Organizational Unit:

Rehabilitation Engineering and Applied Research Lab (REAR Lab)

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https://hdl.handle.net/1853/71920

Parent Organization

Organizational Unit

School of Industrial Design

Organizational Unit

George W. Woodruff School of Mechanical Engineering

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Now showing 1 - 10 of 14

Mechanical performance characterization of manual wheelchairs using robotic wheelchair operator with intermittent torque-based propulsion

(Georgia Institute of Technology, 2020-12-06) Misch, Jacob P.

The current manual wheelchair design process lacks consistent and objective connection to performance-based metrics. The goal of this research was to empirically assess over-ground manual wheelchair performances and identify important design trade-offs through the use of a robotic apparatus with a novel cyclic propulsion control method. This research had four specific aims: 1) to design, implement, and validate torque-based propulsion to emulate the intermittent human propulsion cycle with an existing robotic wheelchair tester, 2) to investigate the influence of incremental mass additions to the wheelchair frame on over-ground propulsion characteristics, 3) to demonstrably improve the performance of a representative high-strength lightweight wheelchair by leveraging existing component-level test results, and 4) to characterize the mechanical performances of representative folding and rigid ultra-lightweight wheelchair frames. The outcomes of this research include an objective, repeatable, and validated test method to assess over-ground performances of manual wheelchairs in realistic contexts of use, as well as insight on the mechanics of the system that were previously under-studied or confounded by variabilities within human subject testing. Controlled propulsion tests are used to identify differences between wheelchair configurations. The outcome variable of propulsion cost represents the energetic requirements of propelling each chair a given distance and has direct relevance to manufacturers, clinicians, and wheelchair users alike. Ultimately, these outcomes will inform clinicians and manufacturers about how configuration choices influence propulsive efforts, which can be used in turn to improve their classification techniques and existing design processes. This knowledge will additionally empower wheelchair users to make informed choices during the wheelchair selection process based on objective mechanical performance metrics.
Designing an Ergonomic Infant-to-Toddler Rocker Based on Anthropometric Data

(Georgia Institute of Technology, 2020-04-27) Ryan, Caitlin Olivia

Currently ergonomics is not a term frequently associated with infant and toddler products. Many of these products on the market like highchairs, rockers and bouncers aren’t designed using anthropometric data on infants and toddlers. The project focused on gather anthropometric data from children between 0-36 months of age as well as aggregating historic data and utilize the measurements to design an ergonomic rocker that would transition or “grow” with a child from infant to toddler. This takes into account not only the objective size of the infants and toddlers but also designing for the differing use cases for each the infant and the toddler user. The infant users are still developing much of their muscle tone and require a rocker to support their feet in long sitting in a semi-reclined position. While toddlers require a rocker that facilitates upright short sitting as well as independent ingress and egress to accommodate their high activity levels. These disparate needs are not currently being met by similar products on the market leading to a shorted life cycle of the product. Anthropometric data was collected on 55 children and used in tandem with knowledge gained from parent surveys, parent interviews and interacting with children to design a new rocker. The prototype was evaluated by both parents and children to make necessary improvements to the design. The final prototype utilized all the information gathered throughout the entire project resulting in an ergonomic adjustable infant -to-toddler rocker.
Using Anthropometric Measurements to Design Ergonomic Infant and Toddler Gear

(Georgia Institute of Technology, 2019-12-05) Pardue, Emily Louisa

Infants grow so quickly that gear can have a shockingly short life span. Parents often do a quick calculation before purchases: divide the cost by how many months it will be used. Thus, products that are meant to “grow-with-me” or last for multiple infant stages are extremely desirable. Infant-to-toddler rockers are an example of this type of product. However, the researchers have found that the current infant-to-toddler rocker models on the market could be improved. The goal of this project was to use anthropometric data of children to design an ergonomic infant-to-toddler rocker. Anthropometric data was collected on 58 children in order to properly size a new design for a rocker which lasts from 0 to 36 months old. Researchers also found based on parent interviews, a survey, and child interactions, that the needs of infants are very different from the needs of toddlers. Infants are still developing muscle tone, and it is important for them to be supported in a semi-reclined position. Toddlers are extremely active and need a device which allows them to ingress and egress independently. Concepts were developed, and prototypes built to demonstrate the new concepts. These prototypes were then tested with parents and children to gather feedback and improve designs. The final design is an ergonomic rocker which adjusts in size and recline angle to serve the infants that need to be secure and reclined, as well as the ambulatory toddlers.
System design of an activity tracker to encourage behavioral change among those at risk of pressure ulcers

(Georgia Institute of Technology, 2019-04-24) Obrien, John James

The Wheelchair In-Seat Activity Tracker (WiSAT) is a sensor-based activity tracker aimed at encouraging in-seat movement among wheelchair users who are at risk of pressure ulcers. Pressure ulcers tend to form in the buttocks or thighs of a wheelchair user due to a lack of pressure redistribution in that part of the body. Pressure ulcers are a serious risk to many wheelchair users due to a plethora of harmful side-effects, such as infection, hospitalization, and long recovery times. However, in-seat movements, such as weight shifts, have been linked with the occurrence of pressure ulcers. WiSAT began as a research tool that enabled researchers to monitor the in-seat activity of wheelchair users during their daily lives through sensor-based reporting, as opposed to relying solely on the self-reporting of research participants. Through the efforts described in this thesis, WiSAT was transformed from a research tool into a consumer product. Specifically, this thesis describes the design, development, and integration of WiSAT’s subsystem through four specific aims: 1. Design and evaluation of a user-interface based upon principles of Health Behavioral Change Theory. 2. Coupling of the Hardware and Smartphone App Subsystems 3. Preparation of the Algorithm Subsystem 4. Integration of the WiSAT Subsystems through Multi-layered Architecture for the WiSAT Smartphone App
Encourage sedentary workers' active seating through product design

(Georgia Institute of Technology, 2018-07-31) Ni, Chenan

The purpose of this project is to design a perturbation system for encouraging active sitting. This product would improve the physical environment within which the sedentary workers work and reduce their incidence of musculoskeletal discomfort. Specifically, the sedentary workers would be able to slightly shift postures without being disturbed by the device through an intervention, therefore, encouraging in-seat movement.
User specific assistive technology: Hand mounted switch control platform design

(Georgia Institute of Technology, 2018-04-27) Yuan, Xiuxiu

The purpose of this project is to design a platform for user specific assistive technology. This platform would allow occupational therapists to design and deliver highly customizable hand mounted switch controls for persons with severe disabilities using rapid prototyping tools. Specifically, occupational therapists would be able to adjust a pre-designed model through an intuitive user interface therefore change the design to meet users’ unique needs. The study first conducted literature review about assistive technology and rapid prototyping, then used participatory approach and human centered design methodology, engaged three occupational therapists to design and develop the platform through workshops and interviews. The aims of this project including designing the switch device, platform user interface and system packaging, and evaluating the designs with the occupational therapists. Findings, limitations and future work were discussed in the end.
Development of component and system level test methods to characterize manual wheelchair propulsion cost

(Georgia Institute of Technology, 2017-11-10) Huang, Morris

The current approach to manual wheelchair design lacks a sound and objective connection to metrics for wheelchair performance. The objective of this research was three-fold: 1) to characterize the inertial and resistive properties of different wheelchair components and configurations, 2) to characterize the systems-level wheelchair propulsion cost, and 3) to model wheelchair propulsion cost as a function of measured component and configuration properties. Scientific tools developed include 1) a series of instruments and methodologies to evaluate the rotational inertia, rolling resistance, and scrub torque of wheelchair casters and drive wheels on various surface types, and 2) a wheelchair-propelling robot capable of measuring propulsion cost across a collection of maneuvers representative of everyday wheelchair mobility. This suite of tools were used to demonstrate the variance manifested in the resistive properties of 8 casters and 4 drive wheels, and the impact/tradeoffs of these components (as well as mass and weight distribution) on system-level wheelchair propulsion cost. Coupling these findings with a theoretical framework describing wheelchair dynamics resulted in two empirical models linking system propulsion cost to component resistive properties. The outcomes of this research empower clinicians and users to make more informed wheelchair selections, as well as offer manufacturers a basis by which to optimize their wheelchair designs.
Aiding lower-limb amputees in traversing uneven terrain through product design

(Georgia Institute of Technology, 2015-08-21) Husack, Mark

The majority of lower-limb amputations are not caused by trauma or cancer, but rather by vascular diseases brought on by Type 2 Diabetes. Many of these patients must have a limb amputated because they have led a sedentary lifestyle and maintained a poor diet for much of their lives. Having a limb amputated can be a wake-up call to these patients, giving them the motivation to change their lifestyle and become more physically active. However, many of these lower-limb amputees are on Medicare or Medicaid and are only covered for their basic walking needs. Due to the high out-of-pocket costs of specialized prostheses needed to perform specific physical activities, it can be more difficult for them to achieve that lifestyle change. This study aims to design a device that will aid lower-limb amputees in traversing uneven terrain with the intent of facilitating outdoor activities.
A smartphone application that informs weight shifting behavior to promote tissue health

(Georgia Institute of Technology, 2015-08-18) Cheng, Philip

One of the most persistent problems affecting wheelchair users is pressure ulcers. These are ulcers that wheelchair users develop in areas of constant pressure or interruption of blood flow to a localized area. Approximately one- third of patients who suffer from spinal cord injuries develop pressure ulcers, and it is a very expensive consequence for these people. Pressure relief exercises can help, but a high percentage of wheelchair users do not perform them enough. Activity trackers today have the ability to sync with smartphone applications to monitor physical activity. The following study uses weight shifting behavior to help wheelchair users. By studying principles of usability engineering and user interface design, the researcher will design a smartphone application that pairs with a weight shift monitoring system to help promote tissue health. The application will illustrate information for the user to make them aware of their behavior and engage them in pressure relief exercises.
The acute effects of physical activity on the stiffness of the plantar skin of people with and without diabetes

(Georgia Institute of Technology, 2013-11-18) Wendland, Deborah Michael

Diabetes affects 25.8 million Americans. Complications related to this growing disease impact public health. One secondary complication of diabetes is changes in skin that can contribute to an increased risk for ulceration. Skin of people with diabetes has not been characterized over time nor has the skin’s acute response to exercise been assessed. The objective of this project was to establish the changes in skin properties over time, within different ambient environments, and after acute exercise. This objective sought to address the central hypothesis that skin will demonstrate decreased stiffness and increased elasticity as a result of acute physical activity. Skin stiffness, compliance, and thickness measurements of the plantar foot were compared across time and environment. Skin stiffness and compliance were also compared before and after treadmill walking. First, three devices were validated. Accuracy of the StepWatch was validated for people using assistive devices. The tissue interrogation device (TID), a novel device that measures tangential skin stiffness, and the myotonometer, which measures skin compliance, were validated using elastomer phantoms. Both were found suitable to measure plantar skin properties. Second, skin properties of 16 persons with and without diabetes were measured over time and environmental condition. Skin was variable across subjects over time, but was stable within subjects over a month, supporting the use of a repeated measures approach to interventional study on the plantar skin in people with diabetes. Previous findings for general skin characteristics were supported including the tendency for persons with diabetes to have a thinner epidermis and a thicker dermis than persons without diabetes. Tangential skin stiffness was determined to be less stiff in people with diabetes when measured in a medial-lateral direction. People with diabetes had lower tissue compliance than those without. Skin properties varied across environmental condition, supporting the consideration of testing environment when evaluating skin. Finally, changes in skin properties were evaluated in 32 persons with diabetes before and after treadmill (TM) walking. Using the TID, skin stiffness (tangential) at the great toe of people with diabetes (663.705±4.796 N/m) and without (647.753±5.328 N/m) were different (p=0.040). Stiffness immediately following TM walking did not differ from pre-walking stiffness, but subsequent trials had increased stiffness. Similar, but not significant responses were noted at the first metatarsal head. Compliance using normal loading increased after walking with statistical differences lasting 30-60 minutes.