Beware of R16 your robot design may be too big.

[Gary Dillard]

Time to think outside the box, but inside the cylinder.

Why does it have to be an arm? Why does it have to be a rotational joint? You can translate infinitely high. Why do you need something besides your robot's forward velocity to impart lateral motion to the ball? Forward initial velocity plus vertical force equals a trajectory.

[David Guzman]

We had to redesign 80% of our robot because we were about 3 inches out of the cylinder. We hope this rule will be STRICTLY enforced. We also hope that they DO NOT change this rule.

[meaubry]

Yes, this rule does require alot of forethought.

Remember that when slicing horizontal sections, the size of the sphere gets smaller and smaller the farther you get from a centerline section, even though the center point stays in the same location.

Claw radial geometry works best if you keep the pivots as wide as possible.

And after grabbing the ball , you may want to consider doing something with it to get it closer to the robot.

Good Luck all - this one will hurt your brain, but it's all in a good way.

Mike

[OZ_341]

Originally Posted by David Guzman

We had to redesign 80% of our robot because we were about 3 inches out of the cylinder. We hope this rule will be STRICTLY enforced. We also hope that they DO NOT change this rule.

Yes in 2002 we decided against a mini-bot to stay within the entanglement rules. When we arrived at competition, every team with a mini-bot ruled the field.
If they let teams slide by on this cylinder issue, it would be extremely unfair to the teams that are currently racking their brains.

If FIRST is going to change the rule they should do now or make a statement that this rule will be strictly enforced. I know you can't make this statement for every rule in the manual, but this one is a make or break decision for teams.

[Sunshine]

Our team ended up recalculating the size of our chassis after reading this thread . We put the "just to be save" factor into our design. In other words, we discussed "worst case" scenario interpretation of this rule.

We ended up reducing the length of our chassis.

Thanks CD and the CD community. I believe that you saved us major headaches down the road.

[EricH]

Originally Posted by iCurtis

I don't have access to CAD (nor am I any good at using it). However, I broke out my handy dandy pen, paper and google (as I left my trusty TI-84 at school), and tried to tackle the size difference. I am notoriously bad at trig, however, so I could be completely off base, becuase I did not get the answer I thought I'd get. I didn't keep track of my work, but essentially, I drew a rectangle inside an 80 inch diameter circle, with the corners being located on the circle. I assumed a fix robot width of 28 inches, and tried to find how far forward once could extend. The answer I got was 74.9ish inches total. Subtracting the robot length (assumed to be 38") this leaves you with about 37" to play with.

It gets worse...I believe that this is without bumpers. Until someone like the GDC tells me otherwise, the bumpers do count as having to fit into the 80" circle. (Now, they don't have to be the full distance around, so you might be able to get away with these measurements, but I'd check them with bumpers.)

[Nuttyman54]

I (and probably a few others) have posted in the Q&A asking for clarification. (dbell, I used your triangle example, so thanks)

[ALIBI]

Bumpers (R08) are part of the robot (R13) and will be considered in the measurement if located on the robot where the 80" horizontal dimension (R16) maximizes. You can maximize the room available for your manipulator by leaving the bumpers off the opposite side. Right now you can do that without breaking any rules as long as any parts of your robot located within the bumper zone that are not covered by bumpers are within 10 degrees of vertical (R19). In addition, all bump to pass signals (G38) must be made with or against a standard bumper and inside the bumper zone. My guess is that when a team leaves the bumpers off to maximize the 80 inches, it will most likely be what becomes the rear of their robot. In order for another team to signal them to pass, the signaling team would only be able to signal if it had bumpers on the front of its' robot (doesn't make sense to signal from the side, you are all ready past them). At the same time, due to other types of manipulators, I can easily see teams that will leave bumpers off the front of their robots which will make it difficult to signal to pass a robot that does not have bumpers on its' rear. I realize that these are all design decisions and tradeoffs are necessary. You can build a succesful robot within these limits.

It seems like R16 (80" cylinder) and R08 (standard bumpers) are un-necessarily opposing eachother. R08 encourages teams to maximize their use of bumpers and R16 seems to discourage the use of bumpers and may make it more difficult to comply with signaling to pass. Another benefit to bumpers is the protection they provide. You could end up with a lot of exposed hard corners on the rear of many robots.

My ramblings have lead me to wonder whether or not R08, R13 or R16 should be modified to somehow leave standard bumpers out of the requirements of R16. Does anyone else see any wisdom in doing that? If a team has all ready decided to leave the bumpers off to maximize their 80 inches, what harm would changing the rules to allow them the opportunity to add bumpers be? I realize that there may be teams that designed to include bumpers and their manipulator to comply, but wouldn't they like to get another couple inches anyway?

[StevenB]

with a cylinder whose center point is tangent to the ground and has a base perpendicular to the ground you can have a robot of INFINITE length! however it would only be able to go 40cm high and thats a semicircular shape

As jgannon said earlier, the rule clearly does not allow this (80-inch-diameter upright cylinder).

We hope this rule will be STRICTLY enforced.

I would be surprised if this is enforced at all, particularly the cylinder version. The only way to really enforce that would be to catch a robot suspected of breaking the volume, then after the match put the robot in a physical device to measure all the way around the circle - a refereeing nightmare.
Last year's 72" rule was similar, but in practice was only called on robots that had deployed ramps outside the home zone. I saw more than a few arms extending out of the box without penalty.
That said, I don't condone knowingly breaking the rule. GP, rather than the referees, will have to cover this one.

[Gary Dillard]

Originally Posted by OZ_341

Yes in 2002 we decided against a mini-bot to stay within the entanglement rules. When we arrived at competition, every team with a mini-bot ruled the field.
If they let teams slide by on this cylinder issue, it would be extremely unfair to the teams that are currently racking their brains.

Don't EVEN get me started on that one. (Reference any of the dozen threads I have mentioned the mouse bot)

[mathking]

I am going to chalk this one up to a good engineering experience for the kids. We did not pay close enough attention to this, and it turns out one of our two possible lifter designs is an arm which will be about 2.5-3.5 inches too long when it lifts through horizontal. Since the arm design is completely done already, we will have a great ball remover (minus the grabber) if we can't get the other system to work!

On a side note, I do not think it will be that hard to referee this one. If you are designed to lift a ball, they will ask you to demonstrate it at inspection and they can measure then.

While it is giving me some increased blood pressure this weekend, I think this rule will make for some great fun as well.

[StevenB]

On a side note, I do not think it will be that hard to referee this one. If you are designed to lift a ball, they will ask you to demonstrate it at inspection and they can measure then.

Until you do it on the field though, there isn't any penalty. They can't fail your inspection because of it, any more than they would be able to fail you for being able to violently ram another robot. The most they could do is make a list of robots to watch.
It's possible that FIRST would make a rule saying that your robot has to be mechanically incapable of exceeding the size limit, but I find that unlikely.
I can see them pulling out tape measures, but as I mentioned above, that isn't equivalent to making sure to robot fits in a cylinder.

[jgannon]

Originally Posted by StevenB

They can't fail your inspection because of it, any more than they would be able to fail you for being able to violently ram another robot. The most they could do is make a list of robots to watch.

It would make refereeing a lot easier if the inspectors could determine if it is physically possible for a robot to exceed the 80" rule and mark it on the inspection sticker. If I know that a robot definitely can't break that rule, then I don't have to focus on supervising to see if it violates it.

[AndyB]

And even if the robot is mechanically capable of leaving the 80" cylinder area, code can allow for mechanisms to be in the right position at all times. (ie: a double jointed arm)

The manual does not outline a process for checking this violation and it is not in the inspection checklist. As I see it now the rule is way to vague to be able to follow correctly. Hopefully they will respond in the Q&A or in the next team update.

Does anybody recall any penalties handed out for this rule last year?

[emusteve]

I don't recall any being handed out at Great lakes.

For our part, after arriving at competition, we found that the process of deploying our gripper caused us to exceed the 72" rule albeit for less than 1 sec., so we tied up the gripper and in the name of GP (and not wanting to be the source of a penalty) didn't deploy it for the entire competition. We could still run defense, and climb on other bots, so we still did fine, and ended up with the Sportsmanship Award. Went home feeling good about ourselves and the competition.

We fixed it, and had fun at Kettering in the fall.

Steve