Author: cressman.11

Evaluation

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In order to evaluate our idea/prototype our team proposed a few different tests. These tests are outlined in the proposal linked here: https://docs.google.com/document/d/1RR0XJ0lT5SbrkakTXGXjWu0pHOj4gL7n4tHE2Zjfsv0/edit?usp=sharing. To overview them the team wished to perform usability tests with older adults/any users to see how users interact with the prototype and gather information on how they use the product. The team also wished to perform fit tests and measure how the device fit in different vehicles to gain insight on if the product fit in a wide variety of vehicles. The team lastly performed FEM analysis on various components like the handles and base to see what force these components could take before failure.

User Testing:

Users were asked to perform a variety of tasks such as sitting in the seat, rotating in the seat, buckling, adjusting handles, etc. As the user performed these tasks the following survey was filled out and feedback was asked for at the end: https://docs.google.com/forms/d/e/1FAIpQLSd_3o9laetFrBsyqnp5vCBwcvCFWgmMUUoZ9Jc3ST3pe2JL-A/viewform?usp=sf_link

Users ranged from age 22-84 and used vehicles such as cars, SUVs, and minivans. The results of these surveys are shown below. Overall, people liked the seat rotation and did not struggle to buckle it. Some people had complaints about comfort but everyone felt like they fit in the seat.

 

 

 

During one of the user tests, the seat handle broke as illustrated below. This showcased a point of failure in our product to be focused on if the idea were to continue with development. Overall, most users had a positive experience with the product. User’s feedback for improvements included moving the locking mechanism position to the side, adding rubber to the bottom pad to prevent slippage, possibly looking at a new cushion design.

Vehicle Measurements:

Measurements were taken with the seat in a wide variety of cars to better understand its fit. A spreadsheet with this data can be found here: https://docs.google.com/spreadsheets/d/1Fzu5ki6l7Eub5tyXiY4yljmx64KMVm15ZoV48BP2PCY/edit?usp=sharing

The measurements were taken at the locations shown below in the picture:

From this data it was found:

  • The average height from ceiling to cushion was 33.3 inches, which is below the male average sitting height of 37.1 and female height of 33.4
    • Potential fix: person could lower their seat
  • Handles hit steering wheel on driver side
    • Product works with just one handle in place
  • Product fits best in larger vehicles
  • No space lost in horizontal direction of testing

 

Finite Element Method Testing:

FEM analysis was performed on the bottom seat plate and seat handle to understand their force limits. Images of these are shown below.

From these handle FOS was 4, and the seat top was found to have large deflection but stress well below yield. Stress concentration would be at flange of product.

Future Steps:

  • Use thrust bearing with a bigger OD to prevent deflection between 2 sliding pieces
  • Replace 3D printed PLA components with metal, especially for load bearing components such as handles and locking mechanism
  • Material and ergonomics of the cushion could be improved, more cushion/better cushion material and the shape of the cushion should hold the user in the seat better
  • Keeping the prototype stable on the existing car seat (rubber)?

Original specifications:

  1. Product fits in vehicles without restricting driver usage
  2. Product is easy to use/operate by one older adult
  3. Product provides surfaces to push off of without breaking

Specifications met?

  • User tests showed product could be used in vehicles, measurement tests showed that product doesn’t fit well in all vehicles without restricting usage
  • User testing showed product operable by one adults
  • User testing and FEM showed that there was an additional surface to push off of, but not a reliable and stable surface; specification not fully met

Seat Improvements:

  • The seat could definitely be improved to be stronger, such as using a metal seat top or using a thrust bearing to increase support.
  • Improve handle stability on base with stronger materials
  • In manufacturing settings parts would be made in molds which might improve strength since all one component
  • In full production would want to make customized bottom cushions to fit in different car’s bucket seats better
  • Could reduce down to one handle maybe?

What we learned: 

  • Learned a lot about the process of product development, both with research and designing a product that solves a problem efficiently.
  • Iterative prototypes are extremely helpful to test new ideas and improvements.
  • How to go about working with users and progressing ideas with users in mind
  • Value of feedback from others beyond just your team; fresh set of eyes

Final Prototype

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After further iterations the final product has been created. The team focused on improving the handle adjusting mechanism and locking mechanism from the previous round of prototyping. The device rotates smoothly when sitting in the car and the handles can be adjusted to the designated height. From the previous round of prototyping, the gripping devices for the handle and locking mechanism were improved and allow the user to pull the rods much easier. Pictured below is the final product in a car, an up-close view of the handle, and the locking mechanism.

     

Prototype Round 4

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In this fourth round of prototyping we wanted to answer the following questions:

  • Should our goal product be a functional or looks like prototype?
  • How can we improve the handles to make them sturdier and fit in the seat while rotating?
  • How can we create more room between the handles without increasing the overall width of the device?
  • What improvement can be made to the locking mechanism to make it more durable?

In order to answer these questions we first took to Solidworks to deep dive and fully design our prototype. We changed the locking bracket so it would be thicker and have two mounting points on top of the seat rather than on the side. Additionally, we changed the handles so the plunger would be moved to the back to allow for more room for the user and avoid hitting the seat itself. The seat size was slightly increased and things including adding fillets to the base for support, cushions, color, and nuts/bolts were added.  This full Solidworks model can be seen in the pictures and video below.

 

The team then used this CAD model to physically build the model. Changes made in the physical model compared to the Soldiworks model included slotting out the the square holed bar. Pictures of this model can be seen below.

 

Moving forward the team would like to address:

  • Continue to investigate options that would allow for more space between handles for persons with wider hips.
  • Add slider block inside handle to increase handle stability when adjusting height.
  • Work on design of “plunger” caps to increase gripability.
  • Look into better material for cushion.
  • Manufacture locking mechanism out of metal
  • Look into new designs and manufacturing methods for plunger pins.
    • 3D printing or Machined pieces
    • Improve actuation by removing threaded section that passes through handle.
  • Try to get back to older adult living facility for more user testing (with covid hopefully going down 🙂 )

 

 

Prototyping Round 3

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For this third round of prototyping our team wanted to focus on making a more ergonomic and fully functional design. In this prototype the team wanted to focus on:

  • Making the seat more ergonomic and softer
  • Improve handle design, to be stronger and more appealing to the eye
  • Ensure the bearing/platform of the seat can support more weight
  • Improve the foam on the bottom of the seat so taller people can also use the seat
  • Find a way to move the handles/seat more adjustable
  • Make a more user appealing prototype

The team took this considerations into place and met with Ohio State’s Kevin Wolf to get additional design opinions and input. Ideas such as using a compressor/air, using one handle, using one locking mechanism, and materials were all discussed. After this design discussion the team began redesigning the handle bars and locking mechanism. For this prototype, the handle bars were redesigned to add adjustability vertically. Initially, the team thought about horizontal adjustment, but realized that in a car space this was not a possibility given room in a seat. To improve the horizontal dimensions of the seat to allow for a more user friendly device for all people, the team moved the handles so they were out wider on the base on flanges. Additionally, to improve space, the locking mechanism was moved to the side of the seat base so it would not affect user movement or space. As a result of this locking mechanism movement, the base also had to be redesigned to accommodate such locking and was configured out of layers. Finally, to improve ergonomics, the under base cushion was changed from solid foam to a shredded foam and a seat cover was also to be added for comfort.

The team first modelled the idea in Solidworks intending to use both stock parts and 3D printed parts. Images of the Solidworks rendering are shown below. Note that these drawings to not include the seat cushions.

 

The prototype was then assembled by the team. Pictures of this assembled product are shown below.

 

This prototype was then tested with three people in three different cars. Pictures of these tests are shown below. Here are the results of these tests:

  • all three people fit in the seat, but one person did express it would have been nice to have more room
  • the seat rotated well, but the handles hit the back of the seat, stopping full rotation
  • seat was too tall for shorter cars, causing people’s heads to be at the ceiling

 

 

This prototype was presented to a stakeholders including an occupational therapist with the main feedback being:

  • ensuring that the base is big enough to support all individuals even those whose hip width might exceed the seat cushion
  • wondering if the armrests could be height adjustable while still maintaining their sturdiness. To address these concerns, in future iterations, the team

To address these concerns, in future iterations the team wanted to make sure that the whole arm rest could be detachable to allow for easy removal from the seat base in the case that more room is needed and increase the seat base to its maximum value by moving the handle plungers to the back. Lastly, the team wanted to add more support to the plungers used within the handle, to add extra strength to the design.

 

Prototyping Round 2

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After receiving feedback on the prototype from the class, in this prototype round we wanted to focus on how to attach our seat to the base securely and how to lock the seat from rotating. The questions we wanted to answer were:

  • How do we want to lock and unlock the seat when rotating?
  • What is the best way to adjust for angles and unlevelness of car seats?
  • How can we attach the device to the car seat?
  • What mechanism can we use in the handles so they can move efficiently and are easy to use?

The team brainstormed ways to lock the seat in place with the handles. Below are the initial design ideas. The idea the team decided to pursue involved putting holes into the base for a pole to fall into, thus locking the seat rotation. This pole would be a part of the handle design. One part of the handle would involve the pole, two stoppers, and a spring in between. One of the stoppers would be encapsulated in the base of the handle with the other exposed to pull up on and the spring to help guide the pole into a hole. As the user rotates they hold up on the lower stop and release to lock it.

For the attachment to the seat, the team wanted to use a buckle and straps. To connect it to the seat, the team had the idea to add slits to the base of the seat platform through which the strap could feed. It could then be buckled around the seat.

The team took these ideas and mocked up the whole prototype in solidworks. Images of these mockups can be seen below and feature the whole handle mocked up with a rod, ceiling flange pieces as the stoppers, a spring, handle encasings to be 3D printed and the base with holes. On the base these slits can also be seen.

The team aimed to 3D print the handle encasing and to laser cut the base and seat. Every other part was to be purchased from stores. Additionally, thick foam was bought to be added to the base of the seat to allow for more molding to the seat bucket.

Unfortunately the 3D printer could not finish in time, so the handles had to be made out of wood for this round. The same mechanism was able to be constructed. The final prototype is shown in a car below.

From sitting and trying out the seat, the team realized the foam purchased may be too thick for fitting in the base and not adding too much additional height. Additionally, the team realized that the seat and handle dimensions are small and not adequate for a variety of people, therefore more adjustability needs to be added to the design. Finally, when testing the rot0tating structure under human weight, the team realized they may need to add spacers or extra support so the top seat does not fall too close to the base, making it hard to turn/lock.

From the class, the team received the following feedback:

  • Consider when you sit the way that the base and swivel seat touch, look at putting spacers in
  • Potentially use a bean bag  instead of thick foam for under the seat
  • Look at amperometric data for what width a seat should be
  • Look into using one handle that is detachable/moveable depending on the side you are on

Narrowing Down Our Ideas

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After the initial brainstorming we went through and decided on some of the more promising ideas to think about more and brainstorm variations/ideas on. Initially we did this by removing ideas we thought were not feasible in the scope of this class. These ideas are seen highlighted in red on this document: Brainstorming Ideas Refined 1.

Remaining we still had a lot of ideas that were similar, so we used our miro board under “Sorted Brainstorming Ideas” to organize them into different categories such as handles that can attach, seat belts, wheelchair transportation, etc.  From this we went through as a team and highlighted ideas in each category that we thought were most promising to iterate on in the next phase.

Initial Brainstorming Ideas

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Here’s a link to a pdf of our initial brainstorming ideas:

Initial Brainstorming Ideas

As a team we came up with about 100 ideas based on the problem areas we defined: stability&balance, use of devices, vehicle height, handles, doors, body of vehicle, vehicle seat, process, medical conditions.

Reflection:

What went well? What went less well?

  • As we were brainstorming ideas we found some of our product categories were easier to come up with ideas for. We were able to think of many ideas to account for the height of the car but struggled to come up with ideas for helping the person maintain balance. We also struggled to come up with ideas once we had a bunch already. We found that many of our ideas started to overlap in many aspects and were very similar. 

What seems promising about your project direction at this point? What seems… less promising? (Keep in mind you’re not evaluating ideas yet!)

  • There seems to be a wide variety of areas that we could choose to focus on in terms of what part of the process or the vehicle to design a product for. Some of the ideas that we came up with were a bit out there so the range of possibilities for the solution to the problems that were determined in the “Problem Definition” assignment might be limited, even with the ~100 ideas the team came up with during brainstorming. 

What (if anything) might you need to research in order to improve your ideas for your next iteration of brainstorming?

  • In order to improve our ideas we might look into existing products on the market. Knowing more about existing products could help us to get inspiration and make sure that we are heading down a path that is novel. As we continue to brainstorm it might help to learn more about the structural components of a car and the materials it’s made out of. We have a fair amount of ideas that connect onto the vehicle, so it will be helpful to know what parts of a car are more feasible for connections.

 

Fully Collapsible Walker Prototype

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This prototype idea looks at making a more easily collapsible walker. The solution aims to make it so that older adults can use their walker to enter a vehicle and easily store it near where they are sitting for easy use when they exit. It will mitigate the need to store a walker in a back seat or trunk which requires retrieval after exiting. In this prototype design the inspiration was a foldable baby stroller which has many joints that bend and allow them to fold up. To prototype this hinged joints on the legs were modeled so that the walker could fold up relatively small. The team is still exploring other ways to make a walker foldable such as with telescoping legs maybe.

Questions:

  1. How to make the design fold small (hinges, telescoping, folding, etc.)?
  2. Does the design fold up relatively small? How small?
  3. What ways can the prototype work with the limited dexterity of older adults?
  4. How can the walker be kept sturdy when in use but also collapsible when not in use?
  5. Can walker be collapsed while in a seated position of a car?

Initial Affinity Diagram

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For the initial organization we arranged our notes into categories based on how the information was collected. This allowed us to focus on distilling notes from one research process at a time. This also enabled us to color the information based on how we collected them and who we collected them from. This was a good first way to just get some of our important information up onto the board in a focused way.