How Important are Rings?

Do you have a video of that robot? If so and you are willing to share, I’d love to see it.


I think 5 goals is a bit excessive.

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In addition, just because you can hold 5 gals doesn’t mean you will. Other good robots will also be able to grab and hold goals. Do you really think you will be able to grab more than 3 goals?


If you use pneumatics for the mogo device, you could potentially use a 8 motor drive and gear it up to something like 400 rpm.


Then during auton, you might be able to race towards the center to get goals, and instead of just trying to pick up the goals, you could assume your opponent is going to do the same, and try to plow into their robot in the neutral zone when they go for the neutral goals. Then you could pick up the next goals after you mess them up.

That could be pretty risky though. And again, they could always try to do the same to you, so it’s still not a guarantee.


While yes, there’s no motor penalty to use pneumatics, there’s still a penalty that I feel many people are handwaving:

You still have to design a pneumatics system into your robot.

This includes mounting the tanks on your robot, mounting the solenoids on your robot, routing hoses, interfacing the cylinders with the rest of your robot, troubleshooting any leaks that you have (or may come up mid-season)… plus you have no compressor - which is huge.

Plus don’t forget that tanks and cylinders are made from stainless steel. There’s a lot of brass in a pneumatics system too. Stainless and brass are heavy materials, which will weigh down your robot.

Let’s also not forget something that even I was surprised by: A lot of tribal knowledge teams had regarding pneumatics has been lost. When was the last time you used pneumatics? When was the last time you used pneumatics with V5? Regaining some of this knowledge may take a non-trivial amount of time.

The race to grab a neutral goal requires you to drive out toward the center of the field. Speed and acceleration are going to be huge for robots that want to win every race. The heavier your robot weighs the slower you’ll accelerate. Want to add more motors to your drivetrain to overcome the weight of your pneumatics system? Well, now you have fewer motors to use elsewhere on your robot for things like scoring rings, lifting goals, lowering platforms, etc.

Yes, you can use unlimited cylinders - but you are limited to the number of actuations you can make since you can’t recharge your pneumatics with an onboard compressor. So it’s not unlimited free energy. Compare this to a V5 motor, which given the current motor usage limits and the V5 battery performance effectively gives you consistent, unlimited usage during a match.

During the 393-era there was a substantial difference in the amount of power a pneumatic cylinder could provide vs. (1x) or even (4x) 393 motors. This was especially true when you factored in PTC limitations and the performance of the battery. This is why the trade off was important.

VRC hasn’t really had a “dodgeball line” mechanic to start a match. The closest parallel I can think of in the robotics world would be the “Can Battle” at the start of a match in FRC’s Recycle Rush.

A lot of teams used pneumatics to deploy their “Can Grabbers”. However, some of the fastest didn’t use pneumatics and actually used motors. Why? Because motors were able to overcome their startup torque and reach full speed faster than the pneumatics system could trigger the solenoid to release air and fill the chamber in the cylinder. We’re talking fractions of a second, but in a race where everyone is basically the same, that’s critical.

Will teams use pneumatics to grab goals this year? Absolutely. It’s a great solution. Is it the only fast solution? No. Once teams start advancing this season and everyone is grabbing goals at basically the same speed teams may start looking at alternatives to give themselves an edge in the race.


The $200 cost per team?


I am curious about the GDC’s game design process. Clearly the GDC designs the game elements to (nearly) work with the basic claw-bot, and the GDC (presumably) creates that year’s “hero robot” as a minimally viable robot for the game. It seems they also consider, to some degree, what advanced teams may choose to do; I’m curious to what degree this happens.

(Honest question, please don’t read any snark into this) Does the GDC physically play the game during the game development phase? If so, does it do so with different “level” of robot quality?


That is actually a very good question that I’ve always wondered as well. Just guessing … yes, they play the game a bit, but with relatively simple robots. Maybe Moby?

Another problem that we are running into is the platforms. The material on top is already starting to bend. Also with some of the bigger robots if you hit the platform only slightly off center - toward the middle of the field - the whole platform pulls up from the tiles as it twists because it is only held down with one standoff to one of those small circle plates under the tiles (I’d like to use the larger/heavier square bases that were used in Tower Takeover).

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all of these issues with the platform are another reason I’m more interested in lifting goals onto it from the side than I am in coordinating a park on it. All the little flaws could add up to make parking unreliable from field to field, especially later in the season when platforms have seen a lot of use.


Yes, there’s a cost. However, I was focusing my post more on the claims that there are no tradeoffs to use pneumatics and that you have to use them to be competitive. That’s not the case. There are legitimate robot design tradeoffs involved with using pneumatics and the tasks many people here are talking about using pneumatics for can be accomplished without pneumatics.

Since you can still play the game, and be competitive, without pneumatics the cost of the pneumatics kits is moot. If there was a part of the game that you absolutely had to use pneumatics for, then discussing cost would be more relevant.

It happens a lot, actually. At a high level, we want a game to be exciting at various levels of play (local events / state champs / worlds). At the same time teams of various skill levels should be able to contribute to a match.

If you’re a team that built a clawbot or hero robot and the robot couldn’t contribute a single point to a match - how inspired do you think you’d be? On the other hand, if you’re a high performing team, how inspired are you going to be if the game isn’t challenging?

Game design is a careful, multi-dimensional balancing act.

The field elements and game objects are tested and played with at various points of the development phase. Sometimes this is formal testing, sometimes it’s informal testing, sometimes it is playing through matches or match scenarios and talking through concerns. For example:

  • In TP there was a test setup that toggled flags with a ball to find when/if the printing would rub off the flags or when the toggle would wear out.
  • Early in the Pitching In development we noticed that resetting the center goal was really difficult, especially if the field was elevated off the floor. This was addressed to make it easier.
  • The TT scoring rules were developed after playing with different ways of stacking cubes and figuring out which cubes we wanted to count and which we didn’t, and how to define the ones we did want to count.
  • At one point the alliance goals in TiP looked just like the small neutral goals. Along the way we became worried that a robot stealing its opponent’s alliance goal would accidentally de-score rings, which would lead to a DQ and a “feel bad” moment for just playing the game. This led us to change the goal to be a single post instead of a tree.

While we do test games, it’s foolish to think that the GDC will figure out every possible idea teams are going to come up with. There are hundreds of thousands of people creating solutions to these games and a much much much smaller group of people designing them.


How would you get the platform to balance without having a robot on it though? I haven’t gotten my hands on the field elements yet but in the videos I’ve seen it looks like the platform tips very easily. Wouldn’t dropping a 3-4 pound goal on top of the platform cause it to tip, leading all the other goals to slide a bit in that direction too? I say “drop” because of the 2" walls on the side of the platform which make it difficult to simply place the goals up there. Again I don’t have the field, just speculating, but I feel like at least by having a robot up on the platform you can actively shift around weight in order to get it to balance. Otherwise I think you’re gonna have a hard time perfectly placing all the goals so that they counterbalance each other.

the platforms are actually quite forgiving,

you can put the goals quite far to one side and the platform stays balanced.


It would be really nice if Vex posted something like @Golf ’s field tour. That way we could all see the individual parts of the field. Either that or a match played. Maybe next year…


Don’t know why I remembered it being a lot wobblier than that. But even so, if you start by putting one goal to the right of the center of the platform in a way that it stays balanced (like in the video), then you can put a goal to the left of that (and it will stay balanced), but as soon as you try to put another goal to the side of either of those first 2 goals, the platform will tip since the third goal would be even farther from the platforms pivots than the first 2.
Then again there are ways to work around this, like if one bot can lift up the platform while the other bot puts a 4th goal on the opposite end to rebalance it. And this is only an issue if you’re able to get 2 neutral goals in the first place. With an odd number of mobile goals you could just start from the very center of the platform and then go adding one mogo at a time on each side, and it would probably stay balanced.

TLDR: I still have no idea what the meta will be and am just posting my thought process at this point


True, but it is not only about the total available power - the number of degrees of freedom (i.e. how many independent actions you can perform) is also very important.

Yes, for a design where there is only one place/action that needs constant speed and power, motors are the way to go, but not for the designs that may need four independent claws - it would be very wasteful to dedicate whole motor to open and close each.

Motors cost 1/8th of your total available power, but incremental cost of adding an extra pneumatic cylinder is much lower and totally makes sense, if you only need to actuate it once or twice in a match.

Yes, there might be a way to trigger a passive claw lock, and if the ability to open and close it at will is strategically important, you can even try to make some sort of fancy power takeoff with ratchets or differentials and bring that power to the end of the rotating claw with complex geartrain, or some clever ropes and pulleys…

However, based on what I’ve seen in previous seasons, the reliability record of such complex systems is not that great.

And, also, controlling pneumatic cylinders from software is so much easier than trying to implement bump resistant mechanical AND-gate with levers.

There may be a handful of teams that can pull off this kind of mechanical wizardry, but I just cannot imagine any serious team, that made it to the dome, entrusting their fate to a Rube Goldberg machine look-alike vs something that has a working track record.

That is a very strong argument. But, if the winning strategy calls for the multiple degrees of freedom to handle multiple objects and functions, then it doesn’t matter if your robot is lightest and fastest, if it cannot fulfill the rest of the functions required to win the game (and relying on random partner to do them is iffy).

However, if you already have pneumatics, it may make sense to start with 8 motor drivetrain and shift some motors into the secondary functions after the initial sprint or as necessary, rather than dedicating motors to those functions or using ratchets and differentials (which add extra weight as well).

It is, probably, more like $400-500, because it looks like you will need 4-6 cylinders (or more) to handle variety of necessary actions in this game.

Once again, this all depends on the number and type of independent actions that are required for the winning strategy. And, as of right now, the best publicly known strategy calls for multiple small, infrequently performed, actions - which heavily favors pneumatics even if there was a one motor penalty for each air tank used.

Maybe, later in the season, somebody comes up with a better strategy. But right now it looks like the future champion robots will need to start with 6-8 motor drivetrain, potentially shift some motors out, have independent locks on multiple mogos (4), be able to lift them, and then be able to collect and score rings as well. (Rings are important, as OP says :slight_smile: )


Not as important as you think. If this were the case, we would have seen more teams using pneumatics in the past when the rule was 8 motors + no pneumatics or 6 motors + pneumatics. There’s definitely a minimum number of degrees of freedom and I’m not sure where that number is, but power is still king.

Especially if you consider that in the past, had you decided to go 6 motors + pneumatics the extra DoF you’d gain would have diminishing returns. Since every actuation releases pressure from the system each time you actuate you have less and less force until you eventually don’t have enough force to move your mechanism.

I think you’re exaggerating what these locks would look like a little. There are lots of examples of semi-passive locks out there. Is this something any team could make? No. Is it something that only a handful of teams will be able to do? No.

Every year I’m completely blown away by the passive/semi-passive mechanisms teams come up with to make their robots fit in the sizing box, give their robot an extra actuation, etc… VRC teams are actually extremely creative in this regard, I would argue, more so than teams in other competitions.


I think the concern is that free pneumatics (yes yes, it’s not infinite free power, but it is still a very useful and powerful system that can now be used with no penalty other than ones inherent in the system) will replace these ingenious and very limited passive actuations.

while passive mechanisms are still going to be viable and are a great way to get extra power and actuations out of a limited robot, pneumatics are undeniably a more powerful and versitile way of achieving actuations than some sort of purely passive mechanism.

Is that neccesarily a bad thing? I don’t know. But I do know that it is more expensive, which is my main issue with the free pneumatics change. It’s pretty clear what the gdc’s stance on the matter is, but for what it’s worth I’d much rather be given a choice between pneumatics and one extra motor than to choose between the superior but expensive pneumatics, or the alternative of no additional power. Which isn’t that big an issue for me personally, but I think that pneumatics simply won’t be in the budget for so many teams, and because of that they are inherently going to be more limited in terms of robot power than other teams.

Also I just thinkl balanced choices are a great way to foster thoughtful design decisions, every team could be able to come up with their choice based on their engineering process and their org’s limitations, instead of just going with the obvious “yes, more power” or perhaps “we don’t have pneumatics, and we aren’t going to buy them, I guess we’re not using them”.

And yes, pneumatics are not an all-powerful tool that will make or break a team’s season. They aren’t good at providing large-power or frequent actuations because of the limited air, but all the low-frequency actuations you can do with them will certainly make a difference in a team’s competitive ability, especially with a game like tipping point with so many possibilities for actuating robot mechanisms.

the idea of sacreficing 2 motors for pneumatics in the past few years has been laughable, not only because you’d lose a ton of available power, but because the past few games has not really had many uses for pneumatics that would be work giving up any motors for. Change up was so simple that a 4 motor robot could play it, there was no need for anything pneumatically powered at all. And tower takeover might have benefited from pneumatic actuations, perhaps with cube locks or other clever mechanisms, but it was also a very power-demanding game, and teams couldn’t afford to lose 2 motors of power.

The reason you can’t compare the tradeoff of previous years to this year is because yes, power is king. But we’ve just been given both full power from motors, and the versatility and actuations from pneumatics with no tradeoffs, and I think the effects of removing any sort of tradeoff will be largely negative, especially among teams that would rather not use pneumatics (either because of price or preference)


But there are tradeoffs, but they’re not in the form the community is used to.

Let’s go back to FRC for a second:

  • In FRC there is no motor penalty for using pneumatics.
  • In FRC the tradeoff is having to design pneumatics into your robot, the weight of the various components, and the cost (which is far more expensive than cost in VRC because of various components FRC requires that VRC does not).
  • In FRC, there is no limit to the amount of air you can store, the number or size of cylinders you can use, and you have an on-board compressor to make sure you have enough air for an entire match. All of these should make pneumatics more attractive to teams.

However, there’s been a growing trend over the last 5-7 years where teams are choosing to NOT use pneumatics. Why?

  • Pneumatics are heavy and overall teams have been trending toward smaller and lighter robots. There’s only so much weight you can remove from a pneumatics system. At the end of the day, if you’re using pneumatics in FRC, you’re dedicating at least 5-10 lbs of your weight budget to it.
  • For many teams pneumatics are problematic. It’s very difficult to build a pneumatics system that does not leak air. These air leaks can be catastrophic if you’re relying on pneumatics for a mission critical part of your robot. You leave your pit full of air, you walk to your match, there’s a delay (maybe two) and next thing you know you’re down 10-20% of your air. Yes, you can recharge during a match, but this means you’re running an extra motor which means there’s less power from the battery available for your other motors.

@technik3k mentioned how a team with dome aspirations wouldn’t bet their season on a Rube Goldberg mechanism. Imagine betting your season on a hose not being cut straight, or a bad teflon tape job on a fitting, or a hose that got pulled out during a match.


While in first the extra weight might be an issue, it is less of an issue in VRC. FRC has a weight limit, and VRC does not.