RoboCupJunior Soccer Rules 2024

Soccer League Committee 2024:
Michael Ambrose
USA
Ryely Burtenshaw-Day
New ZealandIvan Kolarić
Croatia
David Schwarz
Germany
William Plummer
Australia (CHAIR)
Adrián Matejov
Slovakia

Soccer League Committee 2023:
Michael Ambrose
USA (CO-CHAIR)
Javier E. Delgado Moreno
MexicoHikaru Sugiura
Japan
David Schwarz
Germany (CHAIR)
William Plummer
Australia
Adrián Matejov
Slovakia

These are the Soccer rules for RoboCupJunior 2024. They are released by the RoboCupJunior Soccer
League Committee. The English version of these rules has priority over any translations.
Teams are advised to check the RoboCupJunior Soccer site https://junior.robocup.org/ and Soccer forum
https://junior.forum.robocup.org/c/robocupjunior-soccer/5 for procedures and requirements for the international competition and with local tournament organizers for local, regional and super-regional competitions. Each team is responsible for verifying the latest version of the rules prior to competition. Teams
should ask for clariﬁcations on the Forum where necessary. 1
Figure 1 Two teams of two robots with an orange ball on a RoboCupJunior Soccer ﬁeld.

1 The current version of these rules can be found at https://robocup-junior.github.io/soccer-rules/master/rules.html in HTML
form and at https://robocup-junior.github.io/soccer-rules/master/rules.pdf in PDF form.

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Preface
In the RoboCupJunior Soccer challenge, teams of young engineers design, build, and program two fullyautonomous mobile robots to compete against another team in matches. The robots must detect a balland score into a color-coded goal on a special ﬁeld that resembles a human soccer ﬁeld.
To be successful, participants must demonstrate skill in programming, robotics, electronics and mechatronics. Teams are also expected to contribute to the advancement of the community as a whole bysharing their discoveries with other participants and by engaging in good sportsmanship, regardless ofculture, age or result in the competition. All are expected to compete, learn, have fun, and grow.
RoboCupJunior Soccer consist of two sub-leagues: Soccer Open and Soccer Lightweight. These rules
apply for both sub-leagues. There are two main differences between the two leagues.
• Soccer Lightweight is played using a special ball that emits an IR signal. Robots may weigh up to
1.4 2 kg, may have a ball-capturing zone of up to 3.0 cm 3 .
• Soccer Open is played using a passive, brightly colored orange ball. Robots may weigh up to 2.2 kg,
may have a ball-capturing zone of up to 1.5 cm 4 .

A large part of the overall ranking (for the international tournament, ask you regional tournament organizers) is determined by the judged categories. These award points for documentation, design, innovation, achievement. Rubrics and other teams’ documentation
can be access through this forum thread: https://junior.forum.robocup.org/t/2024-awardsrubric-draft/3500

Please see Rule 5, BALL for ball speciﬁcations and Rule 8, LEAGUE REGULATIONS for more details for
speciﬁcations/regulations.
If you would like to start with RoboCupJunior Soccer, please contact the organizer of your regional RoboCupJunior competition and ask them about Rule 9.5, Entry League.
Unless speciﬁed otherwise, all parts of these rules are released under the terms of the Creative Commons
Attribution-ShareAlike License.

Changes from the 2023 RoboCupJunior Soccer Rules
The rule changes developed by the Soccer League Committee in cooperation with the RoboCup Junior
Soccer Community (please continue to post ideas for the future on the forum any time) aim to improve
gameplay.
Detailed changes are listed below and link to the corresponding place in the rule.
• Deleted ”, and may use batteries up to 12.0 V nominal voltage”• Deleted ”, and may use batteries up to 15.0 V nominal voltage”
2 In previous version this said ”1.1”
3 In previous version this said ”, and may use batteries up to 12.0 V nominal voltage”
4 In previous version this said ”, and may use batteries up to 15.0 V nominal voltage”

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• Deleted ”Robots must respond to the ball in a direct forward movement towards it. For example,
it is not enough to basically just move left and right in front of their own goal, it must also movedirectly towards the ball in a forward movement.”• Deleted ”Voltage pump circuits are permitted only for a kicker drive. ”• Deleted ” All other electrical circuits inside the robot cannot exceed 15.0 V for Soccer Open and 12.0
V for Soccer Lightweight. ”• Deleted ”, unless the nominal voltage is obvious by looking at the robot, its power packs and connections”• Deleted ” in Soccer Open and by means of the Kicker Power Measuring Device in Soccer Lightweight”• Added ”Open”• Added ”The Light Weight League power test is passed if after bouncing off of the opposite goal theball does not leave the penalty area of the opposing goal after bouncing back.”• Changed ”1.1” to ”1.4”• Changed ”A robot must touch the ball that is placed no further than 20 cm from any point on its
convex hull within 10 seconds. If a robot does not do so within the time limit, it is deemed to
be damaged. ” to ”Any robot must approach and touch the ball when it is placed on the nearest
neutral spot. It must do this before lack of progress is called. When on its own side of the ﬁeld,
any robot must be able to move the ball from the nearest neutral spot to the opponent’s side of theﬁeld. If a speciﬁc robot does not act this way, referees may deem it damaged at their discretion.
(See ¡¡damaged-robots, Damaged Robots¿¿.) This rule does not apply if the robot is hindered fromdetecting or playing the ball by the opponent.”• Changed ”1100” to ”1400”• Changed ”15.0 V” to ”48V DC / 25V AC RMS”
• Changed ”12.0 V” to ”48V DC / 25V AC RMS”
• Changed ”Voltage limits relate to the ¡emphasis role=”strong”¿nominal values¡/emphasis¿, deviations at the power pack due to the fact that charged will be tolerated” to ”The voltage limit relates tothe maximum voltage at any point and any time on the robot, ¡emphasis role=”strong”¿not nominal
voltages¡/emphasis¿”

Construction and Programming have to be performed exclusively by the students
Robots must be constructed and programmed exclusively by student members of the team. Mentors,
teachers, parents or companies should not be involved in the design, construction, assembly, programming or debugging of robots. To avoid possible disqualiﬁcation, it is extremely important that teams abide
by Rule 8, LEAGUE REGULATIONS, especially Rule 8.2.D, Construction and Rule 8.2.E, Programming, andall other competitor’s rules.
If in doubt, please consult with your Regional Representative before registering your team.

1.1.1

1

GAMEPLAY

1.1

Game procedure and length of a game

RCJ Soccer games consist of two teams of robots playing soccer against each other. Each team has two
autonomous robots. The game will consist of two halves. The duration of each half is 10-minutes. There
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will be a 5-minute break in between the halves.
1.1.2

The game clock will run for the duration of the halves without stopping (except when a referee wants
to consult another oﬃcial). The game clock will be run by a referee or a referee assistant (see Rule 7.1,
Referee and referee assistant for more information on their roles).

1.1.3

Teams are expected to be at the ﬁeld 5 minutes before their game starts. Being at the inspection table
does not count in favor of this time limit. Teams that are late for the start of the game may be penalized
one goal per 30 seconds at the referee’s discretion.

1.1.4

The ﬁnal game score will be trimmed so that there is at most 10-goal difference between the losing andthe winning team.

1.2

Pre-match meeting

1.2.1

At the start of the ﬁrst half of the game, a referee will toss a coin. The team mentioned ﬁrst in the draw
shall call the coin. The winner of the toss can choose either which end to kick towards, or to kick off ﬁrst.
The loser of the toss chooses the other option. After the ﬁrst half, teams switch sides. The team notkicking off in the ﬁrst half of the game will kick off to begin the second half of the game.

1.2.2

During the pre-match meeting the referee or their assistant may check whether the robots are capable ofplaying (i.e., whether they are at least able to follow and react to the ball). If none of the robots is capableof playing, the game will not be played and zero goals will be awarded to both teams.

1.3

Kick-off

1.3.1

Each half of the game begins with a kick-off. All robots must be located on their own side of the ﬁeld. All
robots must be halted. The ball is positioned by a referee in the center of the ﬁeld.

1.3.2

The team kicking off places their robots on the ﬁeld ﬁrst.

1.3.3

The team not kicking off will now place their robots on the defensive end of the ﬁeld. All robots on theteam not kicking off must be at least 30 cm away from the ball (outside of the center circle).

1.3.4

Robots cannot be placed out of bounds. Robots cannot be repositioned once they have been placed,
except if the referee requests to adjust their placement to make sure that the robots are placed properly
within the ﬁeld positions.

1.3.5

On the referee’s command (usually by whistle), all robots will be started immediately by each captain. Any
robots that are started early will be removed by the referee from the ﬁeld and deemed damaged.

1.3.6

Before a kick-off, all damaged or out-of-bounds robots are allowed to return to the playing ﬁeld immediately if they are ready and fully functional.

1.3.7

If no robots are present at a kick-off (because they have moved out-of-bounds Rule 1.9, Out of bounds orare damaged Rule 1.10, Damaged robots), the penalties are discarded and the match resumes with a Rule
1.3.A, Neutral kick-off.

1.3.A
1.3.A.1

Neutral kick-off

A neutral kick-off is the same as the one described in Rule 1.3, Kick-off with a small change: all robots
must be at least 30 cm away from the ball (outside of the center circle).

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1.4

Human interference

1.4.1

Except for the kick-off, human interference from the teams (e.g. touching the robots) during the game is
not allowed unless explicitly permitted by a referee. Violating team(s)/team member(s) may be disqualiﬁed from the game.

1.4.2

The referee or a referee assistant can help robots get unstuck if the ball is not being disputed near themand if the situation was created from normal interaction between robots (i.e. it was not a design orprogramming ﬂaw of the robot alone). The referee or a referee assistant will pull back the robots justenough for them to be able to move freely again.

1.5

Ball movement

1.5.1

A robot cannot hold a ball. Holding a ball is deﬁned as taking full control of the ball by removing all ofdegrees of freedom. Examples for ball holding include ﬁxing a ball to the robot’s body, surrounding a ballusing the robot’s body to prevent access by others, encircling the ball or somehow trapping the ball withany part of the robot’s body. If a ball does not roll while a robot is moving, it is a good indication that theball is trapped.

1.5.2

The only exception to holding is the use of a rotating drum (a ”dribbler”) that imparts dynamic back spinon the ball to keep the ball on its surface.

1.5.3

Other players must be able to access the ball.

1.5.4

The ball needs to stay within the bounds of the ﬁeld, as deﬁned by the walls. If a robot moves the balloutside of the ﬁeld (that is, beyond the walls or above their height), it is deemed damaged. (Rule 1.10,
Damaged robots)

1.5.5

Any robot must approach and touch the ball when it is placed on the nearest neutral spot. It must
do this before lack of progress is called. When on its own side of the ﬁeld, any robot must be able
to move the ball from the nearest neutral spot to the opponent’s side of the ﬁeld. If a speciﬁc
robot does not act this way, referees may deem it damaged at their discretion. (See Damaged
Robots.) This rule does not apply if the robot is hindered from detecting or playing the ball by the
opponent. 5

If placing the ball on a neutral spot would confer a gameplay advantage to one team orreferees don’t place the ball on the closest neutral spot for other reasons a robot is not
required to approach the robot at further away neutral spots.

1.6
1.6.1

Scoring

A goal is scored when the ball strikes or touches the back wall of the goal. Goals scored by any robot havethe same end result: they give one goal to the team on the opposite side. After a goal, the game will berestarted with a kick-off from the team who was scored against.
5 In previous version this said ”A robot must touch the ball that is placed no further than 20 cm from any point on its convex
hull within 10 seconds. If a robot does not do so within the time limit, it is deemed to be damaged. ”

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1.7

Inside the Penalty Area

1.7.1

No robots are allowed to be fully inside the penalty area. As the penalty areas are marked with a whiteline, the Out of Bounds and Out of Reach rules apply as well. (Rule 1.9, Out of bounds)

1.7.2

If two robots from the same team are at least partially in a penalty area, the robot further from the ballwill be moved to the furthest unoccupied neutral spot immediately. If this happens repeatedly, a robot
may be deemed damaged at referee’s discretion. (Rule 1.10, Damaged robots)

1.7.3

If an attacking and a defending robot touch each other while at least one of them is at least partially inside
the penalty area, and at least one of them has physical contact with the ball, this may be called ”pushing”
at the referee’s discretion. In this case, the ball will be moved to the furthest unoccupied neutral spot
immediately.

1.7.4

If a goal is scored as a result of a ”pushing” situation, it will not be granted.

1.8
1.8.1

1.8.2

Lack of progress

Lack of progress occurs if there is no progress in the gameplay for a reasonable period of time and thesituation is not likely to change. Typical lack of progress situations are when the ball is stuck between
robots, when there is no change in ball and robot’s positions, or when the ball is beyond detection orreach capability of all robots on the ﬁeld.
After a visible and loud count 6 , a referee will call lack of progress and will move the ball to thenearest unoccupied neutral spot. If this does not solve the lack of progress, the referee can move the ballto a different neutral spot.

1.9

Out of bounds

1.9.1

If a robot touches a wall or moves completely into the penalty area it will be called for being out ofbounds. When this situation arises, the robot is given a one-minute penalty, and the team is asked toremove the robot from the ﬁeld. There is no time stoppage for the game itself. The robot is allowed toreturn if a kick-off occurs before the penalty has elapsed.

1.9.2

The one-minute penalty starts when the robot is removed from play. Furthermore, any goal scored by thepenalized team while the penalized robot is on the ﬁeld will not be granted. Out-of-bounds robots can beﬁxed if the team needs to do so, as described in Rule 1.10, Damaged robots.

1.9.3

After the penalty time has passed, robot will be placed on the unoccupied neutral spot furthest from theball, facing its own goal.

1.9.4

A referee can waive the penalty if the robot was accidentally pushed out of bounds by an opposing robot.
In such a case, the referee may have to slightly push the robot back onto the ﬁeld.

1.9.5

The ball can leave and bounce back into the playing ﬁeld. The referee calls out of reach, and will movethe ball to the nearest unoccupied neutral spot when one of the following conditions occurs:
1. the ball remains outside the playing ﬁeld too long, after a visible and loud count 7 ,2. any of the robots are unable to return it into the playing ﬁeld (without their whole body leaving theplaying ﬁeld), or
3. the referee determines that the ball will not come back into the playing ﬁeld.
6 usually a count of three
7 usually a count of three

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1.10

Damaged robots

1.10.1

If a robot is damaged, it has to be taken off the ﬁeld and must be ﬁxed before it can play again. Even if
repaired, the robot must remain off the ﬁeld for at least one minute or until the next kick-off is due.

1.10.2

Some examples of a damaged robot include:• it does not respond to the ball, or is unable to move (it lost pieces, power, etc.).
• it continually moves into the penalty area or out of bounds.
• it turns over on its own accord.

1.10.3

Computers and repair equipment are not permitted in the playing area during gameplay. Usually, a teammember will need to take the damaged robot to an ”approved repair table” near the playing area. A
referee may permit robot sensor calibration, computers and other tools in the playing area, only for the
5 minutes before the start of each half.

1.10.4After a robot has been ﬁxed, it will be placed on the unoccupied neutral spot furthest from the ball, facing
its own goal. A robot can only be returned to the ﬁeld if the damage has been repaired. If the referee
notices that the robot was returned to the ﬁeld with the same original problem, they may ask the robot
to be removed and proceed with the game as if the robot had not been returned.

1.10.5

Only the referee decides whether a robot is damaged. A robot can only be taken off or returned withthe referee’s permission.

1.10.6

If both robots from the same team are deemed damaged at kick-off, gameplay will be paused and theremaining team will be awarded 1 goal for each elapsed 30 seconds that their opponent’s robots remain
damaged. However, these rules only apply when none of the two robots from the same team weredamaged as the result of the opponent team violating the rules.

1.10.7

Whenever a robot is removed from play, its motors must be turned off.

1.11

Interruption of Game

1.11.1

In principle, a game will not be stopped.

1.11.2

A referee can stop the game if there is a situation on or around the ﬁeld which the referee wants to discusswith an oﬃcial of the tournament or if the ball malfunctions and a replacement is not readily available.

1.11.3

When the referee has stopped the game, all robots must be stopped and remain on the ﬁeld untouched.
The referee may decide whether the game will be continued/resumed from the situation in which thegame was stopped or by a kick-off.

2

TEAM

2.1

Regulations

2.1.1

A team must have more than one member to form a RoboCupJunior team to participate in the international competition. Team member(s) and/or robot(s) cannot be shared between teams.

2.1.2

Each team member needs to carry a technical role.

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2.1.3

Each team must have a captain. The captain is the person responsible for communication with referees.
The team can replace its captain with another team member during the competition. Each team is allowed
to have at most two members beside the ﬁeld during gameplay: they will usually be the captain and an
assistant team member.

2.2

Violations

2.2.1

Teams that do not abide by the rules are not allowed to participate.

2.2.2

Robots are expected to be capable of dealing with any colors above the walls (e.g. blue, yellow, green
or orange shirts) either in hardware (e.g. limiting the ﬁeld of view from looking up) or in software (e.g.
masking the input image).

2.2.3

The referee can interrupt a game in progress if any kind of interference from spectators is suspected (IRemitters, camera ﬂashes, mobile phones, radios, computers, etc.).

2.2.4

This needs to be conﬁrmed by the tournament organizers if a claim is placed by the other team. A teamclaiming that their robot is affected by colors has to show the proof/evidence of the interference.

3.1.1

3

ROBOTS

3.1

Number of robots / substitutions

Each team is allowed to have at most two robots for the full tournament. The substitution of robots during
the competition within the team or with other teams is forbidden.

3.2Interference

3.2.1

Robots are not allowed to be colored orange, yellow or blue in order to avoid interference. Orange, yellow,
blue colored parts used in the construction of the robot must either be occluded by other parts from theperception by other robots or be taped/painted with a neutral color.

3.2.2

Robots must not produce magnetic interference in other robots on the ﬁeld.

3.2.3

Robots must not produce visible light that may prevent the opposing team from playing when placedon a ﬂat surface. Any part of a robot that produces light that may interfere with the opposing robot’s
vision system must be covered. For Lightweight-speciﬁc regulations see Rule 8.2.B, Infrared interferencein Lightweight

3.2.4

A team claiming that their robot is affected by the other team’s robot in any way must show the proof/evidence of the interference. Any interference needs to be conﬁrmed by the tournament organizers if a
claim is placed by the other team.

3.3
3.3.1

Control

The use of remote control of any kind is not allowed during the match. Robots must be started andstopped manually by humans and be controlled autonomously.

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3.4

Communication

3.4.1

Robots are not allowed to use any kind of communication during gameplay unless the communication
between robots is via Bluetooth class 2 or class 3 8 or via any other device that communicates using the802.15.4 protocol (e.g., ZigBee and XBee).

3.4.2

Teams are responsible for their communication. The availability of frequencies cannot be guaranteed.

3.5
3.5.1

3.5.2

Agility

Robots must be constructed and programmed in a way that their movement is not limited to only one dimension (deﬁned as a single axis, such as only moving in a straight line). They must move in all directions,for example by turning.
9 At least one team robot must be able to seek and approach the ball anywhere on the ﬁeld, unless theteam has only one robot on the ﬁeld at that time.

3.6

Handle

3.6.1

All robots must have a stable and easily noticeable handle to hold and to lift them. The handle must be
easily accessible and allow the robot to be picked up from at least 5 cm above the highest structure of therobot.

3.6.2

The dimensions of the handle may exceed the robot height limitation, but the part of the handle thatexceeds this limit cannot be used to mount components of the robot.

3.7

Top Markers

3.7.1

A robot must have markings in order to be distinguished by the referee. Each robot must have a white
plastic circle with a diameter of at least 4 cm mounted horizontally on top. This white circle will be used by
the referee to write numbers on the robots using markers, therefore the white circles must be accessible
and visible.

3.7.2

Before the game, the referee will designate the numbers for each robot and will write them on the top
white circle. Robots not carrying the top white circle are not eligible to play.
Figure 2 A visualization of the top marker

8 range shorter than 20 meters
9 In previous version this said ”Robots must respond to the ball in a direct forward movement towards it. For example, it is
not enough to basically just move left and right in front of their own goal, it must also move directly towards the ball in a forward
movement.”

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3.8
3.8.1

Additional regulations of the sub-leagues

A tournament may be organized in different sub-leagues. Each sub-league (e.g. Soccer Open and Soccer
Lightweight) has its own additional regulations, including regulations affecting the construction of robots.
They are outlined in Rule 8, LEAGUE REGULATIONS.

3.9

Violations

3.9.1

Robots that do not abide by the speciﬁcations/regulations (see Rule 8.2, Regulations) are not allowed toplay, unless these rules specify otherwise.

3.9.2

If violations are detected during a running game the team may be disqualiﬁed for that game.

3.9.3

If similar violations occur repeatedly, the team may be disqualiﬁed from the tournament.

4

FIELD

4.1

Dimensions of the ﬁeld

4.1.1

The playing ﬁeld is 158 cm by 219 cm. The ﬁeld is marked by a white line which is part of the playing ﬁeld.
Around the playing ﬁeld, beyond the white line, there is an outer area of 12 cm in width.

4.1.2

The ﬂoor near the exterior wall includes a wedge, which is an incline with a 10 cm base and 2 +/- 1 cm risefor allowing the ball to roll back into play when it leaves the playing ﬁeld. Note that the goal should notcontain the wedge.

4.1.3

Total dimensions of the ﬁeld, including the outer area, are 182 cm by 243 cm.

4.2
4.2.1

Walls

Walls are placed all around the ﬁeld, including behind the goals and the out-area. The height of the walls
is 22 cm. The walls are painted matte black.

4.3

Goals

4.3.1

The ﬁeld has two goals, centered on each of the shorter sides of the playing ﬁeld. The goal inner space is
60 cm wide, 10 cm high and 74 mm deep, box shaped.

4.3.2

The goal ”posts” are positioned over the white line marking the limits of the ﬁeld.

4.3.3

The interior walls and of each goal are colored matte, one goal yellow and the other goal blue. It is
recommended that the blue be of a brighter shade so that it is different enough from the black exterior.

4.4
4.4.1

Floor

The ﬂoor consists of green carpet ideally of darker shade on top of a hard level surface. Teams should be
prepared to adjust to different levels of contrast between the green carpet and lines as some events may
be restricted to using lighter shades of green. All lines on the ﬁeld should be painted, marked with tape,or installed as white carpet and be somewhat resistant to tearing or ripping. Lines should have a width of
20mm (±10%).

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4.4.2

It is impractical to set international constraints on carpet other than it being green. In the spirit of thecompetition, teams should design robots to be tolerant or adaptable to different ﬁbers, textures, construction, density, shades, and designs of carpet especially when competing amongst different regions. Teams
are encouraged to visit regional resources or reach out to Local Organization Committee for suggestions
if desiring to build their own practice ﬁeld(s).

4.5
4.5.1

There are ﬁve neutral spots deﬁned in the ﬁeld. One is in the center of the ﬁeld. The other four are
adjacent to each corner, located 45 cm along the long edge of the ﬁeld. They align with the sides of thepenalty areas. The neutral spots can be drawn with a thin black marker. The neutral spots ought to be of
circular shape measuring 1 cm in diameter.

4.6
4.6.1

Neutral spots

Center circle

A center circle will be drawn on the ﬁeld. It is 60 cm in diameter. It is a thin black marker line. It is there
for Referees and Captains as guidance during kick-off.

4.7

Penalty areas

4.7.1

In front of each goal there is a 25 cm wide and 80 cm long penalty area with rounded front corners (15cm
radius).

4.7.2

The penalty areas are marked by a white line of 20 mm (±10%) width. The line is part of the area.

4.8
4.8.1

Lighting and Magnetic Conditions

The tournament organizers will do their best to limit the amount of external lightning and magnetic interference. However, the robots need to be constructed in a way which allows them to work in conditions
that are not perfect (i.e. by not relying on compass sensors or speciﬁc lightning conditions).

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FIELD DIAGRAMS

4.8.2

4.8.3

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5.1.1

5

BALL

5.1

Speciﬁcation for Soccer Lightweight Ball

See Appendix A, Technical Speciﬁcation for pulsed Soccer Ball.

5.2
5.2.1

See Appendix B, Technical Speciﬁcation for passive Soccer Ball.

5.3
5.3.1

Speciﬁcation for Soccer Open Ball

Tournament balls

Balls for the tournament must be made available by the tournament organizers. Tournament organizers
are not responsible for providing balls for practice.

6

CODE OF CONDUCT

6.1

Fair Play

6.1.1

It is expected that the aim of all teams is to play a fair and clean game of robot soccer. It is expected that
all robots will be built with consideration to other participants.

6.1.2

Robots are not allowed to cause deliberate interference with or damage to other robots during normal
gameplay.

6.1.3

Robots are not allowed to cause damage to the ﬁeld or to the ball during normal gameplay.

6.1.4

A robot that causes damage may be disqualiﬁed from a speciﬁc match at the tournament organizer’s
discretion.

6.1.5

Humans are not allowed to cause deliberate interference with robots or damage to the ﬁeld or the ball.

6.2
6.2.1

Behavior

All participants are expected to behave themselves. All movement and behavior is to be of a subdued
nature within the tournament venue.

6.3

Help

6.3.1

Mentors (teachers, parents, chaperones, and other adult team-members including translators) are not allowed in the student work area unless it is explicitly but temporarily permitted by tournament organizers.
Only participating students are allowed to be inside the work area.

6.3.2

Mentors must not touch, build, repair, or program any robots.

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6.4
6.4.1

Sharing

The understanding that any technological and curricular developments should be shared among the
RoboCup and RoboCupJunior participants after the tournament has been a part of world RoboCup competitions.

6.5

Spirit6.5.1

It is expected that all participants, students, mentors, and parents will respect the RoboCupJunior mission.

6.5.2

It is not whether you win or lose, but how much you learn that counts!

6.6

Violations / Disqualiﬁcation

6.6.1

Teams that violate the code of conduct may be disqualiﬁed from the tournament. It is also possible todisqualify only single person or single robot from further participation in the tournament.

6.6.2

In less severe cases of violations of the code of conduct, a team will be given a warning. In severe or
repeated cases of violations of the code of conduct a team may be disqualiﬁed immediately without awarning.

7

CONFLICT RESOLUTION

7.1

Referee and referee assistant

7.1.1

The referee is a person in charge of making decisions with regards to the game, according to these rules,
and may be assisted by a referee assistant.

7.1.2

During gameplay, the decisions made by the referee and/or the referee assistant are ﬁnal.

7.1.3

Any argument with the referee or the referee assistant can result in a warning. If the argument continues
or another argument occurs, this may result in immediate disqualiﬁcation from the game.

7.1.4

Only the captain has a mandate to freely speak to the referee and/or their assistant. Shouting at a referee
and/or their assistant, as well as demanding a change in ruling may be penalized by a warning at thereferee’s discretion.

7.1.5

At the conclusion of the game, the result recorded in the scoresheet is ﬁnal. The referee will ask thecaptains to add written comments to the scoresheet if they consider them necessary. These comments
will be reviewed by the tournament organizers.

7.2
7.2.1

Rule clariﬁcation may be made by members of the tournament organizers and the Soccer League Committee, if necessary even during a tournament.

7.3
7.3.1

Rule clariﬁcation

Rule modiﬁcation

If special circumstances, such as unforeseen problems or capabilities of a robot occur, rules may be
modiﬁed by the tournament organizers, if necessary even during a tournament.

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7.4
7.4.1

8.1.1

8.1.2

Regulatory statutes

Each RoboCupJunior competition may have its own regulatory statutes to deﬁne the procedure of the tournament (for example the SuperTeam system, game modes, the inspection of robots, interviews, schedules,etc.). Regulatory statutes become a part of this rule.

8

LEAGUE REGULATIONS

8.1

Preamble

According to rule 3.8 of the RoboCupJunior Soccer Rules, each league has its own additional regulations.
They become a part of the rules.
For RoboCupJunior , there are two sub-leagues as follows 10 :• Soccer Lightweight• Soccer Open

8.1.3

All team members need to be within the age range speciﬁed in the RoboCupJunior General Rules which
can be found at http://junior.robocup.org/robocupjunior-general-rules/.

8.1.4

As described in Rule 5.1, Speciﬁcation for Soccer Lightweight Ball and Rule 5.2, Speciﬁcation for Soccer
Open Ball, the matches in the Soccer Open sub-league are conducted using a passive ball, whereas thematches in the Soccer Lightweight sub-league are played using the IR ball.

8.2.A.1

8.2

Regulations

8.2.A

Dimensions

Robots will be measured in an upright position with all parts extended. A robot’s dimensions must notexceed the following limits:
sub-league
size [0]heightweightball-capturing zone
voltage

Soccer Open18.0 cm
18.0 cm [1]2200 g [2]
1.5 cm
48V DC / 25V AC RMS 12 [3] [4]Soccer Lightweight22.0 cm
22.0 cm [1]1400 11 g [2]3.0 cm
48V DC / 25V AC RMS 13 [3] [4][0] Robot must ﬁt smoothly into a cylinder of this diameter10 biggest differences are described in Rule 8.2.A, Dimensions
11 In previous version this said ”1100”
12 In previous version this said ”15.0 V”
13 In previous version this said ”12.0 V”

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[1] The handle and the top markers of a robot may exceed the height.

[2] The weight of the robot includes that of the handle.

[3] We strongly encourage teams to include protection circuits for Lithium-based batteries[4] The voltage limit relates to the maximum voltage at any point and any time on
the robot, *not nominal voltages* a .
a In previous version this said ”Voltage limits relate to the nominal values, deviations at the power pack due
to the fact that charged will be tolerated”

8.2.A.2

Ball-capturing zone is deﬁned as any internal space created when a straight edge is placed on the protruding points of a robot. This means the ball must not enter the convex hull of a robot by more than thespeciﬁed depth. Furthermore, it must be possible for another robot to take possession of the ball.

8.2.B

Infrared interference in Lightweight

8.2.B.1

Components designed to emit IR (e.g. ToF, LiDAR, IR distance sensors, IR LEDs/LASERs etc.) are not allowed
and tournament organizers will require such devices to be removed or covered up.

8.2.B.2

In Lightweight, infrared light reﬂecting materials must not be visible. If robots are painted, they mustbe painted matte. Minor parts that reﬂect infrared light could be used as long as other robots are notaffected.

8.2.C
8.2.C.1

8.2.C.2

Limitations

A robot may use any number of cameras without restrictions on lenses, optical parts, optical systems, andtotal ﬁeld of view. Components may be sourced in any way the team sees ﬁt.
14 No voltage may exceed 48V DC or 25V AC RMS at any time and maximum voltage must be available

for demonstration and measurement at inspections. When not in use measurement contacts must be
14 In previous version this said ”Voltage pump circuits are permitted only for a kicker drive. ”

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protected from accidental touches or short circuits. 15 Each robot must be designed to allow verifying thevoltage of power packs and its circuits 16 .
8.2.C.3

Pneumatic devices are allowed to use ambient air only.

8.2.C.4

Kicker strength is subject to compliance check at any time during the competition. During gameplay, areferee can ask to see a sample kick on the ﬁeld before each half when a damaged robot is returned tothe ﬁeld or when the game is about to be restarted after a goal. If the referee strongly suspects that akicker exceeds the power limit, they can require an oﬃcial measurement. See Appendix C, Kicker Power
Measuring Procedures for more details.

8.2.D

Construction

Robots must be constructed exclusively by the student members of a team. Mentors, teachers, parents or companies may not be involved in the design, construction, and assembly ofrobots.

8.2.D.1

For the construction of a robot, any robot kit or building block may be used as long as the design andconstruction are primarily and substantially the original work of a team. This means that commercial kits
may be used but must be substantially modiﬁed by the team. It is neither allowed to mainly follow a
construction manual, nor to just change unimportant parts.

8.2.D.2

Indications for violations are the use of commercial kits that can basically only be assembled in one way
or the fact that robots from different team(s), build from the same commercial kit, all basically look orfunction the same.

8.2.D.3

Robots must be constructed in a way that they can be started by the captain without the help of anotherperson.

8.2.D.4

Since a contact with an opponent robot and/or dribbler that might damage some parts of robots cannot
be fully anticipated, robots must have all its active elements properly protected with resistant materials. For example, electrical circuits and pneumatic devices, such as pipelines and bottles, must be
protected from all human contact and direct contact with other robots.

All driven dribbler gears must be covered with metal or hard plastic.

8.2.D.5

When batteries are transported or moved, it is strongly recommended that safety bags be used. Reasonable efforts should be made to make sure that in all circumstances robots avoid short-circuits andchemical or air leaks.

15 In previous version this said ” All other electrical circuits inside the robot cannot exceed 15.0 V for Soccer Open and 12.0 V for
Soccer Lightweight. ”
16 In previous version this said ”, unless the nominal voltage is obvious by looking at the robot, its power packs and connections”

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The use of swollen, tattered or otherwise dangerous battery is not allowed.

8.2.E

Programming

8.2.E.1

Robots must be programmed exclusively by student members of the team. Mentors, teachers, parents orcompanies should not be involved in the programming and debugging of robots.

8.2.E.2

For the programming of the robots, any programming language, interface or integrated development
environment (IDE) may be used. The use of programs that come together with a commercial kit (especiallysample programs or presets) or substantial parts of such programs are not allowed. It is not allowed touse sample programs, not even if they are modiﬁed.

8.2.F
8.2.F.1

Inspections

Robots must be inspected and certiﬁed every day before the ﬁrst game is played. The tournament organizers may request other inspections if necessary, including random inspections which may happen at
any time. The routine inspections include:• Weight restrictions for the particular sub-league (see Rule 8.2.A, Dimensions).
• Robot dimensions (see Rule 8.2.A, Dimensions).
• Voltage restrictions (see Rule 8.2.A, Dimensions and Rule 8.2.C, Limitations).
• Kicker strength limits, if the robot has a kicker (see Appendix C, Kicker Power Measuring Procedures).

8.2.F.2

Proof must be provided by each team that its robots comply with these regulations, for example, by adetailed documentation or logbook. Teams may be interviewed about their robots and the development
process at any time during a tournament.

9

INTERNATIONAL COMPETITION

9.1

Team

9.1.1

Maximum team size is 4 members for RoboCupJunior Soccer.

9.1.2

Soccer Lightweight team members can participate in the World Championship only twice. After theirsecond participation, they need to move to Soccer Open.

9.2
9.2.1

Interviews

During the international competition, the tournament organizers will arrange to interview teams during
the Setup Day of the event. This means that the teams need to be already present early on this day. Teams
must bring robots, the code that is used to program them and any documentation to the interview.

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9.2.2

During an interview, at least one member from each team must be able to explain particularities about
the team’s robots, especially with regards to its construction and its programming. An interviewer may ask
the team for a demonstration. The interviewer may also ask the team to write a simple program during
the interview to verify that the team is able to program its robot.

9.2.3

All teams are expected to be able to conduct the interview in English. If this poses a problem, the team
may ask for a translator to be present at the interview. If the tournament organizers are not able toprovide a translator, the team is required to do so. During the interview, the team will be evaluated using
so called Rubrics, which are published on the website mentioned in the beginning of these rules.

9.2.4

The Soccer League Committee recommends the implementation of interviews in regional competitions as
well, but this is not mandatory.

9.3

Technical Challenges

9.3.1

Inspired by the major leagues and the need for further technological advancement of the leagues, theSoccer League Committee has decided to introduce so called Technical Challenges.

9.3.2

The idea of these challenges is to give the teams an opportunity to show off various abilities of theirrobots which may not get noticed during the regular games. Furthermore, the Soccer League Committee
envisions these challenges to be a place for testing new ideas that may make it to the future rules, orotherwise shape the competition.

9.3.3

Any RoboCupJunior Soccer team will be eligible to try to tackle these challenges. Unless otherwise stated,
any robot taking part in these challenges needs to abide by these rules in order to successfully complete
it.

9.3.A

Precision shooter

9.3.A.1

The results in soccer are evaluated by the number of scored goals. History usually does not care how they
were scored. For the spectators, however, this usually makes all the difference.

9.3.A.2

This challenge consists of six rounds. In each round, the robot starts from its own penalty area oriented
towards the goal. The ball is placed randomly (by rolling a die) inside this half of the ﬁeld on one of thefollowing spots:
1. Left neutral spot
2. Right neutral spot
3. Left corner of the penalty area
4. Right corner of the penalty area
5. Left corner of the ﬁeld
6. Right corner of the ﬁeld

9.3.A.3

The robot needs to locate the ball and score a goal while staying on its own half of the ﬁeld. Each roundtakes at most 20 seconds.
• The team is free to pick which side to kick from.
• The same robot must be used for all rounds.

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Page 19 of 24• The robot must stay on its half of the ﬁeld for the goal to count, but ”out of bounds” rules do not
apply.

Figure 3 Partitioning of the goal into 6 parts.

9.3.A.4

Initially, the opposite goal is completely open (see Figure 3, “Partitioning of the goal into 6 parts.”). Aftereach scored goal a member of the team rolls a die and the part of the goal that corresponds to the number
on the dice will be covered with a black box. If this part of the goal is already covered, the die will be rolled
again. See Figure 4, “An example state of the goal after two rounds”, where the number 3 and number
5 were rolled on a die after each round and the respective parts of the goal are covered. Note that if
number 3 or 5 will get rolled in the next rounds, a new roll of a die will follow.

9.3.A.5

The result of this challenge is the number of scored goals.
Figure 4 An example state of the goal after two rounds

9.3.B

Penalty Kick

9.3.B.1

In Soccer, a penalty kick takes place after a grave offense happens. The aim of this technical challenge isto see whether something similar can be done within the limits of RoboCupJunior Soccer.

9.3.B.2

The kicking procedure consists of the following steps:
1. All robots as well as the ball are removed from the ﬁeld.

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2. The offending (”kicking”) team places a robot inside its own penalty area, rotated towards its own
goal. A ball is placed at the central neutral spot.
3. The offending (”kicking”) team turns their robot on. The robot needs to stay still for the next 5
seconds.
4. During these 5 seconds the defending team places a robot which is turned off inside its own penalty
area.
5. In order to score a goal, the offending team’s robot needs to move the ball inside the opponent’s
goal. It needs to do so in at most 15 seconds and while staying within the center circle once it
touches the ball.
9.3.B.3

If the offending team’s robot moves before the 5 seconds pass, the result is automatically no goal. Oncethe penalty kick ﬁnishes, the game continues with a Rule 1.3, Kick-off, with the defending team kicking-off.

9.3.C

Vertical kick

9.3.C.1

The introduction of an orange golf ball in Open should open up new options for gameplay. Given thesmaller size and weight of golf balls, it should be possible to kick them not just horizontally (as if in ”2D”)
but also vertically (that is, to get the ball into the air).

9.3.C.2

The task in this technical challenge is to score into the open yellow goal from the other (blue) half of theﬁeld. In order to pass the challenge, the ball can only touch the other (yellow) half of the ﬁeld inside thepenalty area and the goal itself. Note that a golf ball (not necessarily orange) needs to be used.

9.4

Further information on International Competition

9.4.1

All teams qualiﬁed to the international competition must share their designs, both hardware and software, with all present and future participants. These teams are also required to send a digital portfolio
before the competition. Further details on how will be provided by the Soccer League Committee whichacts as the tournament organizers for the international competition.

9.4.2

During the competition days of the international competition (as well as before the event) the team members are responsible for checking all relevant information published by the Soccer League Committee or
any other RoboCup oﬃcial.

9.4.3

There will also be a SuperTeam competition, in which various teams from around the world share theirrobots in one ”SuperTeam” and play against other SuperTeams on a so called ”Big Field”. The full rules ofthis challenge can be found at https://robocup-junior.github.io/soccer-rules/master/superteam rules.html

To make SuperTeam games more manageable at present and make communication between multiple robots in a SuperTeam easier in the future, the Soccer League Committee
will provide each team with a communication module. Each team will be expected to interface with this module using a single 2.54mm GPIO pin at present and the Soccer League
Committee plans on extending this to using UART or I2 C for more complex applications infuture years. More details will be provided by the Soccer League Committee before thecompetition.

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9.4.4

Teams competing in the international competition can receive awards for their performance. Theseawards are decided and introduced by the Soccer League Committee, which publishes all necessary details well before the actual event. In the past years they were awarded for best poster, presentation, robot
design, team spirit and individual games.

9.4.5

Note that as stated in Rule 6.5, Spirit, it is not whether you win or lose, but how much you learn thatcounts!

9.5

Entry League

9.5.1

In order to help newcomers experience the RoboCupJunior Soccer competition, the Soccer League Committee would like to encourage competitions to include a so called ”Entry League”. Although such a league
will not be part of the international competition, the Soccer League Committee still believes that it isworthwhile to make it part of regional and super-regional competitions. To this end, the Soccer League
Committee has prepared a suggested ruleset. 17 Some regional and super-regional competitions alreadyhave rulesets and will likely make changes to the suggested rulesets or replace them entirely for theirevents. 18 Teams should ask their local/regional/super-regional tournament organizers for details on
what Entry leagues (if any) will be running in their region.

9.5.2

The Soccer League Committee will additionally post what it knows on the news thread on the forum(https://junior.forum.robocup.org/t/soccer-entry-league-news-feed/2677).

A

Technical Speciﬁcation for pulsed Soccer Ball

1.1

Preamble

1.1.1

Answering to the request for a soccer ball for RCJ tournaments that would be more robust to interfering
lights, less energy consuming and mechanically more resistant, the Soccer League Committee deﬁned thefollowing technical speciﬁcations with the special collaboration from EK Japan and HiTechnic.

1.1.2

Producers of these balls must apply for a certiﬁcation process upon which they can exhibit the RCJcompliant label and their balls used in RCJ tournaments.

1.1.3

Balls with these speciﬁcations can be detected using speciﬁc sensors but also common IR remote control
receivers (TSOP1140, TSOP31140, GP1UX511QS, etc. - on-off detection with a possible gross indication of
distance).

1.2
1.2.A
1.2.A.1

Speciﬁcations
IR light

The ball emits infra-red (IR) light of wavelengths in the range 920nm - 960nm, pulsed at a square-wave
carrier frequency of 40 kHz. The ball should have enough ultra-bright, wide-angle LEDs to minimize unevenness of the IR output.
17 Avaliable as HTML and PDF at https://robocup-junior.github.io/soccer-rules-entry/master/rules.html and https://robocupjunior.github.io/soccer-rules-entry/master/rules.pdf respectively
18
Examples:
https://www.robocupjunior.org.au/wp-content/uploads/2021/02/RCJASoccer-SimpleSimon2021.pdf,
https://rcj2019.eu/sites/default/ﬁles/Soccer%201-1%20Standard%20Kit%20Rules%202019%20Final.pdf

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1.2.B
1.2.B.1

The diameter of the ball is required to be 74mm. A well-balanced ball shall be used.

1.2.C
1.2.C.1

Coloration

The ball must not have any marks or discoloration that can be confused with goals, or the ﬁeld itself.

1.3
1.3.1

Battery Life

If the ball has an embedded rechargeable battery, when new and fully charged it should last for morethan 3 hours of continuous use before the brightness of the LEDs drops to 90% of the initial value. If theball uses replaceable batteries, a set of new high-quality alkaline batteries should last for more than 8hours of continuous use before the brightness of the LEDs drops to 90% of the initial value.

1.2.F
1.2.F.1

Modulation

The 40 kHz carrier output of the ball shall be modulated with a trapezoidal (stepped) waveform of frequency 1.2 kHz. Each 833-microsecond cycle of the modulation waveform shall comprise 8 carrier pulses
at full intensity, followed (in turn) by 4 carrier pulses at 1/4 of full intensity, four pulses at 1/16 of fullintensity and four pulses at 1/64 of full intensity, followed by a space (i.e. zero intensity) of about 346
microseconds. The peak current level in the LEDs shall be within the range 45-55mA. The radiant intensity
shall be more than 20mW/sr per LED.

1.2.E
1.2.E.1

Drop Test

The ball must be able to resist normal gameplay. As an indication of its durability, it should be able tosurvive, undamaged, a free-fall from 1.5 meters onto a hardwood table or ﬂoor.

1.2.D
1.2.D.1

DiameterOﬃcial suppliers for pulsed balls

Currently, there is one ball that has been approved by the Soccer League Committee:• RoboCup Junior Soccer ball operating in MODE A (pulsed) made by EK Japan/Elekit (https://elekit.co.jp/en/product/RCJ-05R)

1.3.2

2.1.1

Note that this ball was previously called RCJ-05. While you may not be able to ﬁnd a ball with this nameanymore, any IR ball produced by EK Japan/Elekit is considered to be approved by the Soccer League
Committee.

B

Technical Speciﬁcation for passive Soccer Ball

2.1

Preamble

In order to push the state of the art in the Soccer competition forward, while also trying to bridge the gap
between the Junior and Major leagues, the Soccer League Committee chose a standard orange golf ball

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as the ”passive” ball. This is the same choice as the Small Size League makes 19 and since these balls are
standardized, they should be cheap and easy to get anywhere around the globe.

2.2

Speciﬁcations

2.2.A
2.2.A.1

The diameter of the ball is required to be 42mm +- 1mm.

2.2.B
2.2.B.1

SurfaceEngravings and printed labels on the ball’s surface are tolerated. The the ball should not have a soft-touchﬁnish. Teams must be prepared to play with balls as supplied by tournament organizers.

2.2.E
2.2.E.1

Coloration

The ball shall be of orange color. Since the deﬁnition of the orange color in general is not easy, any colorthat a human would deem to be orange and is substantially different from the other colors used on theﬁeld is acceptable. While tournament organizers may supply matte balls to improve camera vision, teams
must still be prepared to play with the balls supplied by tournament organizers.

2.2.D
2.2.D.1

Drop Test

The ball must be able to resist normal gameplay. As an indication of its durability, it should be able tosurvive, undamaged, a free-fall from 1.5 meters onto a hardwood table or ﬂoor.

2.2.C
2.2.C.1

Diameter

Weight

The weight of the ball should be 46 grams (+- 1 gram).

C

Kicker Power Measuring Procedures

All robot kickers will be tested with the tournament ball used in the sub-league they participate in. Kicker
Power will be measured by means of an on-ﬁeld test 20 .
The test is performed as follows:
1. Place robot inside the left corner of a goal.
2. Perform a kick into the opposing goala. The Open League kicker power test is passed if after bouncing off of the opposite goal the balldoes not return further than the front line of to the penalty area it was shot from.
b. The Light Weight League power test is passed if after bouncing off of the opposite goal
the ball does not leave the penalty area of the opposing goal after bouncing back.
19 See the SSL rules at https://robocup-ssl.github.io/ssl-rules/sslrules.html# ball
20 In previous version this said ” in Soccer Open and by means of the Kicker Power Measuring Device in Soccer Lightweight”

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