Review, Rethink and Revise- Erin Simons

Since my last blog post JetSet’s design has undergone some major changes. During the past few classes we’ve met as a team and reviewed our design, discussing how we could improve it. We thought about accurate sizes for the pedals as well as the entire device, the maximum angle the pedal should be in at resting position (described in greater detail in Isha’s blog post), and ways to maximize the ways that users could flex their feet. We made some considerable changes: the pedals will now include balls as well, so users can roll both of their feet along the balls at the same time; the balls will also roll around in channels instead of axles, allowing for more degrees of freedom; and springs and hinges used to attach and compress the pedals have also been substituted.

Sometimes it's hard to explain all of our ideas with just words, so we always have paper handy to sketch out our ideas as we rethink our design (original photo)
Sometimes it’s hard to explain all of our ideas with just words, so we always have paper handy to sketch out our ideas as we rethink our design (original photo)

As our design continues to evolve, Annalise and I are continuing to work on the 3D model in Autodesk Inventor together (as Annalise explained in her last blog post). We’re good at discussing the best ways to perform a function on the software, and aren’t afraid to voice our opinions when we have ideas we think would work better (which I see as a good thing).

Annalise working on our 3D model- because only my computer can run Inventor, we take turns modeling different components (original photo)
Annalise working on our 3D model- because only my computer can run Inventor, we take turns modeling different components (original photo)

For the most part we’re able to overcome all of our design obstacles simply through trial and error and bouncing ideas back and forth, but when we have had trouble we’ve turned to YouTube tutorials. These videos help me because they introduce new tools and shortcuts that make 3D modeling easier, like the “Project Geometry” tool, “Split” tool, and the “Adaptive Component” function. These tutorials are also taught in very entertaining accents (for example, here and here), which makes modeling more fun for me.

I'm by no means on an expert on any of these tools, but I've been able to use them to help me design components more efficiently and precisely (original photo)
I’m by no means on an expert on any of these tools, but I’ve been able to use them to help me design components more efficiently and precisely (original photo)

While the general concept and outline of our design is done, Annalise and I never fail to evaluate our 3D model and determine additional components we can add or fix. Since our last 3D model iteration we’ve added sidepieces at the ends of the pedals and bases, to keep the balls from rolling out of the channels when the pedals aren’t fully compressed. We’ve also made slight adjustments to make sure the channels on the pedals and the base are accurately aligned, and filleted various edges of our model (to make our device less lethal and likely to stab someone). The previous version of our model also did not include adaptive springs, or springs that can extend and compress when the distance between the surfaces they’re constrained to are adjusted. However, not even a YouTube video (or five, for that matter) cleared our confusion of how to create an adaptive spring between two surfaces that were at an angle to each other, such as the bottom of the pedal and the top of the base in our model. While this isn’t necessary for our prototype, since we will be purchasing springs and not 3D-printing them, it’s not a huge problem, but we still want our model to be as authentic as possible (and who doesn’t want to see a computer-generated compressible spring?!?).

Another aspect of our design that Annalise and I discussed for revision was the type of spring used to compress the pedals. The normal spring- whose shape probably pops into your mind when you hear the word “spring”- is called a compression spring. After of our trouble making an adaptive compression spring, the entire JetSet team brainstormed ways we could overcome this predicament. Someone (I believe it was Isha) noticed the spring clamps arranged in a corner of the portable. Essentially large clothespins, these clamps use a different kind of spring, called a torsion spring, to adjust the angle between the two sides of the clamp. Isha and Anjali ordered some torsion springs to test on our prototype, and Annalise and I modeled a torsion spring in Inventor, although we couldn’t make that adaptive, either.

On left: compression spring, which uses energy in a push/pull manner On right: torsion spring, which uses rotational energy (original photo)
On left: compression spring, which uses energy in a push/pull manner
On right: torsion spring, which uses rotational energy (original photo)

Then, while relaxing and reading a book over Thanksgiving break, I realized my reading light closely resembled the pedals on our device. There was a simple hinge in the middle of both the pedal and the base, and extrusions on either side that allowed a compression spring to fit in between, compressing and extending at an angle. The design was straight-forward and easy to print, and Annalise and I are currently working on incorporating this idea into our design. Additionally, this Friday JetSet will be taking a field trip to our local Home Depot to determine the appropriate size springs for this setup.

The built-in hinge makes this design easier to model and print, and the extrusions that the ends of the springs fit over helps keep them in place when bending (original photo)
The built-in hinge makes this design easier to model and print, and the extrusions that the ends of the springs fit over helps keep them in place when bending (original photo)

These past few weeks have taught me that there’s always room for improvement, and that an additional set of eyes, hands, or ears can give you new insight on possible problems or solutions. By meeting as a team we were able to review, rethink, and revise our device to maximize the number of balls the user could roll their feet on, make the dimensions of our device more realistic, and simplify the compression mechanism for our pedals. Additionally, by working together with Annalise we were able to teach each other new techniques for modeling our device. She figured out how to copy sketches in a rectangular pattern. I discovered how to perform a cylindrical joint between a ball and a channel. She figured out how to cut exactly through an entire component with the “All” extrusion. I’m excited to continue uncovering the magical secrets hidden within Autodesk Inventor, and use them to create a spectacular 3D model and prototype.

Our device has come along way in the past few weeks! It's evident that there are significantly more balls for the user to roll their feet around, and the channels allow them to roll their feet in multiple directions, unlike axles (original photo).
Our device has come along way in the past few weeks! It’s evident that there are significantly more balls for the user to roll their feet around, and the channels allow them to roll their feet in multiple directions, unlike axles (original photo).

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