25-01-2009 16:18

thefro526

Re: pic: Is this corner considered protected?

I would have to say, Yes-That Corner is Adequately protected. You might want to add a vertical noodle at the end though.

25-01-2009 16:25

Gdeaver

Re: pic: Is this corner considered protected?

I would say no. Corners must be protected by bumpers extending at least 6" on both sides. The bumper is only on one side of the vertex (corner).

25-01-2009 16:26

Cory

Re: pic: Is this corner considered protected?

Refer back to the string test mentioned in update two.

If you wrap a string around the perimeter of the robot, every point at which the string changes direction is considered a "corner"

Every corner must be protected on both sides by a 6" long bumper segment.

In my mind the angle immediately to the left of the pool noodle you've shown is a corner, and as such the area to the left of that angle and to the right of the trailer hitch mount must be protected by a 6" long bumper segment.

25-01-2009 16:29

Paul Copioli

Re: pic: Is this corner considered protected?

I agree with Cory. I would plan for a 6" bumper on the other side of the corner.

The manual is eally clear on that issue.

Your trailer hitch looks way longer than the spec. Maybe it is an optical illusion, though.

25-01-2009 16:32

Woody1458

Re: pic: Is this corner considered protected?

I would have your bumber team take another look at figure 8-4 on page 11 of Section 8, and rule <R08>, Clause O.

25-01-2009 16:36

dtengineering

Re: pic: Is this corner considered protected?

First of all, I can appreciate how there is confusion over this point. Figure 8-2 in the manual shows a similar bumper configuration, however the Q&A points out that figure 8-2 is not necessarily an example of a legal configuration. http://forums.usfirst.org/showthread.php?t=11257

In this case the corner will likely need to be protected by bumper material on both sides of the corner, and the shortest allowable piece of bumper is 6". http://forums.usfirst.org/showthread.php?t=11218

I can totally understand how teams might have designed their robot in keeping with figure 8-2 prior to the publication of these Q&A responses and assumed that because it was shown in the manual and seemed to be consistant with the intent of the bumper rules (that the first thing to hit a wall or robot is always a bumper) that this configuration of bumper would be legal. Indeed, the GDC, through Q&A and team updates may clarify that this is an acceptable configuration. Based on my reading of the rules as they now stand, however, this is an external corner of the robot that is not protected by bumpers on each side of the corner, and thus is not a legal configuration.

Jason

25-01-2009 18:50

joeweber

Re: pic: Is this corner considered protected?

The next question is what is considered a segment. If you permanently attach a 3 inch piece to a 7 inch piece on a 45 degree angle and wrap the noodle around would that be considered one or two segments.

25-01-2009 19:12

EricH

Re: pic: Is this corner considered protected?

2 segments, if that angle is a corner. (The GDC refuses to define a corner as anything other than what an astute observer would see as a corner.)

25-01-2009 19:45

Gdeaver

Re: pic: Is this corner considered protected?

As I hope you can begin to see the easy way out is to square it off and move on to more critical aspects of the game.

25-01-2009 23:06

Scott Hill

Re: pic: Is this corner considered protected?

Take it step by step.

Initial paragraph relevant sentence..."If implemented as intended, a ROBOT that is driven into a vertical wall in any normal PLAYING CONFIGURATION will always have the BUMPER be the first thing to contact the wall"...

Comply? Yes, assuming the corner on the opposite side of the hitch is similar the BUMPER will hit the wall first.

A. Comply? Yes, the segment appears to meet the 6" min. dim.
B. Comply? Yes, stacked pair of noodles.
c. Comply? Yes, assuming the solid board is a prototype stand-in for the required 3/4" plywood.
D. Comply? Yes, assuming the duct tape is a stand-in for the continuous fabric.
E. Comply? Yes, assuming final weight under 18 lbs, easily attainable.
F. Comply? Yes, assuming easy installation, relatively easy to accomplish.
G. Comply? Yes, assuming rigid robust connection, relatively easy to accomplish.
H. Comply? Yes, granted.
I. Comply? Yes, the exterior corner is protected by the BUMPERS. It passes the initial paragraph vertical wall test.
J. Not applicable to the left end of the BUMPER segment as this is the free end of one BUMPER segment, not a corner or joint between BUMPER segments. The corner/joint shown looks ok.
K. Comply? Yes, assuming 2/3 of BUMPER PERIMETER is protected.
N. Comply? Yes, assuming BUMPER cross section construction requirements met.
O. Comply? Yes, if you lose the miter on the BUMPER backing board at the junction of the segments.
P. Comply? Yes, assuming the BUMPERS are mounted at the correct height in the BUMPER ZONE.

I make several assumptions in this discussion but I think they are permissible in getting to the main point(s) of contention.

With respect to the Q&A reference above by dtengineering (http://forums.usfirst.org/showthread.php?t=11257) which is the GDC's answer to my question, the GDC states "No. Figure 8-2 is intended to only illustrate the legality of some of the possible ways in which BUMPERS could be arranged on exterior corners. Please do not infer any other conclusions from that example." Fig 8-2 shows 5 different BUMPER-corner conditions, 3 labeled "ok", 1 labeled "not ok", and one not commented on. The GDC response also says "...some of the possible ways in which BUMPERS could be arranged..." which leads me to conclude that there may well be additional ways which are not commented on which may or may not be legal.

Since the condition in question has been shown as an example but has not been directly commented on in the MANUAL or the TEAM UPDATES I believe the prudent thing to do is apply the step by step as above. Having done that, as above, I believe the condition can clearly meet the intent of <R08>.

I sincerely welcome challenges/comments to my attempt at logic.

Thanks and apologies for the length,

Scott

25-01-2009 23:24

MrForbes

Re: pic: Is this corner considered protected?

Scott--

The one thing that shows that you might be wrong is the other link that Jason (dtengineering) provided

http://forums.usfirst.org/showthread.php?t=11218

25-01-2009 23:34

Scott Hill

Re: pic: Is this corner considered protected?

Thanks Squirrel, for the comment.

Protected by BUMPERS doesn't necessarily mean having BUMPERS. I think each side with respect to that exterior corner is protected by bumpers because if you push each side into the vertical wall the bumpers will hit first.

thanks,

Scott

25-01-2009 23:35

dtengineering

Re: pic: Is this corner considered protected?

Scott makes a good point, and... let me be clear... I would be happier to see his interpretation be correct than mine. I believe that this design does meet the intent of the rules (to protect robots and the field), and even the wording of the rules. Were I an inspector at a competition and presented solely with this design and the rule book, I would probably declare it as compliant.

Where it may fall short is in the definitition of "protected", as the GDC has stated:

Taking this definitition of "protected" as specifically requiring bumper segments on both sides of an exterior corner, and given that this is clearly a corner on the bumper perimeter (exterior) of the robot, I believe that as an inspector I would be compelled to declare these bumpers as "non-compliant" (whether I wanted to or not... inspectors cannot overrule the Q&A) without further official clarification from the GDC.

Don't get me wrong... I would be happy to see this be legal, but as it stands right now, I don't think it is.

Jason

Edit... Jim and Scott both posted while I was composing this reply... I have gone back to highlight in bold what I consider the crucial part of the Q&A ruling. I believe the use of "bumpers" in the plural, indicates a corner requires more than one bumper... but don't take my word for it.... put it up on Q&A!

25-01-2009 23:45

Mike8519

Re: pic: Is this corner considered protected?

I will also have to say that this configuration is illegal due to the requirement of both sides requiring protection and that protection required to be 6" long BUMPERS.

25-01-2009 23:46

Scott Hill

Re: pic: Is this corner considered protected?

Thanks dtengineering for your comment.

BUMPERS, plural, are protecting both sides of the the corner because the similar BUMPER on the other side of the hitch is involved when that side hits the wall.

scott

edit: more specifically, the left side of the corner in question would be protected by BUMPERS (2) per above, and the right side of the corner in question is protected by the one BUMPER segment that completely covers it and the BUMPER segment to the right which is mitered into at the oblique angle.

25-01-2009 23:49

Mike8519

Re: pic: Is this corner considered protected?

The corner is defined as the singular point where the "string" that defines the bumper perimiter changes angle in someway. The corner shown only has one side protected by a BUMPER.

25-01-2009 23:52

joeweber

Re: pic: Is this corner considered protected?

There are many different views of this question. I thank all for there response. The one consistent thing that I have found is that even if it is legal to do it still may be turned down by the inspector. GDC will only refer you to the rules.

If we turn the corner/angle into a curve will it no longer becomes a problem.

Per GDC
3: A "C" configuration chassis for the ROBOT would be legal if, and only if, it satisfies all applicable Robot Rules.
4: A specific minimum radius threshold to determine the difference between corners and curves has not been, and will not be, defined. A "corner" will be determined to be a "corner" when upon inspection any reasonably astute observer perceives it to be a "corner" and not a curve.

26-01-2009 00:04

dtengineering

Re: pic: Is this corner considered protected?

I've been thinking of a better way to phrase this whole bumper rule thing so that it would serve the purpose and intent of the rule, be easy to test, unambiguous and yet simply and clearly stated.

I would suggest that the GDC could simplify this whole bumper thing by stating:

"When a robot, with trailer attached, approaches a wall, the first part of the robot or trailer to contact the wall shall be a bumper. This may be tested by pushing a 2x4 (representing a long wall) edgewise along the ground towards the robot. If the edge of the 2x4 touches any part of the robot, the robot is not protected."

But... there might be weaknesses in that rule that could lead to ambiguity when inspected by 1300+ teams. I don't envy the GDC their job and support/understand/appreciate their rulings 99.9% of the time. The other .1% of the time, I simply accept the ruling. Like I have a choice!

Jason

Jason

26-01-2009 00:11

Gdeaver

Re: pic: Is this corner considered protected?

What is the cost of squaring out the back end and ensuring this will pass inspection? Does the teams assumption that an angled rear gives some benefit to the trailer robot driving dynamics? The robot and trailer are to the point that the team should be able to test this assumption. I content that with the trailer dynamic our team has experienced, this angled rear design may not be desirable from a driving stand point. The team at this time will only loose a little build time this week modifying the design.
What is the cost if the team decides to stay with the current design and takes their chances that they can plead their case to the inspectors and prevail. If you loose this point at inspection, you will have a nasty day Thursday trying to Kluge up a fix in the pits. Our team has been there done that. I don't want to experience it again. Those who where there on our team now take a very Conservative view to the rules.

26-01-2009 00:18

Scott Hill

Re: pic: Is this corner considered protected?

Jason,

I really like your simple 2x4 test. It is unambiguous, easy to apply, and virtually the same as the vertical wall sentence from the lead paragraph of <R08>. I share your appreciation for the GDC and their efforts in a difficult task. The thing that makes this so critical is that there may well be many teams that show up at regionals (not to mention half way thru build season) with robots that may not comply with whatever the lead inspectors interpretation is and possibly face an insurmountable task to make their robot compliant.

Scott

26-01-2009 08:32

Al Skierkiewicz

Re: pic: Is this corner considered protected?

Scott,
In looking at the picture and visualizing certain field elements, I think it is entirely possible for an unprotected/non bumper portion of the robot to contact a field element or another robot. Certainly, the angle of the trailer tongue shown in the photo would allow a wide variety of possiblities, my robot included. In my mind, the rule that states in part...
R08 The BUMPER location and design have been specified so that ROBOTS will make BUMPER-to-BUMPER contact during any collisions. If implemented as intended, a ROBOT that is driven into a vertical wall in any normal PLAYING CONFIGURATION will always have the BUMPER be the first thing to contact the wall.
I would be hard pressed, from this photo, to be able to prove to myself that your robot design would be able to meet this specification.

26-01-2009 08:34

MamaSpoldi

Re: pic: Is this corner considered protected?

No one has addressed this part of these bumpers... the mitered corners of the plywood backing. This is not legal per rule <R08>.O (see also figure 8-4):

"The BUMPER backing must not extend beyond the “edge” of the ROBOT. The backing of adjacent BUMPER segments must not attach to each other if the attachment would require that the joint extend into the corner (see Figure 8 – 4)."

The pool noodles can wrap around the corner, but the plywood backing must stop at the edge of the frame. (You can see this is figure 8-2 as well, but you may have to zoom in a little to see it clearly.)

Note that in part N of this rule the statement that: " 'Hard' parts of the BUMPER (i.e. plywood backing, fastening system, and clamping angles) may extend up to a maximum of one inch beyond the BUMPER PERIMETER." is referring to the thickness of the backing (ie. the extension perpendicular to the bumper perimeter) rather than the length of the backing.

[This is also clarified in this Q&A posting: http://forums.usfirst.org/showthread.php?t=11279]

Also, regarding the corner protection, I would recommend also reviewing the answer given in this Q&A: http://forums.usfirst.org/showthread.php?t=11236. Our team had similar concerns about our bumper configuration. I agree that if there are doubts it is a good idea to opt for a less controversial implementation if it does not sacrifice any functionality.... or at a minimum have a retrofit already determined and ready to go to avoid too much pain if you are overruled.

26-01-2009 08:53

Gazelleman

Re: pic: Is this corner considered protected?

i agree

26-01-2009 09:02

johnr

Re: pic: Is this corner considered protected?

I would vote no on the bumper,but on a different note,wouldn't this extreme angle of trailer to bot allow an apposing bot to lock you up pretty good. I mean picture a bot driving into the lower left side of picture. Looks like it would be pretty hard to get away.

26-01-2009 11:00

Scott Hill

Re: pic: Is this corner considered protected?

Hi Al,
It's good to hear from you. For the record this isn't Winnovations robot but I think it raises certain points that are important to discuss.

With respect to your point regarding R08 BUMPER to BUMPER contact, the Manual allows up to 1/3 of the BUMPER PERIMETER to be unprotected by BUMPERS. Any ROBOT with a floor accumulator has to take advantage of this allowable 1/3 unprotected offering. Strict compliance with the BUMPER to BUMPER statement you reference would prohibit such accumulators. I don't think prohibition of floor accumulators is the intent of the GDC and I don't see how the portion of this ROBOT which is unprotected by BUMPERS is any more problematic than a floor accumulator opening/unprotected portion of the BUMPER PERIMETER.

Thanks, I look forward to seeing you, your team, and your ROBOT at Midwest

Scott

26-01-2009 11:33

Cory

Re: pic: Is this corner considered protected?

Scott, I think if you read this Q&A response, it is pretty clear that you need a bumper segment on both sides of a corner, even though one bumper segment may adequately protect both sides of the corner.

[edit] This Q&A is the one I wanted-it makes it abundantly clear that both sides of the corner must have their own bumper segment.

26-01-2009 12:03

Paul Copioli

Re: pic: Is this corner considered protected?

Scott,

One important thing to consider is that many of us are picking up from the floor and the "6 inch minimum" + "all sides must have a bumper" GDC clarifications have constrained all of us. The ThunderChicken floor pick-up opening is not as large as we wanted specifically because of the bumper rule. Our robot base design was driven by the bumper rule. Our design is not as cool as we wanted it to be because of the bumper rule.

If any team has a design that looks like the picture at one of my competition, thenn I will bring it up to the inspectors because they will have a significant advantage over everyone esle and it is in violation of written clarifications by the GDC.

The huge advantage on the back of your robot is that you can get your trailer off to the side more to help protect it and you can swing around the trailer more to get a better angle at your opponent.

The advantages on the front side are obvious wrt opening size.

Maybe they left a loophole in on purpose, but if they did, then I say they are lawyering the rules and now we will have to do the same.

For the record, I hate bumpers and designing around the bumper rules, to me, is silly.

26-01-2009 13:22

Triple B

Re: pic: Is this corner considered protected?

Ya, what Paul said
mike d

26-01-2009 17:57

EricH

Re: pic: Is this corner considered protected?

Well, you got your official answer.

http://forums.usfirst.org/showthread.php?t=11600

26-01-2009 20:58

joeweber

Re: pic: Is this corner considered protected?

We figured if we turn the andle corner into a curve we could resove the problem but found the next issue.

Questions about the trailer hitch- I assembles a hitch like the one for the competition trailer (which is different than the team built trailer) and found that the small .615 dia. Hitch pin fits into a 1 inch x 1 inch square tube. There is only about 1 3/8 inch from the pin to the edge of the square tube. Will this limit the amount of turn that the trailer can make and if the aluminum hits the trailer hitch assembly (although it barley fits inside maybe if perfectly centered) will this be a violation of <R18> E..

We want to turn as sharp as possible so we can pin wheel around the trailer for defense.

26-01-2009 23:33

Scott Hill

Re: pic: Is this corner considered protected?

Cory,
The Q&A answer you refer to follows:

Default Re: Bumper Length
1. The statements are not contradictory. The length of a BUMPER is determined by the portion of the assembly the includes all the required elements (pool noodle, fabric covering, clamping angles, and plywood backing) in the cross-section of the assembly. The length of this portion of the BUMPER assembly must be at least six inches. This is consistent with the previous answers and the statements/drawings in Team Update #2.

2. As indicated in Rule <R08-I>, all exterior corners of the BUMPER PERIMETER must be protected by BUMPERS. Both "sides" of the corner must be protected.

3. Rule <R18-E> requires that the ROBOT be designed such that contact between the ROBOT and the TRAILER (other than the Trailer Hitch) must be BUMPER-to-BUMPER. There are no exceptions to this.

To be honest I don't see here where it is abundantly clear that both sides of the corner must have their own BUMPER segment. It is clear that "all exterior corners of the BUMPER PERIMETER must be protected by BUMPERS." and that "Both sides of the corner must be protected." It is easy to create a ROBOT BUMPER PERIMETER which meets the the two statements in 2. above which has a side that does not have bumpers on it, yet the side would be protected. I believe the ROBOT in question at the beginning of this thread could be such a case. All it takes is two sets of oblique angles as part of the BUMPER PERIMETER.

Paul,

You quote ..."all sides must have a bumper"... GDC clarifications. I would like to know where you found that quote. In the Manual, in the team updates, and in the Q&A in it's many replies to questions on this topic I can't find where the GDC has stated "all sides must have a bumper". If any one has knowledge of where, in the above venues they have, please show me.

If you think about this.... if they really wanted each side of the robot to have BUMPER(S) they just have to include in the Competition Manual or the Team Updates the simple statement "all sides must have BUMPERS". When it would be so easy to state "all sides must have BUMPERS", they don't; not in the Competition Manual, not in the Team Updates, and not even in the many replies to questions in the Q&A. In my mind it is doubtful that in all of this communication, all of these communicators have randomly avoided using this simple statement if it clearly expresses their intent. Therefore I don't think it is the GDC's intent to require all sides of a ROBOT to have BUMPERS.

Paul, I look forward to seeing you, and your team and ROBOT at Midwest, and Cory, if things work out you and your folks as well at Nationals, the best of luck to us all,

Scott

27-01-2009 00:01

EricH

Re: pic: Is this corner considered protected?

Scott, this Q&A was posted early on. You also have:
http://forums.usfirst.org/showthread.php?t=10933
http://forums.usfirst.org/showthread.php?t=11056
http://forums.usfirst.org/showthread.php?t=11218

Take them all together or one at a time, Paul has summarized what the GDC has said.

27-01-2009 00:07

Mike8519

Re: pic: Is this corner considered protected?

While there is no rule saying all "sides" must have bumpers it must have corners to form that edge and by the Q&A responses those corners must be protected by 6" of bumper on each side. Extending noodles into the corner for protection does not count as both sides being protected.

EricH's final link explicity states this

27-01-2009 00:31

Kyler

Re: pic: Is this corner considered protected?

curiously enough, the GDC never actually says in http://forums.usfirst.org/showthread.php?t=11600 that the configuration is illegal, only that figure 8-2 is meant to be an example. Just to point that out.

27-01-2009 01:59

dlavery

Re: pic: Is this corner considered protected?

The question in that Q&A post never asked if the configuration on their robot was illegal or not. So of course they did not get a determination of the legality of the configuration.


.

27-01-2009 10:45

Joe Ross

Re: pic: Is this corner considered protected?

Had they asked about that specific robot, they would have been referred to team update 6 and still not get the answer they wanted.

27-01-2009 20:33

5n1p3r

Re: pic: Is this corner considered protected?

technically you only need to cover 3 sides lol, im jk but really i would consider this well over the range of legal. The trailer aint bumpin so it seems perfectly fine lol

27-01-2009 20:45

Mike8519

Re: pic: Is this corner considered protected?

But the rear corner is not protected on both sides

27-01-2009 21:00

Mike Martus

Re: pic: Is this corner considered protected?

As a Lead Inspector in many Michigan Events I can see a headache in the making. I hope many of the bumper issues stated here are not typical.... bottom line is.... the rules rule!

28-01-2009 00:06

Scott Hill

Re: pic: Is this corner considered protected?

the drawing shows a ROBOT BUMPER PERIMETER with BUMPERS (blue) and corner fillers (red) which I think reasonably represents the ROBOT and CORNER in question.

The BUMPER PERIMETER is a polygon. The polygon has 6 corners; A,B,C,D,E,F. 2 of the corners, D,E, have right angles. 4 of the corners, A,B,C,F, have obtuse oblique angles. The polygon has 6 sides; AB,BC,CD,DE,EF,FA.

The corner in question with respect to this thread is corner A. There are 2 sides "of corner A", side AB and side FA.

Each side of the corner, side AB and side FA, is protected by BUMPERS. Each sides protection clearly meets the intent of <R08> ..."If implemented as intended, a ROBOT that is driven into a vertical wall in any normal PLAYING CONFIGURATION will always have the BUMPER be the first thing to contact the wall."... . Side AB has no BUMPERS on it yet the BUMPER configuration clearly meets the intent of the rule, which is clearly stated.

EricH, I enjoy reading your may posts in these fora. I think you do a lot to contribute positively with your comments. However I must take issue with your position on this question. What I believe are the relative sentences from your referenced sources follow, with my comments appended:

Reference #1: "Both sides of the corner must be protected." Comment: they are, see above.

Reference #2: "Both sides of the corner must be protected by BUMPER segments." Comment: they are, see above. "Rule <R08-i> requires BUMPER protection on every corner of the BUMPER PERIMETER." There is obviously BUMPER protection on every corner of the BUMPER PERIMETER, see above drawing.

Reference #3: This reference is not on point because the answer is given with respect to a rectangular ROBOT BUMPER PERIMETER, not the BUMPER PERIMETER in question.

Reference #4: "The interpretation that "both sides of an exterior corner must be protected with segments of bumpers, and the bumper segments must be a minimum of 6 inches" is correct." Comment: both sides of the corner are protected, see above, and the bumper segments in the example can be easily made to meet the 6" minimum dimension requirement.

Mike8519: You state ..."those corners must be protected by 6" of bumper on each side"..... I think if you read carefully the requirements typically state ..."both sides of the corner must be protected"... not, corners must be protected on each side. They do not mean the same thing.

Thanks to all for contributing to the discussion,

Scott

28-01-2009 00:20

EricH

Re: pic: Is this corner considered protected?

Please note the plural form. The GDC has been quite clear on this. There is bumper protection, yes. It is protected by a bumper segment. I'm nit-picking here, but it seems that this would be illegal.

Again, plural form is used.

While the words don't mean the same thing, the first is a subcase of the second. The first is also what the GDC seems to be saying.

I know how we can settle this once and for all. Submit the picture to Q&A. Ask: "Are corners A and B adequately protected under <R08>? If not, why not?" If they don't refer you back to the rule, they will hopefully give a straight answer.

The other option is that they say, "we cannot comment on specific robot designs", in which case I would advise having a more conservative route available at the event or just plain installed on the robot.

28-01-2009 00:32

waialua359

Re: pic: Is this corner considered protected?

I agree with this one. There will be many headaches for inspectors and some very unhappy campers on both sides.

The most simplest solution, while it may not allow teams to be as creative as they wanted to be, is to have a frame, that is unquestionably, legal.

From past experience the last several years, I dont want those headaches again as much as possible.

28-01-2009 00:35

Scott Hill

Re: pic: Is this corner considered protected?

EricH,

Thanks for your comments.

Question: If the plural is required as you say and "protected by a bumper segment" would not be legal, as you suggest, is a robot side legally protected if it is covered completely by only one bumper segment?

I think it would be.

I also don't see how you can consider the first of the two statements as you list them as a subcase of the second. I have never seen the GDC say the first, and I have quite often seen them specifically say the second.

Scott

28-01-2009 00:42

EricH

Re: pic: Is this corner considered protected?

We aren't considering sides, are we? We are considering corners, which are a junction of two sides.

On this, I have reviewed. If the corners must be protected on by six inches of bumpers on both sides, then by definition, both sides are protected. So the second is a subcase of the first, but may also stand alone. I stand corrected.

However, I now have some more things to consider. Several teams have recently asked, "will bending 1 6+" bumper segment around a corner be legal if we don't have backing in the corner and we have less than 6" on one side?" or something to that effect. The GDC has answered no to all cases like this. But if you had a 13" piece of bumper, broken into 2 6" segments and a filled, I'm pretty sure that would be legal. Just some food for thought.

28-01-2009 00:50

Scott Hill

Re: pic: Is this corner considered protected?

EricH,

I believe the statements you included were referencing the sides of the corner.

Thanks,

Scott

28-01-2009 01:25

EricH

Re: pic: Is this corner considered protected?

In which post?

The debate here (to remind ourselves and inform anyone just joining us) is over one simple question: Do both sides of a given corner have to be protected by bumper segments of 6" or more?

I am going to state the full reason for my interpretation. This will take a while, so bear with me.

My response will follow the reverse chronological order in Q&A.

http://forums.usfirst.org/showthread.php?t=11635

3 rules are cited. One is hard parts in a corner, one is the backing. Those aren't relevant here. But the reference to <R08-A> is interesting. Rounding a corner to protect both sides results in 2 segments. Neither is long enough in this case.

The next one regards the design under consideration. http://forums.usfirst.org/showthread.php?t=11600
However, it only covers defining an exterior corner.

http://forums.usfirst.org/showthread.php?t=11609 Clarification that no, you can't wrap a bumper and have it be one segment. From henceforward, I will ignore those Q&As that cover this topic, unless something else is answered.

http://forums.usfirst.org/showthread.php?t=11454
They are considering a similar setup. Note that the GDC says, "We can't rule on specific designs. We leave that to the event inspectors."

http://forums.usfirst.org/showthread.php?t=11471
This one is annoying. It references Bill's Blog and sets off a chain of research. Ah-hah! Bill's Blog has something: http://frcdirector.blogspot.com/2009...r-musings.html
Unfortunately, this is an unofficial channel. Nonetheless, point 3 is important. Remember, Bill is on the GDC. This is by no means official, however. I will deal with the rest of the research later, if necessary.

OK, I lie. This one is referenced to ask the previous question. http://forums.usfirst.org/showthread.php?t=11170
Note: the relevant question, #1 in the second post, is not directly answered. However, the logic is confirmed.

http://forums.usfirst.org/showthread.php?t=11218 is perhaps the most direct. See the GDC's first paragraph. This is one disagreed with earlier. I will simply say, note the plural.

http://forums.usfirst.org/showthread.php?t=11159 is also referenced by the one that references Bill's Blog, though through a chain. #2 is the relevant point here. It's another "answer with a not-quite answer".

http://forums.usfirst.org/showthread.php?t=11056 Here's one for you. They say that at least part of the fourth side of a 4-sided robot must be covered by bumpers. If that holds with an extra 2 sides...

http://forums.usfirst.org/showthread.php?t=10933 and http://forums.usfirst.org/showthread.php?t=11070 address the issue directly and are vaguely answered, at least as concerns this discussion.

Those are all that I could find relating to this topic. Taking those together, I conclude that the corners A and B must have a 6" segment of bumper on both sides, which is impossible due to the location of the trailer hitch. Therefore, a design change must be made. If there are questions as to why I interpret a response the way I do, go ahead and ask; I could be wrong.

Edit: Dave responded in the thread with just the overhead view. His response (barring an official overturning from the GDC via Q&A) is that the configuration won't pass inspection.

28-01-2009 02:10

Tristan Lall

Re: pic: Is this corner considered protected?

It looks like you're suggesting that any bumper design that satisfies the condition in the intent statement offers the required protection. That's not unreasonable, but I don't think that's the way that the GDC understands it.

As a test case for your theory, consider a robot similar to the one you posted above. Move the trailer hitch out of the way (put it in the gap on DE). Delete the section AB. Extend the segments FA and BC to their intersection, and call it G (but leave the bumpers as-is). Delete points A and B, leaving us with rigid segments GC and FG. Now, if we perform those operations on the picture above, we end up with a big sharp corner (at G) that clearly extends beyond the bumpers. This contravenes the condition in the intent statement, and is not protected by segments. But what if we made the angle at G something large, like 170°? There is still a corner (a discontinuity in the radius of curvature), but now the thickness of the existing bumpers allows it to pass the intent statement's condition (the corner doesn't stick out past the outermost edges of the bumpers anymore).

Is it your contention that even though the 170° corner at G is not abutted by any bumper segments, all necessary conditions are met (because the bumper hits first), and it would therefore be legal? If that's the case, then the amount of protrusion (inward or outward) past the edge of the bumpers is the most critical factor in determining protection (under your theory).

Apparently, the GDC considers the condition in the intent statement and the corner protection requirement to be separate, necessary conditions. Furthermore, it looks like they understand corner protection to mean a design with a legal bumper segment on each side of the corner.

Assuming that the function of the Q&A is to guide the interpretation of rules, but not to impose additional constraints*—that being the function of the rules and updates—the GDC's responses regarding corners have been mutually consistent and legal under the rules—so following them precisely ought to be acceptable at any event. (That's your best course of action.)

There might be some room for your interpretation, however: the GDC is describing a legal way to meet an existing requirement (protection of corners per <R08>, part I), but there's nothing in a rule or update that says that this is the only possible way to protect a robot's corners—in fact, to say that there is only one legal mode of protection (without some sort of explicit definition in the rules) is a bit of a stretch of the principle that the Q&A shouldn't be defining new constraints. (Yet, I think that that's implied here.) So as I understand it, you're relying on the fact that the next best thing to a direct definition of protection is the intent statement, and that because your proposed design passes that test, your corners are protected.

Like I said, it's not unreasonable...but you're taking a big risk that the inspectors at any given event will be open to considering that logic, and will arrive at the same conclusion as you, and that FIRST won't clarify things once and for all in an update (ruling against you).

*FIRST has not stated this directly for a couple of years, but that was formerly the rule of precedence. Maybe they made the statements in the 2009 Q&A binding, but neglected to tell anybody....

28-01-2009 09:53

SteveGPage

Re: pic: Is this corner considered protected?

I'm with you on this one Glenn!

I think that the GDC has created rules this time, when all taken together, has the intention of driving design; rather than teams coming up with any and all designs and trying to fit/apply the rules to the design. With the stated bumper constraints - bumper segment size, perimeter coverage, trailer-bumper interaction, etc... there will a limited number of designs that meet those requirements!

836 is going conservative to mitigate risks of an un-approvable design. Long configuration - Front opening of 16" (6" of bumper segments on either side), appropriate opening for the trailer hitch and leaving it at that.

28-01-2009 10:50

banannaman20

Re: pic: Is this corner considered protected?

no actually that will get u a equipment damage penatly because u will end up beding the touge of the trailer and i agree that also doesnt pass the 6" rule