Bumper question

[IndySam]

4.1.6 Bumper Rules
Robots are required to use Bumpers to protect all exterior vertices of the Frame Perimeter. For adequate protection, at least 8 in. of Bumper must be placed on each side of each exterior vertex(see Figure 4‑1, Figure 4‑2, and Figure 4‑3).

OK this is a very important rule as far as robot design is concerned. I hate waiting for answers from the GDC for things like this because it is so important.

While we wait for Q&A to open what are peoples opinion on the 8 in. of Bumper must be placed on each side of each exterior vertex thing?

Will that include the 2.5" beyond the corner or is it from the corner? this makes a 5" difference in possible bumper openings for ball pickup. Opinions?

[DMetalKong]

In my interpretation, the "bumper" is the part that has a hard backing, therefore the 8" required is 8" along the frame perimeter, and does not include the protrusion by any fluffy parts at the corner.

[IndySam]

Thanks David, I tend to agree with you.

The vertex is the corner (if I remember my geometry that I took many years ago) so each side of corner would mean 8" from the corner not boned it.

I think this is going to possibly screw up a lot of teams like the similar rule did in Lunacy.

[the man]

I believe their were some diagrams in the manual. Unless you pose a different question. Would you mind maybe drawing a quick pic?

[plnyyanks]

I believe their were some diagrams in the manual. Unless you pose a different question. Would you mind maybe drawing a quick pic?

Look here for the pictures you're thinking of (http://frc-manual.usfirst.org/viewItem/57#4.1.6)

[akoscielski3]

So we can split the 8 in up right? so 4 in on the right and 4 on the left. (this would be for one Side of the robot)

[KevinGoneNuts]

While I have you all here. I also have a bumper question. Attached is a picture of a bumper idea, after reading the rules it seems that this is alright? I want to be 100% sure. Does it seem okay to you?


11290

[plnyyanks]

While I have you all here. I also have a bumper question. Attached is a picture of a bumper idea, after reading the rules it seems that this is alright? I want to be 100% sure. Does it seem okay to you?


11290

Looks okay to me.

are required to use Bumpers to protect all exterior vertices of the Frame Perimeter. For adequate protection, at least 8 in. of Bumper must be placed on each side of each exterior vertex (see Figure 4‑1, Figure 4‑2, and Figure 4‑3).

Since all your exterior vertices and the required 8 inch covering are protected, it looks legal to me.

[KevinGoneNuts]

Looks okay to me.

Do you know how far it can go into the frame perimeter?

[plnyyanks]

Do you know how far it can go into the frame perimeter?

How far that little inlet can go into your frame? I can't find anything in the bumper rules that specifies that...

[JohnBoucher]

Each set of Bumpers (including any fasteners and/or structures that attach them to the Robot) must weigh no more than 20 lbs

Was it not 15 lbs last year?

[KevinGoneNuts]

How far that little inlet can go into your frame? I can't find anything in the bumper rules that specifies that...

Thank you! Should I bother the GDC about it or should I just leave it? haha

[Joe Ross]

Was it not 15 lbs last year?

Bumpers were last 15 lbs in 2008. They were 18 lbs in 2009, and 20lbs since.

[Jon Stratis]

So we can split the 8 in up right? so 4 in on the right and 4 on the left. (this would be for one Side of the robot)

No. See section 4.1.6:

Robots are required to use Bumpers to protect all exterior vertices of the Frame Perimeter. For adequate
protection, at least 8 in. of Bumper must be placed on each side of each exterior vertex


Emphasis mine. So, if you have a gap between bumper segments (along a straight portion of your FRAME PERIMETER), you'll have (at minimum) 8 in of bumpers on each side.

[slijin]

How far that little inlet can go into your frame? I can't find anything in the bumper rules that specifies that...

You're looking for [R33]; if the width of the gap >= 8", then it can only go 1/4" in; otherwise, there seems to be no apparent limit other than your bot itself.

[EricH]

You're looking for [R33]; if the width of the gap >= 8", then it can only go 1/4" in; otherwise, there seems to be no apparent limit other than your bot itself.
Ah, but if you don't have a bumper in that section, then there is no limit at all! Well, unless you happen to like having two half-robots.

[buildmaster5000]

What defines the bumper zone this year?? In the past, I remember it being from 1 to 7 inches above the ground (2010 excluded. Bumpers were higher that year), but I cannot seem to find where the "bumper zone" is defined in the manual.

Both <R01> and <R29> reference a "bumper zone" for those who are wondering. Please tell me that bumpers are going to be like the height limit last year, waiting for Q&A to open to ask a question that will greatly impact designs...

[the man]

2 to 10 in above the floor.

[Al Skierkiewicz]

Eagle's interpretation is correct. However, in the past this spec was 6" (six) inches.

[slijin]

What defines the bumper zone this year?? In the past, I remember it being from 1 to 7 inches above the ground (2010 excluded. Bumpers were higher that year), but I cannot seem to find where the "bumper zone" is defined in the manual.

Both <R01> and <R29> reference a "bumper zone" for those who are wondering. Please tell me that bumpers are going to be like the height limit last year, waiting for Q&A to open to ask a question that will greatly impact designs...

[R01] actually defines the Bumper Zone as 2"-10" above the ground, just to reiterate what previous posters have pointed out :p

[Steven Donow]

While I have you all here. I also have a bumper question. Attached is a picture of a bumper idea, after reading the rules it seems that this is alright? I want to be 100% sure. Does it seem okay to you?


11290

In contrast to this, if the bumper sections on the right and left of the 12" gap were 4", that would be illegal, right?(This was already kinda answered, but just making sure). Because I know Figures 4.1-4.3 aren't exactly drawn to scale, but they imply otherwise.

[Ernst]

Yes. You need a minimum of 8 inches of bumper on each side of each exterior vertex.

[Al Skierkiewicz]

In contrast to this, if the bumper sections on the right and left of the 12" gap were 4", that would be illegal, right?(This was already kinda answered, but just making sure). Because I know Figures 4.1-4.3 aren't exactly drawn to scale, but they imply otherwise.

No, the 8" specification relates to each side of the vertices in a continuous bumper section. The belief is that something as small as 4" would not protect your robot or another from damage in a collision.

[Cyberphil]

I agree with Al.

The rule states each side of each exterior vertex, which means on one exterior vertex you must have 8" of bumpers on one side and 8" of bumpers on the other side. That means that on the long side of your robot you can have a maximum opening of 22" and on the short side a maximum opening of 12" (assuming your bot is rectangular).

[SenorZ]

I've attached an image from Figure 4-3.
Why is the circled corner not ok?
Is it because
a) it is an interior vertex and cannot be bumper-ed,
b) the adjacent exterior vertex is not covered
c) the straight section of frame connecting it to the exterior vertex is less then 8''

To me it seems like they are saying you can't have a bumper go inside a cut-out. Which is odd.

[Ninja_Bait]

Answer B is covered by the arrow below the one you circled. C is covered in another diagram explaining dimensional rules. A is correct. R27:

Robots are required to use Bumpers to protect all exterior vertices of the Frame Perimeter.

That is not considered an exterior vertex because it is contained in the frame perimeter. The perimeter is defined by the vertical rightmost edge and does not include the inlet.

[GaryVoshol]

To me it seems like they are saying you can't have a bumper go inside a cut-out. Which is odd.

You can have a bumper-like structure inside your Frame Perimeter (FP), but you can't have a Bumper inside the FP.

The difference is in the weight allocation. Any bumper-like structure inside the FP must be counted in the 120 lbs limit. And if you make them color-coded, so that you have 2 of them, you have to count the weight of both pieces at the same time (additional Mechanisms).

Your robot could look somewhat like the circled area except:
-- the bumper-like structure on the inside of the cutout could not extend past the frame
-- the Bumper could not extend past the vertex

[Al Skierkiewicz]

Quite frankly, I don't know why that interior bumper is outlined as "not OK". The rules say that a bumper must attach to the frame perimeter, which it does, it must be a minimum of 8" on either side of an exterior vertex, can't tell since the drawing is not dimensioned, etc. There do appear to be any rules that prevent interior bumpers. If I find out, I will let you know.

[Rocketeeringer]

I don't think there's a rule expressly prohibiting interior bumpers, but from the diagram and their stress on "exterior vertexes" I would just go with bumpers on the outer corners.

Having bumpers on the inside would limit the already limited space available because of the 8" on each side rule, so maybe they want to give us as much room to work with but having the compromise of the exterior vertex and 8" on each side.

[Joe Johnson]

Quite frankly, I don't know why that interior bumper is outlined as "not OK". The rules say that a bumper must attach to the frame perimeter, which it does, it must be a minimum of 8" on either side of an exterior vertex, can't tell since the drawing is not dimensioned, etc. There do appear to be any rules that prevent interior bumpers. If I find out, I will let you know.

I interpret it this way. The FP does NOT include the inside of the U you are not allowed to have a bumper in there... ...that doesn't count as robot weight. If you want to put bumper in there, knock yourself out, it just has to go in your BOM calculations, weight, ...

Joe J.

[Al Skierkiewicz]

Joe,
The rule does not say that bumpers can only exist on the outside of the Frame Perimeter. It simply says they have to be attached Frame perimeter. If one were to assume that the above diagram had no mounting on the inside of cutout, I find nothing that makes it illegal but I am working on it.

[tlivingd]

Quite frankly, I don't know why that interior bumper is outlined as "not OK". The rules say that a bumper must attach to the frame perimeter, which it does, it must be a minimum of 8" on either side of an exterior vertex, can't tell since the drawing is not dimensioned, etc. There do appear to be any rules that prevent interior bumpers. If I find out, I will let you know.


I believe the interior bumper is not ok as FIRST wants an 8" 'strike' zone to minimize damage to other machines. Otherwise below would be legal and leave a point that can cause damage to other machines. not to mention the whole 120 lb weight limit.
EDIT: It maybe good for a rule clarification about exterior angles that are less than 90* and thus protruding within the machine.

https://lh6.googleusercontent.com/-OJ1rNKDuGEk/TwpsrzYUmsI/AAAAAAAAAUQ/xRqPlGLK2T8/s283/Untitled.jpg

[Al Skierkiewicz]

Nate,
The 120 lbs does not apply to the bumpers. Bumpers can weigh up to 20 lbs. As of right now, there is no rule that prevents your drawing from being used. Please expect this to change momentarily.

[Jibsy]

Just want to be really clear here. Since the maximum width of the bot is 28", andy ou need 8" of bumper on each side of that, your very maximum opening on the front is 12"? If you have no frame there, just a gap, does the 8" rule still apply? (Meaning you can't have say an 18" gap with 5" of bumpers on each side?

I would hate for this rule to be interpreted wrong and potentially use an opening 30% smaller than legal.

[Al Skierkiewicz]

Jared,
Current rules require a minimum of an 8" bumper section on both sides of the corner of the robot. Other parts of the bumper rule(s) cover slots, indents and gaps.

[slijin]

Joe,
The rule does not say that bumpers can only exist on the outside of the Frame Perimeter. It simply says they have to be attached Frame perimeter. If one were to assume that the above diagram had no mounting on the inside of cutout, I find nothing that makes it illegal but I am working on it.

<R01>The Robot must have a Frame Perimeter that is comprised of fixed, non-articulated structural elements of the Robot. The Frame Perimeter of a Robot is defined by the outer-most set of exterior verticies on the Robot that are within the Bumper Zone, which is between 2 and 10 in. from the floor. Minor protrusions no greater than ¼ in. such as bolt heads, fastener ends, and rivets are not considered part of the Frame Perimeter.

To determine the Frame Perimeter, wrap a piece of string around the Robot at the level described in [R02]. The string describes this polygon.

Emphasis mine. In short, a bumper intruding into the Frame Perimeter, as Dr. Joe pointed out, would violate this rule.

[Al Skierkiewicz]

Samuel,
As I pointed out earlier, the rules specify that the bumper needs to be attached to the exterior of the frame perimeter. It does not say bumpers have to be outside the frame perimeter. I expect this to be clarified in the near future so watch for Team Updates. In 2011 the rule read as follows...

A. BUMPERS must provide complete protection of the entire FRAME PERIMETER of the ROBOT (i.e. BUMPERS must wrap entirely around the ROBOT). As part of the 100% coverage, BUMPERS must protect all exterior corners of the FRAME PERIMETER.

In 2012 the rule reads...

Robots are required to use Bumpers to protect all exterior vertices of the Frame Perimeter. For adequate protection, at least 8 in. of Bumper must be placed on each side of each exterior vertex (see Figure 4?1, Figure 4?2, and Figure 4?3).

Emphasis mine to show the difference. That difference, while slight in 2011 required bumpers around the entire Frame Perimeter, 2012 rules specify that as a minimum the bumpers must cover the exterior vertices. It does not say that interior surfaces cannot also be covered. I believe that the GDC had intended the rule to prevent bumpers on interior openings in the frame. That is why I expect it to be changed at a future date.

[CrashTestPilot]

I believe the interior bumper is not ok as FIRST wants an 8" 'strike' zone to minimize damage to other machines. Otherwise below would be legal and leave a point that can cause damage to other machines. not to mention the whole 120 lb weight limit.
EDIT: It maybe good for a rule clarification about exterior angles that are less than 90* and thus protruding within the machine.

https://lh6.googleusercontent.com/-OJ1rNKDuGEk/TwpsrzYUmsI/AAAAAAAAAUQ/xRqPlGLK2T8/s283/Untitled.jpg

OK, so per rules as they are stated in rev 00 and 01 this configuration would still be legal but would not meet the intent of having 8" strike zone so the bumper rules are likely to be revised to not allow for such frame?

Also, imagine starting off with a rectangular frame and chamfering two adjacent corners in such way that the chamfer diagonal length was at least 8". If the short wall in between the two chamfers was completely removed to make a ball intake would that satisfy all the rules? Figure 4.2 does not show such configuration. I assume it would also be against the spirit of the rule.

Wait: I think I got it. If the inlet is created by removing a section of straight wall as shown in fig 4.3 it does not create any new verticies for the frame perimeter. If the chamfers are added they will create two new verticies and those need 8" on each side of the vertex.

[Al Skierkiewicz]

Wait: I think I got it. If the inlet is created by removing a section of straight wall as shown in fig 4.3 it does not create any new verticies for the frame perimeter. If the chamfers are added they will create two new verticies and those need 8" on each side of the vertex.

Yes, I think you got it!

[Mik_951]

As you told earlier, the bumpers have to be 2'' to 10'' from the floor. But until where? The bottom of the bumpers or till the higher part of it?

[BHOP]

"Robots are required to use Bumpers to protect all exterior vertices of the Frame Perimeter"

What if you have no exterior vertices...meaning your robot has a circular frame perimeter?

[Jon Stratis]

The bumper zone (2-10" off the floor this year) typically is the zone that the bumpers have to be contained within - the top of the bumper can be no more than 10" from the floor, and the bottom no less than 2" from the floor.

Al - wouldn't a team with that design violate R35? I doubt anyone would consider those interior bumpers to be "approximately" 90 degrees from the other 3 sides of the robot!


[R35]
Teams shall display their team number on the Bumpers in four locations at approximately 90° intervals around the perimeter of the Robot. The numerals must be at least 4 in. high, at least 3⁄4 in. in stroke width, and be either white in color or outlined in white. Team numbers must be clearly visible from a distance of not less than 100 ft, so that judges, referees, and announcers can easily identify competing Robots.

[Al Skierkiewicz]

Eagle,
Are you referring to the indented design? If so, should one side of the indent have numerals and they were visible from that side and you circled the robot at 90 degree intervals (assuming the other sides join each other at 90 degrees) then it is conceivable that a robot could meet that rule with visible numerals on the other three sides. I don't know what the GDC had in mind for robot frame design.

As far as circular frame designs, one interpretation could be that the entire frame perimeter was a continuous vertex and therefore the entire frame perimeter needed to be protected by bumper. I would have to ask for GDC guidance for this case, considering the 8" segment length rule in addition to other considerations. You guys are always challenging us.

[Cyberphil]

I hate to bring up this discussion once again, but we are having a discrepency within our team. Some people believe that you will be able to split up the 8" of bumper on one side of the robot into two 4" pieces (backed by the frame that is). My interpretation of the rules is that each corner of the robot needs to have 8" of bumper on both sides of it, that is on a normal sized robot, the 28" side of one corner needs 8" minimum of bumper and the 38" side needs 8" also. Since this applies to each corner, the maximum ammount of opening on the short side is 12", correct?

Here is a restatement of the rule in question:

4.1.6 Bumper Rules
[R27]
Robots are required to use Bumpers to protect all exterior vertices of the Frame Perimeter. For adequate protection, at least 8 in. of Bumper must be placed on each side of each exterior vertex (see Figure 4‑1, Figure 4‑2, and Figure 4‑3).

I also attached a diaghram. Please post which side you believe to be correct.

[EricH]

Side A, hands down. 'at least 8" on each side of each exterior vertex' is what the rule says; that is what the inspectors are going to call legal.

No questions there.

And yes, the maximum opening (what I think you really meant to say) on the short side is 12" due to the 8". If you want more collection space, use a wide robot.

[Cyberphil]

I did mean Maximum.

This is what I (and many teamates) believe also. I am going to post this to the Q and A anyway, but thank you for your input! It is always greatly appreciated!

[Al Skierkiewicz]

Team Update #2 that came out on Friday adds something to this discussion.

[JChavis]

Since it seems that we are already talking about a square U shape for our bumpers, how should teams go around and place their team numbers on the side with the split bumper?

Should teams place the numbers like this:

1. [0000]_______[____]
2. [000_]_______[____]
3. [00__]_______[____]


Or like this:

4. [__00]_______[00__]
5. [__00]_______[0___]
6. [___0]_______[0___]


Our number is 3490, and I am thinking we should split the numbers across the face of the split side (#4).

[Cyberphil]

Also, there are two answers on the QnA that partially answer my question, but they still will probably not be enough.

Q. In regards to Bumper Rule R27, when it states that "8" of bumper must be placed on each side of the exterior vertex...to provide adequate protection", does this mean that the bumpers themselves must be 8" long and 5" of the robot be covered or the bumpers be 11" and cover 8" of robot?

A. The 8 in. of Frame Perimeter immediately on either side of an exterior vertex must be covered by a Bumper.

The key word in there is immediately, meaning right up against each exterior vertex on both sides. I am convinced, but others still are not.

Also, just recently there was my exact question posted on the QnA:

Does the 8" of bumper on the "side of each vertex" mean that there have to be 8" of bumper from each corner (16" total), or 8" of bumper on that side total (8" total, 4" from each corner)?

Looking forward to when that one is answered.

[engunneer]

JChavis, I'd say option 1, especially if the gap in your bumpers is very wide. There's nothing that says you have to have only one number per side :)


Cyberphil,
From R27
For adequate protection, at least 8 in. of Bumper must be placed on each side of each exterior vertex

8" on each side of each vertex means 8" on the turnwise side, and 8" on the widdershins side. (CW and CCW). The corners need to be protected, but don't count as part of the 8". 8" of frame need to be protected on each side.

[JChavis]

JChavis, I'd say option 1, especially if the gap in your bumpers is very wide. There's nothing that says you have to have only one number per side :)

Well, I guess you're right. I just asked the question just in case field refs can't see a blocked half on a pinned robot. But then again, there are the other remaining 2 sides to show the number....


Thanks!::safety::

[Al Skierkiewicz]

J,
While team numbers may be obvious to you and may meet the rule and pass inspection, there is one thing to consider. (I use this argument during inspection) You want to play on Saturday afternoon and that often requires other teams know who you are. If you make it easy for them, you increase your chances. Marketing is a big key.

[JChavis]

J,
While team numbers may be obvious to you and may meet the rule and pass inspection, there is one thing to consider. (I use this argument during inspection) You want to play on Saturday afternoon and that often requires other teams know who you are. If you make it easy for them, you increase your chances. Marketing is a big key.

Well in that case, would it be okay to place your entire number on BOTH sides of the split face?:ahh:

[Cyberphil]

8" on each side of each vertex means 8" on the turnwise side, and 8" on the widdershins side. (CW and CCW). The corners need to be protected, but don't count as part of the 8". 8" of frame need to be protected on each side.

Ok, I agree with you on that. The rule is questionable at this point. Your reading of the rules also implies you could split the bumpers up into eight 1" lengths of bumper, put them on one side of your robot equally spaced (with two of them filling the corners on each side) and that would be legal. But read the ruling from the QnA (my previous post) about a different question regarding bumpers. The answer on the QnA states:

A. The 8 in. of Frame Perimeter immediately on either side of an exterior vertex must be covered by a Bumper.

My interpretation of that answer is take any exterior vertex, take a tape measure from that exterior vertex 8" along one side the frame. That area is where bumpers must be. Preforming that process on each side of exterior vertex (8 different places) would give you a minimum of 16" of bumper on each side.

For the time being the rule is still up in the air to many people. Just wait until the newest R27 question is answered. It will answer this discrepancy.

[EricH]

Well in that case, would it be okay to place your entire number on BOTH sides of the split face?:ahh:
I think you should ask Q&A that one; I think you'd be OK, but the rule could reasonably be read that more than 4 locations isn't allowed.

But, there are zero restrictions on where else on the robot you have your number. Just make sure that there's a contrasting background behind the number so scouts can read it from the top of the stands. (Hint: Black on clear isn't going to show up very well. Put some paper behind it, though, and it'll stand out.)

[GaryVoshol]

Since it seems that we are already talking about a square U shape for our bumpers, how should teams go around and place their team numbers on the side with the split bumper?

Should teams place the numbers like this:

1. [0000]_______[____]
2. [000_]_______[____]
3. [00__]_______[____]


Or like this:

4. [__00]_______[00__]
5. [__00]_______[0___]
6. [___0]_______[0___]


Our number is 3490, and I am thinking we should split the numbers across the face of the split side (#4).

As a ref, I would prefer method 1/2/3. I want to be able to see the whole number at one time. With method 4, I might get confused between 3490 and teams 34 or 90. Methods 5 and 6 seem particulary obnoxious to me - I think it's the single digit by itself that looks bad (unless you are one of those single digit teams!).

I wouldn't have a problem at all with [3490]_______[3490], provided you don't use one of those numbers as a substitute for the number being on another face of the robot. But as Eric mentioned, you should probably clear it through Q&A.

[Cyberphil]

So, as for the question about R27 (8" on each side of each vertex) this is what the QnA answered:

Q. Does the 8" of bumper on the "side of each vertex" mean that there have to be 8" of bumper from each corner (16" total), or 8" of bumper on that side total (8" total, 4" from each corner)?
A. Please refer to [R27]. At least 8 in. of Bumper must be installed on each side of the vertex.

Does this help our discussion whatsoever? They did not clarify anything we found there to be multiple interpretations of. :(

[Brighid.b]

To everyone, if you are using a multidimensional frame do bumpers need to cover both the bottom and upper deck?? Or is it ok to have the bumpers a tad bit lower then the upper deck but still within bumper zone? And attached to lower deck?

[Al Skierkiewicz]

Brig,
The bumpers must be attached to the frame perimeter and be between 2" and 10" above the floor when the robot is flat on the floor. The frame perimeter is the outermost extent of the frame in the bumper zone. Nothing can extend beyond the Frame Perimeter except the single appendage that may deployed during the match. If the upper deck and lower deck are different dimensions but both exist within the bumper zone, only one can define the frame perimeter. As stated, the perimeter is established by wrapping a string around the exterior vertices of the robot. Remember that in this critical discussion, a team must satisfy all bumper rules. Whatever part of the robot is the larger, the bumpers must be attached to it and it must fit in the size constraints. To add one more item, while bolt heads, welds and other protuberances may cause gaps behind the bumper, the robot must fit into the sizing box with the protuberances. At no time can small items be larger than the specified dimensions given in the robot rules.

[Brighid.b]

So in summation a set of bumpers are legal as long as they are protecting the vertices and the outter most perimeter? if if part of the frame is taller than the place where bumpers would be going?

[Brighid.b]

We have two levels of frame and they are the same dimensions, one is just taller, does the taller part need to be covered?

[EricH]

We have two levels of frame and they are the same dimensions, one is just taller, does the taller part need to be covered?
If you have the bumpers within the bumper zone, on the frame perimeter, and the upper portion is not covered, then you'll be OK. If the upper portion is covered by bumpers and the lower is not, but the bumpers are still within the bumper zone on the frame perimeter, then you'll be OK.

Pending an official inspection, of course.

[Al Skierkiewicz]

To answer your first question,

The other way around. Nothing on the robot can extend outside of the Frame Perimeter...
[R01-2]
The Robot must have a Frame Perimeter that is comprised of fixed, non-articulated structural elements of the
Robot. The Frame Perimeter of a Robot is defined by the outer-most set of exterior vertices on the Robot that are
within the Bumper Zone, which is between 2 and 10 in. from the floor.

AND

[R02]
The Robot must satisfy the following size constraints:

E. no other part of the Robot may extend beyond the vertical projection of the Frame Perimeter (with the exception of minor protrusions permitted per [R01-2]).
If a Robot is designed as intended and pushed up against a vertical wall (with Bumpers removed and appendages retracted), only the Frame Perimeter (or its minor protrusions) will be in contact with the wall.

The whole object to bumpers is to minimize robot damage in collisions with other robots or with field elements.
Emphasis mine.

[pandamonium]

This question may not be 100% relative to the other questions and comments in this thread but it does relate to bumper rules so I figured this is as good a place as any.

What advantages do you really gain from putting more than the required amount of bumpers on robots?

Lets say that in a normal drive configuration my wide left side is all frame but meets the minimum bumper requirements. This will help 3 robots fit on the bridge!! Since all corners need to be protected frame on frame collisions should be minimal. If an opponents bumper intentionally touches a robots frame perimeter that is not covered in bumpers is that a technical foul?

Idk I guess I just don't see a reason why you would want more than the minimum this year...

[Brighid.b]

To answer your first question,

The other way around. Nothing on the robot can extend outside of the Frame Perimeter...
[R01-2]
The Robot must have a Frame Perimeter that is comprised of fixed, non-articulated structural elements of the
Robot. The Frame Perimeter of a Robot is defined by the outer-most set of exterior vertices on the Robot that are
within the Bumper Zone, which is between 2 and 10 in. from the floor.

AND

[R02]
The Robot must satisfy the following size constraints:

E. no other part of the Robot may extend beyond the vertical projection of the Frame Perimeter (with the exception of minor protrusions permitted per [R01-2]).
If a Robot is designed as intended and pushed up against a vertical wall (with Bumpers removed and appendages retracted), only the Frame Perimeter (or its minor protrusions) will be in contact with the wall.

The whole object to bumpers is to minimize robot damage in collisions with other robots or with field elements.
Emphasis mine.

Ok, but both the upper and lower are the same dimensions, same x and z, different y.

[Al Skierkiewicz]

Pan,
Not sure what you are proposing but if you are asking 'if a rectangular robot that has a minimum 8" bumper in each corner but leaves the rest of the frame exposed', is legal the answer appears to be yes if all other bumper rules are also satisfied. Assuming only four exterior vertices.

[Al Skierkiewicz]

Ok, but both the upper and lower are the same dimensions, same x and z, different y.
The Frame perimeter is still defined by the bumper zone. If your robot was the same dimension from the bottom of the base to 60", that is legal even though the perimeter is only determined within the bumper zone. Provided, of course, that even bolt heads and welds do not fall outside the max dimension limits. Under all robot designs, the robot must fit inside the sizing box.

[johnsje6]

Question - does the 8" measurement of the bumper segment mean the plywood backing has to be 8" or is it the overall length, including the overlap with the adjacent side, which would be pool noodle and fabric. If it is the overall length, you could have a chassis opening of about 19" on a conventional chassis?

[IndySam]

Yes, the minimum plywood length is 8"

[Cal578]

The 1/13 update clarifies a few things about bumpers. The important thing is the new figure 4-3 for [R27]:
http://frc-manual.usfirst.org/upload/TU2-1.jpg

Note that the corner on the right side, a little lower than center, that was marked "NOT OK" is now not marked. Apparently, that marking was just a mistake in the original, so it's okay.

Question - does the 8" measurement of the bumper segment mean the plywood backing has to be 8" or is it the overall length, including the overlap with the adjacent side, which would be pool noodle and fabric. If it is the overall length, you could have a chassis opening of about 19" on a conventional chassis?
My interpretation is that the minimum length IN CONTACT WITH THE FRAME is 8", so that doesn't count any plywood extending past the vertex and overlapping with another piece of bumper plywood. Figure 4-4 in [R28] shows that the overlapping plywood is ok, and [R33] with the 1/17 updates says that "each end of the Bumper must be rigidly attached to the Frame Perimeter", so the part extending past the bumper won't count towards the 8". Since this last part is my interpretation, I sure would like to see an update that has dimensions inside the figures showing where this 8" is measured.

[VThokieME04]

Was there any clarification on this type of setup? I can't seem to see anything in the team updates that states otherwise.

I believe the interior bumper is not ok as FIRST wants an 8" 'strike' zone to minimize damage to other machines. Otherwise below would be legal and leave a point that can cause damage to other machines. not to mention the whole 120 lb weight limit.
EDIT: It maybe good for a rule clarification about exterior angles that are less than 90* and thus protruding within the machine.

https://lh6.googleusercontent.com/-OJ1rNKDuGEk/TwpsrzYUmsI/AAAAAAAAAUQ/xRqPlGLK2T8/s283/Untitled.jpg

[EricH]

Was there any clarification on this type of setup? I can't seem to see anything in the team updates that states otherwise.
As a matter of fact, there was. TU#2 revised Figure 4-3 to show that bumpers inside the Frame Perimeter were, in fact, not Bumpers. See above.

Also, note that the poster of that particular post took note that the design was not legal. The reason for that is that the Frame Perimeter runs from the left point on that robot to the right point (on the top) in a straight line, as though you stretched a string across. Bumpers must be mounted on the Frame Perimeter per [R28-E]. So, there's nothing to mount the bumpers to... but the bumpers must be supported... so the entire design doesn't work as planned.

[Al Skierkiewicz]

The team update does not make the frame design illegal it simply calls any bumper like assembly that is mounted inside the frame perimeter "not a bumper". The bumper is the subject of the update.

[SkyWarrior]

I have another question regarding bumpers this year. This still sounds stupid in my head but if the bumper zone is within 2 inches to 10 inches from the ground and the central barrier is 4 inches high how do some of you teams are planning to go from one side of the field to the other side without hitting your bumper wood or any other bumper parts?

Again I have been thinking this question since day one and still could not come up with a nice solution myself. Neither my team knows an answer to this.

I am afraid we may see many broken, destroyed bumpers this year due to the central barrier. :(

[Alchemy99]

ok to answer your question about the bumpers getting in the way of the barrior. if you mount the top of your bumper at the upper most limit, than you go down the length of the bumper you will be at 5 inches, and the barrier is only 4 inches. (bumper comprised of 2-2.5"pool noodles).

dont feel bad, i have had a hard time figuring that out too, because i am so used to mounting the midpoint of the bumper at the midpoint of the frame witch was at the midpoint of the wheels.(aka mid point at either 4 or 3 inches)

[SkyWarrior]

I thought the bumper should be strictly 8 inches between 2 inches from the ground and 10 inches from the ground?

Last year the rule was 1 inches to 7 inches from the ground total bumper height must be 6 inches if i am not mistaken? At least our bumpers were exactly 6 inches high.

If my bumpers are 5 inches high from the ground and still within the bumper zone, would that be legal?

[EricH]

The team update does not make the frame design illegal it simply calls any bumper like assembly that is mounted inside the frame perimeter "not a bumper". The bumper is the subject of the update.
Al, that "not a bumper" makes the frame design illegal due to the bumper mounting rules. Here is my logic sequence. I will use "Bumpers" to designate manual-spec bumpers and "bumpers" to designate non-manual-spec bumpers

Both sides of a vertex of the Frame Perimeter must have 8" of Bumpers. [R27]
Bumpers must be firmly attached to the Frame Perimeter. [R28-E]
The Frame Perimeter definition ([R01] blue box) for the robot in question is a rectangle.
Because the bumpers inside the Frame Perimeter are not Bumpers ([R27], Figure 4-3), they are not adequately protecting the Frame Perimeter vertices in question per [R27]. (I know that's kind of a weird thing to say--something that is adequately protected is not considered adequately protected. But, that's the way the rules are written.) This results in a violation of [R27].
There is no way to attach 8" of Bumper on the Frame Perimeter and have it be supported as required by [R33] with the design in question.
Therefore, because a) [R27] is violated and b) there is no way to turn them into Bumpers without modifying the frame in question to support bumpers as required by [R33] and [R28-E], the robot frame design is illegal.The Update didn't make the frame design illegal, true. It clarified that it was definitely illegal by declaring, once and for all of 2012, that bumpers inside the Frame Perimeter were not, in fact, Bumpers. The bumper rules take care of the rest.

[EricH]

I thought the bumper should be strictly 8 inches between 2 inches from the ground and 10 inches from the ground?

Last year the rule was 1 inches to 7 inches from the ground total bumper height must be 6 inches if i am not mistaken? At least our bumpers were exactly 6 inches high.

If my bumpers are 5 inches high from the ground and still within the bumper zone, would that be legal?
The bumper may be mounted between 2 inches and 10 inches from the ground. However, bumper height is 5 inches (2 stacked 2.5" pool noodles, and a 5" high plywood backing). This gives 3 inches of height in the bumper zone that is not covered by bumpers.

So, if the bottom of your bumpers was mounted 5" off the ground, provided that you built to the rules, then you would most likely be legal. (Subject to inspection, of course.) If the centerline of your bumpers was 5" off the ground, then you'd again probably be legal subject to inspection (5/2=2.5"; 5-2.5"=2.5" at the bottom of the bumpers).

As far as going from one side of the field to the other without hitting bumpers, there are the bridges. You just have to get them tipped to your side.

[Siri]

I thought the bumper should be strictly 8 inches between 2 inches from the ground and 10 inches from the ground?

Last year the rule was 1 inches to 7 inches from the ground total bumper height must be 6 inches if i am not mistaken? At least our bumpers were exactly 6 inches high.I think you're confusing their height and width measurements. This year as with last year and previous years, bumpers must be backed by exactly 5" tall plywood (R07F 2011, R4.1.6A 2012). This year, the minimum length of bumper coverage on each side of each exterior vertex is 8" (R4.1.6). Last year, the minimum length of each bumper segment was 6" (R07D, note that the rules are actually very different between the 2 years).

[Al Skierkiewicz]

Guys,
If you run the numbers on the diagonal of a 5" high vertical pool noodle you will find it to be 6"+. If you tilt the robot in crossing the barrier, the bumper diagonal will place the front edge of the bumper above 10" regardless of where the bumper is mounted. Please note that the GDC responded Friday with a Team Update that speaks directly to this condition.

"The carpet, the Bridge surfaces, and Keys are considered the flat floors – and thus are the reference planes for the Bumper Zone requirements. A Robot in a transitory state of crossing onto/off of a Bridge or Barrier is not considered to be on a flat floor."

[militaryrobot]

While I have you all here. I also have a bumper question. Attached is a picture of a bumper idea, after reading the rules it seems that this is alright? I want to be 100% sure. Does it seem okay to you?


11290
::rtm::
Look legal. Our team is all ways trying to stay in legal and that is our basic bumper desgin
.::rtm::

[usacat6]

Still need clarification about gaps along a frame edge. Assuming Figure 4-1 in the bumper-rule section, and assuming that the displayed bumper segments are such that the portion covering a given edge is 8" (measured from corner to middle of frame), then is there a maximum length of the remaiming exposed frame, or does the amount of exposure not matter?

[EricH]

Still need clarification about gaps along a frame edge. Assuming Figure 4-1 in the bumper-rule section, and assuming that the displayed bumper segments are such that the portion covering a given edge is 8" (measured from corner to middle of frame), then is there a maximum length of the remaiming exposed frame, or does the amount of exposure not matter?
As long as you have the 8" bumper segments from the corners, there is no maximum length of exposed frame. There is also no minimum length of exposed frame.

[GaryVoshol]

Still need clarification about gaps along a frame edge. Assuming Figure 4-1 in the bumper-rule section, and assuming that the displayed bumper segments are such that the portion covering a given edge is 8" (measured from corner to middle of frame), then is there a maximum length of the remaiming exposed frame, or does the amount of exposure not matter?

Well there is a maximum length, since your frame can only be 38" in total. 38 - (2*8) = 22 inches. However, if your frame is smaller, then the maximum exposed part is smaller.

The 8" bumper on corner rule doesn't say anything about what can be in between those corners. It could be an opening (to suck up balls, perhaps?) or it could be an exposed piece of frame. It's whatever your team wants to do within the flexibility of the rules.

[Al Skierkiewicz]

Will,
Please keep in mind that this part of the bumper rule does change from year to year. More often than not, the bumpers were required all the way around the frame perimeter.

[Cal578]

The Team Update 2012-01-24 says
Bumper Rules
[R27]
Figure 4-3 has been updated to correct the portrayal of the Frame Perimeter. ...
But I don't see the updated figure. Did I miss something obvious (I've done that once or twice before 8-) ), or did they forget to include the new figure? Can anyone tell me where to find it?

Thanks!

[Siri]

The Team Update 2012-01-24 says

But I don't see the updated figure. Did I miss something obvious (I've done that once or twice before 8-) ), or did they forget to include the new figure? Can anyone tell me where to find it?

Thanks!They only posted it in the manual itself (http://frc-manual.usfirst.org/viewItem/57#4.1.6), not the Team Update.

[Cal578]

Ah, I did not attempt to open the manual because the hover text still says "The Robot_Rev-". Now that I've opened it, I see it's actually at Rev B (and apparently includes updates after the 1/13/2012 date given for Rev B in section 4.2).

Thanks for the pointer, Siri.

[Ed Law]

There is a question on FIRST Q&A with an inadequate answer from FIRST.

Q. We are deciding to use a square U frame. So, we have to split the 4th bumper into 2 sections. Because of this, we can't decide how to place "3490" on our Bumper. Should we place the 4 numbers on 1 side, or should we split 34 and 90 across the Bumper. R35 doesn't explain how to handle this situation.

A. Per [R35] team numbers must be "clearly visible from a distance of not less than 100 ft, so that judges, referees, and announcers can easily identify competing Robots." Thus they may not be obscured in any way (disconnected, out of order, rotated, upside-down, mirror imaged, etc).

We are a 4 digit number team and we have a short front bumper on the left and one on the right (many teams do this year). I understand each short bumper must be at least 8 inches long. With the [R35] requirement

Teams shall display their team number on the Bumpers in four locations at approximately 90° intervals around the perimeter of the Robot. The numerals must be at least 4 in. high, at least ¾ in. in stroke width, and be either white in color or outlined in white. Team numbers must be clearly visible from a distance of not less than 100 ft, so that judges, referees, and announcers can easily identify competing Robots.

Each letter will be at least two inches wide. How can I fit 4 numbers in an 8 inches width? If I don't leave any space between them, it will not be very readable. Any ideas?

[Al Skierkiewicz]

Ed,
The Q&A seems to indicate that splitting the numbers will not be allowed. I agree that the split is likely to cause some confusion. I can only guess/suggest therefore that the numbers on the short side must be less than 3/4" stroke to satisfy the Q&A response. However, if a vertical pool noodle is placed in the corner of said segment, you would have approx 10.5 inches in which to place numbers. I will ask what inspectors will be expected to check for.

[Ed Law]

Ed,
The Q&A seems to indicate that splitting the numbers will not be allowed. I agree that the split is likely to cause some confusion. I can only guess/suggest therefore that the numbers on the short side must be less than 3/4" stroke to satisfy the Q&A response. I will ask what inspectors will be expected to check for.

Al,

Thanks for the quick reply. But the rule says minimum 3/4" stroke or my robot will not pass inspection. I hope the bumper rule is not going to force 4 digit teams to have minimum 10 inch bumpers just to be able to satisfy the bumper rule. That would be silly and unfair to high number teams.:)

[Jon Stratis]

Ed, I had that exact same question in mind when I read that over lunch today. It certainly seems to make things interesting!

[waialua359]

They only posted it in the manual itself (http://frc-manual.usfirst.org/viewItem/57#4.1.6), not the Team Update.
This caught me also. Thanks.

[Al Skierkiewicz]

Please standby, just don't add numbers to that bumper until we have a firm answer.

[Tristan Lall]

Each letter will be at least two inches wide. How can I fit 4 numbers in an 8 inches width? If I don't leave any space between them, it will not be very readable. Any ideas?Find another font?

Franklin Gothic Heavy, 400 pt 440 pt (with slightly condensed spacing) works nicely. If my estimation is correct, the narrowest stroke on the "4" should be around 0.77 in.

See the attachment. I used Inkscape (http://www.inkscape.org) (free download); you could also use Adobe Illustrator or something similar.

Edit: See this slightly better version. In this version, the short stroke is even thicker.

[jvriezen]

Please standby, just don't add numbers to that bumper until we have a firm answer.


Al, I trust you won't be lobbying for bumper segments wide enough to hold the whole team number, considering your team number is 111 and your team won't be harmed regardless of the answer! ;)

I would hope that the GDC sees the issue here and either allows split numbers or else requires that all teams have at least one contiguous bumper segment on each "side" that is wide enough to display *ANY* four digit number with 4"x3/4" numbers.

[jvriezen]

Find another font?

Franklin Gothic Heavy, 400 pt (with slightly condensed spacing) works nicely. If my estimation is correct, the narrowest stroke on the "4" should be around 0.77 in.

See the attachment. I used Inkscape (http://www.inkscape.org) (free download); you could also use Adobe Illustrator or something similar.

You should actually have about 10.5 to 11 inches, since the short segment over 8" of frame can extend past the vertex for the corner area. But it is still a very tight fit for four digit teams without any 1's or 7's

[EricH]

Something else to consider:

While you're required to put your team number on your bumpers, I haven't been able to find anything saying that putting your number elsewhere on the robot, in addition to on the bumpers, is illegal. It might be a good idea to show that number above the bumpers on a section of robot where you can put full-size numbers (or larger, or slightly smaller). Back in my day, that's the only place we had to put numbers, and most teams did OK in terms of making them visible. (A few... well, let's just say that black tape on Lexan does not show up at all, and leave it at that.)

[Al Skierkiewicz]

John,
Fitting 111 on bumpers is never a problem for us. Getting the numbers in the right order is a constant issue....

[Tristan Lall]

And incidentally, this does involve a bit of a liberty with the "stroke width" requirement. I would typically measure this perpendicular to the stroke axis at the largest part of the stroke, since FIRST does not give guidance on acceptable typography.

If FIRST means that every stroke on every numeral must be 0.75 in wide at every point (presumably measured perpendicular to the central axis of the stroke), then this is a whole lot more complicated. (Also, that would mean nearly every bumper ever numbered over the last couple of years was illegal.) I suppose you could ask the Q&A.

[GaryVoshol]

Letters and numbers are taller than they are wide. A 4 inch TALL number is not 4 inches WIDE, even a wide number like 0 or 8.

Plus, you have the extra 3.5 inches from the "end grain" of the bumper on the adjacent side.

[junefish]

Our bumpers last year had 2-4 inches of "fluffy" parts and they fit the requirements--the fluffy parts were noodles, however, so I'm not sure if that's what you meant.

[Jon Stratis]

Letters and numbers are taller than they are wide. A 4 inch TALL number is not 4 inches WIDE, even a wide number like 0 or 8.

Plus, you have the extra 3.5 inches from the "end grain" of the bumper on the adjacent side.

True... however, look at what is more or less "normal" numbering (at least for our team, and I don't remember us being exceptionally large compared to other teams) from the past few years:
http://www.chiefdelphi.com/media/photos/36401
http://www.chiefdelphi.com/media/photos/34968

Those numbers are about 1/3 of the long length of the robot (including the bumper corners), and over half the short length (plus corners) - that's well over what you can get with an 8 inch segment + corners.

[mrlg220]

Letters and numbers are taller than they are wide. A 4 inch TALL number is not 4 inches WIDE, even a wide number like 0 or 8.

Plus, you have the extra 3.5 inches from the "end grain" of the bumper on the adjacent side.

I agree completely. Plus if you make block letters it will be much easier (round will take up too much space). Our 3464 has no 1s or 7s, but with block lettering and a bit of vertical stretch has enough room to spare. It's not overly distorted, either.

[PAR_WIG1350]

True... however, look at what is more or less "normal" numbering (at least for our team, and I don't remember us being exceptionally large compared to other teams) from the past few years:
http://www.chiefdelphi.com/media/photos/36401
http://www.chiefdelphi.com/media/photos/34968

Those numbers are about 1/3 of the long length of the robot (including the bumper corners), and over half the short length (plus corners) - that's well over what you can get with an 8 inch segment + corners.

Those seem rather wide, the slant seems to be the culprit. Also the spacing between your numbers could be reduced. Vertical, closer numbers should get you down to 8" easily.

[Ed Law]

Al, Thanks for the quick reply. But the rule says minimum 3/4" stroke or my robot will not pass inspection. I hope the bumper rule is not going to force 4 digit teams to have minimum 10 inch bumpers just to be able to satisfy the bumper rule. That would be silly and unfair to high number teams.:)
It is taking FIRST a very long time to answer my simple bumper question in Q&A. While I can wait a little longer before I print numbers on bumpers, I can't keep waiting before I finalize on the robot design. Therefore I have decided to do the silliest thing and to let the bumper rule about size/stroke of the numbers decide how wide my front bumpers are just so we as a 4 digit team can fit our numbers onto the bumper. My front bumpers are now about 11.5 inches wide on each side which forced us to narrow our ball intake width.

[Al Skierkiewicz]

Ed,
Number should not drive your design. Please be patient.

[engunneer]

It is taking FIRST a very long time to answer my simple bumper question in Q&A. While I can wait a little longer before I print numbers on bumpers, I can't keep waiting before I finalize on the robot design. Therefore I have decided to do the silliest thing and to let the bumper rule about size/stroke of the numbers decide how wide my front bumpers are just so we as a 4 digit team can fit our numbers onto the bumper. My front bumpers are now about 11.5 inches wide on each side which forced us to narrow our ball intake width.

Totally agree with Al here. Something as simple as numbering should not drive your design decisions. 8" Bumpers plus the corner filling noodle is plenty of space for 4 digits that meet the rules (including being legible). Even if you don't have a corner noodle (which you should), you can still get legible digits into 8".

11630

[Hawiian Cadder]

You could put two digits on each Bumper in the front.

[engunneer]

You could put two digits on each Bumper in the front.

The Q&A answer specifically says you can't use disconnected numbers.
Thus they may not be obscured in any way (disconnected, out of order, rotated, upside-down, mirror imaged, etc).

[Chomantha1073]

Team 1073 was freaking out about the new Q&A about this until we realized that we could write on the corner parts of our minimum length bumpers. Last year, our numbers took up a horizontal distance of about one foot. Using the 8 inches of frame coverage on each side plus the corner part, we found that we have roughly 11 inches to put our number into. By taking the decoration off of our number 1 and decreasing the width of the zero, we can easily fit our team number on one side. If teams decrease the width of their numbers, since there is no rule against that as long as it is legible, any number should be able to fit if the corner is included.

[EricH]

If teams decrease the width of their numbers, since there is no rule against that as long as it is legible, any number should be able to fit if the corner is included.
[R35] says you need to be careful with that statement. There are possibly a couple of problems.

1) Decreasing the width is OK, provided that the stroke width remains at 3/4" or more and the height remains at 4" or more.
2) The section on the corner is technically between Bumpers (no backing for about 2"). While I don't see too much of a problem with putting number in that area, the GDC might (the rule specifies that the numbers must be on the Bumpers). I haven't seen anybody ask that on Q&A, so I don't know for certain.

[jvriezen]

While I have you all here. I also have a bumper question. Attached is a picture of a bumper idea, after reading the rules it seems that this is alright? I want to be 100% sure. Does it seem okay to you?


11290
This does not look ok to me. I'm assuming the blue parts are bumpers and the dimensions refer to the outer extreme bumper dimensions and not the elements/sides of the frame perimeter.

You must have 8" of frame on either side of each vertex. With an 8" bumper segment where the 8" also covers the corner space, you would only have about 5" of frame at the vertex.

Also, I see that the outer dimensions, which include the bumper are 28x38. Since happens to be the max dimensions of the robot *without* the bumpers, I think you may be confused, as this robot is about 6" smaller than it could be. That being said, I would recommend planning for no bigger than 27x37, because this gives you room for bolt heads and things being a bit 'out of square, because the inspector's sizing box (and the inspectors) are unforgiving about size (and weight)

[jvriezen]

I created a TrueType font specifically designed for FRC to fit on minimal bumpers (8" + 3 1/4" endgrain)

When scaled to 4" tall, the stroke is exactly 3/4" and the width of each digit is exactly 2". With a 1/2" space between digits, a four digit number takes only 9.5", easily fitting on a 11" bumper

http://www.chiefdelphi.com/media/papers/2630