pic: Carmen week1 team 842
 

Re: pic: Carmen week1 team 842
 

Wow, I am really impressed by your design!:D
So this is basically an ackerman steering chassis?
How do you plan on implementing the differential?
How many hours have you guys worked during week 1? :confused:

Re: pic: Carmen week1 team 842
 

Oh, oh. Check the bumper rules. You can't attach a legal standard bumper to those angled faces in front.

Re: pic: Carmen week1 team 842
 

They don't have to, The rules say you have to cover 75% (I think) of the perimeter of your robot.

Re: pic: Carmen week1 team 842
 

2/3, but they also must cover all corners.

It looks rather impressive. Excellent progress for week 1! Good job.

Re: pic: Carmen week1 team 842
 

I would worry about bumper rule I:
in combination with bumper rule A:
So if you need to have a bumper on the front (that's the if), it must be 6 inches long and fastened to the hard robot frame, which in the pictured robot's configuration would put it inside the bumper perimeter and thus illegal according to bumper rule L:

Re: pic: Carmen week1 team 842
 

Wow, thats really nice :D

Re: pic: Carmen week1 team 842
 

Your team needs to look at the update #2 and the bumper rules. Looks good so far. You've accomplished allot for week 1.

Re: pic: Carmen week1 team 842
 

Looks good Carl Hayden! You always do produce a robot quickly and it's helped make 842 a formidable competitor at AZ every year. Our robot is still in the wood and duct tape testing stage!

Did you already order receive a second set of Toughboxes or are those just pulled from last year's robot?

Re: pic: Carmen week1 team 842
 

I'm beginning to think that if you can figure out what the bumper rules mean, then you should be headed to law school, not engineering school :)

We're playing it safe and planning on having a rather conventional outside shape with bumpers covering most of it....and the front will have 6" bumpers on each side of the harvester, in a straight line.

Re: pic: Carmen week1 team 842
 

We ordered them on Mon.and got them Wed.
We are trying to give our programmers all the time we can, to day is our first time off and we feel guilty....

The other ting is we like to get stuff on here at CD to get the critiques so we can make improvements...

Re: pic: Carmen week1 team 842
 

I am guessing then you are going wide drive....

Re: pic: Carmen week1 team 842
 

Does the bumper perimeter have to be rectangular? We are planning on running the bumper into our bot six inches.

Just for example... what if you had an L shaped robot?

Re: pic: Carmen week1 team 842
 

That's the plan right now.

http://www.chiefdelphi.com/media/photos/32297

shows the chassis design. The wood pieces are cut out and almost ready to assemble.

Re: pic: Carmen week1 team 842
 

We will use differential steering on the rear wheels in the code, thats the programmers area, we are the builders, so thats all I can explain

Re: pic: Carmen week1 team 842
 

They seem to be working on it almost all day every day during the week. If you want to check up on them, it's pretty easy....although it's Sunday today.

http://www.ustream.tv/channel/falcon-robotics-team-842

Re: pic: Carmen week1 team 842
 

Where's the cRIO? i.e. The bumper perimeter must be a convex polygon.

Re: pic: Carmen week1 team 842
 

That is interesting, where does it say that it must be convex?

That would settle the dispute......

Thanks for helping to vet us. We don't want to caught at a regional with a violation.

Re: pic: Carmen week1 team 842
 

It never explicitly says that it must be convex, but wrapping a string around a concave polygon will result with the string not following the entire perimeter of the polygon. If you wrap a string around this robot in the bumper zone, it will form a convex rectangle.

Re: pic: Carmen week1 team 842
 

definition per rules
To determine the BUMPER PERIMETER, wrap a piece of string around the ROBOT at the level of the BUMPER ZONE - the string describes this polygon.

We would have our string cross the opening of our bot. It does not say it has to make contact with the bumper zone everywhere. That is an assumption. Our polygon would be a rectangle, never the less we will cover the angles in from the corner with 6 inches of bumper. We think we are ok......I hope

Re: pic: Carmen week1 team 842
 

Would the bumpers be straight (parallel with back of bot) or angled (parallel with angled front sides of bot)?

Re: pic: Carmen week1 team 842
 

I believe the intent is that bumpers must be on the bumper perimeter. You're taking a risky move, and should probably Q&A it.

Re: pic: Carmen week1 team 842
 

It's not just the intent, it's the rule:
What needs to be answered in Q&A is if every side of your robot must have bumpers in order to satisfy the requirement that corners are protected.

Re: pic: Carmen week1 team 842
 

That's the one that I haven't figured out for sure yet...and we're going to assume the answer is "yes". Which really limits the effectiveness of end loading narrow robots like Carmen, unfortunately.

Re: pic: Carmen week1 team 842
 

Another team member pointed this out to me today: the first thing to contact a flat vertical obstacle (aka the wall) must be your bumper. If you have one side completely uncovered, then the first thing to hit that vertical obstacle will be metal.

Re: pic: Carmen week1 team 842
 

angled

Re: pic: Carmen week1 team 842
 

Angled "bumpers" would not pass inspection because technically they are not bumpers at all since they do not lie on the bumper perimeter according to the current set of definitions and both sides of the corner must be protected.

Re: pic: Carmen week1 team 842
 

Ahhh...here's that statement that seemed to me to be missing from the rules.

"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."

from http://forums.usfirst.org/showthread.php?t=11159

Re: pic: Carmen week1 team 842
 

Ok Well according to Jim we are possible ok since we will have the bumpers over the corners and the first part to touch a wall will be the bumpers. Let keep or fingers crossed!

Re: pic: Carmen week1 team 842
 

The problem is the bumpers need to be on the bumper perimeter, which is the edge around the robot, and recessed parts of the frame are not the perimeter. So it looks to me like it's not legal. You'd have to put back the straight pieces across the front, but make them each 6" long, and cover them with 6" long bumpers. This will give a pretty small opening in the middle.

What a bummer, how vague the rules are this year on bumpers...they could have just come out and said what they wanted in the first place.

Re: pic: Carmen week1 team 842
 

..

Re: pic: Carmen week1 team 842
 

I still do not understand why this is not legal.......... If they were to put the bumpers at an angle across those pieces as long as the bumper pieces were at least six inches long, and the corner was not exposed, why isn't this legal?

Re: pic: Carmen week1 team 842
 

Because angled bumpers are not bumpers at all. If they are not on the bumper perimeter they are superfluous padded chassis sections. If you take a piece of string around the outside of the robot (definition of bumper perimeter) the bumpers must be attached to the chassis where the string is.

Re: pic: Carmen week1 team 842
 

This is not necessarily true

Re: pic: Carmen week1 team 842
 

What I should say is that bumpers on a concave angled portion of the robot are not bumpers. Robots with angled front edges.

Bumpers like http://www.chiefdelphi.com/media/photos/30834 are legal types since the bumper perimeter is along those edges

Re: pic: Carmen week1 team 842
 

They are bumpers, but they are not BUMPERS. They don't qualify under the <R08> rules, and would not be exempt from weight/size in <R11>.

Re: pic: Carmen week1 team 842
 

It's important to keep in mind the difference between bumpers and BUMPERS. Some bumpers are not BUMPERS. Bumpers that are angled such that if extended infinitely would pass through the robot chassis are not BUMPERS, because they are not affixed to the BUMPER PERIMETER. As such, nothing attached to the angled pieces on Carmen's front can ever be considered a BUMPER, so even though the corners of the frame could be protected on both sides by pool noodles and fabric, they won't be protected by BUMPERS, and thus run afoul of <R08-I>.

Re: pic: Carmen week1 team 842
 

I wonder if Inspectors would let this design through due to the potential to damage the field.

With the cantilevered front end, if the robot is struck and the front end dips, the metals will be in direct contact with the flooring, potentially gouging it or catching a seam ...

Maybe consider placing plastic carpet skids on the under side ...

Re: pic: Carmen week1 team 842
 

what are you using pneumatics for?

Re: pic: Carmen week1 team 842
 

I have a vested interest in finding out whether this chassis design is legal. It would seem that the bumper rules require (1) that exterior corners are protected by BUMPERS on both sides and all trailer contact is bumper to bumper, and (2) that bumpers can only be attached to the BUMPER PERIMETER.

Unless I'm missing something, both of those conditions cannot simultaneously be met for the front of this robot (Which may or may not be the GDC's intention. Considering that this picture was posted in the Q&A and all that the GDC said was that exterior corners must be protected, it seems like this particular contradiction hasn't occurred to them.)

Re: pic: Carmen week1 team 842
 

I think it has occurred to them, but they don't answer questions directly, they let you figure out the implications for yourself.

Re: pic: Carmen week1 team 842
 

Fredi,
The robot looks great so far. If you are intending to place 6" of bumper on the internal, angled side then I think you are meeting the intent of the rule. However, the rule as written as a few wierd nuances that may get you in trouble.

Here is what I suggest:

1. Write another Q & A showing the exact picture of your robot with bumpers on all sides you intend to place them.

2. In the Q & A clarify theat the bumpers are all made per the BUMPER rules (plywood, etc.)

3. Specifically ask if the BUMPERS on the angled internal sides are considered BUMPERS or not. Ask if they will be considered in the robot weight or BUMPER weight.



What troubles me is that the bumpers on the internal sides are not really legal BUMPERS becasue they are not mounted to the BUMPER Perimeter. My question is how can you cover all corners with legal BUMPERS if one side of the corner is not part of the BUMPER PERIMIETER?

Good luck with getting clarification. WE decided to go traditional wide body becasue we do not have the patience to deal with non-answers from the GDC on such a mundane subject such as bumpers.

Paul

Re: pic: Carmen week1 team 842
 

[EDIT]See GaryVoshol's post below, my interpretation is incorrect[/EDIT]

Paul,

My interpretation has always been that an "exterior corner" is one with both both edges (aka sides of the corner) on the BUMPER PERIMETER. This interpretation would be consistent with the images and text in Update #2. I'm working on getting our password to post in the Q&A.

Does this interpretation seem reasonable to anyone else?

Re: pic: Carmen week1 team 842
 

While your interpretation sounds entirely reasonable, it can't be. That's not how BUMPER PERIMETER is defined:Carmen's front corners with the acute frame angles are outermost vertices, and so by definition are on the BUMPER PERIMETER.

An entirely reasonable interpretation, in my estimation, would be to allow 842 to mount non-standard bumpers on the angled pieces such that with the standard BUMPERS on the side the corners are fully protected. The angled pieces would have to count in the robot size and weight. Whether that reasonable (IMO) interpretation will pass, well I guess it's up to them to gamble or not.

And the GDC is fond of saying, "We do not comment on particular robot designs. Here's the rule."

Re: pic: Carmen week1 team 842
 

Very awesome looking
Great design work

Re: pic: Carmen week1 team 842
 

From the rules, it is difficult to tell if this is legal or not.

Either way, though, have you considered this -

If you add the bumpers to these angled sections, you effectively make the hole in your chassis about 6" narrower - each bumper is 2-1/2 - 3" thick, and they would extend into this opening area.

Depending on how wide the opening is now (hard to tell from the picture) it might become very tight for a 9" game piece.

You might actually have a larger opening by having the front of the robot "flat" with 6" bumpers on each side, giving you a 16" wide opening.

I don't know how this fits in with you ball pick-up ideas, but something else to consider.

Re: pic: Carmen week1 team 842
 

<R08> mentions outermost exterior vertices. The term exterior is never defined, and I always defined it in my head as " both 'sides' of the corner are on the BUMPER PERIMETER."

However, reading the rules and looking at Carl Hayden's robot, I see where my definition falls apart. If their bumpers on the front corner are not exterior vertices, then they have no BUMPER PERIMETER. Yup, I was wrong. :o

Re: pic: Carmen week1 team 842
 

Alright - I didn't pour over all the posts to see if this was asked:

How much does this robot weigh? we have a very similar design but I am really concerned about building it to be robust without weighing a ton.

Re: pic: Carmen week1 team 842
 

I think section 8 of update #2 makes it pretty clear that you cannot have bumpers that angles in and have them be considered legal. Notice the square opening in the illustations. If you could angle the bumpers inward on the corners, then the trailer could go in further.

Re: pic: Carmen week1 team 842
 

45 pounds

Re: pic: Carmen week1 team 842
 

but i heard that bumpers have to cover corners.

Re: pic: Carmen week1 team 842
 

Good news or bad news?

http://forums.usfirst.org/showthread...4097#post24097

Confirms that both sides of all corners must be protected by BUMPERS.

Doesn't explain how a BUMPER could be legally attached inside the BUMPER PERIMETER.

Re: pic: Carmen week1 team 842
 

Very Nice Chassis, Although I think It's not legal.. Bumpers must me atleast 6"

Re: pic: Carmen week1 team 842
 

Final answer: http://forums.usfirst.org/showthread.php?t=11170

Re: pic: Carmen week1 team 842
 

Translation: Carmen as shown in the first post is not legal and has no hope of being legal without relocating the angled sides. That stinks.

Re: pic: Carmen week1 team 842
 

This is kinda off topic but how did you direct connect your toughbox to your wheel??
and does it have bearings in it?

Re: pic: Carmen week1 team 842
 

One way of directly connecting a toughbox to a wheel is a 1/2" keyed hub (see link) for the 1/2" output shaft of the toughbox.

http://andymark.biz/am-0077.html