[robocup-small] Rule changes for 2005

[James Bruce]

Here's the opinion of at least the CMU half of CMRoboDragons.  On the 
issues, as far as I know we're in agreement with Aichi University (the 
other half of CMRoboDragons).  We don't have a single spokesperson 
however, so they may make a separate statement if they wish.

Sean Verret wrote:

>Change 1:
>
>The dribbling distance will be set at 500mm for both active and passive
>dribblers.
>  
>
We agree with this change.  Since it is difficult to tell whether a 
potentially active dribbler is actually running, it makes sense to apply 
the same rule in all situations.  This makes it easier on the referee, 
and encourages multi-robot involvement in gameplay.  500mm seems a good 
match for the current field size.

>Change 2:
>
>For all restarts where the ball has gone out of bounds and the rules
>state the ball is too be placed ON a boundary line or within 10cm of a
>boundary line, the ball will be instead moved towards the middle of the
>field to an imaginary line that is 10cm any of the boundary lines that
>the ball is within the 10cm wall.  Needs rewording but I think it makes
>sense.
>  
>
We agree with this change.  Moving the ball in even a small amount 
should make it much easier for robots to kick the ball such that it 
stays in play.

>Change 3:
>
>The referee box will send a neutral restart command 10 seconds after all
>restarts.
>  
>
Does this mean a team has to take its kick within 10 seconds, or it 
becomes a neutral restart?  That's fine with us, but we want to 
understand the rule completely.  This will allow teams to more easily be 
conservative on restarts, avoiding kick-detection problems in poor lighting.

>Change 4:
>
>No more bluetooth is allowed in the small-size league, and all other RF
>decisions will be left to the OC based on local conditions.
>  
>
How about just saying "No radios within the 802.11b frequency range are 
allowed.  Specifically this includes bluetooth."  I assume that is what 
is meant by the rule.  On the other hand, some teams (such as 
CMRoboDragons) have radios in the 2.4 GHz range, but which can operate 
completely outside the range used by 802.11b.  We'd like to know if this 
is allowed, though of course if its up to the OC we'll ask them.  From 
my understanding of bluetooth, it cannot be made to operate completely 
outside of 802.11's range.

>Change 5:
>
>Corner kicks will follow with change 3.
>  
>
Ok.

>Change 6:
>
>The EC/OC/TC will decide upon ALL yellows, blues, greens, cyans, and
>pinks allowed to be used by robots before the competition and will make
>enough of these colors available at the competition for each team to
>field 6 robots.
>  
>
We think this is in general a good idea, but don't have a very strong 
opinion.  We provided the samples of the previous official colors (in 
2002 I think?), and would be happy to do so again if people are happy 
with those colors (we have found a much better blue that does not fade 
however).  We can get large sheets of all the colors.

Importantly however, if we use official colors, we will need at least 
the guarantee of a minimum brightness level on the fields.  Last year, 
we were promised a certain lighting level, but found the actual level to 
be between 1/2 and 1/4 of the promised value.  We had to use a backup 
system because our primary system could not work on that dark a field.  
We feel this is important enough to bring up, because uneven lighting is 
a software problem, but a very dark field is a camera problem, and 
penalyzes teams that cannot buy expensive top-of the-line cameras.

>Change 7:
>
>We will have 6 robots per team
>  
>
We are against this change.  Several teams have only 5 robots (such as 
CMU and Aichi), many would have trouble affording more, and it is too 
late to ask people to build more for this year.  Other teams building 
robots are probably already part way through building them, and it might 
be expensive to add one now.  A change like this should be a longer term 
goal, and stated concretely well in advance.  In other words, now is a 
good time to talk about how many robots to have in 2006, with a demo 
game this year by the teams who would like the change.

Additionally, we do not feel we know the effects of last year's rule 
changes, as teams were still adapting.  I think adding a robot now is 
premature;  It doesn't seem to solve any concrete problems present right 
now.

>Change 8:
>
>The time of game will include 12 minute halfs, 5 minute half time
>breaks, each team retains its color for the duration of the match and
>colors are decided along with the referee 1 hour before the match.
>  
>
Longer halfs are fine, but we don't see much of a need for it either.  
We disagree with changing the color arbitration.  In poor lighting 
conditions, one color really can be better than another, so it is most 
fair to allow switching.  Teams only need only set down tops with both 
colors to let the other team calibrate.  Most of the time, teams don't 
care about colors and will simply agree not to switch.  So we would 
prefer something like:

1 hour in advance of the game, teams must decide if they are going to 
switch colors at half time, and which color they will start with.  If 
both teams agree not to switch, they will keep the same colors, 
otherwise they will switch at half time.

Additionally, we would like each team to provide blue and yellow 
"example covers" to the other team 1 hour prior to the match.  These can 
be simple paper cutouts with the same patches as the real covers, or 
actual tops.  In this way, even without official colors, or with odd 
tops, all teams should be happy.  In general this is not currently the 
case, but it is not really fair for a team to change its top patterns or 
colors a few minutes before the game.

>Change 9:
>
>There will be no chip kicks allowed during any restart.  Chip kicks (of
>any height) will be allowed during all other situations.
>  
>
We prefer Raul's suggestion of all kicks being indirect and having to 
touch another teammate before being counted as a goal.  We don't have a 
strong opinion however.

We do feel strongly that the 20% rule should be applied without 
exception.  It has served us well for a long time, and relaxing it leads 
to problems where an "attempted kick" might actually grab the ball.  Is 
that dribbling or kicking?  This actually happened to us in 2001 due to 
a poor kicker design, so it will come up.  Also, how long is too long 
for scooping?  I think it is best to avoid the problem by enforcing the 
20% rule at all times.

This also effectively makes chipping difficult but possible, which is a 
good situation.  FU-Fighters and CMRoboDragons chip kickers are hard to 
control in accuracy, which means they are not as much of a huge 
advantage as they might seem.  The also show you can chip within the 
current rules.  Scoop-based kickers which violate the 20% rule have no 
limit to their accuracy, and raise all sorts of problems in terms of 
corner cases for the 20% rule.  Since we are not going to eliminate the 
20% rule in all situations, the only way to avoid those cases is the 
enforce it in all situations.

Jim Bruce
CMDragons / CMRoboDragons