Problem
For those who currently use a walker and require enhanced stability for navigating various terrains or managing balance challenges, ensuring safer and more reliant mobility in different environments. Specifically, we are targeting individuals with mobility instabilities, and the proposed technology would aid in actions of daily living (ADL).
Additionally, using electrodes will cut the cost down significantly from current camera-based eye-tracking devices. Being both more cost-effective and user-friendly, our device will enable users with disabilities to easily navigate computers and other devices.​​​​​
Aim
Our motivation is to create assistive technology that will allow individuals with disabilities to have access to the internet with no extra aid.​​​
Methods
To accomplish this, we will be conducting research and develop an adaptive attachment that can assist with gait to any terrain. We will be testing different iterations of the device with real users, and experts in the field.
Compact Assistance for Reliable Engagement (CARE)
University of Pittsburgh |BIOENG 1351: Senior Design
Deran Beckwith, Nicholas Pho, Charles Oduro, Caroline Howard, Kasey Forsythe, Jason Cutitta
Ethnographic Efforts and Problem Discovery
For the first month of the course, focus was placed on unmet clinical need discovery through interviews. During the initial week, I and the rest of my team individually interviewed 5 different clinicians each in a wide variety of medical disciplines and fields such as P&O, OT, PT Nursing, Orthotics and Prosthetics department, General Medicine, etc. Collection and discussion of ideas condensed the project into 3 potential areas of focus: Gait/Mobility Aids, Reproductive Health, and Assistive Technology.
With these 3 concentrated areas in mind, I helped construct ethnography plans and protocols for each area of interest. These documents would be used to conduct specific ethnographic efforts in each setting like task analysis, observational analysis, and interviewing.
Focused ethnographic efforts to local labs, the University of Pittsburgh Medicine School, HERL, and several clinician interviews revealed that there is a need to mobility aids for those post surgery, and those in longer term care.
SKETCH FOR PROTOTYPE IDEA
We also heard how it was a fairly frustrating issue because with improved aids patients will have more freedom and autonomy. The current solutions are functional, but they are limited by the environments they are used in. This can caused substantial fatigue to the user as they have would need to exsert more energy to do necessary ADLs.
Device DEvelopment
Ethnographic Efforts and Problem Discovery
With the problem clearly defined, our group set out on brainstorming various ideas and concepts independently. After we compiled all ideas and loose sketches from our 6 teammates. I then quickly developed more detailed drawings to use as minimum-viable-prototypes (MVPs) for our continued meetings with HERL, the Pitt Orthotics and Prosthetics Department, and various interviews with physical disability experts and doctors.
Senior Design Project Canvas
Design Brainstorm
Group Brainstorming, and Killer Experiments on MVPs
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Interviewed Clinicians and Assistive Tech Engineers
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Conducted Hazard and Risk Analysis
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Designed and developed the housing for the CARE
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Managed the materials for prototype realization
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Tested housing material and non-newtonian fluid
PERSONAL CONTRIBUTIONS
LOW-RESOLUTION PROTOTYPES
I and members of my team began constructing low-resolution prototypes of the mobility aid attachment. Three different variations were constructed with different types of non-newotnian fluid and coating material. On all three prototypes, the new attachment would provide less resistance than the standard and provide a better deformation fit, thus improving stability and handing of the walker.
LOW-RESOLUTION PROTOTYPE FEEDBACK
I along with some members of my team presented our three low-resolution prototypes to medical professionals, such as OT's, PT's, and assistive technology engineers at HERL for feedback and informal testing on walker attachment. This feedback showed that the housing needed to be more durable. ​Risk documentation was developed around these prototypes such as an initial hazard analysis (IHA), risk summary, fault tree analysis (FTA), and failure modes and effect analysis (FMEA).
A hazard identified in the device was tearing of the plastic coating surrounding the filling material. In the case of the non-newtonian fluid, this could cause slips and falls to occur. This hazard is not present when using more durable cousting, so our team decided to pursue a gel-based coating to reduce risk in our design.
Low-Resolution Prototype Development and Feedback
MEDIUM-RESOLUTION PROTOTYPE
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Intuitive attachment minimizes risk of improper attachment
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Viscous Non-Newtonian Fluid provides more stability and withstands large load minimizing risk of loading failure
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Air-tight seal at attachment point minimizes risk of attachment falling off
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Custom housing tested in a variety of environments and surfaces
further design iterations needed to improve material strength and long-term reliability needed to ensure minimization of risk of housing failure
MEDIUM-RESOLUTION PROTOTYPE FEEDBACK
Informal testing and feedback on the medium-resolution prototype was conducted during February 2025 with End User. The results from these visits showed that the mask with the SLA printed housing was most preferred for comfort and functionality.
Medium-Resolution Prototype Development and Feedback
"PRODUCTION EQUIVALENT" TEST PROTOTYPES
After the previous round of informal feedback with the four variations of the foam mask, I began constructing our team's final engineering test prototype.
This prototype is comprised of I began by modifying the SolidWorks file to fit new size dimensions. Using these dimensions, 3D printed with an SLS printer making the housing out of nylon powder (PA12). This was done in our engineering building's Makerspace, and at Human Engineering Research Labs (HERL). I also hand cut the coating out of thin polyurethane.
​The non-newtonian fluid, and polyurethane coating, and nylon housing were held together by design the housing to hold an o-ring to create a tight seal. To make sure the fluid would is enclosed and prevent airflow into it, the housing used. Firstly, I tried using the natural tension from the polyurethane rubber coating, but just as a backup I just an o-ring. Iinformal verification testing the housing seemed to work well. With the final design completed, our team then began formal verification and validation testing.
The images in the slideshow on the right document some moments during our prototyping process.
FINAL "PRODUCTION EQUIVALENT" PROTOTYPE DESIGN
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Here is a diagram of our team's final prototype showing the components and design of final test prototype. The final prototype is composed of a hard nylon (PA12) housing, a flexible polyurethane rubber coating filled with non-newtonian fluid.
"Production Equivalent" Test Prototype Development
VERIFICATION TESTS
Our team conducted various verification tests focused on functionality and meeting our design specifications. The following verification tests our team conducted were:​
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CHR-01: The device achieved a minimum height of 33 inches with the walker.
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CWR-01: The device did not exceed the maximum width of 32 inches.
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CMR-01: The device weighed no greater than 10 pounds when paired with a walker.
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IVRT-01: The fluid exhibits expected non-newtonian behavior at 0°F, 50°F, and 100°F
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LTES-02: The fluid maintained stability in terms of viscosity and structural integrity when exposed to the specified temperature range for an extended period.
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WR-03: The fluid withstands repeated compressive forces without breakdown or loss of function.
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STVT-01: The fabric resists scratching under realistic use conditions, verifying fabric durability and temperature stability.
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WRUTS-02: The fabric maintains strength with limited tear under tensile loads at various temperatures of simulated use.
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MD-01: The housing material can withstand real-world mechanical stresses, such as impacts and pressure, without deforming or failing.
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NAF-01: The application of the device is within set standards of force.
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NRF-02: The removal of the device is within set standards of force.
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My primarily involvement was the testing for MD-01. The Mechanical Durability Test evaluates the ability of the Compact Assistance for Reliable Engagement (CARE) walker attachment’s housing material to endure real-world mechanical stresses, including impacts and compressive forces. This verification test ensures that the material retains its structural integrity and mechanical properties under stress, thereby ensuring safe and reliable performance in actual usage.
This test will be conducted on the outer housing components made of nylon (PA12), which are SLS-printed models. It will simulate typical mechanical stresses the housing may experience during regular compressive loads.
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The CARE housing successfully met the acceptance criteria by supporting a sustained load of 135 lbs for over 30 seconds without any visible signs of cracking, deformation, or structural failure across all 15 test runs. The results support the use of the nylon (PA12) housing design in the CARE walker attachment. The housing demonstrated sufficient structural integrity to withstand compressive and impact forces representative of those seen during assisted sit to stand and daily use.
VALIDATION TESTS
Our team conducted validation tests by working with End Users in the Greater Pittsburgh Area and obtaining formal feedback from older adults that use mobility aids. During our tests, end users test our our walker foot and provide quantitative and qualitative feedback via a questionnaire. By doing this, we were able to get data from ~8 older adults.
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V&V TEST RESULTS
For results, the device passed for functionality and durability testing, but for the validation usability testing the CARE struggled in performance on carpet, and on uneven outdoor environments. Use of new materials and geometry meant that the device improved overall experience and installation of the CARE. However, all 13 validation tests did pass. End users cited an improvement in mobilitiy and reduction in fatigue while using the CARE as compared to a traditional walker. In the future, the clinical effectiveness of the CARE could be enhanced by improving the coating, so that the walker won't get caught.
Verification and Validation (V&V) Testing and Results
This course focuses on the development of a medical device to address an identified clinical unmet need while providing a thorough understanding of the FDA medical device development process in compliance with 21 CFR 820.30 (Design Controls). Our risk analysis and mitigation strategies adhere to ISO 14971 standards. Throughout the design process, we compiled and maintained a comprehensive Design History File (DHF) to document our progress. Additionally, we gained knowledge on product codes and risk assessment. In alignment with FDA Design Controls, our team created and consistently updated the following "living" documents:
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Ethnography plans for each field of interest
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Ethnography protocols for each field of interest
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Ethnography test reports for each conducted activity
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Initial Hazard Analysis (IHA)
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Fault Tree Analysis (FTA)
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Failure Mode Effect Analysis (FMEA)
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Risk Summary
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Product Design Specification (PDS)
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Traceability Matrix
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Use Case, Intended Use, and User Needs documents
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Verification Test Plans
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Verification Test Protocols
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Validation Test Plans
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Validation Test Protocols
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Header and Methodology for Document Control and Revision