Having seen dozens of robots through Open Alliance and other channels, there’s a very obvious trend occuring: most robots will be taking advantage of the 48" extension limit.
Pits are 10’×10’… robots are generally going to be 25"-30" long with up to 48" extensions. Exasperating this situation is the necessity for extensions to occur quickly to allow for efficient scoring during the game.
It doesn’t take a lot of thought to see the problem.
Many teams aren’t going to easily be able to retract their arms as they’re exiting the field after their match. Giant, head-height, metal levers are going to be rushing through the pits as teams race back from the field to fix their robots between matches, after they inevitability tip over due to being top-heavy.
As a design consideration for teams, it might be beneficial to be able to get your robot within its frame perimeter when it’s unpowered. It’s slightly surprising to me that there wasn’t a more clear direction from FIRST in the game manual on this topic, though it’s certainly too late to add that requirement now.
I’ll be curious to see how events handle this dynamic from both a safety and logistical perspective.
That is what our workshop looks like now. I caught our prototype’s arm a couple of times before it hit students in the head this evening. A student took off the claw and the counter force spring was relieved of a couple of pounds suddenly. I earned my safety ninja mentor badge.
2021 off-season we built a really janky climber arm (it was terrible, only marginally better than the previous climber) for our 2020 robot. It was spring-loaded to deploy and had many issues. Long story short, a couple of us had busted lips by the end of the competition after it deployed itself into our faces.
Curious to hear from some of our FRC historians (largely just people with better specific memory than me) if this has been a historical problem in years with comparable design allowances.
A historical moment in my memory is from 2003, and personally watching the Robowranglers try to diagnose problems of their telescopic swinging arm for knocking the stack of totes from the ramp in the autonomous period.
I’m not sure of the total extension length, but significant to reach across the ramp. Watching from the pits, we saw the robot enable and swing right towards a team mentor at about head level, and without some quick limbo moves they would have taken the brunt of it.
edit: I should note that the cameraman in the picture gives a nice approximation of where your head is in relation to the arm.
I for one do not see this as a problem at all. There will be plenty of teams yelling “ROBOT” at the top of their lungs, so I am confident in my safety.
@ngreen already brought up 2003 spinning arms, but I’ll go back a year further. Back in 2002, there was a team at one of our events that two extendable arms that were designed to grab all 3 mobile goals at once. Think something like Team 71’s famous chokehold-strategy robot (although this was a different team). Every so often you could hear them shout “fire in the hole!” in the pits before the two arms would spring outwards… and into the neighboring pits.
This just sounds like the pits in general prior to 2006 when extension limits were introduced. There were a lot of crazy long reach arms all over the place.
I think most teams will need to retract their arms or else they might risk their robot tipping over and falling off their cart as they wheel it back, which would be even more dangerous. I am less nervous of the extensions themselves than the imbalances that such extensions might create.
I have asked teams to stop shooting game pieces into the aisle so, yes, this is a valid concern.
Edited to add: I have also been hit from behind by a robot cart that was being pushed rapidly down the aisle. I was standing just in front of a pit, conducting a judging interview with the team in the pit. Robots that are extending significantly beyond their frame perimiter while on their carts increases the danger of this sort of thing happening.
