Rule clarification - trailer recessed

Our team was thinking… Is it legal to have a perm. Mount onto your bot but have it recessed in it… The only rule we found was that the trailers bumpers could only touch your bumper( when swinging) but if we perm. Atached it recessed into our bot having our rear bumpers right up against the trailer bumpers… Could we do that??? This would make it more controlable and not swinging around …

This is a question that has been asked a few times. And it needs a clarification from the Q&A to give a proper response.

As a quick note: R18 part D says “outer edge” of the robot.

my team (1307) was thinking the same thing, from what we heard and read, we think that it is doable but that it would rest on the ruling of the judges at the regionals and any other competitions that the robot goes to.

i don’t remember the rule number right off the top of my head, but there is one that states the trailer hitch must be mounted on an outside edge of the robot, not inside it

There is a rule that says that the trailer must be able to swing freely at all times. It sounds like with that idea, it would not be able to swing freely.

You could possibly have a tolerance of an inch or so of swinging (maybe?)
Like not all the way touching but almost. That way it would be technically swining, but also helps in that it only swings a small ammount…

If your robot was U shaped than that “inside” edge would be an outside edge by my thinking.

But the trailer would then be “touching” an edge other than the outside edge. And the trailer seems to be about as long as the robot’s maximum dimensions, so it doesn’t seem to be possible.
Methinks clarification will come with the first update on this rule.

Hence the clarification requirement. Outside edge should have a solid definition

which rule is that? i don’t remember seeing anything like that

corporalchee: that remains to be clarified by the GDC, because that would also technically be an ‘inside’ edge

Just as a general rule, the manual is pretty easy to download so go ahead and wait until you find the rule before posting this. You may restrict someone of an idea on falls information.

Outside edge is well defined under the Bumper rules (last paragraph of Page 3 on the Robot Section). It considers this to bee the POLYGON connecting the outer most vertices. Therefore a robot in a C shape you have the Outside edge of a backwards D

Ok Thank’s woody. That to me more or less makes this idea unworkable.

this is confusing to me C or D ? what

**Edit -**never mind… i get it now… took me a second


BUMPER PERIMETER – the polygon defined by the outer-most set of exterior vertices on the ROBOT (without the BUMPERS attached) that are within the BUMPER ZONE. To determine the BUMPER PERIMETER, wrap a piece of string around the ROBOT at the level of the BUMPER ZONE - the string describes this polygon. The BUMPER PERIMETER may extend up to, but cannot exceed, the maximum ROBOT volume constraints defined in Rule <R11>.

“Outside” is not defined; rather <R18>D says, “D. The Trailer Hitch must be located on an outer edge of the ROBOT structure such that it may easily connect with the tongue of the TRAILER (attached to the TRAILER).”

Thus, the GDC has to be asked in the Forum (when it opens) what “outer edge” in means. I suspect their answer will be, “On the bumper perimeter” - but we don’t know that now.

It probably wouldn’t work even if “outer ege” were to include the inside of a U-shaped robot. Consider this: the last part of R11: The Bumper perimiter may extend up to but cannot exceed the maximum robot volume constraints defined in Rule R11. From what this says, if the inside edges of a U-shaped bot have to have bumpers too, most likely the perimeter wouldn’t sufficiently cover them.

I don’t understand what this means, but it gave me another thought. The trailer hitch, if it protrudes from a flat section of the rear of the robot frame as shown in figure 8.5 of the rules, redefines the BUMPER PERIMETER. That has some very disturbing consequences for the design and placement of your bumpers. (In fact, the bumpers as shown in Figure 8.5 are not legal; the corners of the trailer hitch that would define the perimeter are not protected by bumpers.) I am certainly hoping that the trailer hitch is excluded from the BUMPER PERIMETER.

If the trailer hitch was included in the bumper perimeter, then the hitch would need to be recessed.

My team had the same idea, so thanks for the rule clarification.
Although I had said even without a rule defining this, it seems to be a little (LOT) bit like lawering the rules… For no other reason, I would avoid against this since it isn’t exactly in the spirit of FIRST… imho.

Indeed the Trailer Hitch <R18>, <R08> and <R11> rules do not seem to be in complete agreement.
This will need to be addressed to the GDC. Specifically, I would like to know if the Trailer Hitch will be included in the <R11> maximum dimensions or if it will be excluded.
Once we determine who will be our “Rules Master”, we will ask this specific question.