Official Team Update #2! 1/15/2010
 

Talks about ball possession and stuffs.

http://usfirst.org/uploadedFiles/Rob...Update%202.pdf

Re: Official Team Update #2! 1/15/2010
 

Good update. Answers a lot of questions I feel were still hanging out there.


I'm curious as to what other peoples interpretations are of the new rule regarding controlling a ball.
Part a is the frame perimeter rule we had earlier
part b now states a ball cannot proceed more than 3" into a mechanism above the robot....this seems like it could be interpreted in different ways.

whats everyones thoughts?


Exact quoting for reference:
<R19> ROBOTS must be designed so that in normal operation BALLS cannot extend more than 3 inches inside the FRAME PERIMETER below the level of the BUMPER ZONE.
a) the FRAME PERIMETER below the level of the BUMPER ZONE (see figure 8-5).
b) a MECHANISM or feature designed to deflect balls in a controlled

Re: Official Team Update #2! 1/15/2010
 

I believe that would mean, say, if you had a channel for balls to slide down on top of your robot, no more than 3 inches of the ball could be "in it". Funnels also are illegal.

Re: Official Team Update #2! 1/15/2010
 

Wow, this was a good team update. :ahh: Normally, I dread them because they change the game, but this one seemed to clarify more than anything else.

Re: Official Team Update #2! 1/15/2010
 

Thats my feeling as well.



To give credit where credits due, thanks to the GDC for this update. These were definitely questions that needed answers and you guys responded in what I interpret as a clear manner.



Off to keep building...

Re: Official Team Update #2! 1/15/2010
 

I'm curious as to what exactly "inside" means. From my reading of the rule, any kind of ball deflector, etc. above the bumper zone is legal, which I'm not sure was the intent.

Re: Official Team Update #2! 1/15/2010
 

I think regardless of how they worded it, the intent is very clearly that the GDC does NOT want to see robots designed to deflect balls in a specific manner, or guiding them in any manner above your bumpers other than preventing a ball getting stuck on top.

Re: Official Team Update #2! 1/15/2010
 

A passive deflector seems to be legal according to this update. The way I read the update something like a playground slide shaped funnel is legal, if it is only 3" deep.

Re: Official Team Update #2! 1/15/2010
 

Very challenging to cut down on bouncing though to use such a funnel.

Re: Official Team Update #2! 1/15/2010
 

[MECHANISMS are considered “active” if they are in motion relative to the ROBOT while in contact with the BALL. Resetting or moving MECHANISMS while not in contact with a BALL is permitted as the MECHANISMS are not considered “active.”]

What about a robot part that moves due to forces such as the impact of the ball, or inertia related to robot accelerations? For example, a loose cargo net, which would move if the robot stopped or turned suddenly and of course when hit by a ball. How about a padded surface that gets depressed by a ball hitting it? Both of these are 'moving' relative to the robot while in contact with the ball.

It seems the 'spirit' of the "active" definition seems to apply to mechanisms which move due to robot actuators.

Re: Official Team Update #2! 1/15/2010
 

Im curious about the 13.5" change in the BUMP height. I was in NH for the kickoff and noticed the angle seemed steeper than 45 degrees. What does this height change do for the BUMP?

Re: Official Team Update #2! 1/15/2010
 

The bump didn't actually change since Kickoff. It's just changed in the Manual to reflect it.

I think the angle is still 45 degrees.

Re: Official Team Update #2! 1/15/2010
 

Thanks!

Re: Official Team Update #2! 1/15/2010
 

I'm gonna have to disagree here... They changed <R19> in a big way. Not being able to intentionally affect balls above the bumper zone, while not POSESSING them is huge.

define 'a specific manner'. If i design a robot that looks approximately like this:
and park it in the direction that would deflect balls toward my end, have i violated this rule as updated in TU#2?

Re: Official Team Update #2! 1/15/2010
 

<R19> as modified by update 2 does not read that you cannot intentionally affect balls above the bumper zone while not possessing them.

<G45> always restricted this behavior using an active mechanism, which has now had its definition clarified.

<R19-B> as modified requires that balls only extend a maximum of 3" inside of any (passive) MECHANISM or feature above the BUMPER ZONE that directs the balls in a controlled manner.

In my opinion (which of course doesn't mean anything), the ball does not extend inside the sloped feature you've shown at all so that would be legal. A little bit more clarification though Q&A is probably necessary for this rule.

Re: Official Team Update #2! 1/15/2010
 

Yes, good question, and what if I climb the tower and TILT my robot's flat , previously vertical side in the line of balls falling from the return ramp? Where does the 3" get measured from now that the robot has tilted. Do I have to base this 3" penetration into robot space on my original on-the-floor size, shape and orientation? If I have a tall vertical 60" flat side, and I climb the tower such that I tilt and have returning balls hitting this flat side, if my tilting moves a spot on this flat side near the top more than three inches from a vertical line through the previous UN-TILTED location of this spot, then if a ball hits this spot while tilted, is it a violation. They always make rules with INCH LIMITS that DO NOT ACCOUNT for shifting frames of reference. Then when you ask questions, they dance around this major defect in the rules.

Re: Official Team Update #2! 1/15/2010
 

I believe your design as shown would be perfectly legal. Now, if the angle of that deflection was adjustable, and your deflector was in motion when a ball contacted it (say you're trying to "swat" the ball forward with the deflector by changing its angle relative to the robot), that would not be permitted per the <G45> blue box:

You are free to adjust the deflection angle when your deflector is not in contact with any balls. You are also free to drive your robot around with the deflector in a chosen, fixed angle.


As far as <R19-2> - let's be real here. How does a ball "extend 3" inside" a flat PLANE? It doesn't. A flat deflector above the bumper zone is legal, as long as it is not in motion relative to the robot any time it is in contact with a ball.

I believe the GDC is referring specifically to chutes, channels, funnels, diverters and other above-bumper zone structures designed to more precisely control the direction of ball movement. A diverter that can be pointed toward one goal or the other *would* be legal, as long as the diverter walls envelop 3" of the ball's height or less. Such designs are allowed, but the 3" limitation is in place to prevent *too* much control. Send a ball down a high-walled waterslide versus a typical playground slide with short rails. Which one keeps the ball down the intended path better? The waterslide. Which one is legal for competition use? The playground slide.

Re: Official Team Update #2! 1/15/2010
 

I would say yes, it is a violation. I think it's clear that by parking your robot in such a position, you have demonstrated that you intend to deflect balls, which you can consistently do in a controlled manner with the sloped feature on the robot. The rule update, however, does not mention intent at all, so even just having a sloped part that looks like it may have been designed to do such a thing is iffy (and an inspector's call).

My feeling is that if you can demonstrate that it fits around other robot geometry and is simply to keep the balls from getting stuck on top, they will accept it. A random wedge with no other visible purpose or necessity will probably invite serious scrutiny, and probably deemed illegal if it is used as such in any match.

This is simply how I have interpreted the update, but by no means am I a certified robot inspector or a member of the GDC, so my opinion is only that.

Re: Official Team Update #2! 1/15/2010
 

I think the final thing that needs to be clarified to distinguish between Evan's interpretation and the interpretation adopted by Travis and I is what it means to be inside a feature.

I don't think that a ball can be inside a ramp. As a contrast I believe that a ball can be inside a playground slide shaped funneling feature. In my opinion such a feature complies with the rules if it is 3" deep or less.

Re: Official Team Update #2! 1/15/2010
 

No matter what the meaning of the rule it will be up to the inspectors to intrepid them. One set of inspectors may go a little one way and another set of inspectors could go the other way. How will they get a consistent interpretation at the competition? How far can we go with the design and be safe from major reconstruction?

Re: Official Team Update #2! 1/15/2010
 

Evan,

I disagree with you. Look carefully at G45 in update 2:

The key phrase is "relative" to the robot. So, as long as the slope is not changing relative to the robot when the ball makes contaact, it is legal. The robot is allowed to drive around all you want to influence the direction of the balls. The intent is to stop us from creating a slapper or kicker above the bumpers.

Re: Official Team Update #2! 1/15/2010
 

I went back and re-read the update and the two rules in combination, and I think you're right. I had glossed over the part before the updated R19 where they mention complete enclosure.