[robocup-small] November RoboCup SSL Update and Response to Request of Transparency

[Carla Cosenza]

Dear SSL Community,


We have been striving for a long time to increase actual soccer game-on time during SSL games. Unfortunately, despite several rules iterations, our analysis over the game logs from RoboCup 2018 and 2019 show that we are still far off the mark - games had an average of only 20% actual game-on time during RoboCup 2018, and 15% actual game on time during RoboCup 2019. To make the situation worse, we have far more special game states than game on.


All the recent events have been caused by the lack of established procedure for making big changes with rapid adoption for the Small Size League. We were trying to decrease the amount of time not spent on actual soccer during matches and did not manage to come to an agreement. In order to prevent this, we are creating a method for these decisions. Due to its importance, it will be discussed in Bordeaux with representation of all teams and committees.


For RoboCup 2020, we have created a proposal for rule changes: https://docs.google.com/document/d/1EBfKZfXEYq2SpcLzUb7OE68vlUKjJnk_tnaulR5CMO8

You can also find an immutable copy of the document attached to this mail. We encourage teams to give us feedback by the end of November. You can use the comment and suggestion mode or reply to this mail.

If there is well justified concern, we’ll consider it when finalizing the rule changes. Some of the most notable changes are:


Walls for field boundaries in some Div A matches

In order to verify the possibility of removing the out of bounds part of the field, we are going to test, in some division A matches, having walls on the boundaries of the field. This will result in having less game states and less time spent placing the ball after it leaves the field. Each team will be required to play at least one game with the walls during the group stage and before the match starts, both teams need to opt out of the walls in order not to use them. The objective of this change is to reduce the amount of time spent not playing soccer during the matches. Our statistical analysis has shown that games had an average of only 20% actual game-on time during RoboCup 2018, and 15% actual game on time during RoboCup 2019.


11 robots and field size for Div A

Having Div A reach 11 robots has been on the SSL roadmap for this year and it will happen. Div A teams will be allowed to have up to 11 robots on field. The only difference is that there will not be an increase in field size. We have measured that even if we do not change the field size, taking Div A to 11 robots will provide a bigger area per robot value (4.9m²) than the current configuration for Div B does (4.5m²).


Match Statistics

When discussing rule changes, we need some facts and numbers from past RoboCups to support or reject arguments. We also need to evaluate the effects of changes that were made. That’s why we started to establish a standard statistics database. The SSL committee commits on updating and evaluating these statistics each year.

The code can be found here: https://github.com/RoboCup-SSL/ssl-match-stats

We will prepare an area on the SSL website with more information on this soon.


Qualification requirements

We will update the specifications for the qualification videos for Div A. Team have to demonstrate passing (with a more precise definition) and ball placement. Both can still be demonstrated by game play footage, but we will limit the duration of the video for both divisions. This is to encourage teams to work on smooth game play. Details will be included in the qualification webpage<https://ssl.robocup.org/robocup-2020-qualification/>.


Technical challenges

We will repeat a version of the SSL-Vision Blackout Challenge. Both divisions are eligible to participate. We will also have a Ball Placement Challenge for Div B teams only. All Div B teams will be required to participate in the Ball Placement Challenge. The intention is to prepare Div B teams to move to Div A. More information about these challenges will be announced later. The current work-in-progress status can be found on GitHub: https://github.com/RoboCup-SSL/technical-challenge-rules.


Other reminders and updates

  *   As stated in the previous email, all teams will be required to bring posters in order to present their changes and improvements to the other teams. Like last year we will schedule a poster session where team members can present and discuss poster contents.

  *   We are still testing April Tags for SSL Vision. Initial implementation works correctly but more testing is needed. We do not anticipate forcing teams to use the April tags at this competition. However teams should start preparing for tags other than the currently butterfly patterns.


All of these changes were based on the long term goals of the Small Size League. The main intended effect is to:

Spend more time solving the game-on regular soccer problem, not on non-soccer behaviors.

In particular, we anticipate ball handling (stealing, possession, dribbling, passing) to be more important now. We are also trying to propose challenges to help Div B teams reach Div A, since Div B is intended to simplify the entrance of a new team to the league.


Team Leader Online Meeting

We would also like to invite the team leaders for an online meeting in order to clarify any concerns and discuss the decisions for RoboCup 2020. We ask each team to fill out this form (https://docs.google.com/forms/d/e/1FAIpQLScXR8BGCPYzZVHh0YUw8S75rYmV5HmCZk6xdenIvRXbV5yhbQ/viewform?usp=sf_link) with the name and email of their team leader so we can send out the invite for the meeting.


We look forward to hearing from you!


Thank you!


The Technical, Organization, and Executive Committees of the Small Size League
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