12-03-2015 08:28

lynca

Re: pic: Team Xbot #488 2015 Robot

Looks terrific and high quality !

I would like to see match video but it look like glacier peak has not posted videos yet. http://www.thebluealliance.com/team/488/2015

Good luck at Shorewood!

12-03-2015 11:17

Kevin Sevcik

Re: pic: Team Xbot #488 2015 Robot

What are you guys calling a West Coast drive with the wheels on the inside and the belts and pulleys on the outside? Is it a Northwest Coast drive or something?

I'm interested to see how this worked, since we prototyped a chain lift and I was pushing for it arguing a similar roller carriage with leveling bumps design. The team decided it was too complex if I wasn't there daily to manage it, which I couldn't really argue with. But I still want to see how it works in practice.

12-03-2015 11:40

tickspe15

Re: pic: Team Xbot #488 2015 Robot

All match videos from PNW events are uploaded shortly after the given match is played. Under the current system videos sometimes take a long time to get linked on the blue alliance.

https://www.youtube.com/user/FIRSTWAVideo

12-03-2015 11:42

MrJohnston

Re: pic: Team Xbot #488 2015 Robot

You can find all the matches from Glacier Peak here:
https://www.youtube.com/playlist?lis...1SbYQeYsOEKJoS

12-03-2015 11:50

Madison

Re: pic: Team Xbot #488 2015 Robot

Unfortunately, there's not much to see yet. We were doing okay in practice, but during matches, we had a lot of trouble acquiring totes from the landfill efficiently.

The drive should be called, "Oops, what can we do to fix this?" I made a ridiculous mistake and we had to start the design from scratch at the end of week 3. This drive is a result of that; it was a way to salvage as many of the COTS parts we'd already purchased and to minimize the need to buy many more. In the end, over two robots, the mistake probably cost the team something like $3000.

Kevin -- The chain lift is too complex. Especially our implementation. Y'all made the right choice.

This season's been rough.

12-03-2015 17:15

Kevin Sevcik

Re: pic: Team Xbot #488 2015 Robot

Ouch. We nearly made a similar mistake. Long wheelbase + 6" mecanums and clamping gearboxes meant we'd be dragging the gears on the platform crossing it. Various members wanted to up to the 8" AM mecanums because they were "stronger" and PDV-able. I wanted the Vex for weight. We already had a chassis together, so we're lucky we checked and discovered the AMs would've been too wide. We're just squeaking under width as is. And we were 120# at Dallas, so we didn't have weight either. Heh.

Sad to hear about the complication of a chain lift. It seemed like a good way to gain positive control of the crates. We're currently working on weight to add a clamping system on our internal elevator stacker so we can better control the totes and not have to worry about them flying out if we bump something.

12-03-2015 17:25

JesseK

Re: pic: Team Xbot #488 2015 Robot

We did a single #35 chain drive as well. At Pittsburgh we weren't terribly efficient at the landfill, but it seems to be that the hook profile has a lot to do with it. We had an active anti-sag kicker which wouldn't quite hit the tote in the same spot every time, knocking them off on occasion. No active intake though. We're debating on whether an active intake would even help, given the other obvious things we have to change with our hooks. Thing is, everything seemed 'fine' before bag day.

All around tough, but I'll share the results of our tuning.

Just make sure the tote is square to the frame before lifting. That will save several seconds per tote - being slow at first, but far more efficient than the totes falling off.

12-03-2015 18:39

Madison

Re: pic: Team Xbot #488 2015 Robot

In my case, I didn't pay attention to the space between the yellow totes and the angled player station walls and found that we wouldn't be able to position the robot in our desired starting position for a three-tote autonomous. We redesigned the frame (and, in fact, the rest of the robot) to envelope part of the tote so we could fit in that space, but a million other things have come up that make achieving that autonomous strategy a distant possibility.

The wheels ended up on the inside because the parts we'd ordered from Vex were for a dead axle sheet metal drive. We could've cantilevered the mecanum wheel and driving pulley off one side of the versablock, but that made me nervous, so we ended up with this weird drive.

It performs well. It's a little unstable and will rock from side to side, but we're bottom-heavy enough that we don't tip.