|
|
|
![]() |
|
|||||||
|
||||||||
![]() |
| Thread Tools | Rate Thread | Display Modes |
|
#106
|
|||||
|
|||||
|
Re: Fasteners extending outside the FRAME PERIMETER
Quote:
Too me the rules were clear. Yes that axle bolt defined the perimeter so the bumper would have to be outside that perimeter. The only exception was that small clearance holes or pockets were allowed in the bumper backing material to allow that axle bolt. How does that exception become translated to allow that axle bolt or rivet or whatever not covered by that backing material? |
|
#107
|
|||||
|
|||||
|
Re: Fasteners extending outside the FRAME PERIMETER
Quote:
That bolt defined the FRAME PERIMETER. If you had a 26"x36" frame with fasteners sticking out in the BUMPER ZONE 1/4" on each side right in the corners, your FRAME PERIMETER was a 26.5"x36.5" rectangle. This meant the rest of your robot had to fit within a vertical projection of this 26.5"x36.5" rectangle per <R16>. After Update 6 this robot now has a FRAME PERIMETER of 26"x36". Any parts that fall within the 26.5"x36.5" projection but outside the 26"x36" projection went from perfectly legal to a violation of <R16>. I'm not sure what part of this you disagree with so feel free to grab any of the steps out of the above and show me where I may be wrong (and I most certainly may be) |
|
#108
|
|||||
|
|||||
|
Re: Fasteners extending outside the FRAME PERIMETER
After reading the discussion, and talking about it, and rereading the rules, I came to the conclusion that the rule was ambiguous before Update 7.
So you're both right. Apparently Paul might have made a wrong assumption....which is easy to do when the rules are ambiguous. Or he made a literal interpretation of what the rules said before update 6. I learned a while back to err on the conservative side when the rules are ambiguous. Unfortunately it's usually hard to see that the rules ARE ambiguous unless you can see both interpretations. Usually we can't! |
|
#109
|
|||||
|
|||||
|
Re: Fasteners extending outside the FRAME PERIMETER
Quote:
From the update: Note: to permit a simplified definition of the FRAME PERIMETER and encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER, minor protrusions such as bolt heads, fastener ends, rivets, etc are excluded from the determination of the FRAME PERIMETER. The key words are encourage a tight, robust connection between the BUMPERS and the FRAME PERIMETER show that the change was for the bumper area and not the rest of the frame. I think if you assumed that changed the frame perimeter then I think your made a huge leap of logic (just my opinion.) But say I do agree with your scenario and they did change the perimeter definitions. They changed it on day 20 where frame designs should have been already finished and then after seeing the ambiguity they created quickly released clarification 4 days later. A fast and reasonable response. |
|
#110
|
||||
|
||||
|
Re: Fasteners extending outside the FRAME PERIMETER
Quote:
Unfortunately, it's not exactly clear whether this is intended to be an imaginary string wrapped around the projection of all such points in a plane, or wrapped around the outermost subset of points that are coplanar within the bumper zone. (Imagine that on a rectangular robot, two opposite sides have bolts at 10.5 in from the ground, and the other two sides have bolts at 15.5 in from the ground; how do you wrap that string and still meet the definition? If we're talking string, then concavity in 3-D is the same as in 2-D—i.e. not allowed. How do you define "outermost"—is this with respect to a centroid? Which one, and how do you find it?) In any case, if your outermost bolts within the bumper zone are near the corners of your rectangular robot, we can use your example as a rough approximation for the purposes of discussion. |
|
#111
|
||||
|
||||
|
Re: Fasteners extending outside the FRAME PERIMETER
So having thought about this a while and re-read the details several times I can see where this definition is coming from.
Last year the "pockets in the bumper backing" ruling came out mid-season to allow teams to legally use the Kitbot as provided. The heads of the kitbot axle bolts would have been in violation for the majority of teams that used this setup otherwise. (The fact that the instructions said to assemble it with open corners was a separate issue that cause other inspection problems, but I digress...) This year the kitbot changed a bit with the "legs" to lift the chassis portion up above the drive wheels. If used as provided , the kitbot would provide the start of a legal frame unlike last year. Many teams (mine included) used a kitbot setup similar to last year and now have an issue with bolt heads protruding out below the bumper zone. The shift in bumper zone to a higher position than it was in the past is what is causing problems here. The fact that a the kitbot as provided is legal for the update 7 version of the frame perimeter is a good thing. Unfortunately for those of us who used modified or alternate frames the previous version of the frame perimeter was either different or ambiguous. Now it is clear, and it is also different from many people's previous interpretations. We are lucky in that we have enough space to play with to build in an extension to our frame perimeter in the bumper zone. I hope that all teams have enough wiggle room to play with here. I fear that this will be an issue for quite a few teams. This is a detail that can be tough to pick up on. I hope that folks in the CD community can help out local teams who may not be up to speed on this definition. Thanks, and good luck! Rob |
|
#112
|
|||||
|
|||||
|
Re: Fasteners extending outside the FRAME PERIMETER
Quote:
What I intended to portray was each corner of the robot having a bolt coming out of each face directly adjacent to the corner, so 2 bolts per corner, 8 total. This should result in the rough approximation you suggested. |
|
#113
|
|||||
|
|||||
|
Re: Fasteners extending outside the FRAME PERIMETER
Quote:
In this example, the extended bolt heads defined the vertices of the FRAME PERIMETER. But you have to then consider that the in the area in between the bolt heads, the FRAME PERIMETER is now in free space 1/4 inch away from the actual frame structure of the robot. Under Rule <R07-I>, the BUMPERS must attach to the FRAME PERIMETER. Not 1/4 inch inside the FRAME PERIMETER (where the actual frame structure is located), but directly to the FRAME PERIMETER. Which means that for the portion of the BUMPERS between the bolt heads, the BUMPERS would not be supported. But under Rule <R07-M>, the entire length of the BUMPER backing must be supported and not in free space. Thus, this configuration would have been in violation of at least one, and potentially more, rules. The revised wording corrected this entire situation and gave you a clean way to bolt your frame together and securely attach the bumpers without a violation. -dave . |
|
#114
|
|||||
|
|||||
|
Re: Fasteners extending outside the FRAME PERIMETER
Touchè! Dave, thank you very much for chiming in here. This makes the purpose of Updates 6 and 7 much more clear.
|
|
#115
|
|||||
|
|||||
|
Re: Fasteners extending outside the FRAME PERIMETER
Quote:
Quote:
See DL's post. |
|
#116
|
||||
|
||||
|
Re: Fasteners extending outside the FRAME PERIMETER
I'm sorry this is getting out of hand, I am having a hard enough time understanding what is illegal and legal and I've been around FIRST for 6 years. The lawyering of these frame perimeter rules is going way to far, the GDC tells us to not lawyer the definition of the rules and try and understand the intent of the rule, however these frame perimeter rules are getting so lawyered and technical that I can't even explain it to the students I mentor.
This is a high school robotics competition, can we please make these frame perimeter rules easier to understand so the high school students I work with can sit down with the manual and understand them?? I understand the intent of the rule, to have the outside frame of the robot support the Bumpers in the Bumper Zone. But if this means I can't have my bumper frame protrude perpendicularly up from my the outside of my lower drive frame because of the #10 screw head that is holding our drive shafts in makes it illegal, this is getting way to technical. Yea there are ways that we can 'hack' our frame to fit the technicalities of these rules even though it is already all welded together, but I don't see why we would waste our time changing it when our frame meets the intent of the rules. |
|
#117
|
||||||
|
||||||
|
Re: Fasteners extending outside the FRAME PERIMETER
Dave, all;
I will be clear about this. There was no ambiguity in my mind in the rule prior to update 6 that is why I couldn't be conservative with regards to the ambiguity. The original rule never stated that bolts don't count so it is my "common sense" that bolts sticking out within the bumper zone had to define the frame perimeter. How could I logically make an exception? So I want to get this straight: The original rules actually intended to make every sheet metal + rivet construction robot illegal this year? GDC members are not blind so they see how many robots are constructed. Everyone keeps talking about bolt heads, but even rivets are illegal. That, to me, is just plain stupid. Every year there is something: G22, G14 ... well this year I know what it is.... Well, at least I'll have some fun with it at IRI. This is simply irritating. We'll get by, but I'm not really concerned about my teams. Paul P.S. - JVN says 148 will be bringing lots of extra shim strips with us to Dallas and Houston. 217 will be bringing the same to Finger Lakes, Cass Tech, and Troy. There will be many teams that are totally blind sided by this because they do not have as much "common sense" as some people on CD and they don't check CD. |
|
#118
|
|||
|
|||
|
Re: Fasteners extending outside the FRAME PERIMETER
What if we all just went back to a time that I'll refer to as "B.B." or Before Bumpers and all you had to do with build a robot that fit inside the sizing box?
Can I throw this one up to the GDC to consider?? I know bumpers are most likely here to stay, but honestly the headaches they create is not worth the little bit of cushioning provided to the robot during a match. If you can't stand the heat..... I dunno, just my $.02 |
|
#119
|
|||||
|
|||||
|
Re: Fasteners extending outside the FRAME PERIMETER
Quote:
It was clear, understandable, and a degree in constitutional law wasn't necessary to understand the dozens of clauses, exemptions, and the exact DEFINITIONS of various aspects of the robot and the game. |
|
#120
|
|||
|
|||
|
Re: Fasteners extending outside the FRAME PERIMETER
Paul, I think what Dave was trying to say, is that even by the original rule, if your frame perimeter consisted of a piece of metal, with a row of rivets heads on it, this would not meet the requirement to fully support the bumper along its length, since it is supported at only at the rivet heads. So, in this type of a design, a shim/spacer would have been needed all along anyhow, before any updates. Although, I suppose if small indentations were made in the bumper backing to clear the rivets, the bumper would have been supported by the metal which is inside the (as previously defined) frame perimeter, not at the frame perimeter itself.
And let's think about the following too. In theory, any member defining the frame perimeter that is not perfectly planar does not fully support the bumper. There exists no such surface. So the question becomes, what is the maximum allowable space between the bumper backing, and the frame perimeter, for which the bumpers shall still be considered "fully supported." I would argue up to a 1/4 inch should be deemed acceptable. Materials and manufacturing methods have a tolerance... Silly, I know... Something needs to be done to make this all simpler for everyone. Maybe I'm looking at this wrong, but I have been in FIRST for 9 years now, and I still can't figure out how I would explain this rule to anyone. Let's also remember that many inspectors have never even seen a FIRST robot before. This will never work. Last edited by sanddrag : 03-02-2010 at 19:30. |
![]() |
| Thread Tools | |
| Display Modes | Rate This Thread |
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| kicker extending outside of robot | caincteam2777 | Technical Discussion | 5 | 17-01-2010 22:42 |
| Frame Perimeter x Bumpers | sloteera | Rules/Strategy | 8 | 14-01-2010 11:18 |
| Frame Perimeter? | jimbot | General Forum | 2 | 10-01-2010 13:48 |
| Holding of Game-Pieces Outside the Robot Perimeter | MikePres | General Forum | 2 | 24-01-2009 07:21 |
| Ramps extending outside of the home zone | Shomron1690 | Rules/Strategy | 31 | 20-03-2007 13:49 |