Figure 1: Physical Quantum Edge 3 wheelchair. Adapted from [1]
<aside> ⚠️ Problem Statement Project: Lightweight Waterproof Control System Protection ****for Wheelchairs Objectives:
Functional requirements:
Our client, Tiffany, is a 33-year-old woman living with spina bifida, a condition affecting mobility from the waist down[2] and is required to use a wheelchair, the Quantum Edge 3 (Figure 1) to be specific. Despite these challenges, Tiffany leads a very active life, working at Walmart, socializing, and pursuing hobbies like dance.
The primary objective of this project was to develop a water-resistant mechanism that gives the client full control over wheelchair movement in hazardous weather conditions. The mechanism must be durable, portable, cost-efficient, weather-resistant, and user-friendly. The mechanism must have a low mass (under 1kg) for the wheelchair to support, and must not interfere with the client's range of motion. The design we wanted to construct also followed a list of functions including, fully enclosing the control interface, being water-proof, having a collapsable design, being easy to attach and detach the mechanism and being easy to repair in the long term.
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Timeline of the project (02/17/2024 - 04/10/2024)
The team demonstrated exceptional collaboration and individual effort, achieving all milestones within the designated timeframe. Each team member contributed significantly to every milestone, ensuring an equal distribution of tasks among all members. For this project, the team worked collaboratively, with each member contributing their unique perspective to a shared task.
<aside> 🧑⚕️ To begin the project, we began by obtaining some information from the client. This included notes from in-person and online client meetings, research on the client's conditions and currently available resources.
With our research, we began problem-framing and deciding on some objectives and functions. With these objectives and constraints, we developed an initial testing plan and metrics to measure each one. With this, each team member took an objective to do additional research to aid in our design process. For my research, I researched how to make a design portable and user-friendly.
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Figure 2: Spina bifida visual [2]
Figure 3: My initial concept sketch
<aside> 💡 Using the morphological chart we developed previously, we individually selected a few of the means and created two new refined concept sketches.
The means I selected for my first design were: Handle, clamps and plastic covering, respectively The means I chose for my second design were: Magnets, hooks, and a protective box, respectively
At this time, we also received some design review feedback from our TAs. While they did like our designs they pointed out some important things to consider before prototyping, such as, avoiding motorization, no large attachments, being easy to manufacture, and avoiding placing things behind the client.
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Figure 5: My second refined concept sketch
Figure 6: My initial prototype of the design
Table 3: Weighted decision matrix with all the team’s designs
Table 1: Client notes taken from the initial client visit
| Potential Conflicts | - Has trouble with salt and debris getting stuck in wheels
<aside> 🧠 Next, we each individually began generating some ideas based on the research we had completed. Since I completed research on portability and user experience, my initial concept tried best to follow both these objectives while still keeping its primary function.
With this initial concept, we also made some additional changes to our constraints by adding ergonomics, as the mechanism must not impede the client’s movement. We also created a morphological chart containing our primary functions and various means of satisfying them.
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Table 2: Morphological chart with our functions and means
| Function | Means | |||||
|---|---|---|---|---|---|---|
| Ease of use | Lever | A handle | Button | Magnets | Hooks | Touch sensor |
| Attachment to wheelchair | Hinge | Velcro | Magnets | |||
| Hooks | Joints | Clamps | ||||
| Protect the control panel from rain | Umbrella | Plastic covering | Protective box | Triangle roof | Mini tent | Clear Garbage bag |
Figure 4: My first refined concept sketch
<aside> 🧱 With the refined sketches I designed, I selected the one I thought would be most optimal, which was my first design. Physical prototyping was somewhat difficult with the materials I had on hand, so I improvised by forming most of the frame with paper rods and a clear garbage bag to simulate the clear plastic covering.
The prototype I made was mostly physical and focused as it is a physical model of what I envisioned and has similar features to the refined sketch but is portrayed differently.
With these initial prototypes everyone developed, we created a weighted decision matrix (Table 3) to see which designs performed the strongest and used their features to aid us when designing our refined prototype.
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<aside> 🪞 I found this project to be very hands-on and a great project to strengthen my understanding of designing and manufacturing, as well as collaborating with different people on the same project. Unlike any other project I have completed, we were given minimal information and resources, and was very open-ended. While this means our design can look and perform how we want, it can be hard to take inspiration or get advice for a problem that is not being collectively solved by other teams. That being said, we were successful in utilizing all the resources available to us as a team and design and model a mechanism that satisfied all of our objectives and constraints. While this project did not introduce any new software or hardware to me, it was the most hands-on and collaboration-heavy project, making it a great project to showcase my creativity and problem-solving skills.
Something that could be improved is the aluminum rods used as the frame of the mechanism. The aluminum that was used was quite soft and was able to be bent easily upon impact. While it would also be easy to bend it back into shape, it seems impractical for the client to do that themselves. Instead, I would replace this with stiffer stainless steel rods. The reason these were not used earlier is that they are harder to get access to with the thickness we wanted, as they would have to be imported from the USA and would not arrive within the timeline for this project. Additionally, the cost per length was also quite higher, making the manufacturing price higher as well.
Additionally, I believe the attachment mechanism of the plastic covering to the frame could have been improved The clips we 3D printed relied on nuts and bolts to keep everything attached. While this allowed for a robust design, it would make it harder for future repairs if the plastic were to ever get damaged and needs replacing. A solution to this would be to have magnets embedded withing the plastic covering and the frame, allowing for easy and quick removal if ever needed. This would also help with portability as it can be stored in two smaller parts rather than a single larger part.
Throughout this project, I have gained a deeper understanding on the significance in teamwork and collaboration. No part of this would be completed to a high standard alone and within the given time frame. This project also enlightened me on how significant the problem framing part of the design is and not to focus on the solution, but rather on the problem. Participating in this project has provided me with the skills and insights necessary to make a significant impact on my future design pursuits. By the end of this project, our team designed a functional mechanism that satisfies all of our objectives and constraints. his project demonstrates a measurable advancement in my design, modelling, and fabrication abilities.
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