The field of play must be rectangular and of the following size:
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Division A: 13.4 meters times 10.4 meters with a playing area of 12 meters times 9 meters
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Division B: 10.4 meters times 7.4 meters with a playing area of 9 meters times 6 meters
The exact field dimensions and the field markings at the venue may vary by up to ±10% in each linear dimension.
The two figures below show the dimensions of the field, the goals and special field areas, measured in millimeters between the line centers. Figure 1 shows the dimensions for division A and figure 2 for division B.
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The numbers in the figures below show the distances in millimeters between the line centers. |
The playing surface is green felt mat or carpet. The floor under the carpet is level, flat, and hard.
The field surface will continue for 0.7 meters beyond the field lines on all sides. The outer 0.4 meters of this runoff area, separated from the robot area by a 0.1 meters tall black wall, is used as a designated walking area for the referee and the assistant referee. The remaining 0.3 meters are the field margins.
The field of play is marked with lines. All lines are 0.01 meters wide and white (paint, spray, white carpet or strong tape). Lines belong to the areas of which they are boundaries. Distances between lines are measured from their centers. Distances from a robot are measured from its nearest side to the respective measurement point, with an assumed radius of 0.09 m.
The playing area is defined by four field lines. The two longer field lines are called touch lines. The two shorter field lines are called goal lines.
The field of play is divided into two halves by a halfway line that runs along the width of the field and through the center of the field. The halfway line is parallel to the goal lines.
The goal-to-goal line runs along the length of the field, passing through the center of the goals and the field. The goal-to-goal line is parallel to the touch lines.
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This line is used to provide adequate features for the geometry calibration of the vision software and for optional local localisation of robots. |
The center circle is located at the center of the field with a diameter of 1 meter. The center is at the crossing of the halfway line and the goal-to-goal line.
The penalty mark defines the point from which a team executes a penalty kick against the opponent goal. It is located on the goal-to-goal line and 8 meters (division A) or 6 meters (division B) away from the opponent’s goal center.
Goals must be placed on the center of each goal line and anchored securely to the field surface. They consist of two 0.16 meters high vertical side walls joined at the back by a 0.16 meters high vertical rear wall. The inner face of the goal has to be covered with an energy absorbing material such as foam to help absorb ball impacts and lessen the speed of deflections. The inner goal walls are white, the outer goal walls, edges, and tops are black.
The distance between the side walls is 1.8 meters for division A and 1 meter for division B, and the goal is 0.18 meters deep. The goal walls are 0.02 meters thick and touch the goal line, but do not overlap or encroach on the field lines or the field. Figure 3 and figure 4 show these details for division A and division B respectively.
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The numbers in the figures below show the distances in millimeters. |
The ball is a standard orange golf ball. It weights approximately 0.046 kilograms and its diameter measures 0.043 meters.
For official matches, the organizing committee provides the ball.
The shared software used in the Small Size League is maintained by the technical committee, though everyone is encouraged to contribute. The technical committee members however guarantee that any changes made less than three months before the next RoboCup do not break compatibility.
Each field is provided with a shared central vision server and a set of shared cameras. This shared vision equipment uses the community-maintained SSL-Vision software (https://github.com/RoboCup-SSL/ssl-vision) to provide localization data to teams via Ethernet in a packet format that is to be announced by the shared vision system developers before the competition. Teams need to ensure that their systems are compatible with the shared vision system output and that their systems are able to handle the typical properties of real-world sensory data as provided by the shared vision system (including noise, latency, or occasional failed detections and misclassifications). The vision patterns on the top of the robots must adhere to the specifications of SSL-Vision, and must be of the standard color paper as specified in the SSL-Vision documentation.
Besides the shared vision equipment, teams are not allowed to mount their own cameras or other external sensors, unless specifically announced or permitted by the respective competition organizers.
SSL-Vision defines an additional tracker protocol that contains filtered and enriched tracking data. Messages are not published by SSL-Vision itself, but for example by some automatic referees. It is meant to be used by the game controller and by teams that do not yet have their own sophisticated filter.
A game is controlled by the community-maintained ssl-game-controller (https://github.com/RoboCup-SSL/ssl-game-controller). It is operated by the game controller operator. The software translates decisions of the referee and the automatic referee into Ethernet communication signals that are broadcast to the network. It maintains the state of the game, tracks all events and acts as a proxy between all participating parties in the game.
The game controller has a network interface for the playing teams. They can automatically change their keeper id, they can signal a robot substitution intent for the next opportunity, and they can send an advantage choice for handling game stopping after yellow cards.
One or more automatic referee applications can supervise a game and report offenses to the game controller. At least one automatic referee is required per game. If more than one automatic referee is connected to the game controller, a majority vote can be applied.
New automatic referee implementations can be provided, given that the source code is open-sourced. New implementations must be announced at least three months before the competition. The technical committee decides if an implementation will be used or not.
The Game Event Table shows which game events an automatic referee implementation must be able to detect. Individual game events can be disabled completely or in some automatic referee implementations if both teams and the technical committee agree.
A remote control for each team can optionally be provided by the tournament organizers. It is a physical device that allows entering the following commands:
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Raise a challenge flag
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Request a timeout
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Request robot substitution
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Request emergency stop
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Change the keeper id
It may also provide feedback information, like:
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Number of yellow cards and when they are due
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Number of robots currently allowed
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Number of robots currently on the field
The remote control may only be used by the robot handler. There is always only one remote control per team, per match.
The official implementation for the league can be found on GitHub: https://github.com/RoboCup-SSL/ssl-remote-control.
The communication flags are used to avoid gesturing and yelling with the referee during a match. These flags are responsible for communicating various intents, such as: timeouts, emergency stops, manual robot substitution and challenges.
The referee or game controller operator has to acknowledge the communication flag. Any gesturing and yelling will be considered unsporting behavior, punished by a red card after the first warning.
The communication flags are provided by the organizers of the competition. A remote control software or device can be provided and replace physical flags. Any other solution that the organizers find feasible can also be used.