or incomplete. Amputees typically compensate for the loss of sensory information by relying on haptic feedback from the stump-socket interface. Unfortunately, this is not an adequate substitute. Areas of the stump that directly interface with the socket are also prone to painful irritation, which further degrades haptic feedback. The lack of somatosensory feedback from prosthetic legs causes several problems for lower-limb amputees. Previous studies have established that the lack of adequate sensory feedback from prosthetic limbs contributes to poor balance and abnormal gait kinematics. These improper gait kinematics can, in turn, lead to the development of musculoskeletal diseases. Finally, the absence of sensory information has been shown to lead to steeper learning curves and increased rehabilitation times, which hampers amputees from recovering from the trauma. In this study, a novel haptic feedback system for lower-limb amputees was develped, and studies were performed to verify that information presented was sufficiently accurate and precise in comparison to a Bertec 4060-NC force plate. The prototype device consisted of a sensorized insole, a belt-mounted microcontroller, and a linear array of four vibrotactile motors worn on the thigh. The prototype worked by calculating the center of pressure in the anteroposterior plane, and applying a time-discrete vibrotactile stimulus based on the location of the center of pressure.

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Date Created
2018-05

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Jaipur Prosthetic Foot Fatigue Machine

Description

This Honors thesis is analyzing the Jaipur Prosthetic Foot; we are using a foot from Bhagwan Mahaveer Viklang Sahayata Samiti (BMVSS) to test the durability of the foot and where the critical fatigue points are located. Our testing design will

This Honors thesis is analyzing the Jaipur Prosthetic Foot; we are using a foot from Bhagwan Mahaveer Viklang Sahayata Samiti (BMVSS) to test the durability of the foot and where the critical fatigue points are located. Our testing design will be based off of computer simulation to point out the critical points that the test machinery should accentuate. The machine will be set to sample and save data at interval times throughout the accentuated walking cycle in order to record the point where the foot begins to show wear.

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Date Created
2015-05

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Lightweight Transradial Prosthetic Able to Withstand Mechanical Forces during a Human Fall

Description

This paper proposes a new framework design for the lightweight transradial prosthesis. This device was designed to be light-weight, easily manufactured, inexpensive, and to have a high interstitial free space volume for electrical components and customization. Press-fit junctions between fins

This paper proposes a new framework design for the lightweight transradial prosthesis. This device was designed to be light-weight, easily manufactured, inexpensive, and to have a high interstitial free space volume for electrical components and customization. Press-fit junctions between fins allow for little or no adhesives, allowing for easily replaceable parts. Designs were constructed out of chipboard and run through an assortment of tests to see if each design iterations met structural design specifications. There were four main design iterations tested: 4, 8, 12 fin designs, and a 4 fin design with additional angled fins for torsional support (4T). Compression, torsion, and 3-point bending tests were all performed on each cylindrical iteration. Basic tensile and material testing was done on chipboard to support results. The force applied to a human arm during a fall is approximately 500 lbf [13]. Compression tests yielded a strength of approximately 300 lbf for the cylindrical designs. ANOVAs and T-tests were performed to find significance in compressive strength between the design iterations with the varied number of fins (p<<0.05). The torsional strength of the human arm, without causing great strain or discomfort has a max value of approximately 15 Nm [14]. This matched the torsional values of the 4T. design [14]. The 4, 8, and 12 designs' torsional strengths were linear with values of approximately 4, 7, and 12 Nm respectively. The 3-point bending test yielded the flexural stress and strain values to find compressive strength in the convex direction as well as the displacement and deformation in each sample. The material chipboard was found to be variable with elastic modulus, Poisson's ratio, and tensile strength. Each experimental procedure was done as a proof of concept for future prosthesis design.

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Date Created
2016-05

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Haptic discrimination of object size using vibratory sensory substitution

Description

Humans constantly rely on a complex interaction of a variety of sensory modalities in order to complete even the simplest of daily tasks. For reaching and grasping to interact with objects, the visual, tactile, and proprioceptive senses provide the majority

Humans constantly rely on a complex interaction of a variety of sensory modalities in order to complete even the simplest of daily tasks. For reaching and grasping to interact with objects, the visual, tactile, and proprioceptive senses provide the majority of the information used. While vision is often relied on for many tasks, most people are able to accomplish common daily rituals without constant visual attention, instead relying mainly on tactile and proprioceptive cues. However, amputees using prosthetic arms do not have access to these cues, making tasks impossible without vision. Even tasks with vision can be incredibly difficult as prosthesis users are unable to modify grip force using touch, and thus tend to grip objects excessively hard to make sure they don’t slip.

Methods such as vibratory sensory substitution have shown promise for providing prosthesis users with a sense of contact and have proved helpful in completing motor tasks. In this thesis, two experiments were conducted to determine whether vibratory cues could be useful in discriminating between sizes. In the first experiment, subjects were asked to grasp a series of hidden virtual blocks of varying sizes with vibrations on the fingertips as indication of contact and compare the size of consecutive boxes. Vibratory haptic feedback significantly increased the accuracy of size discrimination over objects with only visual indication of contact, though accuracy was not as great as for typical grasping tasks with physical blocks. In the second, subjects were asked to adjust their virtual finger position around a series of virtual boxes with vibratory feedback on the fingertips using either finger movement or EMG. It was found that EMG control allowed for significantly less accuracy in size discrimination, implying that, while proprioceptive feedback alone is not enough to determine size, direct kinesthetic information about finger position is still needed.

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Date Created
2016

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Advancements in Prosthetics and Joint Mechanisms

Description

Robotic joints can be either powered or passive. This work will discuss the creation of a passive and a powered joint system as well as the combination system being both powered and passive along with its benefits. A

Robotic joints can be either powered or passive. This work will discuss the creation of a passive and a powered joint system as well as the combination system being both powered and passive along with its benefits. A novel approach of analysis and control of the combination system is presented.

A passive and a powered ankle joint system is developed and fit to the field of prosthetics, specifically ankle joint replacement for able bodied gait. The general 1 DOF robotic joint designs are examined and the results from testing are discussed. Achievements in this area include the able bodied gait like behavior of passive systems for slow walking speeds. For higher walking speeds the powered ankle system is capable of adding the necessary energy to propel the user forward and remain similar to able bodied gait, effectively replacing the calf muscle. While running has not fully been achieved through past powered ankle devices the full power necessary is reached in this work for running and sprinting while achieving 4x’s power amplification through the powered ankle mechanism.

A theoretical approach to robotic joints is then analyzed in order to combine the advantages of both passive and powered systems. Energy methods are shown to provide a correct behavioral analysis of any robotic joint system. Manipulation of the energy curves and mechanism coupler curves allows real time joint behavioral adjustment. Such a powered joint can be adjusted to passively achieve desired behavior for different speeds and environmental needs. The effects on joint moment and stiffness from adjusting one type of mechanism is presented.

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Date Created
2017