Driving long?

[Aren Siekmeier]

So now that a lot of previews, teasers, and partial reveals are coming out, I'm noticing a substantial number of robots with a ~38" long drive base. I'm curious what motivated these decisions. You're almost completely removing any chance of balancing 3 robots, but perhaps there are other benefits? (crossing the bump, getting into corners, etc.)

So why did you decide to drive long?

[Joe Schornak]

We're going long mostly to counter center of gravity and tipping issues while crossing the bump and climbing the bridge. Our ball collection and storage system takes up a significant area between the wheels, so lots of components have shifted upward on the robot. A long base will keep the center of gravity over the wheelbase when the robot tilts. It also lets us put the shooter higher on the robot for the same reason.

Also, mecanum wheels work just fine for taking the robot up the bridge sideways. I forsee on problems in getting three long robots on the bridge, as long as you designate one team to balance and the other two teams to hold very still.

[Ninja_Bait]

Long bots with a low, centered CoG should still be able to balance three at a time, if the end robots hang off their front wheels.

[pfreivald]

We intend to drive on, rotate (zero turn radius), and then either slide sideways as necessary *or* drop our traction wheels so that we won't move while our partner(s) get into position in order to achieve balance.

[thefro526]

This is only the second year since I've been on 816 that we had the Wide vs. Long debate, the first being 2009 where building a long base was almost like handing a victory to a capable opponent that could drive reasonably well.

We ended up assessing a few parameters and came to the conclusion that we could build either a long or wide robot without too much hassle and have them both be about equally competitive. These discussions finally culminated in the decision to build a 'Short Long' of sorts. For all intents and purposes, our foot print is ~32"x27.75" - It's only about a bumper's length longer than a wide robot, which shouldn't cause too many issues with bridge balancing. If all goes well, when it's on the bridge, due to some creative weight positioning, it should effectively be smaller than most wide robots.

I'd imagine that the primary reason that many teams have gone long this year is for ease of traversing the field at speed. Having driven both Long and Wide Bots at ~12-13 fps on flat fields, I can say that a wide bot requires the driver to be much more aware of the robots size than with a long.

[jwfoss]

Originally Posted by thefro526

We ended up assessing a few parameters and came to the conclusion that we could build either a long or wide robot without too much hassle and have them both be about equally competitive. These discussions finally culminated in the decision to build a 'Short Long' of sorts. For all intents and purposes, our foot print is ~32"x27.75"

We came to a similar conclusion. After last year we talked to our drivers about what they would like to see moving forward. They loved the 2-speeds we ran last year but wanted the robot to be more stable and have a more predictable center of turning. When this years game was released we determined that stablity while tranversing the bridge/barrier was going to be critical to our design. We finalized on an 8wd (5" Colsons), with dropped center wheels (1/8"). Our overall chassis size is smaller than your average "long" robot at ~34" x 26".

[Grim Tuesday]

We decided to go for wide for two reasons: Firstly, it makes balancing easier with three robots. Sure, you can go for long and rotate on the bridge, but that takes time. What if you could have scored 6 extra points in that time? Our second conclusion was that balls would be a tough commodity in this game, so it was essential that we were able to collect them easily. Thus, a larger surface for the collector was necessary, and we put it on our wide side. We're keeping our CoG low, so we can still go over the barrier.

[pfreivald]

Originally Posted by Grim Tuesday

We decided to go for wide for two reasons: Firstly, it makes balancing easier with three robots. Sure, you can go for long and rotate on the bridge, but that takes time.

Less than a second for us, and we can drive sideways afterward. I wouldn't recommend it without a zero-turn-radius robot.

Originally Posted by pfreivald

We intend to drive on, rotate (zero turn radius), and then either slide sideways as necessary *or* drop our traction wheels so that we won't move while our partner(s) get into position in order to achieve balance.

Do I hear an octocanum drive from 1551?

[Jon Stratis]

We figure balancing 3 robots is going to be a lot harder than some people think - especially since no one is going to be trying it until the elimination matches. You'll see a lot of teams try for 3 and not get any bonus points because of it, being beaten by people going for two who get it because they've had a lot of practice doing that.

[pfreivald]

Originally Posted by SuperNerd256

Do I hear an octocanum drive from 1551?

I don't know what would make you think that... http://www.youtube.com/watch?v=7GbrprUtC4o

[Madison]

I am not too surprised by the number of teams driving in a long configuration, but I am surprised by the number of them using a <=12" opening for ball collection.

[pfreivald]

Originally Posted by Madison

I am not too surprised by the number of teams driving in a long configuration, but I am surprised by the number of them using a <=12" opening for ball collection.

Don't you expect that most of them will have some kind of deployable appendage for collection?

[Madison]

Originally Posted by pfreivald

Don't you expect that most of them will have some kind of deployable appendage for collection?

I am sure lots of folks will, but I've come across a number of pictures here that show narrow ball collection openings. Perhaps that'll feature an additional system that funnels balls into that narrow opening, but that hasn't been clearly the case so far.

[pfreivald]

True that. It hasn't been clear on our videos so far, but we've got a deployable collector. I've just assumed that everyone else driving longways does, too... (Except perhaps some inexperienced teams that don't realize how critical it is.) I think in this game that even if we were driving wide, we'd still have a deployable collector!

One of the primary reasons for driving with the long orientation for us was barrier crossing; another is center of gravity driving up the bridge.