New Vac Bot!

New vac bot in process Name tbd

If numbers are correct, expect ~300lb of downforce O_O btw, this is a 15lber

idk about the inrunner through the top

Yeah, I'd try to stick with the old side-by-side model if possible but I seem to recall there being problems with belts.

[EDIT] Very complicated alternative: 3D printed impeller mounted to an outrunner.

The green motor is a CC CMS36 5700kv. I'm planning on making a cover for it. Cuddlebunny did not have direct drive and thus did not get to use the vac to a higher potential. I decided that most things cannot touch the middle of my robot anyways besides bar spinners so I just went with it.

Saw this on FB, looks really cool

IDK too much about VAC bots but did you consider putting in a set of wheels in the middle?
im not sure how 6wheel would compare 4 wheel but i Feel that with all that downward force why not use the extra traction?


How did spiderpig/cuddlebunny like the load on the gearbox shafts? Consider slave shafts and timingbelts?

I guess that's a reasonable consideration, but with that in mind I might make a few changes to the chassis to take advantage of the fact that you don't expect to drive upside down.

@ jeeves: I think the shaft is supported on both ends by bushings/bearings - they've never had problems with the shafts (only with a bad choice of wheels on the larger robot, which they learned from).

Yeah, I still need to figure out how to at least move around if I'm flipped just in case the vac dies.

We made the first prototype of the vac bot 2 years ago and I'm taking on the same configuration. Back then, no one was able to pull it off the ground except Alex M. but no one was really sure what he did. Anyways, it was able to get 2-3 PSI, and since my footprint is ~130 sq in., that should translate to 300-350lbs of downforce.

The drive motor shaft are supported in bearings.

As of today, I have made changes and I shall make renders of them soon (I hope).

i'd be more worried about the bot being inverted rather then the motor gettting hit.

From what I know about vac bots is that you dont need the typical size bruchless to run the fan.
If you want to direct drive it why not try to mount it to the can of an outrunner like they do with the bug bots.

Yeah, still working on a way to make it invertible. It currently is direct drive. I'm not sure if I'm missing something, sorry :/

@Alex: Just wondering, how many has there been besides Cuddlebunny, Spiderpig, and that really bulky 30lber? Spiderpig and Cuddlebunny were running on the same unit which was not using an great motor. Also Cuddlebunny was a pain to work with O_O i still have nightmares...

http://picasaweb.google.com/OddBallButler/3lbSpinningDrumBotBuildReport?feat=embedwebsite#5420428069844202018

Heres an example of what im talking about. The outside of an outrunner spins unlike an inrunner. You could use the outside of the motor as the shaft.



Im sure Will or Mr. Dubard would be able to explain this better in person

Alex wrote:

oooooohhhhhh paint!!!!

professional i knowwww!

invest in some super magnets, after all most botsiq floors are steel right?

@koolaid64: We thought of that already and didn't go so well. Someone was saying that the floor is stainless steel, thus a magnet would barely do anything.

@Alex: oh I was asking if there were anymore besides those 3

@Cody: The previous vac unit used an outrunner as well due to the design (the height of the robot was determined before the vac unit was made...). I haven't been able to find an outrunner with a nice Kv. The one we were using before was from Scropion and the Kv was somewhere in the 1000s. Also with the impeller (fan), that we have, I don't think we would be able to fit an outrunner motor in it. Anyways, we have all the parts for the vac unit on hand already (need to check if we have the metal laying around)

P.S. - That's a really nice paint

You might be able to get away with a very small outrunner mounted as-is to the impeller instead of the gigantic inrunner you have there now. The reason I think you can do this is running the impeller shouldn't require much torque at all even at very high speeds. This means you can get away with some of the larger micro outrunners, which have kV ratings going well into the range you're looking for. (Still, have someone double check how much power output you actually need to run the impeller at the desired speed)

Which outrunner would you recommend? I don't think any of the ones I've seen has the Kv I want. I don't need a lot torque. With this motor, I'm expecting about 63,000 rpm. The total height is about 3". The side plates are only 1.5" high

Btw, I'm going to be running on a 3S lipo.

because of the limited resistance and the idea the its not going to be used as the regualr weapons we see used is the reason why i figured you could use something comparible to an axi 2208 (almost 2000 rpm/v)

I completly looked past your desired rpm before

Ok, so I came up with a crazy idea in the shower. So I'm currently at 14lb in my new build and I have left is the cover for the weapon motor. My idea is to cover it with a foam noodle and duct tape. I think it would hold up okay (Unicorns, I love them vs. Sting 'Em) because I didn't see that much damage even at a head one collision and grind. I want to leave some weight so I can brainstorm up some modular things I can put on.

1. It's a lot lighter than using Al
2. It's easy to make and replace
3. I don't expect that area to get hit much anyways


Here is a video of it in action at Mayhem in Miami 2010
I had one of the freshies drive for me since I thought they could have some fun with it
https://www.youtube.com/watch?v=-_d-y7pwnOo

Good idea, bad idea?

That fight was actually vs Sting WMD, which was only running with 1 side of the drivetrain working.....

A good win none the less!!

@rjw: Oh sorry, my bad. Question, was the reason why Sting WMD got KO'd due to battery or did it get stuck on the foam? Or was it something completely different?

from what I was told, started with only 1 drive motor working and they never charged the battery

rookies....

WMD needs a 2650 45c 6 cell , fully charged just to make it thru 3 minutes with the drum spinning at any upper rpm rate

Lokoyo wrote:

Which outrunner would you recommend? I don't think any of the ones I've seen has the Kv I want. I don't need a lot torque. With this motor, I'm expecting about 63,000 rpm. The total height is about 3". The side plates are only 1.5" high

Btw, I'm going to be running on a 3S lipo.

I'd say take a look at some of the mini outrunners; they might be too small, but they might not in which case you can reduce the height of your robot significantly (shorter motor). I suspect you can find out exactly what power output is necessary based on the vacuum units you have right now in [what used to be and may still be, unless you've renamed it] Cholo. The places I'd look at are: the actual speed of the impeller (use a tachometer or some equivalent), and the current draw & voltage being run through the motor. With that you should have enough information to get a good picture of what the vacuum needs to operate, and you can then go and select the motor that will best deliver for your target characteristics.

the micro motors are probably your only shot of that Kv out of a outrunner but pay attention to the lipo range also

or you could always make your own

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5344