This image wasn’t originally created by me, but I think it needs to be talked about more than it is. The spacing of robots for climbing the tower is going to be more of a challenge than people might think. This image depicts some theoretical drivetrain widths. In my teams opinion a robot should be roughly 22 in wide to ensure that there won’t be any major issues with climbing next to other robots.
I think a safer solution would be to climb at different heights. The ones at the diagonal batters could climb just above the goal, and the center climbs to the top.
The bumpers would interfere before the rest of the robot width-wise.
Is anyone making their robot with a 120 inch frame perimeter? we are usually several inches smaller…
Also, what are the odds that there will be 3 scaling robots in a match? I guess in elims you could pick your alliance for 3 scalers, but I kind of doubt it will be common at most regionals.
701’s current plan is to scale to the top and clip there with a gate latch-style spring loaded mechanism. This was an idea because we have gotten to the point of foregoing gas spring lifting and have opted for a motorized lift. As our current plan is to keep our robot low for the bar defense, a pneumatically engaged ratchet system is nearly out of the question due to complexity and space concerns.
So basically we need to reach the top in order to passively clip and stay after robot power is off. The second reason now is to ensure that we can scale with at least one more alliance member. The final reason is because reaching the top is a crowd-pleaser. Sure we could opt to go for the minimum height for points, but why not go the extra distance and do something more entertaining? I feel obligated to make up for Recycle Rush. FIRST isn’t just for inspiring students on FIRST teams. It’s also for inspiring those who attend a competition, and when we have a spectacle, rather than the bare minimum, we can inspire and entertain those who would otherwise not have the same level of interest as ourselves. It’s easier to convince attendees of the effectiveness of FIRST in our communities and their people when they’ve got the WOW factor in the back of their minds.
Of course we say that it’s not all about the robot, but for the audience members who are at a competition for the first time and/or are not that familiar with the FIRST model and vision, from their perspective, the robot is indeed everything. After all, they see a sign in the front of the venue that says FIRST Robotics Competition. They’re gonna expect robots, and they’re gonna expect competition with entertainment value. If we wanted to make it clear for the common attendee, the sign might instead say FIRST Not All About Robotics Competition (FNAARC). 
We are (minus a fraction of an inch to make it clear we’re compliant during inspection), and it’s hard enough as is. Any shorter, we can’t comfortably make our desired drive geometry work. Any narrower, and the boulder doesn’t comfortably pass through our bumpers. And we’ve barely scratched the surface on the fun times that will be forcing all the electronics to fit in this thing.
I would say that a better takeaway from this image is, make sure you’re gripping the bar well, and can hold on at non-ideal angles. Suspended robots in this position will push on each other causing their bases to rock or rotate in odd and unpredictable ways, rather than just simply not fitting, and your latch system should be able to handle this, instead of designing to operate in isolation.
Also, note that the two 28" robots may not be able to get to where they are even if they’re just resting on the Batter, because of the dividers between the sides of the Batter.
One thing I would propose strategically if I were drive team coach again is this:
For three climbers:
Case 1:* All robots stop at different heights.*
The highest climber goes first, and the next highest follows, and the lowest goes last. Timing this so all three scale will be crucial.
**
Case 2:** *Two robots stop at the same height and one stops at a different height. *
Ensure that the robots that stop at the same height are on the opposing sides of the castle tower, with the differing robot in the middle
**Case 3: ***All robots stop at the same height.
*
Meet with alliance members pre-match and figure out which permutation of robot placement minimizes scaling interruption. Perhaps, depending on climb speed, this minimization can be better achieved by letting the fastest go first. Your alliance would have to share measurements, or possibly get all three robots on the practice field. If not, find an area in the pits to set up the robots to figure out the best permutation.
For two climbers:
**
Case 1:** Both robots can scale on the opposing sides (stopping height irrelevant).
*
Let both robots scale the sides, timing is not relevant as they will not contact
**
Case 2:* One robot MUST scale the middle while one can scale the side, and both robots stop at the same height.
Let the robot who scales faster scale first, followed by the second. If possible, plan pre-match which configuration will minimize robot interruption.
**
Case 3: **One robot MUST scale the middle while one can scale the side, and both robots stop at differing heights.
Let the robot that scales higher scale first, followed by the second
If you want to scale with multiple robots in a match, plan to be able to scale from any side, as this will be important in deciding who goes where.
Also, be aware that if robots are contacting and scale at different rates, it is possible for a robot to be pushed higher by an adjacent robot and risk unlatching from the bar on the castle tower. This is a factor that must be considered when attempting a strategy that involves robots scaling adjacent sides. It’s the alliance’s decision to weigh the benefit vs the risk.
Remember, there are also dividers on the batter so, chances are, that will put a similar restriction on robot size assuming you need to drive onto the batter to lift.
But robots don’t need to be rectangular.
Ultimately by posting this image I was hoping to show teams that 28" wide robots would be a problem for a few reasons. They approach the tower off-center if they come in on a side because the wall is so close by, and they overhang quite a lot. Problem is if you’re 22 inches wide, you have a 6 inch opening for the 10 inch ball. You have to balance these differing constraints.
Ultimately for a variety of reasons not limited to what’s depicted in this image I’ve moved away from thinking about hanging at all.
In the future please don’t take images off of my Facebook page and repost them publicly without asking me first. I would have been fine with it in this case, but that’s not a thing you should just assume is okay.
It’s tougher than it first appears…although I"m sure we’ll see a few teams make it look really easy
If you’re using a kitbot chassis and you make your robot 22" wide, your CIM motors won’t like that very much since they’ll be trying to occupy the same physical space.
There are many key design parameters teams may need to account for this year. Glad to see someone posted your work Chris!*
*Hopefully people ask you ahead of time in the future…
We’re more concerned with the dividers in the batter. I don’t even think robots of the shown width can fit adjacent (or close to adjacent) with the tower in the configuration shown.
Keep in mind the dividers on the batter are only 6" tall. As long as your 5" tall bumpers are above that height (i.e. 6-12"), all you have to worry about is your robot chassis fitting (and not your chassis + bumpers fitting). That gives you like 6" of width to play with.