This still looks pretty weak. I highly recommend at least adding another crossbar but even then I can see this entire chassis twisting after a big hit. Drivetrain problems are not problems you want to have, If you can’t move you can’t score. Not being able to move is not fun.
Yeah, my idea is to have whatever side of the frame that has mechanisms on it, the opposing side will have another cross beam.
I left the front and back open for now for whatever scoring mechanism we need for the game, the super structure for that will add more cross supports.
When we build this for real to test over the off season it’s gonna get rammed pretty hard so we will see.
Not everything has to be about winning. If it works and the students like it, no big deal. This does have the added advantage of remaining under 2" tall along most of its length, so a plate can be placed right on top of the side plates to protect electronics and motors.
That being said, the way you’re using plates over 2x1s still rubs me the wrong way. Your side plates are still way less stiff than they should be or could be with just tubes.
If you add a crossbar opposite the side of the manipulators the tweaking problem might be ok, but even if you do that I would still move your center crossbar closer to the end of your chassis.
Also, using 6 775pros DOES NOT give you more power than a CIM drive! Theoretically if you ran all the motors at 60A, you could generate more output power, but in practice you won’t be running your 775s more than half that much. That’s why most of the 775pro drivetrains this year and last year were geared so slowly (relatively of course; 15fps is fairly slow for this year in my book).
It also has the advantage of folding like a taco along most of its length. Which is why I was trying to get some of the apparent advantages out of OP so any suggestions on how to remain mobile for more than the first 5 seconds of driving wouldn’t interfere with them.
How does this compare in cost to a Kitbot, or even a custom chassis with more standard COTS drive gearboxes? Also, I second Anand’s comment about using some sort of tubing. Right now, you’re just asking for misalignment on your shafts.
6 775pros may be equal to a 4-CIM drive in some respects, but keep in mind you are gearing this for something below 15fps. 1072 and 299 geared for 17fps easily this year, and 115 geared for 21+fps off of just 4 CIMs. Doing that with a non-shifting 6 775pro option is asking for trouble.
Right now your chassis is H-shaped. If you add a crossbar on one side, it’s a rectangle with two pairs of spindly plates sticking out connected with standoffs. A good hit from the side will bend the chassis inwards, not to mention ruin your bellypan.
That’s why I said “Doing that with a non-shifting 6 775pro option is asking for trouble” because unless you make it traction limited at a low current, the 775s will burn out quickly. CIMs are much more forgiving and tend to die long after a brownout has occurred.
Yes. I’ve said multiple times now that this is going to be in a perpendicular drop drive/h-drive setup anyways.
It’ll probably only have one traction wheel on each side and the rest be Omni’s or mecanum wheels.
I think you’ll be fine with 1/8th plate if you tie the 1/8" plates to the beam and if you are pretty generous with your spacers between the plates. I’d even consider making C channel out of small lengths of the same profile you use to make beam and then you can install them at the bottom between the rails or even here and there between the chains (since when have FIRSTer been scared away by nightmare assemblies?
1/8 plate is pretty strong stuff if you know how to design supports.
Also, don’t forget that you have a bumper that ou can potentially use to strengthen the chassis.