Fasteners extending outside the FRAME PERIMETER [Archive]

martin417

24-01-2010, 16:50

I plan to have this question posted on the Q&A, but thought I would ask the CD community as well. What do you think?

<R16> During normal operation no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER, except as permitted by Rule <G30>.
Note: This means no “mushroom-bots.” If a ROBOT is designed as intended, in normal operation you should be able to push the ROBOT (with BUMPERS removed) up against a vertical wall, and the FRAME PERIMETER will be the only point of contact with the wall.

In the past, there have been allowances for fasteners, ie: bolt heads, rivets, etc used as fasteners for holding parts of the robot together, have been allowed to extend outside the FRAME PERIMETER. Will that be the case this year, or are teams required to design their robots so that all fasteners are flush with the frame?

engunneer

24-01-2010, 17:02

In the past, there have been allowances for fasteners, ie: bolt heads, rivets, etc used as fasteners for holding parts of the robot together, have been allowed to extend outside the FRAME PERIMETER. Will that be the case this year, or are teams required to design their robots so that all fasteners are flush with the frame?

you need to adjust the placement of your end quote tag

Also, I don't recall there being a provision allowing fasteners outside the 28x38 footprint. Can you point to a Q&A or rule from the past? If your fasteners are outside the 28x38 size limit, you won't pass inspection. If your robot expands to play the game outside of that limit, then you are no longer in NORMAL CONFIGURATION per the rules.

We've certainly played the game before where we had to shave 1/8" off the robot to fit in the box. Switching from hex head to flat head bolts/screws can help you a lot in a pinch.

silv940

24-01-2010, 17:09

I plan to have this question posted on the Q&A, but thought I would ask the CD community as well. What do you think?

No, they slide a bar that checks to see if you robot is in compliance. If a bolt is sticking out and the bar hits it, you don't pass. You would have to shave the bolt or take it out so that the bar can slide freely. They will make you shave off as little as 1/32 if the bar doesn't slide. They haven't allowed allowances since we joined FIRST in 2005. We keep our robot at 27 1/2" by 37 1/2" to allow for bolts.

MrForbes

24-01-2010, 17:12

They check the overall size (by sliding the bar across the sizing box), so if ANYTHING exceeds the 28 x 38" limit it will not pass.
But last year they had a QA response that allowed fasteners to fit into small cutouts in the bumper, and be outside the frame perimeter

We make our robot an inch small on each side...it always grows!

IndySam

24-01-2010, 17:39

Teched3

24-01-2010, 17:59

If you have protrusion on the exterior of the frame, I believe that rules (IMO) intention is to allow you to provide clearance so the bumpers will fit solidly against the frame. Your robot must go into the sizing box and pass. Make your frame smaller to ensure it will pass with protrusions.:) :)

engunneer

24-01-2010, 17:59

Thanks for clarifying that. Your interpretation that the head of a bolt can be outside the frame perimeter appears to be correct, as long as there is a small clearance pocket in the bumper backing.

It may be worth it to Q&A this for heights not contained in the bumper zone.

martin417

24-01-2010, 18:01

you need to adjust the placement of your end quote tag

Also, I don't recall there being a provision allowing fasteners outside the 28x38 footprint. Can you point to a Q&A or rule from the past? If your fasteners are outside the 28x38 size limit, you won't pass inspection. If your robot expands to play the game outside of that limit, then you are no longer in NORMAL CONFIGURATION per the rules.

We've certainly played the game before where we had to shave 1/8" off the robot to fit in the box. Switching from hex head to flat head bolts/screws can help you a lot in a pinch.

Not sure about your comment on the end quote tag, the entire question I plan to ask on Q&A is inside the quote, and nothing else is....

But as to the rest, I said FRAME PERIMETER, I said nothing about exceeding the maximum dimensions of 28" x 38"

What I was talking about was the parts used to hold the frame together. If I built a robot that was constructed of 12" long pieces of aluminum channel, mitered at the corners, the frame perimeter would be 12" x 12". If I held those pieces of channel together with screws, and those screw heads protruded above the surface of the channel, they would be outside the FRAME PERIMETER. I cannot cite the reference, whether robot rule or Q&A (I don;'t have time time to go look) but there was a specific note last year about fasteners outside the frame perimeter being allowed. I know this to be true, and our robot had such fasteners, and passed inspection at Peachtree, Palmetto, and championships. I just want to be sure the same allowances are in place this year.

martin417

24-01-2010, 18:38

The question is not outside the robot max size but outside the frame perimeter.

because of this being allowed again this year

<R07> D. Each BUMPER segment must be backed by a piece of ¾-inch thick by 5-inch tall piece of plywood. Each piece of BUMPER backing must be a minimum of 6 inches long. Small clearance pockets and/or access holes in the BUMPER backing are permitted, as long as they do not significantly affect the structural integrity of the BUMPER.

I would assume they will allow some protrusion again this year.

Since the frame of the bots this year will likely be quite tall (the bumper zone starts at 10" off the floor), the bumper zone is relatively small in proportion to the height of the bot. My concern is with fasteners in the current design that are below the bumper zone. No pockets in the bumper backing will be required to clear the bolt heads, but they are ~3/8" above the surface of the frame, therefore, by strict interpretation of <R16> would be in violation. I will need to see a ruling from the GDC.

MrForbes

24-01-2010, 18:47

My experience with the sizing box in 2008 makes me want to build the parts that are below and above the bumper zone to a size at least half an inch smaller than the bumper part of the frame.

Something about the sizing box not having a level base. We checked it. Not something you want to have to deal with.

mikelowry

24-01-2010, 19:03

I just asked the question on the Q&A.

sanddrag

24-01-2010, 19:15

martin417

24-01-2010, 20:13

It seems to me that if you have a fastener head sticking out of a frame member, then that fastener head now defines the frame perimeter. If you wrap a string around your robot and over the fastener heads, and it is more than the allowed dimensions, you are in violation. Why even take the chance? Build it smaller.

I don't understand the difficulty people are having with this question. I clearly stated that the question did not involve extending outside the allowed NORMAL CONFIGURATION (28" x 38"). And the definition of FRAME PERIMETER IS CLEAR:
"To determine the FRAME PERIMETER, wrap a piece of string around the ROBOT at the level of the BUMPER ZONE (emphasis mine) I also stated that the protruding bolt heads are below the bumper zone (again, well within the 28" x 38" requirement) so no, the bolt heads do not define the FRAME PERIMETER. I have been through inspection, and understand clearly how size requirements are tested.

I do know that in the past this allowance has been made and wondered if it would be again.

Al Skierkiewicz

25-01-2010, 08:50

Martin,
The language is the same as in previous years. The frame perimeter includes the bolts and whatever else may be sticking out of the robot frame. It is this size that is determined to be within the robot sizing parameters when in the box. The rules for pockets in the bumpers is the same as well. It allows teams to make small holes in the back of the bumpers to accommodate secure mounting of the bumpers to the robot frame without the added clearance provided by fasteners.

The full definition is this..
FRAME 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 FRAME PERIMETER, wrap a piece of string around the ROBOT at the level of the BUMPER ZONE - the string describes this polygon.
As further explained here...
<R16> During normal operation no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER, except as permitted by Rule <G30>.
Note: This means no “mushroom-bots.” If a ROBOT is designed as intended, in normal operation you should be able to push the ROBOT (with BUMPERS removed) up against a vertical wall, and the FRAME PERIMETER will be the only point of contact with the wall.

Therefore as I interpret the sum of rules, the bolt heads that are in the bumper zone define the frame perimeter and any other projections outside the bumper zone cannot extend beyond those set by the frame perimeter except as applied in <G30>.
Hope this helps.

Vikesrock

28-01-2010, 17:53

I was hoping the GDC would be rather speedy in responding to this question as it affects our frame design as well.

As it stands our upper frame is 26.5" wide. The lower frame is the same width, but the bolt heads for the wheel axles will protrude from the lower frame. In prior years this would not have been an issue as the bumpers were at the height of the lower frame and could have a clearance hole drilled in the back for each bolt head.

With the rules as they stand now, it seems like there may be a quick fix if the GDC comes back saying that fastener heads outside the Frame Perimeter at a non-bumper zone height are illegal. You could put identical fastener heads protruding from the frame members supporting the bumpers and drill clearance holes in the bumper for them. These fasteners would redefine the frame perimeter to a size large enough to cover the fastener heads on the lower frame.

Al Skierkiewicz

28-01-2010, 18:17

Vikesrock

28-01-2010, 18:28

Kevin,
If it helps, bolt heads have always been tested with the box. If in the past you drilled out the back of the bumpers as allowed, the frame perimeter was still set by the maximum dimension of the bolts.

The obnoxious part is that the axle bolts for many teams this year are not in the BUMPER ZONE and thus do not set the FRAME PERIMETER. If an upper frame supporting the bumpers and a lower frame supporting the wheels are the same width and the upper frame has no protruding fasteners the axle bolt heads on the lower frame will be outside the FRAME PERIMETER and will violate <R16>.

I was suggesting that a simple workaround if these lower fasteners are not declared legal through the Q&A may be to have identical bolt heads in the level of the BUMPER ZONE so they redefine the FRAME PERIMETER as you mention in your post. This vertical projection of this larger FRAME PERIMETER would enclose the axle bolt heads preventing the <R16> violation.

I'm hoping the GDC makes all this moot with an answer to 1771's Q&A, as this workaround is more like a loophole

GaryVoshol

28-01-2010, 19:24

Kevin,
If it helps, bolt heads have always been tested with the box. If in the past you drilled out the back of the bumpers as allowed, the frame perimeter was still set by the maximum dimension of the bolts.

Al, are you confusing FRAME PERIMETER and NORMAL CONFIGURATION? Normal configuration is the size that has to fit in the box, bolt heads and all.

The FRAME PERIMETER is a subset of that, the polygon defined by the string stretched around the robot at the BUMPER ZONE level. Even if the FRAME PERIMETER is only 20x30", nothing is supposed to be wider than it, not even a bolt head, whether that is outside 10-16" off the ground. Even if it would fit in the sizing box.

Now, are you going to be measuring for that? So the 1/4" extension of a bolt causes the robot to fail inspection? Or are the inspectors and refs only going to be eyeballing it?

artdutra04

28-01-2010, 19:45

The least nitpicky and anal retentive solution to this would be for the GDC to allow static (non moving) fastener heads to stick out no more than 0.25" from the FRAME PERIMETER, as long as they still fit inside the sizing box. This meets the spirit of the rule of the FRAME PERIMETER (it's not like having a button head stick out an 1/8" from the FRAME PERIMETER, but still within the NORMAL CONFIGURATION, will give that team magical super powers or some unfair advantage) while allowing leeway for teams that can't/won't buy flat head bolts and a countersink tool.

The GDC has been getting better about these kind of situations lately, with relaxed tape rules, relaxed pneumatic rules, etc so I'm hopeful this will be the outcome here.

I was suggesting that a simple workaround if these lower fasteners are not declared legal through the Q&A may be to have identical bolt heads in the level of the BUMPER ZONE so they redefine the FRAME PERIMETER as you mention in your post. This vertical projection of this larger FRAME PERIMETER would enclose the axle bolt heads preventing the <R16> violation.If GDC is fervent that the FRAME PERIMETER means the FRAME PERIMETER and that means absolutely no exceptions whatsoever, not even for fastener heads, then this is exactly what we are planning on doing: just installing dummy bolt heads to redefine the FRAME PERIMETER. Fine, we'll jump through your hoops and sit and play dead, but we won't enjoy one second of it.

Rich Kressly

28-01-2010, 19:54

As an aside, and as a general rule, we always design out robot to be at least 1 inch smaller than max footprint in all directions, allowing for any covers or fasteners, or stuff that may happen later.

The thing that would make this easiest this year would be to design the "lower" part of your frame to be a little smaller than the "mid" or "upper frame" that your bumpers attach to.

DonRotolo

28-01-2010, 20:01

Thank you Rich. Our design has the 'lower' frame (at wheel level) just a bit smaller than the 'upper' (bumper zone) frame, about 1/2" on all sides. The upper frame is just under 27" wide.

The simple solution is not adding dummy fasteners, but a 1/4 (or 3/8", whatever) strip along the outside of the frame perimeter. Nothing says it can't be birch plywood (lightweight) strips.

In theory, the lower frame could be as much as three inches smaller, eh?

Al Skierkiewicz

29-01-2010, 07:57

Gary,
I believe, as you suggested, that the FRAME PERIMETER in the strict definition is the outside of the frame including any fasteners in the bumper zone. It is those dimensions that would also define the extent to which fasteners and other parts can extend out from the robot body because that now defines the NORMAL CONFIGURATION. I think it will be fairly easy to tell with the robot in the sizing box with no bumpers. As the rules allow clearance holes and pockets in the backing of the bumper (R07, D), I believe the GDC is allowing the fasteners and therefore the FRAME PERIMETER to merge with the inside of the bumper as they have in the past. Depending on individual design, it may be necessary to have a team rotate their robot to test all sides to insure compliance with these rules as the sizing box really has only two solid sides.

martin417

29-01-2010, 09:14

Everyone keeps focusing on the sizing box. This question has nothing to do with the max legal size for NORMAL VOLUME. Only with frame perimeter. The sketch below is of a 12" square bot, which could never have issues with the sizing box. However, as the rules currently read, is not legal. Since we have not yet recieved an answer, the only alternative is to desigh the bot so that this does not occur. If this is truly illegal, I would expect a great deal of trouble for some teams at inspection this year.

http://picasaweb.google.com/mwilson417/Robot2010#5432165905013862322

thefro526

29-01-2010, 09:21

Everyone keeps focusing on the sizing box. This question has nothing to do with the max legal size for NORMAL VOLUME. Only with bumper perimeter. The sketch below is of a 12" square bot, which could never have issues with the sizing box. However, as the rules currently read, is not legal. Since we have not yet recieved an answer, the only alternative is to desigh the bot so that this does not occur. If this is truly illegal, I would expect a great deal of trouble for some teams at inspection this yer.

I read through the discussion here and we ran into the same problem last night which resulted in us narrowing our chassis by about .5".

Now that I've thought about it more, I think that there should be some sort of concession made for bolt heads extending outside of the frame perimeter, but within the maximum sizing volume. I know the last two robots we've built on the C-base had bolt heads extending outside of the frame perimeter and I'd assume most teams using it this year would have the same issues...

Hmm.

Al Skierkiewicz

29-01-2010, 09:40

Martin,
As I look at your drawing, there are no fasteners in the bumper zone and so those dimensions (12 x 12) become the FRAME PEERIMETER. Therefore the fasteners at the bottom of the chassis extend beyond those dimensions. If this robot was placed in the sizing box, the fasteners outside the bumper zone would contact the vertical sides of the box before the frame in the bumper zone and would therefore not meet the definition (as I understand the rules at this date) even though the robot is significantly smaller than the sizing box.

MrForbes

29-01-2010, 09:53

The least nitpicky and anal retentive solution to this would be for the GDC to allow static (non moving) fastener heads to stick out no more than 0.25" from the FRAME PERIMETER, as long as they still fit inside the sizing box.

Won't work too well if you used 3/8" axle bolts...the heads are more than 1/4" thick. Wonder what the magic dimension is?

It's an interesting can of worms, it's good to see this much discussion about it, because this is an issue that many inexperienced teams will probably overlook.

Vikesrock

29-01-2010, 10:02

Won't work too well if you used 3/8" axle bolts...the heads are more than 1/4" thick. Wonder what the magic dimension is?

It's an interesting can of worms, it's good to see this much discussion about it, because this is an issue that many inexperienced teams will probably overlook.

All the 3/8" hex cap screws on McMaster seem to have a head thickness of 15/64".

MrForbes

29-01-2010, 10:07

What about the kit bolts? Seems to me that the 3/8" bolts usually have a head around .290" thick?

We're using 1/2" axle bolts this year :)

(the heads are welded to the frame, and the threads stick out not quite as far as the FRAME PERIMETER, but still.....)

Andrew Y.

29-01-2010, 10:19

im almost positive that in past years, the robot perimeter has included static boltheads...otherwise there will be A LOT of counter sinking on our hands:yikes:

Vikesrock

29-01-2010, 10:23

im almost positive that in past years, the robot perimeter has included static boltheads...otherwise there will be A LOT of counter sinking on our hands:yikes:

In past years these bolt heads were inside the Bumper Zone

engunneer

29-01-2010, 10:39

To illustrate Kevin's (Vikesrock) workaround using Martin's drawing:
If the image Kevin posted shows an illegal configuration? Does this one?

http://picasaweb.google.com/lh/photo/LinRrNdMCbrU_uiVuUFBuQ?feat=directlink

Also, would the frame perimeter now be defined as the red lines in my drawing, or is it the same as before, because of the bolt head into bumper provision?

Al Skierkiewicz

29-01-2010, 11:01

This does appear to be the gist of this discussion. Confusing isn't it?

martin417

29-01-2010, 18:53

Team update #6 really confuses the issue. The new wording:

Note: to permit a simplified definition of the FRAME PERIMETER and encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER, minor protrusions such as bolt heads, fastener ends, rivets, etc are excluded from the determination of the FRAME PERIMETER.

It sounds like the intent is to allow bolt heads, etc, but what it actually says is that they are not allowed. If they are excluded from the determination of FRAME PERIMETER, then, by definition, they extend beyond the FRAME PERIMETER, and are therefore illegal by

<R16> During normal operation no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER, except as permitted by Rule <G30>

(<G30> does not contain an exception to allow bolt heads to extend beyond the frame perimeter).

But <R07> D states that clearance pockets are allowed in the bumper backing for bolt heads etc. I believe the intent of the rule is to allow the bolt heads to extend past the perimeter, but the wording of the rule is very clear that it is illegal, even though clearance pockets for the illegal bolt heads are permitted.

Careful wording of any document that sets rules or guidelines is very important. It should never be open to interpretation. The language in the rules as written is concise, and not open to interpretation. I just believe that it says something different than what the writer intended.

Al Skierkiewicz

29-01-2010, 21:39

Jones571

29-01-2010, 21:44

mikelowry

29-01-2010, 21:54

Martin,
Team Update 6 modifies the definition of the FRAME PERIMETER and as such modifies the rules that reference the definition including R16. My impression then is that fasteners as described in TU6 will not be considered to be outside the FRAME PERIMETER in the bumper zone or elsewhere. The drawings displayed this afternoon in this thread are therefore legal.

The update does not modify the definition of the FRAME PERIMETER, it simply says that fasteners are excluded from the determination of it. Which essentially means that even the workaround that was mentioned earlier (using identical dummy bolts in the bumper zone to enlarge the frame perimeter to allow bolt heads to protrude below the bumper zone) will not work because the dummy bolts will not define the FRAME PERIMETER. Thus with the current wording no bolts are allowed to protrude from the FRAME PERIMETER in any place.

However, I agree with Martin, that the update was misworded and the intent of the update is to allow fasteners to protrude, even though the update clearly states that no fasteners can protrude anywhere.

Al Skierkiewicz

29-01-2010, 22:15

Tristan Lall

29-01-2010, 22:19

Team Update 6 modifies the definition of the FRAME PERIMETER and as such modifies the rules that reference the definition including R16. My impression then is that fasteners as described in TU6 will not be considered to be outside the FRAME PERIMETER in the bumper zone or elsewhere. The drawings displayed this afternoon in this thread are therefore legal.Sorry to disagree with you again, Al.... :o I'm with Martin on this one.

By definition, the frame perimeter is measured within the bumper zone. That hasn't been changed in Update #6. The update only modifies the method by which you identify the frame perimeter. It doesn't modify any of the consequences of exceeding the (newly-defined) frame perimeter. (Such as <R16>, <G30> and by extension, <S04>.)

Rather than allowing some uncertainty about whether a protruding fastener in a pocket was sufficiently protected by bumpers to satisfy <R07A> (it probably would have been), and whether the frame perimeter would have had to follow the contour of that protruding fastener irrespective of the pocketing (this could have been true if the pocketing was intended for use by bumper fasteners only, rather than fasteners in general), I think FIRST opted to simplify everything and give a straightforward method for employing the <R07D> pocketing allowance.

However, with regard to the robot size limit—you're absolutely right. That constrains the total size of the robot, irrespective its frame perimeter.

martin417

29-01-2010, 22:25

Martin,
Team Update 6 modifies the definition of the FRAME PERIMETER and as such modifies the rules that reference the definition including R16. My impression then is that fasteners as described in TU6 will not be considered to be outside the FRAME PERIMETER in the bumper zone or elsewhere. The drawings displayed this afternoon in this thread are therefore legal.

I agree that allowing the protrusions was probably the intent of the new wording, however, it was not the result of that wording. If you exclude the fasteners from the determination of the frame perimeter, then said perimeter is defined by the frame members. Anything outside the frame members is, by definition, outside the frame perimeter. There is no wiggle room. It can't be interpreted any other way. The frame perimeter is defined by the outermost vertices on the robot, exclusive of fasteners.

I'm not trying to be a pain, but words do have meanings, and in this case, I don't see any way to read those words except as stated above.

Al Skierkiewicz

29-01-2010, 22:32

Tristan Lall

29-01-2010, 22:56

Tristan,
Team Update 6 is excluding the fasteners from defining the FRAME PERIMETER which in turn defines the vertical plane defined by the same. This ruling makes the determination of G30 easier for the refs, easier for the robot inspectors to determine <R16> and it takes the worry away from teams trying to apply a fix to fasteners that hold the frame together. It is rather an elegant solution, don't you think?I think Martin provided an excellent summary directly above. By excluding the protrusions within the bumper zone from the frame perimeter, you make the frame perimeter polygon smaller (than it would have been under the original rule). Therefore, if you were relying on a bolt (in the bumper zone) directly above or below another bolt (outside of the bumper zone) to extend your frame perimeter and make the 2nd bolt legal, you have to make a design change (because the 1st bolt no longer counts as part of the frame perimeter).

I agree that it makes determination of <R16> and <G30> easier, but only because there's no longer any need to take certain protrusions into account (which could have been hidden behind the bumper and thus especially difficult for referees to call).

I imagine that the hoped-for response would have excluded bolt heads (etc.) located outside of the bumper zone from scrutiny under <R16> and <G30>. That's not the change that the GDC chose to make.

So, with regard to the images posted earlier, Martin's is still illegal, and Branden's is now made illegal. (In both cases, the bolts in the lower frame violate the frame perimeter.)

Scoutin' Master

29-01-2010, 23:00

I have to agree, the rule does say that the frame perimeter is not determined by any bolts, fasteners, or rivets protruding from the frame at the bumper level. This would only prevent a team from extending their frame perimeter using dummy bolts, it mentions nothing about bolts outside of the bumper zone. I would have to assume that these would be illegal because of Rule G<30>.

I would try to keep any bolts, fasteners, or rivets that are outside of the bumper zone inside your frame perimeter, just to be safe!

Just my interpretation and $.02!

MrForbes

29-01-2010, 23:18

quote from a curious person about this issue:

"another solution is to just put a piece of quarter inch plywood around your frame in the bumper region"

engunneer

30-01-2010, 06:39

So, with regard to the images posted earlier, Martin's is still illegal, and Branden's is now made illegal. (In both cases, the bolts in the lower frame violate the frame perimeter.)

I agree with this interpretation. Both drawings are illegal. The axle bolts are outside the frame perimeter.

mikelowry

30-01-2010, 08:27

Mike and Corey,
The team update modifies the definition of Frame Perimeter and uses these words...
"minor protrusions such as bolt heads, fastener ends, rivets, etc are excluded from the determination of the FRAME PERIMETER."
It does not modify the sizing rule <R90> nor does it modify the NORMAL CONFIGURATION as it is used in <R10>

<R10> During the MATCH, the ROBOT will assume one of two operating configurations. When in each configuration, the ROBOT shall fit within the limits shown below (note: these limits are defined in reference to the ROBOT, not the FIELD).

NORMAL CONFIGURATION
Max horizontal dimension Rectangular space no more than 28 inches (71.12cm) by 38 inches (96.52cm)
Max Height 60 inches (152.40cm)
Max Weight 120 pounds (54.43Kg)
FINALE CONFIGURATION
Max horizontal dimension 84 inch (213.4cm) diameter vertical right cylindrical volume
Max Height 90 inches (243.8cm)
Max Weight120 pounds (54.43Kg)

So if a robot fastener does not fit within the sizing box which is designed to test the max horizontal dimensions of 28" x 38", the team will need to make some modifications to do so.

We already established that this discussion has nothing to do with the NORMAL CONFIGURATION limitations. I understand that nothing whatsoever (except for the allowance made for a some type of kicker) can extend past the 28x38 footprint while in NORMAL CONFIGURATION. This discussion is about the FRAME PERIMETER. The problem still exists even if you have 12" by 12" robot. Then your FRAME PERIMETER would be decided by your frame members within the bumper zone. Any bolts that protrude from the FRAME PERIMETER, but NOT the NORMAL CONFIGURATION would be "excluded from determination" of the FRAME PERIMETER. Thus, they would extend past the FRAME PERIMETER and be illegal, and they would not allow for identical bolts below the FRAME PERIMETER either.

Al Skierkiewicz

30-01-2010, 10:10

OK,
Now I see what you are worried about. I interpret the update to include the intrusion of all fasteners. If they are excluded from determining the frame perimeter at the bumper zone, and the frame perimeter is a series of vertical planes, then any fastener that would be legally excluded at the bumper zone must also be excluded if they exist outside the bumper zone.

Chuck Glick

30-01-2010, 10:21

There is a simple answer to all of this.

Please refer to the diagram below (taken from R07 in manual):

http://img709.imageshack.us/img709/3430/bumperrules.jpg

The 1" allowance for hard parts that has been highlighted.

Questions you should ask yourself:
1. Are the bolt heads in question within the 28"x38" box? Yes = Good, No = Fix that first.

2. Are the bolt heads on the frame perimeter? Yes = You're fine. No = Go to question 3.

3. If not on frame perimeter, are the bolt heads within the 1" zone allowed by the bumpers? Yes= You're fine. No = Fix that.

Its not that hard. Don't lawyer the rules and you'll find the intent of the rule that was there before.

Al Skierkiewicz

30-01-2010, 10:23

Uh, Chuck,
The hard parts reference construction of the bumpers not the robot. Sorry...

Chuck Glick

30-01-2010, 10:28

Al,

I understand that, however it appears that the GDC's intent for this rule is that the bumpers are the first thing all bots contact. Therefore, if your "protrusions" (that are within the 28"x38" box) are within this 1" hard parts zone, you should be fine.

I understand that this is not what the rule is referring to at all, but I am trying to apply the rules in a method that doesn't lawyer the rules. I will draw up a diagram to show what I am trying to convey in an easier way.

EricH

30-01-2010, 10:37

Chuck, we're working with the robot frame, not the bumpers. You might get further with the pocketing part of <R07>.

Taken as a whole, the rules imply that you can have minor protrusions. Take the update by itself, and the rules say that nothing can be beyond the frame perimeter except the bumpers (and, probably, their mounting system) without penalty.

What they should have said: Small protrusions (axles, bolt heads, and the like) are excluded from both the determination of the FRAME PERIMETER and violations of [applicable rules regarding going beyond the frame perimeter].

Chuck Glick

30-01-2010, 10:49

Eric,

I get that as well. The rules intent as it seems is that the frame perimeter, that the bumpers attach to, is the max dimension of the robot.

Say team A has built a standard "box" frame where their drive rails are the same size as the "frame perimeter, But they use hex bolts to have as their drive axles. All of this assembly fits within the 28"x38" box that we all have come to know and love, but as per this new frame perimeter ruling, these bolts are 1/4" farther out than the frame perimeter above them. Now for this example, lets say that the box itself is a 20"x30" frame, and where the bolts protrude make the lower area a total of 20.5"x30.5". This is now where the bumper rule comes in. If you were to attach the bumpers on the "frame perimeter" which is 20"x30". Now, the 1" allowance all the way around makes it possible that the protrusions you have below to be within a 22"x32" box, that is defined by the bumpers. All hard parts of your robot are within both the 28"x38" box AND within the 1" added perimeter of the bumpers.

http://img690.imageshack.us/img690/7381/bumpersavior.jpg

Does this make sense?

Vikesrock

30-01-2010, 10:50

I understand that this is not what the rule is referring to at all, but I am trying to apply the rules in a method that doesn't lawyer the rules. I will draw up a diagram to show what I am trying to convey in an easier way.

While I understand the desire to not try and lawyer the rules, in this case we are not lawyering the rules to gain an advantage, we are lawyering the rules in a way that makes our current frames illegal.

The intent of this lawyering is not that we want our frames to be illegal, but rather that we want either the rules clarified or we want to be sure we have to modify our frames to comply. Having the inspector do the lawyering when we're at the competition and rule our robot is illegal is not a scenario I'm comfortable gambling with.

EDIT: While the post you made directly above this one makes perfect sense to BE the rule, unfortunately I do not believe that is currently the case. The 1" hard parts rule comes from <R07-N> which specifically makes reference to the BUMPERS.

GaryVoshol

30-01-2010, 13:18

Chuck,

Hard parts refers only to the bumper itself (<R07N> "“Hard” parts of the BUMPER ...") or bumper covers (<R12B> "i.e. no further than any other hard parts of the BUMPER"). These rules have nothing to do with the frame or other parts of the robot.

Your diagram shows the problem in the rules, both original and as amended in Team Update 6. You have bumpers flat against a flat FRAME PERIMETER. The protrusion you show is outside the vertical projection of the FRAME PERIMETER, and thus fails <R16>. Team Update 6 excluded minor protrusions of the FRAME PERIMETER itself, but not protrusions such as you show. (The FRAME PERIMETER is defined as the maximum robot size in the BUMPER ZONE.)

It is Al's and my belief that the GDC may have meant Team Update 6 to exclude protrusions such as you illustrate, but that is not the way it was written. In fact, it makes it worse, because before this exclusion, you could have a matching small protrusion in the BUMPER ZONE which would expand your FRAME PERIMETER, making the lower protrusion equal to the projection of the FRAME PERIMETER, not a violation.

Chuck Glick

30-01-2010, 13:22

Lets just hope the GDC clears this up quick. I hope that the interpretation that you, Al, and I all have is what the intent is. It's a shame that when things are written in such a manner it can cause threads like this to emerge.

nitneylion452

30-01-2010, 15:15

It's been cleared up.

Section 8 – The Robot, Rev F has been updated to include the following edits:
FRAME 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 FRAME PERIMETER, wrap a piece of string around the ROBOT at the level of the BUMPER ZONE - the string describes this polygon. Note: to permit a simplified definition of the FRAME PERIMETER and encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER, minor protrusions such as bolt heads, fastener ends, rivets, etc are excluded from the determination of the FRAME PERIMETER.

Team update #6

engunneer

30-01-2010, 15:58

It's been cleared up.

Team update #6

There's no argument about the determination of the FRAME PERIMETER. The lingering question of this thread (Post TU#6) is whether the bolt head protrusion rule only applies to bolt heads in the bumper zone, of it it applies to all bolt heads that may protrude from the vertical projection of the FRAME PERIMETER.

For people who need to nail down robot dimensions (all of us) it seems safer to assume that bolt heads outside the BUMPER ZONE may not leave the boundary defined by the vertical projection of the FRAME PERIMETER. Any robot designed within this interpretation is always legal, while the other option has a chance of not being legal.

Joe Johnson

30-01-2010, 16:04

Paul Copioli

30-01-2010, 16:49

I can tell you with absolute certainty that the intent of the rule is to allow the heads of fasteners to stick out past the frame perimeter to allow the bolting of axles, etc. I have read the update several times and the update specifically excludes fastener heads from the definition of frame perimeter.

In this case, maybe a picture can say 1,000 words. Just show the picture and be done with it.

I do think that some of you are reading way too into this update. They are trying to help us here so we don't all rest our bumpers on screw heads. I am proceeding with our protruding bolt heads below the bumper.

Alan Anderson

30-01-2010, 22:00

I can tell you with absolute certainty that the intent of the rule is to allow the heads of fasteners to stick out past the frame perimeter to allow the bolting of axles, etc. I have read the update several times and the update specifically excludes fastener heads from the definition of frame perimeter.

I think we all agree on the intent of the rule.

The problem is that instead of permitting reasonable protrusions, the actual wording makes minor protrusions illegal, period. They stick beyond the FRAME PERIMETER by definition, and the rules still prohibit any part of the robot from doing that (except for two seconds at a time) in NORMAL CONFIGURATION.

EricH

30-01-2010, 22:22

No disagreement on the intent. The disagreement is over the wording used. The wording of the rules disallows anything beyond the frame perimeter. Ditto for the wording of the update, which shrinks the frame perimeter slightly.

The wording of other rules indicates that small protrusions are allowed. This is implied, not stated, so what is stated is the rule until shown otherwise. Therefore, if a bolt head is sticking beyond the frame perimeter, the robot is illegal. (I can already hear inspectors all over the country cringing, pulling their hair out, and screaming--there's always that one team that builds right up to the size without allowing for bolts in the first place. Now multiply that by about 1700.)

Better wording would have said that minor protrusions would not be used in either the determination of the frame perimeter of determination of violations of the frame perimeter.

Chris Fultz

30-01-2010, 22:53

If the protrusions are excluded from the determination of the perimeter, then how can they then be in violation of the perimeter.

This one seems straightforward.

mikelowry

30-01-2010, 23:05

If the protrusions are excluded from the determination of the perimeter, then how can they then be in violation of the perimeter.

This one seems straightforward.

They are excluded from determination. Meaning the FRAME PERIMETER is only determined by frame members. Thus, any bolts protruding from the frame members would also be protruding from the FRAME PERIMETER and would be illegal according to rule <R16>

EricH

31-01-2010, 00:45

Chris (and others who are asking/explaining), a picture is worth a thousand words. The attached picture is representative of one side of a typical robot. The red line is the frame perimeter's vertical projection. Under <R16>, anything to the right of it (bumper side) is a rules violation, except the bumpers.

What two items do you see extending out to the right of the line? Yep, two bolts.

Before Update #6, the upper bolt defined the perimeter, saving the lower bolt from going beyond the perimeter. After Update #6 (and before Update #7), the upper bolt no longer defines said perimeter.

Chris Fultz

31-01-2010, 07:24

If the protrusions are excluded from the determination of the perimeter, then how can they then be in violation of the perimeter.

This one seems straightforward.

My first sentence was a statement, not a question.

The update says that the protrusions are excluded in determining the perimeter. Therefore, they cannot be considered in voilation of the frame perimeter if they are not considered when defining it.

It is sort of like the weight rule and batteries. Your weight limit excludes the battery. If you pass weight without the battery, then you cannot be considered overweight when you put the battery in.

engunneer

31-01-2010, 08:08

That is exactly the unanswered question, Chris.

The protrusions at the level of the bumpers are indeed excluded for determining the frame perimeter. There is no argument here, since the team update #6 makes it clear.

However, <G30> explicitly lists all things which are allowed outside the frame perimeter. <G30-a> in particular limits all things from being outside the frame perimeter below the bumper zone, except for the 2 second exclusion, and that is only allowed for ball interaction.

The big difference between this year and previous years is that the bolts for wheels and things used to also be in the bumper zone, and are part of the protrusion exclusion. Since the bumper zone is so much higher this year, this is no longer the case, and they need to be treated as any other part of the robot and kept within the frame perimeter.

If the GDC were to update <G30> to expand the protrusions allowed to the entire height of the robot, then the different drawings in this thread would become legal. Until, then I still say it's safest to assume they are not, and plan accordingly.

Inspections this year may be particularly tricky!

Tristan Lall

31-01-2010, 09:28

My first sentence was a statement, not a question.

The update says that the protrusions are excluded in determining the perimeter. Therefore, they cannot be considered in voilation of the frame perimeter if they are not considered when defining it.

It is sort of like the weight rule and batteries. Your weight limit excludes the battery. If you pass weight without the battery, then you cannot be considered overweight when you put the battery in.Unfortunately, you can't think of it that way.

The frame perimeter is (by both the original and the amended definitions) determined based on things within the bumper zone—when determining the frame perimeter, you're therefore only considering fasteners within the bumper zone. Nothing outside of that zone is relevant to "the determination of the FRAME PERIMETER".

Checking for compliance with <R16> and <G30> is a process that is not changed in any way by the update. You take the defined frame perimeter (which excludes minor protrusions in the bumper zone), and you find the extent to which the rest of the robot protrudes around it.

The key is that Update #6 only deals with the definition of frame perimeter. All of the rules that rely on that definition are unaffected.

On the subject of intent, I don't think it's so self-evident that the GDC intended to allow minor, non-frame-perimeter protrusions. After all, the rationale from the update was "to permit a simplified definition of the FRAME PERIMETER"—mission accomplished—"and encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER"—which has nothing at all to do with fasteners outside the bumper zone.

I don't disagree that letting minor protrusions (anywhere on the robot) exceed the frame perimeter would have merit. But based on the text of the update, I don't see a compelling reason to assume that we should be expecting the rule to change, or that the GDC miscommunicated their intent.

In any case, this won't be a huge deal to solve (if the rules remain as-is). Since it's (hopefully) well-understood that none of this applies to the maximum robot size, presumably any team using non-frame-perimeter protrusions on their robot will also have space to include a series of shim plates behind their bumpers to extend the frame perimeter outward.

martin417

31-01-2010, 10:31

My first sentence was a statement, not a question.

The update says that the protrusions are excluded in determining the perimeter. Therefore, they cannot be considered in voilation of the frame perimeter if they are not considered when defining it.

It is sort of like the weight rule and batteries. Your weight limit excludes the battery. If you pass weight without the battery, then you cannot be considered overweight when you put the battery in.

No, it's nothing like the battery rule. <R10> A states:

A. Exception: solely for the purposes of determining compliance with the weight and volume limitations, these items are NOT considered part of the ROBOT and are NOT included in the weight and volume assessment:

This is crystal clear. No argument. The wording in question is not a rule, it is a DEFINITION. That wording DEFINES the frame perimeter. It make no rule about what may or may not extend past that perimeter. That definition is clear. By that definition, the frame members alone define the FRAME PERIMETER, the fasteners are excluded. The RULE this wording affects is <R16> and is equally clear:

During normal operation no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER, except as permitted by Rule <G30>.

I don't see any argument. From a lawyer point of view, (and the inspector is, and must be, a lawyer about the rules) The RULE refers to the DEFINITION. Both the RULE and the DEFINITION are clear. Regardless of intent, or how the GDC meant it, it is currently illegal for fasteners to extend outside the frame members.

Again, I am not trying to cause problems, but to prevent them. Inspectors and teams should abide by the wording of the rule, teams can't be expected to guess the intent of the framers and try to abide by that intent.

martin417

01-02-2010, 07:00

I have asked our team contact to post the following question on the Q&A. Let's hope for a speedy answer to clear this up. Just for informational purposes, our team has decided to re-design the robot to eliminate any fastener protrusions, we can't wait any more.

With the new wording for the definition of FRAME PERIMETER, any fasteners that protrude from the frame members, regardless of where they are located, are now excluded from the determination of the FRAME PERIMETER, so the FRAME PERIMETER is now determined only by the frame members. This is a more restrictive definition of the FRAME PERIMETER.

<R16> states: During normal operation no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER, except as permitted by Rule <G30>.

<G30> does not make allowances for fasteners. So by <R16> and the definition of FRAME PERIMETER, no fasteners may protrude from the frame members. However, <R07>D appears to allow clearance pockets, presumably for fasteners protruding from the frame members.

After much discussion, it is our opinion that the intent of the GDC is to allow fasteners to protrude from the frame members, therefore beyond the frame perimeter. The current wording of the rule and the definition of the FRAME PERIMETER prohibit such protrusions.

Can we get a clearly worded (yes or no) answer to this question:

Are fasteners allowed to extend beyond the frame members (as long as they are inside the max dimensions)?

If the answer is yes, can we get a rule or definition change so that there will be no questions at inspection?

EricH

02-02-2010, 18:15

The GDC has responded in Update #7. However: the exclusion from <R16> for fasteners in the bumper zone apparently does not apply to fasteners above or below it. Status quo again...

The next question to ask is: Given the exemption for fasteners in the bumper zone, what about fasteners and similar items above and/or below the bumper zone? Is the exemption intended to also apply to them, or is it only in the bumper zone?

mikelowry

02-02-2010, 19:00

Just asked the next logical question on the Q&A:

We understand that according to team update 7, minor protrusions such as fastener ends, bolt heads, etc. within the bumper zone, are permitted. Will there also be an exception made for similar minor bolt head protrusions that are below the bumper zone? Such as for drivetrains and such?

martin417

02-02-2010, 19:17

I'm not sure it's necessary to ask. It looks clear this time. I would bet that they were careful in their wording to say exactly what they wanted to say, and to express their intent. In that, I am glad that we re-designed the robot to eliminate the axle bolts beyond the frame perimeter, they were definitely below the bumper zone. Sadly, I expect this to be a major problem for teams that don't pay careful attention to rules and updates. I would expect to see many teams failed at inspection for this rule, and long lines at inspection as they are re-inspected. I hope they can get legal in time to compete.

Vikesrock

02-02-2010, 21:05

Sadly, I expect this to be a major problem for teams that don't pay careful attention to rules and updates. I would expect to see many teams failed at inspection for this rule, and long lines at inspection as they are re-inspected. I hope they can get legal in time to compete.

I completely agree. I totally missed this when we did our initial frame design.

For rules compliance we will likely be going with some 1/4" plywood to widen out our upper frame.

Another cleaner looking option would be to make threaded axle support blocks that rest in the C-channel and eliminate the need for a bolt head or nut to sit outside the frame

Joe Johnson

02-02-2010, 21:29

I completely agree. I totally missed this when we did our initial frame design.

For rules compliance we will likely be going with some 1/4" plywood to widen out our upper frame.

Another cleaner looking option would be to make threaded axle support blocks that rest in the C-channel and eliminate the need for a bolt head or nut to sit outside the frame

But at least teams have time to fix it.

I honestly have no dog in this hunt as the robot our team is building meets the rule without even the fastener head exemption in the bumber zone* but I am really glad that this was addressed soon and clearly.

Well done GDC.

Joe J.

*this being the first year back in the game in a while and therefor not poluted with prior year's rulings, I read the rules and thought they were pretty clear. So... I used C channel facing outward for both the bumper mount structure and the robot chassis. As noted above, it leaves plenty of room for screw heads. Recommended.

Vikesrock

02-02-2010, 21:42

But at least teams have time to fix it.

....

Well done GDC.

Joe J.

This is true, assuming they know they have a problem.

I am in no way blaming the GDC for me being dumb when working on our frame. The rules as written were crystal clear and we plain and simple messed up.

Luckily the dirty fix requires very little work and the clean one may be well within our capabilities as well (the question becomes is it worth the time)

EDIT: Paul's post made me think about this a bit more and I now agree with him that Update 6/7 could be extremely obnoxious for teams. A vertical member with a fastener at the bottom (below the bumper zone) and at the top (in the bumper zone) was previously perfectly fine and is now illegal.

To be fair there certainly was a rules oddity here that needed addressing. The rules allowed for the bumpers to be pocketed to allow room for fasteners, but the bumpers had to be mounted to the frame perimeter which was defined by these fasteners.

I still feel the appropriate way out of this hole is allowing for minor protrusions as defined in Update 6/7 to stick out from the vertical projection of the Frame Perimeter (whether above, below, or in the bumper zone) provided everything stays within the 28"x38" box.

Paul Copioli

02-02-2010, 21:51

sanddrag

02-02-2010, 22:17

Vikesrock

02-02-2010, 22:23

I still can't understand why teams don't just build their robots an inch smaller than the sizing box. All this debate over bolt heads sticking out is just silly.
The rule should read like this:
"We're bringing a box with these dimensions. You better be sure ALL of your robot fits in it"

Once again, this issue is NOT ABOUT the sizing box.

This issue could affect a 12"x12" robot. If the frame has an upper level in the bumper zone that is 12"x12" and a lower level that is 12"x12" below the bumper zone any fasteners sticking out of the lower frame are illegal per <R16>.

The very, very bad thing is that if fasteners stick out both inside and outside the bumper zone you were legal before Team Update 6 and now you're not. Making such a ruling at the end of week 3 is frankly unacceptable.

Joe Johnson

02-02-2010, 22:53

No, no, no. This is not good job GDC! Bad GDC, bad GDC. We are in week 4 of the build season for Pete's sake. This makes no sense to me at all. On the scale of things that matter to them, this should be in negative land.

Good job GDC. I didn't need the sleep anyway.

Paul,
What part of rule <R16> did the GDC screw up?

<R16> During normal operation no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER, except as permitted by Rule <G30>.

They gave us some freedom to have screw heads under the bumper but we had no right to expect that this would extend outside this space. There was a question, it was answered relatively fast and while there is time to work around it if you have to.

I don't see how we can blame the GDC.

Joe J.

sanddrag

02-02-2010, 23:11

Once again, this issue is NOT ABOUT the sizing box.

This issue could affect a 12"x12" robot. If the frame has an upper level in the bumper zone that is 12"x12" and a lower level that is 12"x12" below the bumper zone any fasteners sticking out of the lower frame are illegal per <R16>.

The very, very bad thing is that if fasteners stick out both inside and outside the bumper zone you were legal before Team Update 6 and now you're not. Making such a ruling at the end of week 3 is frankly unacceptable.I guess I didn't fully understand the issue. So, to make this theoretical 12x12 team described above compliant, they would need to make their upper level say, 13x13?

Vikesrock

02-02-2010, 23:16

I guess I didn't fully understand the issue. So, to make this theoretical 12x12 team described above compliant, they would need to make their upper level say, 13x13?

Exactly. Or somehow modify things so the bottom fasteners don't stick out.

Paul Copioli

02-02-2010, 23:43

Chris is me

03-02-2010, 00:15

Even more ridiculous, if I have a sheet metal drive base and I have rivets all over it to hold it together, this update makes the rivets below the bumper zone illegal.

I guess if you have your bumper mounting parts of the sheet metal chassis a quarter inch out from the rest of it, you could still rivet it.

I share your frustrations, though, despite no changes being needed for my team's robot. This isn't an acceptable week 4 change.

sanddrag

03-02-2010, 00:19

Paul, I see exactly where you are coming from now that I understand the issue. This is a design-altering rules change, not just a clarification. Perhaps they should make it so bolt heads may be excluded, at the discretion of the team.

Joe Johnson

03-02-2010, 00:27

Joe,

Prior to update 6, the fasteners, etc within the bumper zone defined my frame perimeter. After update 6 & 7 they did not. What this means is that all of us who made sure the bolt heads within the bumper zone stuck out more than the bolt heads below the bumper zone to be within the rules are now illegal and it is the start of week 4.

In short, our robot was legal on Thursday, and now it is not. How can you not see a problem with that?

Even more ridiculous, if I have a sheet metal drive base and I have rivets all over it to hold it together, this update makes the rivets below the bumper zone illegal.

Ridiculous

You are right about the idea that if you line up rivet or bolt heads or whatever. I missed/forgot that (I say forgot because I knew it at one point but not at another). I apologize to you, Paul, for not understanding your point of view.

As to the rivets below the bumper zone, unless they were lined up with ones in the bumper zone then they would have always been illegal. Am I right on this?

I see at least 3 possible paths.

First, FIRST could realize that they were trying to do one thing and (perhaps) did another instead (by taking away the heads on the bumper zone they took away the head below it) and go to a mixed definition that allows for your heads to be legal as long as they are below heads in the bumper zone but for bumper mounts to be secure.
Second, FIRST could allow all fasten heads to count for robot overall size but not for extending beyond the FRAME PERIMETER
Third, Teams could mount a small (hopefully light) spacer on the robot at the bumper zone that spaces the FRAME PERIMETER over the tops of the fastners.
I think 2 is the most reasonable given where we are. I don't think they are going to go for it. I suppose 3 is the safest bet because it is in the team's control.

Joe J.

Vikesrock

03-02-2010, 00:31

First, FIRST could realize that they were trying to do one thing and (perhaps) did another instead (by taking away the heads on the bumper zone they took away the head below it) and go to a mixed definition that allows for your heads to be legal as long as they are below heads in the bumper zone but for bumper mounts to be secure.
Second, FIRST could allow all fasten heads to count for robot overall size but not for extending beyond the FRAME PERIMETER
Third, Teams could mount a small (hopefully light) spacer on the robot at the bumper zone that spaces the FRAME PERIMETER over the tops of the fastners.
I think 2 is the most reasonable given where we are. I don't think they are going to go for it. I suppose 3 is the safest bet because it is in the team's control.

Joe J.

This seems like a pretty good summary of the options at this point.

Our team is hoping for #2 and planning for #3.

Chris is me

03-02-2010, 00:53

I guess it's not a quick fix, but perhaps teams whose robots break this new rule change could slap some material over their bumper zone to make it thicker? i.e. 4 thin pieces of lexan as long and wide as the bumper or something, with holes for the bolt heads, that makes the bumper perimeter thicker. It's easier than redesigning a drivetrain because rivets or bolts stick out.

Jonathan Norris

03-02-2010, 01:22

Wow update 7 is frustrating... so this means our screw heads and washers keeping our drive shafts in are now illegal, great.

Yea I know is some sort of wording this was always illegal, but I don't undersand why FIRST would go to the effort, in week 4, to define how we must design the area beneath our bumpers in such a specific way. In all honesty this is a very unenforceable rule defined so late in the season, that some 'elite' teams are going to have a tough time meeting. I feel sorry for teams who built their frame out of sheet metal and rivits. These rulings makes me think that the GDC didn't even consider the realistic consequences of this definition, and how unenforceable it will be.

eugenebrooks

03-02-2010, 01:32

Recognizing this gray area in the rules, we always knew that we could glue on a spacer in the bumper zone to exceed the extension of any fasteners (in our case welds) lower down on the robot. At this point it looks like this is what we will have to do and we will need to make it weigh as little as possible.

Any suggestions for a suitably light spacer material?

Eugene

R.C.

03-02-2010, 01:44

artdutra04

03-02-2010, 01:51

Well this make sheet metal designs a bit more difficult... back to the old flat head bolts with PEM nut option.

For those which cannot change their fasteners to flat head bolts, here's the McMaster part number that I think will save a lot of teams this year: 8782K12

1" wide x 1/4" thick polypropylene strips at $0.53/foot. Polypropylene is among the lightest and cheapest commonly available plastics, but even still, installing this strip around the outside of your robot perimeter will add just over a pound.

For comparison, using a 1/4" x 1" strip of Lexan will add over 1.3 pounds.

EricH

03-02-2010, 01:51

You could also try getting some balsa wood. That's pretty light--in fact, a lot of R/C airplanes are made from it.

Rick TYler

03-02-2010, 02:03

For those which cannot change their fasteners to flat head bolts, here's the McMaster part number that I think will save a lot of teams this year: 8782K12

1" wide x 1/4" thick polypropylene strips (...) will add just over a pound.
(...) 1/4" x 1" strip of Lexan will add over 1.3 pounds.

6mm Okoume plywood in a 1" wide strip around the robot would add about .6 pounds. Double-layer corrugated cardboard might even be lighter than that.

GaryVoshol

03-02-2010, 07:57

As to the rivets below the bumper zone, unless they were lined up with ones in the bumper zone then they would have always been illegal. Am I right on this? Not precisely. Previously if you had a row of rivets along your FRAME PERIMETER, they would have extended the PERIMETER along that side. Any rivet above or below the BUMPER ZONE, but still within the horizontal limits of that row, would have been protected.

You could also try getting some balsa wood. That's pretty light--in fact, a lot of R/C airplanes are made from it.

6mm Okoume plywood in a 1" wide strip around the robot would add about .6 pounds. Double-layer corrugated cardboard might even be lighter than that.Can you say "Squish!" Both of these materials would negate the whole intent of the reason for exempting protrusions in the first place, which was to ensure that bumpers were firmly attached to a solid frame member. I don't see anything that would prohibit the use of the materials. It's just that by using them, you make the bumpers less stable, not more robust as was noted for the reason it was changed in Team Update 6.

Next question, how are inspectors going to measure this for compliance? The old see-what-touches-a-vertical-wall-first test doesn't work. How can an inspector tell that your lower frame is or isn't really 1/8" smaller than your frame in the BUMPER ZONE which defines the FRAME PERIMETER?

Rob

03-02-2010, 08:36

I am with the group that rates this change to the design rules as unacceptable when presented at this time in the build season.

I hope that there is a misinterpretation here and that whatt appeared to be a previously acceptable condition will prevail.

While we have the ability to extend the size of the bumper zone by 1/4" in each direction it will require the purchase of some new material as well as the cutting of new bumper wood. This is simply a shuffling of words that created a great deal of waste.

A ruling like this creates the appearnace that the author of this update does not understand what teams go through during the build season. I hope that sanity prevails over misunderstanding and we do not see any other game changing updates during the season.

Rob

Mike Betts

03-02-2010, 08:48

...Next question, how are inspectors going to measure this for compliance? The old see-what-touches-a-vertical-wall-first test doesn't work. How can an inspector tell that your lower frame is or isn't really 1/8" smaller than your frame in the BUMPER ZONE which defines the FRAME PERIMETER?

I can not answer for other inspectors, but I always bring a 6 foot level with me... I have only had to use it a few times...

Mike Betts

03-02-2010, 09:02

I still can't understand why teams don't just build their robots an inch smaller than the sizing box. All this debate over bolt heads sticking out is just silly....

I agree completely. I can see a rookie team being blind sided by this but I have no sympathy for a veteran team.

If you have designed your frame too close to "exactly" 28x38, then you have opened yourself up to problems regarding variations in dimensions and of "squareness" of the sizing box and you should be prepared for failure.

Likewise, if you have designed so close to the "bumper perimeter" that the (admittedly subjective) robot inspection is in jeopardy, you be prepared for a rough time on Thursdays...

Please use common sense!

JMHO,

Mike

johnr

03-02-2010, 09:10

I will admit that after the last couple of years that i read the rules with an eye towards,"What does the gdc want all the robots to look like this year?" For some reason a flat top upside down pyramid came to mind. Now i know why. I feel bad for the inspectors that are going to have to tell a team that their rivet heads are out of perimeter.

martin417

03-02-2010, 09:28

I agree completely. I can see a rookie team being blind sided by this but I have no sympathy for a veteran team.

If you have designed your frame too close to "exactly" 28x38, then you have opened yourself up to problems regarding variations in dimensions and of "squareness" of the sizing box and you should be prepared for failure.

Likewise, if you have designed so close to the "bumper perimeter" that the (admittedly subjective) robot inspection is in jeopardy, you be prepared for a rough time on Thursdays...

Please use common sense!

JMHO,

Mike

Please read the thread before posting! As has been repeated MANY times throughout this thread, this debate has nothing to do with violating the sizing box, A 12" square robot can still be iin violation of this rule. If you don't understand what I mean, read back through this thread and it will become clear.

Joe Johnson

03-02-2010, 09:36

Please read the thread before posting! As has been repeated MANY times throughout this thread, this debate has nothing to do with violating the sizing box, A 12" square robot can still be iin violation of this rule. If you don't understand what I mean, read back through this thread and it will become clear.

I think he may be referring to those teams that say they cannot space their bumper out (and thereby extend the FRAME PERIMETER) without having the robot be outside the 38"X28" overall size limit.

Joe J.

jgannon

03-02-2010, 10:44

Likewise, if you have designed so close to the "bumper perimeter" that the (admittedly subjective) robot inspection is in jeopardy, you be prepared for a rough time on Thursdays...

Please use common sense!
C'mon, man... you can't possibly tell me that "common sense" would have dictated that a bolt head protruding from your frame 15" off the ground is legal, but a bolt head protruding by the same amount 4" off the ground is not.

Look around this thread for a minute. When you see a WFA winner saying his interpretation of the rule is correct with "absolute certainty", and he turns out to be wrong, something has gone terribly, terribly awry.

MrForbes

03-02-2010, 10:57

Can you say "Squish!" Both of these materials would negate the whole intent of the reason for exempting protrusions in the first place, which was to ensure that bumpers were firmly attached to a solid frame member.

You can easily poke your finger into balsa wood or corrugated cardboard. But if you lay a piece of either on the floor, then place a piece of 3/4" plywood on it, and stand on it, what happens?

If there is sufficient surface area behind it for support, these soft materials will probably work very well as bumper shims, to bring the FRAME PERIMETER out past the fastener heads in the lower part of your robot.

Rick TYler

03-02-2010, 11:13

I can not answer for other inspectors, but I always bring a 6 foot level with me... I have only had to use it a few times...

Whacking team captains with a 6-foot level might be satisfying, but it probably violates some rule or another. Sorry.

IndySam

03-02-2010, 11:23

Paul,
What part of rule <R16> did the GDC screw up?

<R16> During normal operation no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER, except as permitted by Rule <G30>.

They gave us some freedom to have screw heads under the bumper but we had no right to expect that this would extend outside this space. There was a question, it was answered relatively fast and while there is time to work around it if you have to.

I don't see how we can blame the GDC.

Joe J.
I'm with you Joe. I thought the rule was clear from the start.

I think it just shows how people can look at the same rules and have different conclusions. That's why the GDC's job is so hard.

IndySam

03-02-2010, 11:35

C'mon, man... you can't possibly tell me that "common sense" would have dictated that a bolt head protruding from your frame 15" off the ground is legal, but a bolt head protruding by the same amount 4" off the ground is not.

Look around this thread for a minute. When you see a WFA winner saying his interpretation of the rule is correct with "absolute certainty", and he turns out to be wrong, something has gone terribly, terribly awry.

I can tell you that because that's exactly what common sense told me. The bolt protruding rule was to allow to help with bumper attachment and support. How does a bolt protruding 4" of the ground hamper mounting bumpers? So why would it be allowed?

I have nothing but respect for PC and have learned much from him over the years. Just because he is a WFA doesn't make him always correct.

Vikesrock

03-02-2010, 11:43

I can tell you that because that's exactly what common sense told me. The bolt protruding rule was to allow to help with bumper attachment and support. How does a bolt protruding 4" of the ground hamper mounting bumpers? So why would it be allowed?

I have nothing but respect for PC and have learned much from him over the years. Just because he is a WFA doesn't make him always correct.

But he was. The rules were clear, whatever stuck out the farthest in the Bumper Zone defined the Frame Perimeter, whether that was an axle or a bolt or a a hot glued army man.

Update 6 changed that, which may have shrunk the Frame Perimeter for some teams. If these teams were designing to fit inside the projection of their old larger Frame Perimeter and now do not fit inside the new smaller Frame Perimeter then this rule has taken a legal design and made it illegal. In week 4 that just does not seem to be a fair thing to do.

IndySam

03-02-2010, 12:08

But he was. The rules were clear, whatever stuck out the farthest in the Bumper Zone defined the Frame Perimeter, whether that was an axle or a bolt or a a hot glued army man.

See that's where we will have to agree to disagree.

Too me the rules were clear. Yes that axle bolt defined the perimeter so the bumper would have to be outside that perimeter. The only exception was that small clearance holes or pockets were allowed in the bumper backing material to allow that axle bolt. How does that exception become translated to allow that axle bolt or rivet or whatever not covered by that backing material?

Vikesrock

03-02-2010, 12:16

See that's where we will have to agree to disagree.

Too me the rules were clear. Yes that axle bolt defined the perimeter so the bumper would have to be outside that perimeter. The only exception was that small clearance holes or pockets were allowed in the bumper backing material to allow that axle bolt. How does that exception become translated to allow that axle bolt or rivet or whatever not covered by that backing material?
Note: Caps denote references to official definitions, not anger or frustration.

That bolt defined the FRAME PERIMETER. If you had a 26"x36" frame with fasteners sticking out in the BUMPER ZONE 1/4" on each side right in the corners, your FRAME PERIMETER was a 26.5"x36.5" rectangle.

This meant the rest of your robot had to fit within a vertical projection of this 26.5"x36.5" rectangle per <R16>.

After Update 6 this robot now has a FRAME PERIMETER of 26"x36". Any parts that fall within the 26.5"x36.5" projection but outside the 26"x36" projection went from perfectly legal to a violation of <R16>.

I'm not sure what part of this you disagree with so feel free to grab any of the steps out of the above and show me where I may be wrong (and I most certainly may be)

MrForbes

03-02-2010, 12:22

After reading the discussion, and talking about it, and rereading the rules, I came to the conclusion that the rule was ambiguous before Update 7.

So you're both right.

Apparently Paul might have made a wrong assumption....which is easy to do when the rules are ambiguous. Or he made a literal interpretation of what the rules said before update 6.

I learned a while back to err on the conservative side when the rules are ambiguous. Unfortunately it's usually hard to see that the rules ARE ambiguous unless you can see both interpretations. Usually we can't!

IndySam

03-02-2010, 13:02

Note: Caps denote references to official definitions, not anger or frustration.

That bolt defined the FRAME PERIMETER. If you had a 26"x36" frame with fasteners sticking out in the BUMPER ZONE 1/4" on each side right in the corners, your FRAME PERIMETER was a 26.5"x36.5" rectangle.

This meant the rest of your robot had to fit within a vertical projection of this 26.5"x36.5" rectangle per <R16>.

After Update 6 this robot now has a FRAME PERIMETER of 26"x36". Any parts that fall within the 26.5"x36.5" projection but outside the 26"x36" projection went from perfectly legal to a violation of <R16>.

I'm not sure what part of this you disagree with so feel free to grab any of the steps out of the above and show me where I may be wrong (and I most certainly may be)

From the update:
Note: to permit a simplified definition of the FRAME PERIMETER and encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER, minor protrusions such as bolt heads, fastener ends, rivets, etc are excluded from the determination of the FRAME PERIMETER.

The key words are encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER show that the change was for the bumper area and not the rest of the frame. I think if you assumed that changed the frame perimeter then I think your made a huge leap of logic (just my opinion.)

But say I do agree with your scenario and they did change the perimeter definitions. They changed it on day 20 where frame designs should have been already finished and then after seeing the ambiguity they created quickly released clarification 4 days later. A fast and reasonable response.

Tristan Lall

03-02-2010, 13:32

That bolt defined the FRAME PERIMETER. If you had a 26"x36" frame with fasteners sticking out in the BUMPER ZONE 1/4" on each side right in the corners, your FRAME PERIMETER was a 26.5"x36.5" rectangle.

This meant the rest of your robot had to fit within a vertical projection of this 26.5"x36.5" rectangle per <R16>.There's a little problem with that reasoning: although they don't go right ahead and say it, by giving the string example in the definition, it's clear that the definition of frame perimeter refers to the minimal convex polygon within the bumper zone. For many designs, that's different from the minimal bounding quadrilateral (which you're describing). (There are even a couple of possible—but unlikely—cases where this isn't the minimum quadrilateral either.)

Unfortunately, it's not exactly clear whether this is intended to be an imaginary string wrapped around the projection of all such points in a plane, or wrapped around the outermost subset of points that are coplanar within the bumper zone. (Imagine that on a rectangular robot, two opposite sides have bolts at 10.5 in from the ground, and the other two sides have bolts at 15.5 in from the ground; how do you wrap that string and still meet the definition? If we're talking string, then concavity in 3-D is the same as in 2-D—i.e. not allowed. How do you define "outermost"—is this with respect to a centroid? Which one, and how do you find it?)

In any case, if your outermost bolts within the bumper zone are near the corners of your rectangular robot, we can use your example as a rough approximation for the purposes of discussion.

Rob

03-02-2010, 13:32

So having thought about this a while and re-read the details several times I can see where this definition is coming from.

Last year the "pockets in the bumper backing" ruling came out mid-season to allow teams to legally use the Kitbot as provided. The heads of the kitbot axle bolts would have been in violation for the majority of teams that used this setup otherwise. (The fact that the instructions said to assemble it with open corners was a separate issue that cause other inspection problems, but I digress...)

This year the kitbot changed a bit with the "legs" to lift the chassis portion up above the drive wheels. If used as provided , the kitbot would provide the start of a legal frame unlike last year. Many teams (mine included) used a kitbot setup similar to last year and now have an issue with bolt heads protruding out below the bumper zone. The shift in bumper zone to a higher position than it was in the past is what is causing problems here.

The fact that a the kitbot as provided is legal for the update 7 version of the frame perimeter is a good thing. Unfortunately for those of us who used modified or alternate frames the previous version of the frame perimeter was either different or ambiguous. Now it is clear, and it is also different from many people's previous interpretations.

We are lucky in that we have enough space to play with to build in an extension to our frame perimeter in the bumper zone. I hope that all teams have enough wiggle room to play with here. I fear that this will be an issue for quite a few teams. This is a detail that can be tough to pick up on. I hope that folks in the CD community can help out local teams who may not be up to speed on this definition.

Thanks, and good luck!

Rob

Vikesrock

03-02-2010, 13:40

There's a little problem with that reasoning: although they don't go right ahead and say it, by giving the string example in the definition, it's clear that the definition of frame perimeter refers to the minimal convex polygon within the bumper zone. For many designs, that's different from the minimal bounding quadrilateral (which you're describing). (There are even a couple of possible—but unlikely—cases where this isn't the minimum quadrilateral either.)

I was careful (but not particularly clear) to include "right at the corners" in my wording.

What I intended to portray was each corner of the robot having a bolt coming out of each face directly adjacent to the corner, so 2 bolts per corner, 8 total. This should result in the rough approximation you suggested.

dlavery

03-02-2010, 13:43

Note: Caps denote references to official definitions, not anger or frustration.

That bolt defined the FRAME PERIMETER. If you had a 26"x36" frame with fasteners sticking out in the BUMPER ZONE 1/4" on each side right in the corners, your FRAME PERIMETER was a 26.5"x36.5" rectangle.

This meant the rest of your robot had to fit within a vertical projection of this 26.5"x36.5" rectangle per <R16>.

This is exactly the sort of situation that many people are not fully considering. It appears that many wanted to implement this configuration, or some close variation of it, and are alarmed that the revised wording of the rule appears to complicate their ability to do so. But you have to understand that under the original wording of the rules, this configuration led directly to an illegal ROBOT that would have been rejected at inspection.

In this example, the extended bolt heads defined the vertices of the FRAME PERIMETER. But you have to then consider that the in the area in between the bolt heads, the FRAME PERIMETER is now in free space 1/4 inch away from the actual frame structure of the robot. Under Rule <R07-I>, the BUMPERS must attach to the FRAME PERIMETER. Not 1/4 inch inside the FRAME PERIMETER (where the actual frame structure is located), but directly to the FRAME PERIMETER. Which means that for the portion of the BUMPERS between the bolt heads, the BUMPERS would not be supported. But under Rule <R07-M>, the entire length of the BUMPER backing must be supported and not in free space. Thus, this configuration would have been in violation of at least one, and potentially more, rules.

The revised wording corrected this entire situation and gave you a clean way to bolt your frame together and securely attach the bumpers without a violation.

-dave

.

Vikesrock

03-02-2010, 13:50

...

The revised wording corrected this entire situation and gave you a clean way to bolt your frame together and securely attach the bumpers without a violation.

-dave

.

Touchè! Dave, thank you very much for chiming in here. This makes the purpose of Updates 6 and 7 much more clear.

IndySam

03-02-2010, 13:52

Right, that's the problem. Protrusions below the BUMPER ZONE used to be allowed so long as they were within the FRAME PERIMETER, which could be defined by corresponding protrusions in the BUMPER ZONE. Then a change was made that only impacted the BUMPER ZONE, thus pushing protrusions below it out of spec.

If protrusions are within the frame perimeter then they are not protrusions. They are legal parts within the perimeter. I don't see how you make the leap from that in any way.

That's not what happened. A clarification was made that introduced ambiguity, and then a further clarification changed the rule entirely, weeks after kickoff, when frame designs should have been already finished.

Update 6 introduce the ambiguity. Update 7 clarified the rule and did not change the original rule at all.

See DL's post.

Jonathan Norris

03-02-2010, 14:25

I'm sorry this is getting out of hand, I am having a hard enough time understanding what is illegal and legal and I've been around FIRST for 6 years. The lawyering of these frame perimeter rules is going way to far, the GDC tells us to not lawyer the definition of the rules and try and understand the intent of the rule, however these frame perimeter rules are getting so lawyered and technical that I can't even explain it to the students I mentor.

This is a high school robotics competition, can we please make these frame perimeter rules easier to understand so the high school students I work with can sit down with the manual and understand them??

I understand the intent of the rule, to have the outside frame of the robot support the Bumpers in the Bumper Zone. But if this means I can't have my bumper frame protrude perpendicularly up from my the outside of my lower drive frame because of the #10 screw head that is holding our drive shafts in makes it illegal, this is getting way to technical. Yea there are ways that we can 'hack' our frame to fit the technicalities of these rules even though it is already all welded together, but I don't see why we would waste our time changing it when our frame meets the intent of the rules.

Paul Copioli

03-02-2010, 17:58

Dave, all;

I will be clear about this. There was no ambiguity in my mind in the rule prior to update 6 that is why I couldn't be conservative with regards to the ambiguity. The original rule never stated that bolts don't count so it is my "common sense" that bolts sticking out within the bumper zone had to define the frame perimeter. How could I logically make an exception?

So I want to get this straight: The original rules actually intended to make every sheet metal + rivet construction robot illegal this year? GDC members are not blind so they see how many robots are constructed. Everyone keeps talking about bolt heads, but even rivets are illegal. That, to me, is just plain stupid.

Every year there is something: G22, G14 ... well this year I know what it is....

Well, at least I'll have some fun with it at IRI.

This is simply irritating. We'll get by, but I'm not really concerned about my teams.

Paul

P.S. - JVN says 148 will be bringing lots of extra shim strips with us to Dallas and Houston. 217 will be bringing the same to Finger Lakes, Cass Tech, and Troy. There will be many teams that are totally blind sided by this because they do not have as much "common sense" as some people on CD and they don't check CD.

gren737

03-02-2010, 18:12

artdutra04

03-02-2010, 18:46

What if we all just went back to a time that I'll refer to as "B.B." or Before Bumpers and all you had to do with build a robot that fit inside the sizing box?

Can I throw this one up to the GDC to consider?? I know bumpers are most likely here to stay, but honestly the headaches they create is not worth the little bit of cushioning provided to the robot during a match. If you can't stand the heat.....

I dunno, just my $.02I liked those days. You had a starting size limit, a total weight limit, and that was pretty much it for size and weight restrictions.

It was clear, understandable, and a degree in constitutional law wasn't necessary to understand the dozens of clauses, exemptions, and the exact DEFINITIONS of various aspects of the robot and the game.

sanddrag

03-02-2010, 19:23

Paul, I think what Dave was trying to say, is that even by the original rule, if your frame perimeter consisted of a piece of metal, with a row of rivets heads on it, this would not meet the requirement to fully support the bumper along its length, since it is supported at only at the rivet heads. So, in this type of a design, a shim/spacer would have been needed all along anyhow, before any updates. Although, I suppose if small indentations were made in the bumper backing to clear the rivets, the bumper would have been supported by the metal which is inside the (as previously defined) frame perimeter, not at the frame perimeter itself.

And let's think about the following too. In theory, any member defining the frame perimeter that is not perfectly planar does not fully support the bumper. There exists no such surface.

So the question becomes, what is the maximum allowable space between the bumper backing, and the frame perimeter, for which the bumpers shall still be considered "fully supported." I would argue up to a 1/4 inch should be deemed acceptable. Materials and manufacturing methods have a tolerance...

Silly, I know...

Something needs to be done to make this all simpler for everyone. Maybe I'm looking at this wrong, but I have been in FIRST for 9 years now, and I still can't figure out how I would explain this rule to anyone. Let's also remember that many inspectors have never even seen a FIRST robot before. This will never work.

Don Wright

03-02-2010, 19:46

I can't help but wonder how this will really be checked and enforced at the competitions (especially for really small protrusions like rivets...)

Vikesrock

03-02-2010, 21:11

P.S. - JVN says 148 will be bringing lots of extra shim strips with us to Dallas and Houston. 217 will be bringing the same to Finger Lakes, Cass Tech, and Troy. There will be many teams that are totally blind sided by this because they do not have as much "common sense" as some people on CD and they don't check CD.

Thanks for the idea Paul. I will try to make sure our team does the same for teams up here in MN.

Steve W

03-02-2010, 22:21

I can't help but wonder how this will really be checked and enforced at the competitions (especially for really small protrusions like rivets...)

As it says in the explanation, if they push the robot against a wall, only the frame perimeter would touch the wall. If you run your hand down the side of the robot and feel a bump then you violate the rule.

A mentor and RWFA winner says that the rule is "stupid". If the robot has bolt heads (or whatever) that protrude from the frame perimeter hold the bumper off of the frame, small holes can be drilled to "encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER".This makes so much sense and last year they finally got it right. NOW......

From the update:
Note: to permit a simplified definition of the FRAME PERIMETER and encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER, minor protrusions such as bolt heads, fastener ends, rivets, etc are excluded from the determination of the FRAME PERIMETER.

So bolt heads are not part of the perimeter except that the robot perimeter has to fit flush against the wall. I don't understand now for sure.

Joe Johnson

04-02-2010, 00:09

As it says in the explanation, if they push the robot against a wall, only the frame perimeter would touch the wall. If you run your hand down the side of the robot and feel a bump then you violate the rule.
<snip>

I am getting old, but I just now really read that bit about the wall. I know I read it 10 times but I didn't READ it.

Suppose I have a cube bot, perfectly flat sides of whatever dimension, is this robot legal (assuming I put bumpers on it at the right height and it is within the size limits, etc...)?

I had assumed yes, but now I think no because the entire robot side will hit the wall.

Wait, no, this doesn't say anything about the bumper zone only hitting the the wall, just the FRAME PERIMETER. But wait didn't the definition of the FRAME PERIMETER include the BUMPER ZONE...
FRAME 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
Yes, it does.... But then, that push against the wall bit was in a blue box so perhaps it doesn't really apply... ...except there is another blue box that says something about No Mushroom bots -- which is crazy because, to me, a short robot with the FRAME PERIMETER extending out beyond the edges of the lower robot is almost exactly what I would think of when you say "Mushroom bot" but it is in a rule saying that this is NOT what you want...

....I am totally confused.

It is late, I will see things clearly in the morning.

Joe J.

sanddrag

04-02-2010, 02:50

except there is another blue box tha says something about No Mushroom bots -- which is crazy because to me a short robot with the FRAME PERIMETER extending out beyond the edges of the lower robot is almost exactly what I would think of when you say "Mushroom bot" but it is in a rule saying that this is NOT what you want... Glad I'm not the only one confused. All along, I had no idea what they meant by "no mushroom bots", and yes, to me it seems this is exactly what you would want in order to satisfy the rule. Does FIRST know about some rare inverted mushroom that I do not?

martin417

04-02-2010, 07:17

I am getting old, but I just now really read that bit about the wall. I know I read it 10 times but I didn't READ it.

Suppose I have a cube bot, perfectly flat sides of whatever dimension, is this robot legal (assuming I put bumpers on it at the right height and it is within the size limits, etc...)?

I had assumed yes, but now I think no because the entire robot side will hit the wall.

Wait, no, this doesn't say anything about the bumper zone only hitting the the wall, just the FRAME PERIMETER. But wait didn't the definition of the FRAME PERIMETER include the BUMPER ZONE...

FRAME 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

Yes, it does.... But then, that push against the wall bit was in a blue box so perhaps it doesn't really apply... ...except there is another blue box tha says something about No Mushroom bots -- which is crazy because to me a short robot with the FRAME PERIMETER extending out beyond the edges of the lower robot is almost exactly what I would think of when you say "Mushroom bot" but it is in a rule saying that this is NOT what you want...

....I am totally confused.

It is late, I will see things clearly in the morning.

Joe J.

Perhaps the GDC is taking a lesson from the ancient Chinese. Inscrutability lends the impression of wisdom, and disguises folly.

Manoel

04-02-2010, 07:53

Glad I'm not the only one confused. All along, I had no idea what they meant by "no mushroom bots", and yes, to me it seems this is exactly what you would want in order to satisfy the rule. Does FIRST know about some rare inverted mushroom that I do not?

They want a mushroom bot, except they don't... The thing is, the mushroom pileus (cap) HAS to be the frame perimeter, not something above. Either way, you have a mushroom bot, only one of them being legal. Anyway, that fungal reference is in a blue warning box and, as stated at the top of the manual, they don't have the weight of a rule and, whenever contradicting a rule, are void.