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LEGO Soccer

Name of Event: Lego Soccer
Robots per Event: Two on Two
Length of Event: Two 7-minute halves
Robot Weight Range: 2 kg
Robot Dimensions: Goalie: 8"x8" / Striker: 10"x10"
Arena Specifications: 44" x 96"
Robot Control: Autonomous
Engineering Principles: Computer Science, sensor integration, mechanical engineering, fuzzy logic
Event Summary: Classic soccer game played with two LEGO Mindstorms robots to a side. The ball emits an infrared signal detected by all robots. "Striker" robots try to move the ball downfield to socre against the opponent goalie bot, while the opposing team tries to do the same. All robots are programmed to be autonomous.
         

1: The Field and the Ball

(a) Field dimensions
A printed sheet 44 inches wide by 8 feet long, with actual playfield approximately 7 feet long. Field is enclosed by wooden sides, and there is no "out of bounds area." Ball may be bounced off of the edge of field. The field will always e oriented in a North/South manner, with the blue goal being on the north end, and the red goal being on the south.

(b) Markings on the playground
The inner field is dark green, 24 inches deep. The sides of the field gradiate from dark green to white by the edge.

(c) The goals
The goal area is 16 inches wide by 6.5 inches deep. The back posts are surrounded by Lego bricks stacked 6 inches high (blue on the north end, red on the south end.)

(d) The goal line and goal area
The goalie area is white, 24 inches wide by 10 inches deep.

(e) The ball
The ball used is a HiTechnic IR emitting ball.
2: The Players
(a) The overall system
A match shall be played by two teams, each consisting of 2 robots. Teams may swap out robots during the match, so long as the replacement robots meet the same criteria as the robot being replaced.

(b) The robots.
There will be two robots per team. One striker/forward playing robot, and one goalkeeper.
1. The robots may have colored stickers or lego bricks on them to identify them as being from the red or blue team. There should be a way of distinguishing each robot from the others.
2. The weight of either robot should be limited to a maximum of the robot should be 2kg.
3. Goalkeeper - The goalkeeper robot can be no larger than 8 inches wide by 8 inches long. It may have retractable parts, but at no time shall a fully extended retractable part exceed the 8x8 footprint. The goalkeeper robot should always stay within the white goalie area of the field.
4. Striker - The striker robot can be no larger than 10 inches wide by 10 inches long. It may have retractable parts, but at no time shall a fully extended retractable part exceed the 10x10 footprint.
5. The robots can be wheeled or have legs.
6. While a match is in progress, if the referee blows his whistle, the human operators should stop all robots.
(c) Substitutions
Four substitutes shall be permitted while a game is in progress. If a team wants to substitute robots, the team manager should inform the referee. Only the referee may allow the substitution. The time keeper should record the substitute. At half time, unlimited substitutions can be made. When a substitution is desired while the game is in progress, the concerned team manager should call 'time-out' to notify the referee.

(d) Time-out
The human operator can call for 'time-out' to notify the referee. The referee will stop the game in case the call for time out does not have any effect with goal situation. It is recommended that the referee should call time outs when the ball is located in the opponent area when a team calls the time out. The game will restart with free-ball position on the side of the time-out calling team. Each team will be entitled for two time-outs in a game and each shall be of 3 minutes duration.

(e) Fallen Robots
In the event a robot falls and cannot stand up by itself (even if wheeled), the operator is NOT allowed to stand it up. The operator should inform the referee, who will stand-up the robot.
3: Transmissible Information
Robots must be fully autonomous. No remote controlling by a human of the robots is allowed.
4: Programming
Robots may be programmed in any language. Officials may ask to see printouts of the program(s) being used in each robot.
5: Game Duration
The duration of a game shall be two equal periods of 7 minutes each with a half time interval for 5 minutes. An official timekeeper will pause the clock during substitutions, while transporting an injured robot from the field, during time-out and during such situations that deem to be right as per the discretion of the timekeeper. If a team is not ready to resume the game after the half time, additional 5 minutes shall be allowed. If the team is still not ready after the second break, that team will be disqualified from the game.
6: Game Commencement
(a) Before the game starts, a coin toss will decide starting team sides (Blue or Red). Red team drives north towards the blue Lego goal area, while blue team drives south torwards the red goal area. Teams switch sides at half time, so should be prepared with multiple programs or a program which can change sides before commencing play.

(b) Prior to the commencement of the game, both teams will be allowed to position their robots freely in their own area and within the center circle. At the beginning of the first and second half, and after a goal has been scored, the ball should be kept within the center circle and the ball should be kicked or passed towards the team's own side. With a signal from the referee, the game shall be started and all robots may move freely.

(c)At the beginning of the game or after a goal has been scored, the game shall be commenced/continued, with the positions of the robots as described above.

(d) After the half time, the teams have to change sides. They should be prepared to change programs during this time to account for the change in compass orientation and goal colors.

(e) The game will be started by the referee. The organizer should prepare the devices to start the both system by the button. After the "Call" ready from the referee, players should be ready to hit their start buttons..
7: Method of Scoring
(a) The winner
A goal shall be scored when the whole of the ball passes over the goal line. The winner of a game shall be decided on the basis of the number of goals scored.

(b) The tiebreaker
1. In the event of a tie after the second half, the winner will be decided by the sudden death scheme ("Golden Goal"). The game will be continued after a 5 minutes break, for a maximum period of three minutes. The team managing to score the first goal will be declared as the winner. If the tie persists even after the extra 3 minutes game, the winner shall be decided through penalty-kicks. Each team shall take three penalty-kicks. In case of a tie even after the three-time penalty-kicks, additional penalty-kicks shall be allowed one-by-one, until the winner can be decided. All penalty-kicks shall be taken by a single robot and shall commence with the referee's whistle. A penalty-kick will be completed, when any one of the following happens:
2. The goalkeeper catches the ball with its appendages (if any) in the goal area.
3. The ball comes out of goal area
4. 10 seconds pass after the referee's whistle.
(c) Disqualification
- If a human controller steps on the field during play, that human/robot pair will receive a yellow card. If the same player steps on the field again, the player will receive a red card.
- In case a team can not finish the whole match because of disqualification or technical problems, or gives up the match. The team which can not finish the match is declared the looser.
- In case after the end of the first half the goal difference is more than 15 goals, the game will be stopped and declare the loosing team as the looser.
- In case the robots are moving uncontrolled and they may harm other robots, referee can stop the match and declare that the team is disqualified.
- If a team is not ready to start the game on time, additional 5 minutes shall be allowed. Even after the allowed additional time if such a team is not ready to continue the game, that team will be disqualified from the game.
- If a team is not ready to resume the game after the half time, additional 5 minutes shall be allowed. Even after the allowed additional time if such a team is not ready to continue the game, that team will be disqualified from the game.
- Only team manager can lodge a protest. If a player attempts to lodge a protest, the ref will give the player a yellow card. If the protest continues, the player will get a red card.
8: Fouls
A foul will be called for in the following cases.
1. Colliding with a robot of the opposite team, either intentionally or otherwise: the referee will call such fouls that directly affect the play of the game or that appear to have potential to harm the opponent robot. When a defender robot intentionally pushes an opponent robot, a free kick will be given to the opposite team. It is permitted to push the ball and an opponent player backwards provided the pushing player is always in contact with the ball.
1. More than two robots from the same team block the ball, more than 20 seconds
2. One robot blocks the ball without any external contact with other robots.
3. More than two robots including goalkeeper robot are locating in Penalty area
2. It is permitted to push the goalkeeper robot in the goal area, if the ball is between the pushing robot and the goalkeeper. However, pushing the goalkeeper into the goal along with the ball is not allowed. If an attacking robot pushes the goalkeeper along with the ball into the goal or when the opponent robot pushes the goalkeeper directly then the referee shall call goal kick as goalkeeper charging.
3. Attacking with more than one robot in the goal area of the opposite team shall be penalized by a goal kick to be taken by the team of the goalkeeper. A robot is considered to be in the goal area if it is more than 50% inside, as judged by the referee. Defending with more than one robot in the goal area shall be penalized by a penalty- kick. No more than 1 attacking robot can stay in the goal area for longer than 30 seconds. (A robot is considered to be in the goal area if it is more than 50% inside, as judged by the referee. ) An exception to this is the situation when the additional robot in the goal area is not there for defense or if it does not directly affect the play of the game. More than one robot can not stay in the goal area longer than 30 seconds.
4. The referee shall judge the penalty-kick situation when the additional robot in the goal area is not there for defense or if it does not directly affect the play of the game.
5. The goalkeeper robot should kick out the ball from its goal area (Law 1. (d). ) within 10 seconds.
6. Giving a goal kick to the team of the goalkeeper will penalize the intentional blocking of a goalkeeper in its goal area.
7. Only the referee shall be allowed to touch the robots. Yellow/red cards will be given (as above) should the human player touch any robot on the field.
8. The number of robots on each side will be limited to two from the attacking team, and three on the defending team (including the goalkeeper.) The goalkeeper cannot leave his side of the field, although he can leave the goal area.
9: Play Interruptions
The play shall be interrupted and relocation of robots shall be done by a human operator, only when:
1. A robot has to be changed.
2. A robot has fallen. The referee can either stop the match and stand the robots, or stand the robot while the match continues. Operators should ask for the referee to stand up their robots.
3. A goal is scored or a foul occurs.
4. Referee calls goal kick (Law 12) or free-ball (Law 13). Only the team manager can call a time out. In this case the referee stops the game when the ball is located in the opponent area.
10: Free Kick
Free kick will be given in following situations;
1. More than two robots from the same team block the ball, more than 30 seconds
2. One robot blocks the ball without any external contact with other robots
3. More than two robots including goalkeeper robot from the same team are locating in Penalty area (Area A + Area B) There are six points (FK): 4 free-ball positions plus 2 positions in the middle. Only one robot can be between the ball and the goal, which should be outside of a circle with the radius 60 cm. Other opponent robots should be behind the ball and also outside of the circle with the radius 60 cm. All attacking robots should be located behind the ball, but may be located inside of the circle.

In following situation the free kick will be given.

1. More than two robots from the same team block the ball, more than 30 seconds
2. One robot blocks the ball without any external contact with other robots
3. More than two robots including goalkeeper robot are locating in Penalty area.
4. In case more than three robots are either attacking or defending (attacking with maximum number of three robots, defending with two robots and the goalkeeper is allowed)
5. When a defender robot intentionally pushes an opponent robot, a free kick will be given to the opposite team (Law 8. 1. ). The ball will be placed at the relevant free kick position (FK) on the playground. The robot taking the kick shall be placed behind the ball. The attacking team can position its robots freely within its own side. The two defending robots are allowed to be placed at the leftmost and rightmost sides in touch with the front goal area line. With the referee's whistle all robots can start moving freely.
Position: There are six free kick positions (FK). In case free kick situation is happened. The nearest FK position will be selected. In case the attacking robot causes the foul, penalized by FK in the opponent area, the FK position in the area of the attacking robot should be selected. Only one robot can be between ball and the goal, which should be outside of a circle with the radius 30 cm. Other opponent robots should be behind the ball and also outside of the circle with the radius 30 cm. All attacking robots should be located behind the ball, but may be located inside of the circle.
11: Penalty-Kick
A penalty-kick will be called under the following situations:
1. Defending with more than one robot in a goal area (Law 8. 4. ).
2. Failure on the part of a goalkeeper to kick out the ball from its goal area within 10 seconds (Law 8. 6. ).
3. When the Free-Kick situation is occurred in Penalty Area (Area A +B)
4. When any one of the human members touches the robots without the referee's permission, while the game is in progress (Law 8. 8. ).
5. More than three robots except goal keeper are defending in the penalty area.
When the referee calls a penalty-kick, the ball will be placed at the relevant penalty kick position (PK) on the playground. The robot taking the kick shall be placed behind the ball. While facing a penalty kick one of the sides of the goalkeeper must be in touch with the goal line. The goalkeeper may be oriented in any direction. Other robots shall be placed freely within the other side of the half-line, but the attacking team will get preference in positioning their robots. The game shall restart normally (all robots shall start moving freely) after the referee's whistle. The robot taking the penalty-kick may kick or dribble the ball.
12: Goal Kick
A goal kick will be called under the following situations:
1. When an attacking robot pushes the goalkeeper in its goal area, the referee shall call goal kick as goalkeeper charging (Law 8. 2. ).
2. Attacking with more than one robot in the goal area of the opposite team shall be penalized by a goal kick to be taken by the opposite team (Law 8. 3. ).
3. Attacking with more than three robots in the penalty area of the opposite team shall be penalized by a goal kick to be taken by the opposite team.
4. When an opponent robot intentionally blocks the goalkeeper in its goal area (Law 8. 7. ).
5. When the goalkeeper catches the ball with its appendages (if any) in its own goal area.
6. When a stalemate occurs in the goal area for 10 seconds.

During goal kick only the goalkeeper will be allowed within the goal area and the ball can be placed anywhere within the goal area. Other robots of the team shall be placed outside the goal area during goal kick. The defending robots should be located on the center and other robots should located in the own area. Two attacking robots should be located in the opponent area and two robots in its own area.

The attacking team will get preference in positioning their robots anywhere on the playground, but it must be as per Law 8. 3. The defending team can then place its robots within their own side of the playground. The game shall restart with the referee's whistle.

13: Free-Ball
The referee will call a free-ball when a stalemate occurs for 10 seconds outside the goal area. When a free-ball is called within any quarter of the playground, the ball will be placed at the relevant free ball position (FB). One robot per team will be placed at locations 50 cm apart from the ball position in the longitudinal direction of the playground. Other robots (of both teams) can be placed freely outside the quarter where the free-ball is being called, but with the rule that, the defending team will get their preference in positioning their robots. The game shall resume when the referee gives the signal and all robots may then move freely.
14: Referee and officials
For a match, the following officials are necessary

1. Referee.
(a)The referee should lead the match.
(b) Each match is controlled by a referee who has full authority to enforce the Game rule in connection with the match.
(c). Referee ensures that robots, communication, color patches etc that are used for the match meets the requirements of the rules.
2. Time keeper. An official timekeeper will pause the clock during substitutions, while transporting an injured robot from the field, during time-out and during such situations that deem to be right as per the discretion of the timekeeper. The timekeeper may be the same preson as the referee.

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