15-12-2015 02:08

KohKohPuffs

Re: pic: 1736 Robot Casserole Offseason WCD

Interesting design. What is the weight? Also, what made you guys choose colsons over blue nitrile tread wheels?

15-12-2015 10:03

jeremylee

Re: pic: 1736 Robot Casserole Offseason WCD

I've estimated around 37 pounds as shown. If we drop back to 4 cims, that'll put us around 31 pounds. As for wheels, it's possible we may try blue nitrile, but the main concern is that the increased traction may lead to more brown outs.

15-12-2015 10:33

asid61

Re: pic: 1736 Robot Casserole Offseason WCD

Are you planning on adding a bellypan? They greatly increase the stiffness of the chassis, but if you've run without on in the past that would be intersting.

15-12-2015 10:34

Chris is me

Re: pic: 1736 Robot Casserole Offseason WCD

Plenty of great reasons to use Colsons over blue nitrile, but if you're concerned about brownouts then 6 CIMs is far more of a risk factor than the wheel choice.

15-12-2015 10:51

notmattlythgoe

Re: pic: 1736 Robot Casserole Offseason WCD

I would imagine in most cases when a belly pan is not in the model they just didn't model it, not that they aren't going to have one.

15-12-2015 11:13

nuclearnerd

Re: pic: 1736 Robot Casserole Offseason WCD

Can you add more detail about your bumper mounts? Unless you make all four sides as one piece, wouldn't the draw latches tend to flip the bumpers upwards? Or is there a secondary support I can't see?

15-12-2015 11:26

Ty Tremblay

Re: pic: 1736 Robot Casserole Offseason WCD

The strongest way to make bumpers is to make them as one piece. This is most likely what they're doing. They'll probably have a hard stop so the bumpers can only go down so far, then the latches will pull the bumpers in and down against the hard stops.

15-12-2015 11:30

notmattlythgoe

Re: pic: 1736 Robot Casserole Offseason WCD

This is really what I wanted to do on our 2014 bot since we had a one piece bumper.

15-12-2015 14:00

jeremylee

Re: pic: 1736 Robot Casserole Offseason WCD

Plan is for a one piece bumper to slide on from the top. Still need to add a latch or two on the front and back.

And yes, we'll have a belly pan. I don't know the exact details as the electrical team takes care of that aspect, but it's similar to the pre-drilled polycarbonate.

15-12-2015 14:16

jeremylee

Re: pic: 1736 Robot Casserole Offseason WCD

I understand that 6 cims at stall is likely a problem. Has anyone confirmed we can stall 4 cims without being worried about a brownout?

16-12-2015 11:28

notmattlythgoe

Re: pic: 1736 Robot Casserole Offseason WCD

I believe the ultimate goal is to design so you are traction limited so you can't stall your motors, but I'm no engineer so don't that that as law.

16-12-2015 12:42

AustinSchuh

Re: pic: 1736 Robot Casserole Offseason WCD

I can pretty much confirm that if you stall 6 CIMs, you will brown out. Brownouts happen pretty early with the roboRIO. We were seeing brownouts with 4 CIMS in high gear accelerating from a stop towards the middle to end of the match.

16-12-2015 13:08

jeremylee

Re: pic: 1736 Robot Casserole Offseason WCD

This confirms my theory, 4 cims may be "safer" from a brownout, but that alone may not avoid a case of the brownout blues. Better to make sure you are traction limited or have some form power limiting implemented.