Interactive Structures Lab
Creating more inclusive and customizable medical devices
Skills
Concept Development,
Design Research,
3D Modelling,
Rapid Prototyping,
DFA,
User Testing,
Interdisciplinary Collaboration
Timeline
12 weeks
(June 2022 - Aug 2022)
Team
Tracy Meng,
Victoria Nguyen,
Julia Anitescu,
Karen Kang,
Prof. Alexandra Ion (faculty of HCI at CMU)
Tools
Rhino 3D,
SolidWorks,
CNC Router,
Laser cutter,
3D printer (PLA & TPU)
Overview
Our task was to examine and experiment with the spring properties of a metamaterial 'ruffle' structure and implement it in different medical device contexts. My main focus was developing the carpal tunnel brace and the bypass socket to test the ankle prosthetic.
Problem Space
Current commercially available prosthetic limbs and medical support braces can be very expensive and inaccessible for people who rely on these devices to live their daily lives.
How might we create an adjustable yet affordable carpal tunnel brace & lower limb prosthetic that can be easily constructed and distributed world wide?
Research
Gain insight on industry standards, trends, and market gaps
Price
Looking into various brands and models of prosthetics, the average cost of a below knee prosthetic is around $12,000 USD. This high cast can make these devices inaccesible for many users who rely on them.
Goal: Using the developable metamaterial structure, we are hoping to reduce this price by at least a factor of 2.
Additionally, there does not seem to be a standardized scale to compare prosthetic options and individuals needing them are rarely able to try out different kinds to find the best fit for them prior to having to make a heavy financial comittment.
Market Size
To get a better understanding of the how our product fits in with existing solutions, we also examined how many people in the US need prosthetics/ some form of lower limb support. Even though below knee amputations are decreasing annually due medical innovations, thousands of people annually are still in need of prosthetics that remain affordable yet customizable in the US alone.
Carpel Tunnel Cases
While applying the metamaterial 'ruffle' structure to an ankle prosthetic is the primary focus of the research, we did want to explore alternative applications and other aspects of the body that the ruffles could be used to support. We honed in on the problem of carpal tunnel syndrome. Through some initial research we realized it is extremely prevalent especially today — COVID19’s work from home protocols drastically increases the chances of improper wrist posture.
User Studies
Who are we designing for? What are their needs, desires, and pain points?
Key Insights - Below-Knee Prosthesis
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Enables a good range of motion and does not limit physical activity.
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Made of a lightweight and flexible material that is easy to move around in.
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Prosthetic structure is customizable and can be modified in a simple and quick way for different applications and user preferences.
Key Insights - Carpal Tunnel
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Must be secure on the wrist and maintain a neutral position.
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Wearing it throughout the day for extended periods of time must be comfortable.
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The brace should be customizable so that it is effective for different laptops keyboards and work stations.
Prototyping & Testing
Iterate rapidly, evaluate, re-iterate, and repeat
Paper Prototypes
We first started with paper prototypes to better quantify the possibilities of this ruffle structure. This rapid prototyping allowed us to experiment with what kind of shapes, directions, stiffness capabilities and methods of constructions we can implement.
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Plastic Prototypes
This prototype phase pushed us to think about assembly and attatchments further. In the carpal tunnel prototype tape was sufficient enough to secure the type of plastic used, however with the prosthesis a thicker plastic was used. We ended up drilling holes at key junctions and using smaller nuts and bolts to create and secure the ruffle structure.
Final Below-Knee Prosthesis Prototype
This material allows for stability as well as flexibility for maximum mobility. One great thing about this material is it can be rolled into a tube that allows for easy transport anywhere. The holes drilled into the sheet to create attatchment points can be adjusted to create a more custom fit, and the overall design of each ruffle is based on the forces a foot needs to withstand in that area. This allows for the most realistic and accurate design.
Adjustable Height Bypass Socket
The development of the bypass socket was one of my main tasks this summer. It was crucial to develop this supporting component so that we could user test out prosthetsis prototype. The goals for fabricating this were to design something that could be adjustable for different users, utilizing simple materials and construction methods so that it could be produced quickly and cheaply.
Final Carpal Tunnel Brace Prototype
The final carpal tunnel prototype is made from a thicker black plastic which maintainted the flexibility of earlier materials but with added rigidity and durability. The material was relatively easy to work with to puncture nodal points for screw attachment. This prototype was modular, and using these attatchment nodes, users can adjust angle of the brace by inserting or removing ruffles.
