Robotex 2011 football competition

Football rules

1. Field
1.1 Dimensions of the field
1.2 Covering
1.3 Markings of the playing-field
1.4 Defense area
1.5 Goals
1.6 Beacons
2. Balls
2.1 Specifications
2.2 Layout of the balls
3. Number of robots and team size
4. Requirements for robots
4.1 Mechanical requirements for robots
4.2 Electronic requirements for robots
4.3 Controlling requirements for robots
5. Referees
5.1 Assistant referees
6. Competition format
7. Game
8. Round
9. Penalty round
10. Score
10.1 Scoring in rounds
10.2 Scoring in penalty rounds
11. Technical inspection
12. Demo game
13. Round of vanity

robotex_football_rules_(eng).pdf

1. Field

1.1 Dimensions of the field

The playing-field is rectangular and its dimensions are: length 4500 mm, width 3000 mm. The white lines marking boundaries are part of the playing-field. The playing-field is surrounded by a 100 mm high and 20 mm wide white (color info) laminated wood wall to prevent the balls and the robots from exiting it. See figure 1 for the measurements and the markings of the field.

Figure 1. Measurements of the field.

1.2 Covering

The field consists of a green (picture) felt carpet (Expomat 626) placed on a hard smooth surface. The cover extends beyond the walls marking the borders of the playing-field: 800 mm from the goal boundaries and 500 mm from the longer boundaries. The whole area covered in carpet is called competitors area. Only competitors and referees are allowed to be in the competitors’ area, spectators are not allowed on any part of the covering. See figure 2 for playing-field and competitors’ area.

Figure 2. Competitors’ area is indicated in blue, playing-field in green.

1.3 Markings of the playing-field

The playing-field is marked by white (color info) lines. Areas include the lines that define them. All lines are 50 mm wide. The half-way line divides the field in two equal parts. An 800 mm diameter central circle with a diameter of 800 mm is marked around the centre of the half-way line. The circle and the outer white line (dimensions: 3800x5300 mm) are meant for the next year’s task and have no importance this year.

1.4 Defense area

Defense area is marked in front of a goal and consists of two quarters of a circle (radius 500 mm) united by a line parallel to the shorter side of the field. From the other side it is limited by the shorter side of the boundary of the playing-field. See figure 3 for the exact marking.

Figure 3. Goal and defense area (indicated in blue).

1.5 Goals

The goals are centered on the shorter sides of the playing-field and are on the same level with it. The goals are located outside the boundaries of the playing-field reaching the outer lines of the field. The goals are open from above and marked with either blue (color info) or yellow (color info) cloth.

The goal is 200 mm high, 250 mm deep and 700 mm wide from the inside. The lower edge of the cloth marking the goal is open to stop the balls from rolling back to the playing-field.

The upper cross-bar is made of grey aluminum profile (20x20 mm cross-section) and is not marked in any way. Infrared beacons are attached to a bar located at the centre of the backside of the goals. The height of the beacons is 400 mm from the covering of the goal. See figure 4 for goals and walls of the playing-field. For a more detailed view of the goal see figure 5.

Figure 4. The walls and goals are marked with blue.

Figure 5. Goal with the bar meant for attaching a beacon.

1.6 Beacons

The beacons emit infrared light (wavelength: 950 nm) modulated on a 33% work period on a frequency of 36 kHz. During the competition, Vishay TSUS5400 IR LEDs will be used in beacons. To receive the above mentioned signal, a regular IR receiver equipped with a demodulator, for example Vishay TSOP2236, can be used.

To forward information, the IR signal is pulse-width modulated on a frequency of 50 Hz, and its working period determines the beacons number. Beacon numbers from 1 to 4 correspond working periods 1.00 ms, 1.33 ms, 1.67ms and 2.00 ms. In principle, the beacons forward a standard servomotor control signal.

In a playing-field, the numbers of beacons are 1 and 3 or 2 and 4. The PWM signals emitted by the beacons are 10 seconds offset to avoid interference. The following figure illustrates the IR signal sent out by the beacons:

NB! All frequencies and periods may vary by 10%.

2. Balls

2.1 Specifications

The ball is a Srixon AD333 standard orange golf ball which is:

spherical
orange
weighs approximately 46g
has an appoximate diameter of 43 mm

More information about the balls can be found on: http://www.srixon.co.uk/golf-balls/ad333-orange/

The balls together with the yellow and blue cloth used for marking the goals on a white background are displayed in figure 6.

Figure 6. The balls side by side with a white background and the yellow and blue cloth used for marking the goals.

2.2 Layout of the balls

In the beginning of each round 11 balls are placed on the playing-field. The layout of the balls is random, but symmetric to the diagonal for each competitor. New layout will be drawn at the beginning of each game.

3. Number of robots and team size

One robot for each team will be competing on the field at a time. The number of registered members per team is limited to six. Apart from the competition there will also take place a Demo game where two robots for each team will be competing on the field at a time. (See chapter 12. Demo game.

4. Requirements for robots

Robot is a fully autonomous machine that carries its own power source, motion mechanisms, and its own control-systems.

4.1 Mechanical requirements for robots

During the whole competition the robot must fit in a cylinder with the diameter of 35 cm and the height of 35 cm in a game situation.
Maximum weight of the robot is 8 kg.
Robot is not allowed to imitate any part of the field.
a. It is not allowed to use the yellow (värvivhemik) and blue (värvivahemik) of the goals in the exterior design of the robot.
b. It is not allowed to use the orange (värvivahemik) of the balls in the exterior design of the robot.
c. It is not allowed to use the green (värvivahemik) of the field in the exterior design of the robot.
During the game the robot may not cover the ball in a greater extent than the radius of the ball (21.5 mm).
When lifting the robot the ball must drop free.
Robot is not allowed to intentionally separate parts to the field during a game.

Allowed methods of moving the ball:

Forbidden methods of moving the ball:

4.2 Electronic requirements for robots

Robot is not allowed to use LEDs during the rounds (except in case of mutual consent of the competitors). The use of LEDs in indicators and sensors is allowed.
If light sources are used, the intensity of them should not be dangerous to the human eye or they must be shielded from direct observation.
If lasers are used, their output power (average over 1 second) must be less than 1mW/mm2.
Robot may not intentionally deceive the optical sensors (including the camera) of other robots.
Emitting infrared light that interferes with signal of the emitters on the goals is prohibited.

4.3 Controlling requirements for robots

Remote controlling of the robot during the game is prohibited (Sending out a one way signal from the robot and sending the starting signal to the robot are allowed)
Robot may not operate with more than one ball at a time.
Robot is not allowed to damage the field or parts of it, other robots, balls, judges, the opposite team, spectators nor other people surrounding the field.
Robot is not allowed to take the balls out of the goal.
Robot is not allowed to leave the playing-field during the round.
Unauthorized people are not allowed to touch the robot without the permission of the team.

Robots that do not meet the requirements will not be able compete at the competition.

5. Referees

Each game is coordinated by a referee who will ensure the compliance of the competition and the games with competition rules. The referee is assisted by two assistant referees, one for each goal.

Referee:

carries out the technical inspection of all robots and decides which ones are allowed to compete (see 11. Technical inspection);
ensures the compliance of the balls and their layout with competition rules (see 5. Referees);
ensures the compliance of the beacons with competition rules and makes sure that they are working properly (see 1.6 Beacons);
starts, stops and ends the game;
informs competitors and assistant referees of the beginning and the end of round (see 8. Round);
informs competitors and assistant referees of the beginning and the end of penalty round (see 9. Penalty round)
may pause or end the game in case the competition rules are violated;
may pause or end the game in case of external disturbing factors;
may pause or end the game in case there is a chance that a robot might damage the field, the other robot, or endanger the people surrounding the field;
may remove misbehaving team members and spectators from the field and its surroundings;
may consult assistant referees in situations where they had a better overview of the game situation;
ensures that spectators don't enter the competitor's area (see 1.2 Covering);
shall communicate at the end of the game the score and other relevant information to the organizers.

Decisions of the referee about the game and rounds are final. The referee has the right to change his or her decision in case any relevant additional information reveals.

5.1 Assistant referees

Assistant referees assist the referee during the games.

Assistant referee:

oversees one goal in every round;
indicates the final score of the goal (the total number of balls inside a goal and of those that have passed through the goal) to the referee at the end of each game;
may signal the referee to stop the game.

6. Competition format

The format of the competition is a double elimination tournament which means that the winners compete in the Winners Bracket and the losers continue competing in the Losers Bracket. A defeat in the Losers Bracket means that the competitor is no longer eligible to win and falls out of the tournament. The winner of the Losers Bracket competes against the winner of the Winners Bracket.

7. Game

The game will consist of up to three rounds and a penalty round, if needed. The team that wins more rounds is the winner of the game. If the score is tied, the winner will be the robot that wins the penalty round. If the winner is not determined at the end of a game, the team that has scored the most goals in rounds will be the winner. If both teams have scored the same number of goals, an additional round will take place where the robot has to empty the playing field from 11 balls by scoring 11 goals. Both robots will get a minute to do so and the winner will be the robot that scores 11 goals faster. If there are still balls left on the field after the round, the robot that has scored more goals wins.

The sides will be drawn before the game and they will be switched between the rounds. Teams will get two minutes max to switch sides. If both competitors agree, the break can be shorter.

At the beginning of each round a new layout of the balls will be drawn.

8. Round

The duration of each round is 90 seconds. At the beginning of every round, each robot will be placed in the right-side corner of their side (seen from behind the goal) so that it touches at the same time both walls of the field (called starting position). The round begins and ends with the signal of the referee. After the end signal the teams must stop the robot.

9. Penalty round

Penalty round is played with one ball. The defender starts from the starting position; the striker starts from in front of the goal and behind the line marking defense area (seen from above, the line may not be covered). The ball is placed in the centre of the circle (central circle). The defender is allowed to either try to get the ball and score or to stay and defend the attack.

The robots take turns attacking, the starter will be drawn. The robot will get 30 seconds to strike. In total, both teams will receive up to three attack attempts. An attack begins when the referee gives the signal. An attack ends when the referee gives the signal or when the ball has entered a goal. After the end signal, the team has to stop the robot.

10. Score

10.1 Scoring in rounds

The score will be counted at the end of each round. Every ball that is inside a goal or has gone through it is worth one point. The ball must cross the white line of the goal by 100% (seen from above) or it doesn’t count as a point. The balls that bounce back from the goal will stay in the game and won’t give points.

The team that has more points at the end of the round wins it.

10.2 Scoring in penalty rounds

In the penalty round, the scoring takes place by an attack pair. An attack pair is when both teams have made one attack. Each ball that enters a goal gives a point. A penalty round ends if the score is not tied after an attack pair, and the team that scored wins.

11. Technical inspection

Technical inspection takes place in the morning of the competition. During the inspection, the referee verifies the compliance of the robot with the rules (see chapter 4. Requirements for robots) and tests its capability. In order to demonstrate its capability, the robot must score alone at least one ball out of eleven that are on the field within 90 seconds. Robots that do not meet the requirements will not be able compete at the competition.

12. Demo game

Demo game will take place on this year’s field after the competition is finished. It won’t affect the result in any way. Both teams will have two robots per team. The maximum number of team members is 12.

The game will be played with one orange golf ball that will be placed in the centre of the field at the beginning of the game. Robots start from the corners of their side of the playing-field. There can only be one defending robot at a time in a goal defense area. The requirements for robots listed in chapter 4 apply to demo game. The robots of the same team are allowed to communicate with each other during the game.

The game consists of two rounds; a round lasts for five minutes. Teams switch sides between two rounds. Every ball that enters a goal gives one point. If a ball enters a goal, the game will be paused on the signal of the referee. The ball and the robots will once again be placed to the starting position. The game will continue on the signal of the referee.

Each team will play one game with all others in the demo game.

13. Round of vanity

It will be possible to demonstrate the beauty of the robots on both days of the competition. The robots which are not competing at the moment may use last year’s pitch to demonstrate their light and other effects. They may also use five orange golf balls. The round of vanity is intended to give all teams the opportunity to demonstrate their robots to the visitors. The field will be positioned in such way that it won’t interrupt the competition and that the spectator will get a chance to get up close, see the robots and ask questions from team members.

robotex_2011_jalgpalli_reeglid_(est).pdf