A competitive l1 swerve robot which the only manufacturing resource is a hacksaw

Technical CAD
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I was bored, so I made this robot in a couple of hours. The idea was that I wanted to build something that could be constructed quickly and require 0 manufacturing resources while being competitive.

Is this the most competitive robot you can build? Probably not. Is it the most optimal way to do it? Yeah no. I just wanted to see how far you can go without manufacturing anything and build an entire robot doing that while only taking a few hours to design the whole thing.

I priced it out with a friend, and it was under four thousand dollars (with electronics not including stuff in the KOP), which is a lot, but considering there’s swerve and electronics are expensive, that’s good enough for me.

Constraints:

  1. As little manufacturing or precision work as possible. The only thing you need to do is cut tubes and shaft to length. (which hopefully is possible)
  2. 0 tapping
  3. Using laser cutting/2d cnc resources is allowed, fabworks and scs are used
  4. As much stuff from 1 COTS supplier as possible. (like 95 percent rev)
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  5. Drilling basically doesn’t exist. if you need some level of precision, use a laser-cutting service.
  6. 1 Part studio, 1 Assembly for the entire robot (for fun)

The polycarbonate + aluminum plates are bought, I could have used a box tube system instead of the large 1/4 plate, but I didn’t think it would be pretty and it would require some amount of drilling into the tube/adding extra plates to support it and make it strong, which would be kind of redundant.

The driving shaft is coupled using the two max planetaries, so you don’t need to tap the shaft.

All other shafts are retained using shaft collars.

I couldn’t bother with belt cc distances, but you could probably buy all the belts you needed from vbelt guys for an extra 20-30 dollars or so.

Fasteners are not cadded because I want to go to read before I go to bed.

Using maxtube for the intake allows for pre-cut configurations of 7 and 15, which decreases the manufacturing time and need for precision. It was a first for me to use this tube, so it was a little bit awkward at first to figure out how to design with it and make it work.

Inspired heavily by team 1561, thanks for the inspiration!

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I was gonna say that this looks a lot like roboducks, then read the last line lol.

They had an issue where the front hex shaft kept bending, in my unfinished roboducks copy cad i have the pivot point lower so the arm will automatically go up when it gets hit straight on (they had the issue when collecting cubes from the double subsystem. They replaced the shaft with a steel one to counteract this issue, but I think putting the pivot point lower would be better.

I’m kind of worried about the impact resistance of your front plate.

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This small detail is missed on a lot of intake designs. By simply having the intake rotation point lower than the outermost part of the plate will allow the mechanism to naturally deflect upwards when ran into a wall (most of the time) similar to the dynamics of a 4 bar or a linear rack and pinion intake.

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Reminds me alot of team 9000 Zebra cakes robot.

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Nice work!

Now do it again but you can’t use any outside machine shop or laser services :sweat_smile:

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I think they did everything in house. Maybe @marshall can shed some more light.

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Correct.

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Dropped the pivot a little bit so it deflects up (i love parametric cad), running a max spline dead axle setup, so I think it’ll be pretty strong regardless.

Also added a hard stop for the polycarb plate

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If I were to build that, I think I’d still be worried about the aluminum hex shaft bending because it doesn’t deflect up enough. It might be fine, but in my head I see that being bent.

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This hex shaft? The chain + max spline should be able to protect from shock loads in the setup I am running right now. 1561 direct drives the hex shaft, which may result in the bending that you were worried about.

This setup seemed to work on the arm robot I built during the season, which survived significantly harsher loads (slamming long arm against wall) compared to this. That being said, I’m curious about any potential improvements to make it more robust.

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Sorry, I’m talking about the hex shaft holding the front roller wheels.

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Ah, you’re correct. I can add a front box tube/round tube to protect it.

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might raise the tube for easier game piece access, but you get the idea.

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i would also like to point out that this design followed an arbitrary restriction on trying to stick to only rev COTS products, we could have cut costs more by using other vendors. this was mentioned in the post i am blind

the under 4000 total did not include the rio, the battery, or the pdh, but even with these it comes out to 4284 roughly, not including shipping.

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Oh I was making a joke of building a robot from COTS parts with ONLY a hacksaw, not so much the use of vendors lol. (I think it’s doable but you would definitely end up with some odd dimensions.)

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There’s a tradeoff in there of using vendors to make custom plates. During a build season, I think it’s worth doing a custom plate and ordering it to simplify manufacturing, especially if the COTS solution is overbuilt or has a high part count. I bet teams could find a manufacturing sponsor for plate or ask local teams too.

Last season, I had Fabworks basically laser all of our 1/8 plate even if we had an omio, just because it reduced the amount of machining error by a lot and freed up our machining by a good amount.

For the belly pan, I’ll be happy to let a service take care of it lol. Making a belly pan by hand takes up a ton of student hours and it can get frustrating (but it’s possible!).

I bet REV knows of a better way of running my design without the custom plate, but I’m happy with the first attempt that I made for fun on a whim.

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Now do it again with no wrist and only one motor outside of drive.

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Bumper cutout?

9101?
(This but belted together)
https://imgur.io/ja8NBwc

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He’s referring to the OP’s post.

While the delivery of the post can be interpreted in less-than-great fashions, I understand the notion. Designing a robot that can be manufactured by “only” a hacksaw, and then including parts that have to be outsourced to laser cutting and machine shop services seems rather counter-intuitive. It doesn’t really fit the low-budget/low-resource model at that point. And, as with the example you provided, similar concepts can be executed in-house without using machining resources that low-resource teams would likely have access to (cordless drills).

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here ya go

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I think you can use duct tape or something to constrain the cubes if that’s a major issue.

Used round tube to prevent popping, but 1x1 with tube endcap works too, either or.

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