15 in the works

I'm working on a 15 lb drum spinner to take to college with me to kickstart the CMU team. All I can say is AXi 5320/18.








I still need to modify my drawing for the back end - i've revised the design a bit lol. and for some reason, the H shaped frame pieces in solidworks were like 2 degrees NOT SQUARE and it was fluffing ME UP. so i kinda gave up for a bit. i'll redraw them eventually... solidworks is nice and kinda cool but not necessary - i can make do with my 2D cad lol

Very nice Dan....looks like a bit of copperheads drum is going with you...

The bevelled front end and offset motors are almost identical to the ttatt bots that we are working on at the moment...

Wow Dan that looks nice. I'm interested to see how you're going to mount the axi motor from the inside like Will.
Sprocket on the shaft or direct connect to the motor housing? If it's an out-runner that is.

Just for kicks, how tall is the whole robot? Will my bar be able to smack it around or will I be the one being back-handed? Lol.

I want to do a 120 next year so I kind of don't want to redo Tornado Mini, but if I do, we'll defiantly have to grudge each other. I've always been curious what a really well designed drum spinner would do to a bar/full body spinner. I fought angry turtle and I left some pretty good gouges in their drum but a head on Copperhead vs Blender? Ohhhh.

Just out of curiosity, why do you want to use the 5320's? I think it only has about 400 rpm/v but a lot of other axi series motors draw less amps with twice the yield. What's special about those?

SenaiERI

Cause he's planning on running dual voltage and since its direct driven its only gonna be 1:1 gearing he'll need all the torque he can get

Cody Harris wrote:

Cause he's planning on running dual voltage and since its direct driven its only gonna be 1:1 gearing he'll need all the torque he can get

Oh yeah, it's going to be direct drive. Duh, he'd want more torque than speed.
I can't believe I missed that. Finals must be getting to me.

What do you mean by he'll run it on dual voltage?
Doesn't that usually refer to a device being able to run on either 110/220 volts without a transformer?

SenaiERI

he'll split his battery packs and run like 14 volts maybe to the drive and around 22 to the weapon motor

i was thinking 11 to the drive, but yeah. that's the idea.

the bot's gonna look ridiculous... you'll see when i finish my solidworks model. i'm still working on it. (I'm doing EVERYTHING not just blocks and outlines lol)

and yes. the weapon motor needs as much torque as i can get with a decent amount of speed (~5000 RPM) which i get with the 5320/18.

:]

im geussing maybe 5-6in drum?
Are you planning on using a mamba max?

that robot looks bad booty can't wait to see it in action.

I haven't even looked into the brushless control lol... I am exploring new territory with this. If that's what you'd suggest, then it's likely.

it's a piece of 4" schedule 40 steel pipe. if that helps scale everything.

There a little bit bigger but they have a forward and reverse and figuring you symetrical design it would make sense to have.
Have happened to ever hear of the 12lb bot Attrition, i just was showed the bot and i think it would be a decent inspiration for yours
https://s30.photobucket.com/albums/c320/jamisongo/12lber%20Attrition/

If you're looking for Brushless controllers, I would suggest Jeti Series Controllers. They work very well and are remarkably durable, unless your name is Matt and you happen to catch yours on fire.

This one worked great for me. They are kind of pricey, but most brushless controllers are.
http://www.hobby-lobby.com/advance_plus_77_amp_opto_brushless_motor_controller_2978_prd1.htm

SenaiERI

P.S. From what I understand, it's a good idea to have a controller that can handle a few more amps than your motors will ever need. The one above can handle 77 amps and your motor is rated at 78 so I don't know if you want to use it or not, but I'm fairly certain that's how Matts caught fire.

Jeti's are amazing and is what we have always used, like i said castle stuff doesnt work in our bots
The only down side to them is they are omni directional, unlike the mamba max
Its gonna come down to if you want it or not, the mamba max are very popular although ive never used them

The extra amperage is a good idea, if you take them right to the limit they will either stall or short

yeah, and the mamba max says it's only rated for up to 3s lipo. I'm planning on 6s for the weapon motor... :/

so i'd have to get the Mamba MONSTER max which is like 30 bucks more - $168.99 on robot marketplace

*sigh*

this is going to be an expensive project...

Okay. with everything as-is (assigned masses to all non-solid components) and a steel drum, the entire thing weighs 19.98 lbs. OUCH. I need to lighten stuff. The drum weighs 8.04 lbs, so that's the biggest problem. A titanium drum in the model brings it to 16.62 which is still going to prove difficult... I'll work on where I can take weight out and what dimensions I can change. (and this is without the brushless ESC, wiring, back/front armor [lexan?] and the top armor/baseplate.

Dan Curhan wrote:

yeah, and the mamba max says it's only rated for up to 3s lipo. I'm planning on 6s for the weapon motor... :/

so i'd have to get the Mamba MONSTER max which is like 30 bucks more - $168.99 on robot marketplace

*sigh*

this is going to be an expensive project...

It is misleading...their motor/esc combos are rated at 3s, becausen the motor is 3s.

We've run them at 5s and may try 6..but the monster is just that...also heavier

Dan Curhan wrote:

Okay. with everything as-is (assigned masses to all non-solid components) and a steel drum, the entire thing weighs 19.98 lbs.

Maybe you could just add 10 pounds and take it to 30 lb competitions?

Dan,

I think you need to be careful when looking as the battery rating with ESC's. From what I understand, 5s Lithium usually refers to 5s lithium poly, but a lot of people use the A123 batteries with are Li fe ion. The difference in voltage is what I think they care about and usually when they say 5s lithium or li-poly, it 5 times 3.7v which is 18.5 v, but the A123's are 5 times 3.3 which is 16.5 volts per pack. You might be able to get away with running a ESC rated at 3-4 li-poly and run 5, maybe 6, li fe ion if the voltage matches up.

Again this is just what I've heard so I could be wrong. But it might help in your ESC hunt.

Oh and as for your weight problem, I have the perfect solution. ABS! Why not make your drum out of ABS? It's light and very sturdy. I would recommend it for all small class robots. -_-

SenaiERI

P.S. For anyone reading that and didn't get the sarcasm associated with ABS, it was a joke. Just FYI.

hahahaha or weapons-grade black delrin!

yeah, no. haha.

you're right about a123s being 3.3v instead of 3.7 like most lipos.
my battery is looking like a 6s lipo pack split with a common ground, and two + leads, one at 11.1V and the other at 22.2V (3s and 6s). A123s are much heavier to get near the same voltage, and with the low Kv of my super-powerful motor, I need a fairly high voltage... idk if you saw my post with my battery spread on it, but i spent hours looking up all kinds of lipos and comparing their data (including a123s)... i didn't, however, look at any Li-ion batteries, so I'll do that at some point. For now, though, the battery fits PERFECTLY in the bot, so i'm a little hesitant to change to a less-controversial battery type.

granted, the baseplate is solid 1/4" aluminum, the side panels each have a ton of extra weight in them, the frame has a wall thickness of .060" which is quite thick for tube steel (i can probably get away with ~.040 or so), the drum is really inefficient weight-wise as it has three 3/8" thick rings that are like 1/2" wide to support stuff internally, so those can be lightened substantially... umm.... there's definitely things I can do. However, I think I want to bring the side panels down in front of the wheels, so they're protected more - I wasn't thinking of using anything ridiculously strong - I actually modeled them out of plastic...

Well I didn't see your battery spread but I'm also not an electrical person. I mean, I crimped Tornado Mini's wires with pliers for heavens sake, but my robot didn't explode or catch fire so that's all I'm happy about.

Maybe we should have an electrical seminar/tutorial, for those of us electrical dummies. OHHH a battlebot youtube channel dedicated to helping noobs with their first robots and to keep people up to date on BB stuff. CALLED IT!
Ah never mind, you do it Dan.

By the way, this thing looks mean. Way overkill and it looks awesome. Got a name for it yet?

SenaiERI

SenaiERI wrote:

I crimped Tornado Mini's wires with pliers for heavens sake

Never ever ever ever ever ever ever ever EVER try crimping small wires with needlenosed pliers, I was trying one time, and the pliers broke, half of the pliers snapped off and went flying.

Well I used regular pliers. They did their job.
Actually, while I was half way done doing the wiring on Tornado Mini, I realized that there were crimps on the underside of my wire strippers. DUH!

SenaiERI

hahaha why on earth would you be crimping with needlenose??
i don't have a name for it yet... i was thinking some play on words with the word drum... like

innuendrum
drumination
indruminitable
conundrum
tornadrum
the ugly drumling lol

idk

Cuz I was at home, didn't have any devices for crimping at home and the regular pliers were too big for the part I was trying to crimp and I figured, "Hey, needlenose pliers will work!" and then I had my mother hold the wire while i used both hands to try and crimp it, and then the pliers broke and almost hit her in the face.

indedrumable
drumbo the robot
drumbo
drumnation
Ozydrumdias
Superdrum
Dr. Drum
Drumo
The Drum Knight
Drumby