[robocup-small] Penalty Kick

[Ulfert Nehmiz]

Hi Alireza

First of all, let me express my personal hope that you and all team members of
your and the other Iranian teams are fine and you will be able to join us at
RoboCup09.

Now, facing your question:

I get your point, and I also think that this constraint might be a bit too
strict for the SSL as it is today.

But, and this is only a guess, this rule might be a survivor of the origins of
SSL when there was no omnidirectional driving. So, this rule was made to prevent
the goalie to be in clear advantage to the attacker (when taking the penalty).
This might have been included as "some robots are not designed to move and
accelerate equally well in all directions" (as you said). If this is the case,
there is an improvement in gameplay made by this rule as it forces the goalie to
behave like a realistic goalie (e.g., no human goalie would look sidewards when
facing a penalty).

I think that every team's robot has a clear front, and this is what is called
the "face" in the rules just as you guessed, too. I think facing the ball is the
normal positioning of a goalie in SSL, as the goalie might have to try to clear
the ball. The penalty rule might prevent teams from having an optimized
"penalty-goalie-positioning and driving", as this is unrealistic.

So, what to do with this: We certainly should not change the rules before
RoboCup09 as there is too little time left. Maybe we can discuss this issue at
RoboCup again and agree on a change for the next year. Maybe we can even have
this discussion at the Referee's meeting at the beginning of the event, then all
teams and all referees will know how to handle this.

Best regards
Ulfert

P.S.: This might be the right moment to remind all teams once again that you are
requested to bring a team of referees to Graz. If you have been to RoboCup or a
national open before, you will already know how refereeing works in details and
that it is not as complicated as you might have thought before. Nevertheless, we
will have a referee-meeting with a short demonstration at Graz as a short
reminder or a short instruction for the new referees. Please make sure that you
have read the rules carefully (not only as a referee, by the way), if you have
any questions feel free to post them :)

Alireza Haghshenas schrieb:
> Hi all
> 
> in the rules, the defending goalkeeper receiving a penalty kick should 
> remain facing outward the goal
> 
> 1- why is there such a rule? in all other rules only the position of the 
> robot is important and no distinction is ever made about different parts 
> of the robot.
> 2- strictly speaking, there is no formal definition of the robot "face". 
> The natural feeling is that the robot's flat side with kicker should be 
> considered as face. But there is no requirement on the existence and 
> uniqueness of such a "face".
> 
> what's my real intention for asking these questions: some robots are not 
> designed to move and accelerate equally well in all directions. While 
> -in my opinion- putting such a constraint on the goal keeper makes no 
> improvement to the gameplay, it decreases the keepers mobility and 
> responsiveness.
> 
> I think it's better to remove the constraint.
> 
> Bests,
> Alireza Haghshenas
> 
> 
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