An overview of the referee commands and how they interact with the game state, is given in [Game States].
When the stop command is issued, all robots have to slow down to less than 1.5 m/s. Additionally, all robots have to keep at least 0.5 meters distance to the ball and are not allowed to manipulate the ball.
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If the ball moves very quickly, it is hard to always keep the required distance to the ball, especially since the speed of the robots is limited during stop. Therefore, it is sufficient if it is obvious to the referee that the robots try their best to follow the distance rule. |
The stop command is used to pause the game after the ball crossed the field lines (including goals) or an offense occurred as well as to prepare the start or resumption of the game after halt, timeouts and automatic ball placement. The robot speed limit and the minimum distance to the ball allow the referee or assistant referee to place the ball safely and without interference.
When the halt command is issued, no robot is allowed to move or manipulate the ball.
There is a grace period of 2 seconds for the robots to brake.
The halt command allows the referee to interrupt the game immediately whenever an emergency occurs (for example when a robot gets out of control). It is also used to recalibrate the vision software during a game if the vision expert considers it necessary and the referee agrees and for robot substitution. Additionally, the referee is free to issue the halt command at will.
The halt command is always followed up by stop. Enough preparation time should be given to teams, before the game is continued. The game controller will wait for up to 10 seconds after a halt command, but the game can be continued if robots are prepared already.
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As a rule of thumb, the game should always be halted when humans other than the referees are entering the field. |
After the game was stopped, the ball must be placed on the appropriate position, depending on the event that occurred. The automatic ball placement is the preferred way to place the ball at the designated position on the field by the robots of the teams without human interaction. If this is not possible, the referee places the ball manually.
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During manual ball placement, the game should be in stop to allow robots to prepare for game continuation. |
No ball placement is required if all of the following constraints are fulfilled:
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The ball is closer than 1m to the designated position.
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The ball is inside the field.
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The ball is at least 0.7m away from any defense area.
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The ball is stationary.
In this case, the game can be continued as soon as all robots keep the required distance for stop.
A ball is considered placed successfully by the robots if
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no more than 30 seconds passed since the placement command
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there is no robot within 0.05 meters distance to the ball if the next command is a free kick for the placing team
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there is no robot within 0.5 meters distance to the ball if the next command is a force start
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the ball is stationary
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the ball is at a position within 0.15 meters radius from the requested position
No further commands will be issued by the game controller until the automatic placement is complete. The game will be continued by the game controller as soon as the ball is successfully placed, but not earlier than 2 seconds after the ball placement command has been issued. A failed placement will result in a free kick for the opposing team. If this team failed to place the ball as well, the ball is placed by the referee and game continues with the original command.
For each team a ball placement failure counter is incremented on each placement failure and decremented for successful placements. It can not get negative.
The non-placing team must not interfere the ball placement task.
When the ball goes out of play, the following rules decide, if automatic ball placement is applied:
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The referee has to place the ball for all kickoffs and all penalty kicks
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For a free kick, the team that brings the ball into play must place the ball
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For a force start, a team is drawn by chance and must place the ball
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The ball must be visible and must not be inside a field corner, a goal corner or behind the goal, before the ball placement starts
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The referee can decide to place the ball manually at any time
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The referee can decide to disable automatic ball placement for the rest of the game. TC/OC must agree with this decision
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When a teams placement failure counter reached 5, it is not allowed to place the ball for the rest of the game half. All free kicks that were a result of the ball leaving the field, are awarded to the opposing team. For all other rule violations or when both teams failed to place the ball, the ball is placed by the referee
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If no team can place the ball, the ball is placed by the referee or the assistant referee. Both the referee as well as the assistant referee are advised to use a so-called ball handler (a long, preferably black stick-like device) to move the ball.
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The ball may still be moving when the placement command is issued. |
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The game commences directly after ball placement. The team receiving the ball may shoot immediately and leave the opposing team little time to arrange defensive actions if needed. |
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It is allowed to enter the defense area during ball placement. |
Ball placement is mandatory for all teams in division A. Teams in division B may decide, at any time before or during the game, not to place the ball for the rest of the game by talking to the referee, who in turn tells the game controller operator to disable ball placement for this team. In this case, the team is allowed to bring the ball into play, after the ball was placed by the opposing team. If the opposing team fails to place the ball or no team can place the ball, it is placed by the referee or the assistant referee.
After the ball has been placed, the game is resumed using one of the following commands.
For two-staged referee commands, when normal start is sent, an attacker may manipulate the ball. A match cannot be resumed directly via normal start.
Normal start is used for kick-offs and penalty kicks.
The ball has to be placed in the center of the field by the human referee.
When the kick-off command is issued, all robots have to move to their own half of the field excluding the center circle. However, one robot of the attacking team is also allowed to be inside the whole center circle. This robot will be referred to as the kicker. No robot is allowed to touch the ball.
When the normal start command is issued, the kicker is allowed to shoot the ball. A goal may be scored directly from the kick-off.
When the ball is in play, the kicker may not touch the ball until it has been touched by another robot or the game has been stopped (see double touch). Also, the restrictions regarding the robot positions are lifted.
Both half times as well as both overtime periods (if needed) start with a kick-off. Chapter [Match Preparation] describes how to determine the attacking team.
Additionally, after a goal has been scored, the receiving team restarts the game with a kick-off.
The ball placement position for a free kick depends on the event that led to the free kick. This position is valid if there is at least 0.2 meters distance to all field lines and 1 meter distance to either defense area. If an event requires the ball to be placed at a position that contravenes this rule, it has to be placed at the closest valid position instead.
When the free kick command is issued, robots of the attacking team are allowed to approach the ball while robots of the defending team still have to stay at least 0.5 meters distance away from the ball (the same distance as in stop). One robot of the attacking team is allowed to shoot the ball. This robot will be referred to as the kicker. A goal may be scored directly from the free kick.
When the ball is in play, the kicker may not touch the ball until it has been touched by another robot or the game has been stopped (see double touch). Also, the restrictions regarding the robot positions are lifted.
Free kicks are used to restart the game after a foul has occurred. Additionally, goal kicks and corner kicks are mapped to free kicks.
When the force start command is issued, the game is immediately resumed and both teams are allowed to approach and manipulate the ball again.
A neutral forced start is used in situations where no team is clearly in favor, such as:
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the game had to be stopped without a specific reason.
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both teams are at fault.
The procedure of a penalty kick is as follows:
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The ball is placed by the human referee on the penalty mark.
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When the penalty command is issued:
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The defending keeper has to move to the goal line between the goal posts and keep touching the goal line.
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One attacking robot is allowed to approach the ball but not allowed to touch the ball.
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Throughout the penalty kick procedure, all other robots have to be 1m behind the ball such that they do not interfere the penalty kick procedure.
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When the normal start command is issued, the attacker is allowed to manipulate the ball. The ball has to only move towards the opponent goal, as measured by its x coordinate in the coordinate system of SSL-Vision.
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When the ball is in play, the defending keeper may move freely again.
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If the ball is still in play after 10 seconds, the game is stopped.
A goal is awarded if:
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the ball touches the inner surface of a goal wall or the ground of the goal of the defending team, starting from when the normal start command is issued.
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the defending team commits any foul.
The game is continued with a kick-off when a goal is awarded.
A goal is not awarded if:
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the ball crosses any field lines outside the goal.
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the defending keeper touches the ball such that the ball speed vector changes direction by at least 90 degrees in 2D space.
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the attacking team violates any rule.
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the ball is still in play after 10 seconds.
The game is continued by a goal kick for the defending team when a goal is not awarded.
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The restrictions defined for scoring goals, including the ball height limit of 0.15 meters, do not apply here. Other rules like the excessive dribbling limitation for example do. |
Additional time is allowed for a penalty kick to be taken at the end of each half or at the end of periods of overtime.
Penalty Kicks are used to punish unsporting behavior and multiple defenders.
When the match is stopped, the ball is considered out of play until it has been brought into play.
When the match is resumed, the ball is considered in play until the next stoppage occurs. The match is resumed when
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force start has been issued.
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the ball moved at least 0.05 meters following a kick-off, free kick or penalty kick.
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10 seconds passed following a kick-off.
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5 seconds (Division A) or 10 seconds (Division B) passed following a free kick.
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see double touch for the rationale of the 0.05 meter distance |
If the yellow card is shown as a result of unsporting behavior, the referee may decide to immediately halt the match. In this case, the match continues with a free kick for the other team.
Upon receipt of a yellow card, the number of robots allowed on the field for the penalized team decreases by one. If, after this decrease, the team has more robots than permitted on the field, a robot must be taken out.
A yellow card does not lead to a stop automatically. If the ball is in play, the team will have 10 seconds to automatically remove the robot. If a robot is not taken out within time, the game is stopped for manual substitution and continues with a Forced Start. The 10 seconds can be extended indefinitely by the other team by sending an advance choice to the game controller.
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This rule implies that after receiving a yellow card, the game might not be automatically stopped. However, the game will be stopped if the foul that led to the yellow card causes a game stoppage, e.g. dropping parts. Therefore, if one of those fouls occurred, the team is allowed to manually remove the robot. |
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No penalty will be given to the team that couldn’t get the robot out of the field in time. However, in the future there will be a penalty like this: If the robot gets manually substituted, the ball is placed on the goal-to-goal line and 1.5 meters away from the teams defense area and the opposing team gets a free kick. |
A team cannot score a goal while having more than the allowed number of robots on the field.
After 120 seconds of playing time (measured by the game controller), the yellow card expires and the number of allowed robots is increased by one. The team may put a robot back in during the next opportunity.
When a team has two not yet expired yellow cards and receives another yellow card, this card will be turned into a red card instead.
Yellow cards are used to punish teams that committed multiple fouls.
Yellow cards can also be given by the referee to punish fouls or unsporting behavior.
A red card behaves like a yellow card, except: It does not expire until the end of the game.
Red cards are given by the referee to punish severe fouls or unsporting behavior.
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For example, serious violent contact by the robots or disrespectful behavior towards the referees can result in a red card. |
A Forced forfeit means that a team instantly loses the current game with a score of 0 to 10.
A team can be forced to forfeit if it is unable to play with at least one robot that satisfies the rules.
A team can only be forced to forfeit in agreement with members of the technical committee and the organizing committee.
A Disqualification means that a team immediately drops out of the tournament and places last. It will not be eligible to receive any trophies.
A team can be disqualified if members of this team don’t follow safety guidelines, rules of the venue or commit similarly severe offenses.
A team can only be disqualified in agreement with members of the technical committee and the organizing committee.