As per R402, it seems like we can have different height bumpers, as long as they’re all below 7.5", correct?
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You are correct, as long as they are in the zone.
The side bumpers could even angle up to meet the high bumper if you wanted.
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But could I have my bumpers on an actuator?!
Up and down isn’t relative to the frame perimeter if frame perimeter is always a horizontal plane. It is for the argument of extending mechanisms. Up and down might not be covered because of the wording used. Might be worth a QA to clarify. The first part of “Bumpers shouldn’t move” I think rules that out though even if the second half is more specific.
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Yes you can funnily enough! glad you asked!
So yo need to be careful with the rules here because everything is measured relative to the frame perimeter. But if you frame perimeter moves relative to the drive train and the bumpers stay in the zone you are fine! (this is the same way jumping robots work. )
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So basically you can have your FRAME PERIMETER on an actuator, with the bumpers securely attached to the frame perimeter. But you can’t have an actuator connected to only the bumpers themselves.
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Not quite as you worded it, see R101.
I would use more words, just more verbose for the sake of matching the rules. But you captured the core concept.
I would put a frame perimeter (basically a frame and bellypan with bumpers) down , then have an internal subframe with the drives (and whatever else) the subframe move relative to the main frame.
Yes it is semantics , but the wording does matter to work well with the rules.
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People need to remember that the FRAME PERIMETER (as defined in R101) is not the same as a ROBOT’s frame (undefined but generally understood term). The FRAME PERIMETER is measured as the maximum extent of any parts of the ROBOT in the BUMPER ZONE. It doesn’t matter if those parts are considered to be what we commonly refer to as the “frame”. Often it is the same, but it doesn’t need to be. The FRAME PERIMETER is fixed. And the BUMPERS must be attached to the entirety (this year) of the FRAME PERIMETER (R401).
“Frame” parts can extend beyond the FRAME PERIMETER like any other ROBOT part, subject to extension limits for the year. And “frame” parts could move up and down, as long as that doesn’t cause the BUMPERS to move outside the BUMPER ZONE.
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To be clear, R101 (FRAME PERIMETER must be fixed) doesn’t give any option for the shape of the frame perimeter changing.
However, the difference between:
- “the frame perimeter moved with respect to the rest of the robot”
or
- “some internals of the robot moved with respect to the frame perimeter”
is going to be a call made by the LRIs at your events.
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Fortunately I have not had to escalate beyond a LRI, in fact I have had a pretty great experience overall with inspectors.
I will say there are some inspectors (and teams! ) That have preconceived notions of how rules work. The frame perimeter is the staring point for everything robot related, it is the root object that everything is attached to. This can make some laughable situations due to lack of definitions. I.e. use the old racing trick of running a thin wire around the robot over large gaps and calling it the frame perimeter.
To your point: be prepared for how people view the rules and their interpretation to be different than your own. Know the rules and have the relevant rules/definitions laid out and how they apply if you are going to do something weird.
Guys, R101 is very specific and has not changed for a while.
R101
*FRAME PERIMETER must be fixed. The ROBOT (excluding BUMPERS) must have a FRAME PERIMETER, contained within the BUMPER ZONE and established while in the ROBOT’S STARTING CONFIGURATION, that is comprised of fixed, non-articulated structural elements of the ROBOT. Minor protrusions no greater than ¼ in. (~6 mm) such as bolt heads, fastener ends, weld beads, and rivets are not considered part of the FRAME PERIMETER.
The bumpers must be attached to the FRAME PERIMETER and additionally, they must remain in the BUMPER ZONE and not move per R402 and R403. They do not have to be parallel to the floor and all segments do not need to be at the same height, but all segments must be in the Bumper Zone. As always, the Bumper Zone is evaluated as if the robot is standing on the floor per R402.
As a help, there is very few changes to the Bumper Rules section. One is that bumpers must cover the entire FRAME PERIMETER with no more than a 1/2" gap between segments. Corner only bumper designs are not legal for the 2024 season. There is a minor change in Fig 8-8. It does not change the rule just the Fig. Gaps of no greater than 1/4" to allow for weld beads and bolt heads remains legal as in the past.
The Bumper Zone is established so that robot to robot contact is always at the height that allows bumper to efficiently protect every robot on the field.
And please, (your inspectors and audience plead with you) follow R405 and have your bumpers match the alliance colors Red and Blue.
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Two schools of thought here.
-
IF the bumper in question is fixed, though higher, is it legal? The gap rule is relegated to the distance between bumpers…not about the height distance (aside from the ground) between bumper set.
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The other side is why not raise all sides to the same level?
- Yes. So long as the bumpers are fixed, and all within the bumper zone, there is no rule stating that they have to be at the same height. One segment can be higher or lower than the segment next to it.
- I suspect it has to do with game piece control. A high bumper on one side would allow a game piece underneath it, putting it in a position where you could manipulate it without exceeding your frame perimeter. Other bumpers being lower means that game pieces couldn’t enter from those sides, which would be useful if your manipulator couldn’t interact with them from that angle, or if you were worried about them getting stuck if they entered from those sides.
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Piggybacking onto Al here, the confusion is likely in how rules like G413 are typically written.
FRAME PERIMETER has a definition that can be found in the R101 and in the GLOSSARY.
G413 should probably be written like G417. In G417, the explanation is:
A ROBOT may not use a COMPONENT outside its FRAME PERIMETER (except its BUMPERS) to initiate contact with an opponent ROBOT inside the vertical projection of that opponent ROBOT’S FRAME PERIMETER.
We get so used to that idea of the “vertical projection of the ROBOT’S FRAME PERIMETER” that we start to view the FRAME PERIMETER as that projection itself.
Given the way G413 is written (and past year’s are the same), there really should be less than 1ft allowed on the horizontal plane. Any vertical difference forces us to look at the hypotenuse to determine what the extension from the FRAME PERIMETER is. Given it’s historically not been called this way, I wouldn’t expect it to be this year. But, it’s an odd inconsistency in the rules that also helps lead towards the confusion in this thread.
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Jeff, I got a little confused by that last paragraph. R102 gives a method for determining projections outside of the FRAME PERIMETER. The GDC has answered this issue several times in the past. The vertical projection of the FRAME PERIMETER extends to infinity and the only modifier is R105 which changes year to year based on game challenge.
Al! R102 discusses STARTING CONFIGURATION. In that rule, it explicitly states “no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER…”
It works well for inspection and for the start of a MATCH. It also includes what it would see as minor protrusions that can be an exception to this requirement.
G413 discusses expansion limits. For part A, it has “as measured when it’s resting normally on a flat floor” to allow for the height measurement to be relative to the ROBOT instead of changing as the orientation changes. That all makes sense.
For part B, it states “it may not extend more than 1 ft. (~30cm) from its FRAME PERIMETER.” Keeping in mind the black text supercedes the blue box when the two aren’t in agreement, the blue box here is measuring in a different way than the rule is explaining. By not including the same language we see in R102, the extension may not be more than 1ft from the FRAME PERIMETER. The blue box shows designs that extend 1ft from the vertical projection of the FRAME PERIMETER instead. The B example in the blue box is definitely more than 1ft from the FRAME PERIMETER, while not being 1ft from the vertical projection of the FRAME PERIMETER.
The lack of a mention of the vertical projection in rule G413 is awkward (and really should be corrected IMO)
I had this same thought too.
I really wanted to post watch rule R408C (the blue box) too with this design, make sure you are not intentionally creating a ramp effect doing this.
And to your second point, excellent place for an intake inside the frame…IF that was the goal for the intentional “opening”.