pic: MVRT 115 El Toro 7 teaser



im sure u can guess :wink:

Niceee!!! Planetary inside of the wheel?

Well its more like the gearbox for the Drill inside the wheel.

is that for a crab-drive type of drive train?

that is known as a planetary gear set where there are center shafts (sun gears) that connect to the outer gears (planets)

btw that drive looks really cool…what materials are the gears made out of(knowing that they will have to be robust to take the wearing that the wheels do)

also what are you guys using for out side material… I understand if you can’t answer because it is only a teaser but i am looking forward to seeing those things up close and personal

Based on what Inventor colors certain materials, the gears are steel (pretty obvious) everything light gray is 6061 aluminum.

[edit] that doesnt look like a planetary gearbox. See the pictures of 258’s swerve modules from last year. Im betting it’s the same concept.

Cory

Yup… its a really shiny design. I’ve got it in the shop and its… really shiny. Yea by the way I designed it. So… ask away about how it works. Yup… I didn’t want it revealed… but it got out. Have fun.

By the way, it costs 1600 bucks for all 4 modules, so we won’t have anything else on our robot this year. Maybe a battery. Nope.
Yea just kidding. Just… watch out.

[edit] By the way, this is the old design. As you can see, the wheel WAS made from 3 peices. Now… one. Yea… hogged out 1.5 inches of solid aluminum. By the way, to give you an idea of how big it is… the wheels are 6" diameter.

Well… team 258’s design was huge and heavy, like 20 pounds per module. Also, this design is different because the motor and the wheel are on the same axis, and the gear reduction is INSIDE the hollow wheel. This makes for a very compact design, and actually very robust. Let me post some more pics, since the design has changed a bit.

Just for the record…

Our modules were heavy, but not that heavy. They could have been extremely light if we had done some simple machining on the gears, and used different brackets to mount the modules. The drill assemblies were about 10lbs (including the vertical shaft, aluminum washer, mounting bracket, and sprocket) and the CIM assemblies were 12-ish lbs. Our sweep diameter was quite small, too (about 6.8" for the drill module, and 8.5" for the CIM module). Our sweep diameters could have been even smaller had we not designed to fit under the 14" bar.

Also, having the wheel and the motor share centers doesn’t necessarily make your module’s sweep diameter small, especially when you’re talking about a module for the CIM motor. What makes the sweep diameter small is trying to place the midpoint of the length of the motor and geartrain directly over the pivot point of the module. If you don’t do that, you’re already behind the game when it comes to conserving space. I don’t mean to say that you’re not significantly cutting down the sweep. It looks nice.

Veselin,
I’m curious as to what pitch gears you’re using in your assemblies. We used 20DP gears, except for a 0.7M gear that mated with the drill motor pinion. I don’t really have a reference point, but it looks like you’re using 24DP or smaller gears. Looks nice Veselin. I’m looking forward to seeing it at events :).

Veselin,
I’m curious as to what pitch gears you’re using in your assemblies. We used 20DP gears, except for a 0.7M gear that mated with the drill motor pinion. I don’t really have a reference point, but it looks like you’re using 24DP or smaller gears. Looks nice Veselin. I’m looking forward to seeing it at events :).

Gear reduction for the CIMs is 20 pitch, and for the drills its all .7 mod. Boy what a pain it was to get those gears!!! Yea… mostly aluminum, except for the shaft the whole thing rests on… thats steel. Gears too…
So yea, its a really nasty, but cool, design. We’re geared to go about 10 ft/s, so we’re fairly fast. The machining was really crazy though. As I said, the wheels are made of solid blocks of aluminum. Most of the parts needed to be CNCed. So, see you all at the competitions.

Any more questions, I practically live here.

I’m curious as to what you guys chose your main strategy goals to be this year that you feel swerve is nessesary. Yes its a great for added mobility, but is the weight and complexity, and not to mention at least one other motor to turn them really worth it for you guys? If you don’t want to discuss your strategy that’s fine, just pointing out that if you have the ability to build something, it doesn’t mean you always should.

That aside, does your new design with the wheels from a single round of aluminum still have the reductions inside of the wheel or have they moved outside?

Oh yea… we hollowed out this enormous block, so it still looks very much the same. Just less bolts to hold it together. But yea… I don’t think that we really NEED swivel. You never need anything truly, you could always use the drill motors provided by FIRST. Swivel drive might come out to be useful in this year’s game. You never really know how the game will be played out. Our team voted for swivel, so now we have swivel. For me, its just a design challenge. I find more satisfaction in building the robot than winning with it. Hey, thats just me. I don’t represent my team too well hahaha.

And by the way on the issue of weight, the drill module is 6 pounds, the CIM is 7.5 pounds. Not too heavy I would say.

I think that’s a really great reason to build this drive system. I am very proud of how you guys challenge yourself every year with something new on the robot. I remember at 01 it was the auto-balance code, 02 was the 4 motor drive system, and 03 was the stacker. I cannot wait to see this drive system from one of the best robot builders in the Bay Area. Very cool! Be sure to post real pictures as soon as possible.