[robocup-small] Major rules proposals for 2007

[James Bruce]

Dear small-size community,

The TC would like to announce the major proposed changes for the 2007
rules ("Major" changes are those which may affect hardware systems).
We are soliciting feedback from teams on several issues, so we would
encourage teams to read and comment on these proposals before they
become permanent for 2007.

If possible, we would like teams to discuss these changes internally
and come up with a single opinion on each of the proposals.  Please
state your team affiliation when posting a response on behalf of a
team.  You can also participate in the discussion as an individual (or
ex-team member), but please mention that you are speaking on your own
behalf.

We will follow the feedback up shortly with proposed "minor" changes
which affect gameplay but which do not affect hardware design.

  - The 2007 TC.

P.S. Please accept our apologies for getting far behind schedule.  We
are trying to catch up now and finish soon, hopefully ahead of last
year's rules finalization.


--------------------------------
   PROPOSED MAJOR RULES CHANGES
--------------------------------

==== FIELD SIZE ====

Proposal: Increase field size slightly for 2007.  The outer dimensions
of the field remain the same, but the inner dimensions are increased
by 200mm in both directions.  This is achieved by shrinking the
"margin" outside the area of play from 300mm to 200mm.

TC: The TC is evenly split on this issue, so we would like to hear
from teams as to how they feel about this change.

Note: Although the outer field dimensions will remain unchanged this
year, this current TC is considering a major field size increase for
2008 and beyond.  Thus, teams should design their systems with this in
mind.  Because it takes teams time to adapt to field size increases,
we are working on a multi-year roadmap which will be provided to guide
future TCs.  Like the mid-size league (as well as FIFA), the field
size in the future is likely to be provided as a range, rather than
the current fixed dimensions.


==== SEMI-AUTOMATIC REFEREE ====

This year we will be adopting an ethernet-based referee, which allows
teams a measure of self-refereeing.  It is based on the concept
demonstrated at last year's RoboCup by Plasma-Z.  Participation this
year will be voluntary, but strongly encouraged.  The referee program
will still have a serial output like the old referee program, but that
interface may not have the full functionality of the new ethernet
interface.

Note: Teams are encouraged to consider computer hardware with an
additional ethernet interface, as the referee will be on a special
local network to avoid interference.


==== ROBOT KICK SPEED LIMITATION ====

Proposal: Limit the maximum speed a ball can be kicked, to something
like 10m/s.

TC: We would like to adopt this rule, both for safety reasons and to
avoid an arms race.  However, we would like feedback from teams about
whether they feel this is important, and if so, which speed limit to
use.  To keep it concrete, please consider only 2 m/s increments
between 6 m/s and 12 m/s, or "no limit".

Penalty: Goals scored or deflections off of opponents using kicks
above the limit will result in a freekick for the other team.
Enforcement would mainly be by team cooperation, along with a static
measurement at the beginning of the competition.  During a match, a
referee will have to use his judgement, along with evidence from any
participating automatic referees.


==== ROBOT KICKER SAFETY ====

Proposal: Limit maximum voltage of energy storage for kickers.
Kicking devices are also not allowed to use explosive chemical
reactions to power their kick.

TC: This is another safety issue, and we would like teams to give
their feedback as this as safety is a community issue.  The limits we
will consider are 100V, 150V, 200V, and 250V, or "no limit".  The TC
has a slight preference for 200V as this allows many teams from last
year to run unmodified, and is not above the household AC current in
most countries.


==== NEW GOALS ====

The TC (and OC) is exploring the option of redesigning the goals to
better absorb ball impacts and avoid high speed rebounds.  This could
take the form of foam or even changing the back to a net.

The TC would like to hear from teams on this issue, in particular if a
change from the current solid color painted goals would negatively
affect a team.  The change to the goals is being considered due to
high-speed kickers as well as the lack of current teams using local
vision sensing.


==== BALL ====

The current ball will not be changed for this year, but the TC is
strongly considering different balls for 2008 and beyond.


==== STRICT ENFORCEMENT OF BALL HOLDING RULES ====

This is not a rule change as much as a statement of future enforcement
policy.  Last year, robots were checked for rules compliance before
the competition, and many teams failed tests for overall dimensions
and ball holding.  Teams should expect this again for 2007, and are
encouraged to resolve issues before coming to the competition.

While some rules are easy to check, the "20% ball holding" limit can
be difficult to evaluate, in particular with scoop-style chip kickers.
While a few teams were allowed to compete in 2006 with possibly
questionable chip kicking mechanisms, for this year we note that it is
the TEAM'S RESPONSIBILITY to provide evidence of conformance.  This
can take the form of demonstrating it is statically legal in all
configurations (by far the easiest route), by measurements and
equations demonstrating mathematical conformance, by high speed camera
evidence, or other physical demonstrations of conformance.  Teams with
questions about conformance are encouraged to send email to the TC.