H6 Buildlog / OpenAdro Development

VEX V5 General Discussion General Forum
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About a year ago (ish, maybe longer) I bought myself a Makerbot 5th Gen 3D printer with one goal in mind, design and implement a 3D printable robotics platform.

No biggie, right? I mean this is basically the task of inventing a VEX or LEGO platform.

Oh and I wanted it to be cross compatible with VEX. In part because I intend to use some VEX parts in this kit of parts, like the motors and electronics that would be impossible to develop myself, and in part because it would make this kit useful to existing VEX teams.

Early concepts were pretty simple…

http://polynomic3d.com/user/smith/XPB1.PNG

But quickly evolved…

http://polynomic3d.com/user/smith/XPB2.PNG

And like most of the things I do, some limited success was achieved.

http://polynomic3d.com/user/smith/10259919_323730457826679_5297405687867870556_n.jpg

http://polynomic3d.com/user/smith/1911140_326084200924638_5580354483458251591_o.jpg

http://polynomic3d.com/user/smith/10929923_323441817855543_3452924334969910824_n.jpg

But alas, the Makerbot really wasn’t up for the task, and so the project was shelved, which is sadly the usual fate of most of my projects.

I reenvisioned the project with a new sort of take or idea with this:

http://polynomic3d.com/user/smith/X1.PNG

But quickly realized that these parts were going to be very hard to print. There was actually an entire other design iteration that I don’t seem to have any pictures of, and don’t feel like digging up the CAD for that was even harder to print. But anyway…

I sold the Makerbot, and eventually bought myself an Ultimaker 2, oh and I’ve become a member of a makerspace at my university that has a Form 2, Markforce and Taz, so I have four printers and two CNC’s at my disposal.

But the goal is still to produce a robotics platform that is 100% 3D printable (minus basic hardware and electronics of course). So ideally the kit should be printable on my UM2 without jumping through crazy hoops.

Anyway, I’ve been working very diligently on a new iteration of this concept, and this is what I have…

Whereas all the other concepts had serious printability issues and usually broke down in one way or another, this concept is actually pretty well thought out and robust. And for those of you wondering, no it’s not just a holonomic drive. I’ll obviously expand the kit to be more, but for now this is my test case.

Initial test prints aren’t quite there, but almost, which is awesome!

http://polynomic3d.com/user/smith/IMG_20160730_153357.jpg

I don’t want to over promise here but in the highly unlikely to happen, wishful thinking, long term, I’d like to refine this and create an open source community around it. A low cost, extendable, open platform could do a lot of good. And I don’t want to brag too much, but I’ve designed this to be 100% VEX U legal, which is pretty cool.

In the much more likely to happen short term, this will be my next robot and will give me the means to produce more advanced content for YouTube, which I’m sure is going to make a lot of people around here happy.

The holonomic base pictured is 17.5" x 17.5" and sits roughly 2.5" off the ground (ground to top of plane).

So I wanted to include you guys in this and get some feedback. I’ll use this post as a Q&A / buildlog.

I may also need to test these parts on an array of different 3D printers, so if you have access to a printer and want to help me out, posting below what printer you have access to would be great. No commitment or anything, it’d just be nice to get a general idea.

Thanks,
-Cody

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Looks really cool and exciting Cody. Since you asked for feedback here are my thoughts.
Is the middle going to be rigid enough with all those holes?
I’m not a big fan of the small omni wheels. They don’t roll sideways as nicely as the bigger ones in my experience.
It looks like there isn’t much room for an intake at the front. I guess this year it’s not as big of a deal since a lot of people are using flip-down scoops, though.
Hope the stars align and you finish this project. Good luck!

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Do you happen to have an estimate on how much the drive would weigh? Would it be lighter than a standard aluminum holonomic drive?

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Thanks! Yeah it’s been a fun journey regardless of outcome. I’ve learned a lot.

3D printing is more art than science. There are a number of materials and ways to print something like this.

I’ll be printing these parts in Ultimakers PLA for now with various infill settings. PLA so far has held up pretty well in around the 50% infill range, but I haven’t printed that part specifically. Because holes create more surface area they may actually end up strengthening the part because of the way 3D printers slice the model. Those holes are guaranteed to get both a number of shells around them as well as the top and bottom layer counts. But until I actually get around to printing that part, I won’t know.

I’m more concerned with play between parts and the normal 3D printing woes, namely warping and bed adhesion.

Good to know. I’ll have to play with them, I have a set but I never actually used them.

Yeah this isn’t aimed at a particular game. Also I’ve had that issue with all my designs. The way to get the maximum gap in the front is to basically build a square box. Not sexy enough for my liking.

Thanks!

Ohhh that’s tricky. I could do a volumetric guestimate but that won’t matter because of the actual slicing. I won’t have a guess until I finalize on slicer settings, and even then I won’t really know until I actually print them. And then that would be material specific.

My guess is that this will be somewhere between an aluminum frame and a steel one when printed in PLA. I’m guessing that Nylon would yield lighter parts because you could get away with less material.

In general more material is going to be heavier but stronger so it’s a classic design trade off. If you specifically wanted a light frame you could likely shave off a lot of material in the slicing process and use something stronger like ABS or Nylon to get that outcome.

If you went completely crazy and printed with fiberglass or carbon using the upgraded Markforce then I’m sure you could beat out aluminum, but that printer is super expensive. My understanding is that the one Inworks has doesn’t have the carbon upgrade or I’d definitely try it.

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sorry if i sound stupid and simple minded, but that is sick

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Looks great!

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We have a Uprint SE Plus, prints in ABS with color options. I am always willing to try new stuff. You can message me here or shoot me a text and chat. I would love to help out and we are planning on making a fully 3D printed open class robot for this year so if we can meet that goal and help you out we would love to help!

Adam 816-726-7343

PS- I am the advisor of the team posting this.

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I have a TAZ4 in my classroom. ABS, HIPS, PLA plastics in stock for experimenting. Let me know if you want to try anything. Your design is pretty cool!

Are you willing to start a repository of your files for others to play with and tweak? Or is this something you would like to keep private and monetize in the future? I totally understand either way.

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Awesome, that’s quite a high end printer you have there, shouldn’t have any issues creating these parts.

Very cool, I don’t know if this kit of parts will satisfy your needs, not likely as is but it may serve as a good example of what it is you want to accomplish for your students.

Awesome thanks! I do have access to a TAZ, but it’ll be worth the effort to have another team try these parts out on that platform.

I’ll be publishing all the files under GPL v3. I’ve pushed them to my Github:

https://github.com/csmith105/H6

To be clear, this is the project AS IS. I’m working on my robot first, then the kit of parts. This whole project is kind of a learning experience.

http://polynomic3d.com/user/smith/IMG_20160807_111934.jpg

Parts are printing well. I think I finally have my UM2 dialed in.

The new Bourne movie sucked.

I’m waiting on payouts from college to continue, I need a bunch of parts to move forward and am quickly running out of filament so things may go quiet for a little while here.

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Given how things are going, this platform is likely to turn into H6.

Some of you are familiar with my previous robots and how I tend to name them. Regrettably H5 never made it, but life goes on.

So, H6 it is.

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Ours is an ObJet Connex350 for prototyping.

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Good bit of random info you got thrown in there.

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Some updates:

The kit of parts is now called OpenAdro and a community will be built at OpenAdro.com when I get around to it. I’m leaning towards Drupal for the site and phpBB for the community. Thoughts on this are welcome.

The scope of what I want to do in this regard is pretty crazy. It won’t succeed unless I can really leverage a CMS like Drupal. I’ve attempted web apps before and failed spectacularly, so we’ll have to see.

Work on H6 continues. I’ve started a material library and am working on figuring that out. I’ve cleaned up some of the files in the repo, mostly just old mirrored parts. There are still a few files that need renamed and reworked. In general the hole pattern has had a slight printability tweak since the last photo I posted.

I’m tentatively but likely going to use the Arduino Zero as the brain for this robot / system. It’s not the cheapest or most available board out there but offers some unique features I really like. I’ve opted not to use the Raspberry Pi as the primary brain for a number of reasons all of which have to do with the OS stack. I’d prefer something easier and faster to get going and a dedicated microcontroller for the robot control makes sense. The Zero is a bit overkill in this regard, but hey 16 bit PWM drivers, a 48 MHz clock, 32-bit CPU and real time debugging are features I just can’t pass up.

This is not to say that I won’t be working with the RPi3, but it will serve as a co-processor of some kind. This is also an interesting opportunity to swap the Vex Cortex and Arduino Zero in terms of functionality. I want the platform to essentially work for teams that have and want to use Vex’s control stack and those who don’t. For someone starting up, a $50 microcontroller that’s several times faster than the Cortex is more appealing than the $250 Cortex, while a team that’s already invested in Vex and already has a Cortex is going to want to use the essentially free hardware.

Ideally we’ll develop a complete control stack, right now I’m hoping to use a Bluetooth module and a PS4 controller to interface with the Arduino Zero. I love the PS4 controller, and I believe as a $60 device it offers a vastly superior control solution over the $150 Vex Joystick. Also I suspect a lot of the robotics students here already have one of these controllers so it’s essentially yet another free component.

Power distribution is likely going to be my next big headache. Getting power from point A to B isn’t all that easy, especially when you consider the safety concerns. I’m probably going to need to create some kind of custom breadboard for this. I don’t love this solution as it will be difficult to reproduce but I lack the ability to create PCB’s both from a capability perspective and a knowledge perspective.

More thought on this is required. This may very well be one of those parts that needs to be fabricated.

http://polynomic3d.com/user/smith/mc_bracket.PNG

I’ve created a mounting plate that will mount either a Raspberry Pi 2-3. a Beaglebone Black or an Arduino to any 0.5" system, including VEX. It’s a neat little part, it’s VEX U legal and available on my GitHub. I still have to work on the specific spacers for it, but the idea is basically there.

This part is kind of interesting because everything else in the kit is on a 0.5" Voxel scale, but this part is kind of like a half-block in Minecraft, being just 0.25" tall. It actually worked out great with the hex nuts for 8-32.

It’s kind of interesting but making this public has pushed me to be even more perfectionistic than usual, a scary thought I know. This is by far the most complete and professional robot I’ve created. Overall I’m quite happy with the progress I’ve made. Let’s hope No Man’s Sky doesn’t completely side track me.

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