Many teams have intake systems that reach out beyond the bumpers. This is an important system that appears very much at risk against defensive play.
Say your robot have an intake system out beyond the bumpers and is driving forward and another robot blocks your robot. This could be a high impact collision that could damage the intake system. Rules say that teams can block. Rules also say don’t try to hurt other robots. My sense is if you drive around with your intake out its at your own risk. But I’m not sure. How do others address this situation?
Conversely how to have an intake survive a hit? The obvious approach is to avoid a hit. I expect most team can withdraw the intake. Our team has decided to have a one way operation and just drop the intake down. Another approach is to have our robot drive backwards to that the intake is behind. But still it gets crazy in the matches. So we are planning how to survive a hit. The approach is a flexible polycarbonate structure that has some ability to absorb an impact. I’m not at all confident its possible to absorb a hard hit. Or a self inflicted wound of ramming into a side wall. We are planning on having multiple intake structures to swap out if damage occurs. Disposable intake structure.
Many teams will break intakes. Most teams are not abusive enough in testing their robots mechanisms in such a way as to cause them to fail. I have 5458 drive their robot full speed into a solid wall to make sure their electronics are still good and that it doesn’t break stuff like intakes. You always want a strong intake that can take hits, but usually you can’t get it strong enough and you need to find ways to protect it while playing. Having spares is a great idea, but try to break it on purpose while driving the bot if you can to see HOW it will fail, you might be able to improve it.
You may want to make an upgrade after reading G24. As long as you’re being run into you’re fine but if you’re doing the running into at all you’re at risk. Not counting the whole “damage part of your robot” problem…
I’d be happy to take a look and see if there’s a quick way to get that to be a two-way motion.
Not completely following exactly what questions you’re asking but generally it seems like you’re on the right track.
The most robust and ideal solution is to retract the intake so that all collisions occurs at the bumpers. This not only prevents your intake from breaking but also shrinks your robot footprint allowing you to sneak through gaps and not get entangled. We’ve also found our drivers will drive much more aggressively when they can just ram the bumpers into walls to stop (compare our driving slow or backwards in 2013/2016/2017 vs years we stowed in 2014/2018/2019).
If you can’t retract, or want to survive even while extended, you should
Build your intake out of 1/4" polycarbonate (good mix of stiffness and flexibility)
Use protector plates on exposed belt runs (see our champs 2019 intake) and use maybe also 3D print or make your pulleys have extra large flanges.
Standoffs running across plates should have a decent enough annulus (not too thin of wall) so that they dont cut/bite into the polycarb when shock loaded).
Pivots should probably be at least 3/8" diameter 7075-T6 shafts or alloy steel shoulder bolts.
Don’t use things like drawer slides that’ll just get bent when hit from the side.
Bushings (teflon or Oilite) are probably better than bearings when in low rpm situations such as the pivot point for the intake deploy (not a roller live-axle).
Keep holes in plates small as those are the stress riser locations where the plates will crack.
Other robots with great polycarbonate intakes would be 118 in 2019 or 1678 in 2014.
Lastly, intake roller themselves need to be able to survive hitting something like another robot’s superstructure or the vertical posts of the truss rendezvous point in this year’s field. Consider making rollers out of larger OD steel or polycarbonate tube instead of thunderhex shaft which can easily get permanently bent. If you have the weight and packaging ability putting a “beater bar” such as a 1x1x1/8" aluminum tube on the front of the intake to shield those impacts from more delicate live axles would be good. See us in 2016 for a examples of a square beater bar, could also be round tho.
We ran an intake in 2018 that at the start of the match, the elevator raised, and the intake dropped down staying out of the frame perimeter. It wasn’t locked down so if we drop the arm on the cube, the intake just hinged out of the way. What we ran into though was match 70 at MSC-Consumers Energy. It ultimately got replayed due to field error I believe, so the video seen on The Blue Alliance isn’t actually what happened in this event I’m describing.
We went to intake a cube on our side of the field, and the other alliance had sent 5712 over to defend. During them backing into us to get in our way, they ran into our intake, with the wheels spinning. It launched a panel off their robot, resulting in our intake sucking in a rope hanging off their robot. We got stuck in a pulling match essentially, both teams trying to get free. We resulted with a yellow card and a destroyed intake. The damage done to our robot was almost at the point I remember where we debated stepping out of alliance selection if we couldn’t find a reliable way to get it fixed, the intake was just destroyed, and this wasn’t thin aluminum. It was 3/16" wall, 2" x 4" aluminum tube turned into a C mounted on a 2" x 1" x 1/8" with solid aluminum inserts welded in the last few inches. With the help of 2767 (supplying a reamer, holding lights, vacuums, etc.) , we were able to get the arm, fixed enough to play Qual 77, and replay of Qual 70. We found spare parts in our cabinet from our practice bot that allowed us to rebuild our intake (new C channel, older version of 2" x 1" mounting system, etc.) and allow us to be competitive in the playoffs.
We learned a lesson after that if the part leaves the frame, it needs to come back in.
Do note that when you say “Rules also say don’t try to hurt other robots”, the combination of G24 and G25 basically says “parts of your robot that are outside your frame perimeter can be damaged/destroyed without penalty.”
I think in general teams will try and avoid crashing into deployed intakes at full speed, but if it happens anyway, the rules don’t provide you much support.
Absolutely. Our 2018 robot was so badly planned that the main game component (cube grabber) was designed so horribly that we had to shake it to have it drop. Wasted time, wasted resources, just a horrible intake on an ok robot. The driver that year was so careful to not bump into the walls with the intake (to prevent further demolition of the intake as we worked on it for basically our first competition) that we just became a climber + buddy hang.
Also, a warning about polycarb intakes - don’t use polycarb tubing. You’ll lose the rigidity of aluminum tubing and end up with something that cracks easily when hit. Stick to sheet so your mechanism will actually comply.
We have to drive around with another robot and see how it does. I expect the intake on ours will pop up over the other robot’s bumpers, and cause foul inducing damage to the other robot inside it’s frame perimeter.
My rules for extending outside the frame are you either:
1> Build it so strong that it cannot break (weakness is it’s usually heavy)
2> Build it so flexible that it bends like a reed in the wind (Weakness – it typically isn’t touch it and own it)
3> Build 4 of them, so you can replace it (weakness – it takes up your spare parts allocation)
This year we are building an intake internal to the robot
I can say as a defensive driver last year that you have to be very careful about when your intake is out. I would always play my game while trying to avoid robot damage in the process which caused us to get only one or two fouls the entire season while pretty much exclusively playing on the opposing side of the field last year. However if we found out that your robot couldn’t hold game pieces if rammed we would take the opportunity to let out some hits. I have no idea yet how defense would work this year but I’d be prepared for taking full court full sends from teams who find they can’t score enough. My thought on intakes being out is that it is fine if your drive team is skilled enough to have enough situational awareness and good reaction time to bring it in before it gets obliterated. This year our intake has some beefy pneumatics for this very reason so it doesn’t get destroyed by sitting out too long.
What spare parts allocation?
There is no withholding allowance or any similar restriction I can find in the rules this year.
No bagging or drayage means no way to police this short of rule C5 saying you may only have one complete robot.
I say build in some flexibility and bring spares of anything that could extend out of the bumper zone and or have loads transferred through said parts causing damage like mounts.
I’ve tried to build both “bomb proof” and flexible over the years and the best solution was to engineer in a graceful failure point (read as deforms without failing) where you can easily swap it out between matches if needed. Don’t design in shear pins or things that will disable you mid match.
You can always try to learn how to drive effectively with the back of the robot. If you can station yourself sideways across the rendezvous or use the back end to hit opposition teams, you will not be putting your intake at risk as a defense bot. This does however come with practice, but some of the best defense bots never need to actually hit the other bots, they just need to predict and block a scorer’s path.
Ever since I’ve joined the team we have lived by “touch it and own it”, which leads us to get some serious over bumper intakes. Each year, we’ve made sure to be able to retract it, as when some of the defense gets hot, we can pull our intake in and bump our way past them. This came in especially handy last year with some of our best moments in defense being preceded by the intimidating thwack of our intake slamming back into our robot.
I agree with what you are saying. However, it is completely within the rules to ram full speed into robots, as long as the contact is BUMPER TO BUMPER, or outside the FRAME PERIMETER (G24, G25). There is no “intent” rule on damage caused from an impact on a deployed mechanism. Most such impacts I have seen are caused by poor defensive play. However, I have seen some that really looked like they had intent to damage. While I would suggest that is not playing within the spirit, it certainly is still within the rules.
Given that the best solution is to either be able to stow your mechanism or get it out of the way. One risk with just raising it, is that it might allow you to get inside the FRAME PERIMETER of another ROBOT, before you get BUMPER to BUMPER contact, and that is a G25 on you if damage occurs, and a G24 if you were moving towards the point of contact.