1. Overview
This year’s SDP course revolves around a game similar to football, but with the exceptions that tackling is not allowed, and dribbling is very limited. This is to prevent what we have seen in previous years, where football matches sometimes became sumo wrestling. The no dribbling rule allows your robot to move a bit while you turn and aim, but you are not allowed to dribble the ball for a great distance. You can kick it and then recapture it, but you’re encouraged to work with your teammate(s) as much as possible.
The rules here are modelled on the RoboCup Small Size League Rules.[1] However, the rules have been simplified to require less stopping of play, and require fewer specific cases to be programmed into the robot.
The rules are subject to change, although an e-mail will be sent to SDP students if a change occurs.
2. Rules Summary
Each game will have two halves, and teams will switch sides at half time. Each half starts with a kick off, taken by one robot and from which the ball must be kicked forward. Teams score goals to get points. There is a defence area in front of each team’s goal, which only one member of that team should be in at any given time. Teams are not required to nominate roles to their robot - i.e. the goalkeeper can change during the match. A team should not touch the ball in their opponent’s defence area.
When a robot has the ball, it is expected to pass it away, and will be penalised if it travels too far (i.e. no dribbling). Passing to yourself is ok, but the ball must travel away from the robot before being recaptured. Passing to yourself is not ok at kick off.
Tackling is not allowed, and contact in general is strongly discouraged. Accidents happen, but you’ll be penalised if the referee deems that contact was deliberate, or if your robot is just too darn clumsy.
If a robot misbehaves or if nothing happens for a while, the referee will most likely move the ball, either to give the advantage to the other team or to keep things moving. If a robot misbehaves too much it may incur a timeout, or be sent off the pitch.
3. Field of Play
There are two pitch rooms, and the fields of play and equipment in each room are as similar as possible. In addition, where possible teams are allocated practice areas with a similar surface.
3.1. Dimensions
The field of play is rectangular, of nominal sizeNxNmm. The field is surrounded with a wall of approximate height 100mm. You are permitted to bounce shots off this wall. The layout and dimensions of field pitch are shown below. All dimensions are nominal, and may vary by +/- 10% in practice. We’ll try our best but lines may also not be perfectly straight.
The corners of the pitch contain triangular ramps to prevent balls becoming stuck in difficult to retrieve positions. These ramps have a 100mm side.
3.2. Field Surface
The pitches are set out directly on the floor of the computing labs, on short pile carpet tiles with grey patterning. The floor is fairly level, but Forrest Hill is an old building. You should practice to ensure that you can cope with any slight irregularities.
3.3. Surface Markings
The field of play is marked with lines. All lines are40mm wide and matt white.
The field of play is divided into two halves by a halfway line that runs along the width of the field and through the centre of the field.
A mid-line runs along the length of the field, passing through the center of the field. Use this line as a feature for localisation and to help with vision calibration.
The triangular corner ramps are also white in colour.
3.4. The Defence Area
There is a defence area at each end of the field. Each defence area is a rectangle of lengthNmm and widthNmm, with one long edge colinear with and centered on the goal line. The lines marking the defence area are part of the defence area.
Only one defending robot should be in the defence area at a given time. Attacking robots are not allowed in the defence area at any time.
3.5. Penalty Mark
For each half field the penalty mark isNmm from the midpoint between the goalposts and equidistant to them. The penalty mark isa white square of 60mm side.
3.6. Goals
Goals are located on the center of each goal boundary, and are formed by the bounding wall. The goals areNmm wide andNmmdeep. The walls of the goals are white in colour. There is a slight lip at the mouth of each goal. The ball must clear this lip for a goal to be scored.
3.7. The Ball
The ball is a standard Lego Mindstorms red ball. It is a 52mm sphere.
3.8. Camera
Above each pitch is a camera facing directly down. The camera is located near the center of the pitch, but not directly above it, and is in a different location in each pitch room due to physical constraints. You should calibrate for the camera location in each room.
4. Robots and Equipment
Each group will build one robot, and groups join together to form teams for matches.
4.1. Number of Robots
A match is played by two teams, each consisting of two robots. Each robot must be clearly numbered so that the referee can identify them during the match. A match may start with fewer robots on the field. The robots of a team do not have to be assigned specific roles for a match.
4.2. Size
A robot must fit inside a box with dimensions200x180x180mm.
Kicking or catching devices may extend outwith these dimensions only when actively kicking, catching, or holding a ball. The specified dimensions may not be exceeded for longer than a 5 second period unless a ball is being held.
4.3. Robot Construction
Any red, yellow, or blue pieces of Lego used in construction should not be visible from above. (Insulating tape or paper/card can be used to cover offending bricks)
Any red used should not be visible from any of the sides, i.e. by other robots, should they be using any form of colour sensors. This includes red lego and red LEDs etc.
There should be no loose/trailing wires.
No devices are allowed which damage, interfere with, jam or otherwise unfairly obstruct other robots.
Robot wheels (or other surfaces that contact the playing surface) must be made of a material that does not harm the playing surface. No spikes.
4.4. Wireless Communication
Robots can use wireless communication to computers located off the field. You will be assigned a frequency/channel for your team to use with the provided RF sticks. If using the RF sticks you must use this frequency only to limit interference with other robots.
You are permitted to implement other wireless communication methods, as long as they do not interfere with other robots or teams. You must notify the course organisers if you intend to do this.
4.5. Computation and Equipment
You may use the provided university equipment, e.g. DICE machine, to run code for your robots. You may not use your own laptops, smartphones, etc. or any other device not available to all students. You may use equipment bought with your group’s budget off-field, i.e. to aide your remote computation. You may not use any sensors or output devices located remotely from your robot, other than the overhead camera provided and those for wireless communication.
4.6. Team Color
Before a game, each of the two teams has a colour assigned, namely yellow or blue. All teams must be able to use either colour. The assigned team colour is used as the centre marker colour for all of the team’s robots.
4.7. Standard Pattern
Teams are required to use a certain set of standardized colours and patterns on top of their robots. Each group will be given a plate which conforms to the standard, and which they must affix to the top of their robot. The team colour will be placed in the middle of the plate for each game.
Each team will must use one each of these two plates:
The front of the robot is the kicker - i.e. the top plate must be oriented towards your main kicker, so that other teams can identify this and plan strategies accordingly.
4.8. Autonomy
The robotic equipment is to be fully autonomous. Human operators are not permitted to enter any information into the equipment during a match. Human operators may give commands to start and stop the robot, and tell the system decisions of the referee - for example to tell the robot that a penalty kick will occur.
4.9. Dribbling
Dribbling devices are permitted, including devices which spin the ball and devices which hold the ball. No adhesives are allowed.
However, the distance which a ball may be dribbled is very limited. To allow for turning and slight manoeuvring, the ball may be dribbled a distance of no more than 200mm.
A robot begins dribbling when it makes contact with the ball, and stops dribbling when there is a separation of at least 500mm between the ball and the robot.
4.10. Obscuring the Ball
The ball should remain visible to the overhead camera at all times, as far as practically possible.
The test for whether a robot obscures the ball is as follows. With the centre of the robot directly underneath the overhead camera, no more than 20% of the ball should be obscured.
This means that robots should have no significant overhangs which can obscure the ball, and the grabbing/dribbling devices should allow at least 80% of the ball to be seen.
The ball may be momentarily obscured during a kick or catch, but robots should be designed such that a failed catch or kick does not lead to obscuration of the ball. The referee’s decision on this is final.
Example top down view of different robots. With the camera directly above, no more than 20% of the ball may be obscured.
4.11. Kicker Power
Your kicker must not be so powerful that it can kick faster than other robots can react.
The rules enforce a nominal speed limit, but in practice we will test this by testing how far your robot can kick. A line will be marked in one of the pitch rooms, showing a start point (from which to kick) and a maximum end point. When tested, you'll need to have your robot kick at full power, and the ball must not pass the maximum end point.
The exact distance of this test will be specified shortly, but is likely to be about 2.5-3m.
4.12. Infringements
A rules check will be performed on each robot before each competition. Any robot found to violate a rule must be modified to be compliant before it will be allowed to participate in matches.
4.13. Robots removed from the field
Robots may be required to be removed from the field by the referee.
A team may ask the referee for permission to remove one of their robots.
In all cases, before a robot is replaced on to the field, the permission of the referee must be gained. You must not place a robot on the field without getting the permission of the referee, especially while the ball is in play.
5. The Referee
Each match is controlled by a referee whose decision is final. The referee is responsible for ensuring that the robots meet the requirements above as well as enforcing the rules of the game. The referee will start and stop play, award goal scores, penalties, placed balls, and penalise robots who misbehave - enforcing the rules for fouls and misconduct.
The referee can also reposition the ball at their discretion, for example if it becomes stuck, or if a robot holds it for too long.
The referee may call a time-out at their discretion, for example if equipment malfunctions.
The referee may also take action against team members who do not conduct themselves in a professional manner - e.g. robot handlers who pick up their robot without first getting permission may be replaced.
The referee may be assisted by one or more assistant referees.
6. Duration of the Match
6.1. Periods of Play
Each match lasts two equal periods of 3 minutes, unless otherwise specified. There is a nominal 1 minute interval between halves. The referee may extend the interval, but will not shorten it without the consent of both teams.
The referee may, at their sole discretion, allow for time lost, for example due to equipment malfunctions or wasting time.
6.2. Extra Time
Competition rules allow for two further equal periods to be played. Typically this might happen in the knockout stages of a competition in the event of a draw - see the competition rules for more detail.
7. Start and Restart of Play
7.1. Preliminaries
If both teams have the same preferred colour, a coin toss will decide which team gets their preferred choice.
A coin is tossed and the team which wins the toss decides which goal it will attack in the first half of the match.
The other team takes the kick-off to start the match. The team that wins the toss takes the kick-off to start the second half of the match.
For the second half of the match the teams change ends and attack opposite goals.
7.2. Kick-off
A kick-off is a way of starting or restarting play:
- at the start of each half of the match
- after a goal has been scored
- at the start of each period of extra time, where applicable
A goal may not be scored directly from the kick off, the ball must be touched again by a robot or contact a wall of the pitch before a goal can be scored.
The kick-off procedure is as follows:
- all robots are in their half of the field
- All robots are at least 300mm from the ball until the ball is in play, except for the robot taking the kick
- the ball is stationary on the centre mark
- the referee gives a signal
- the ball is in play when it is kicked and moves forward
- the kicker must not touch the ball a second time until the ball has touched another robot, a wall of the pitch, or has been stationary for 10 seconds or more
After a team scores a goal, the kick-off is taken by the other team.
For a foul or misconduct listed later, the appropriate action is taken. For any other infringement of the procedure, or at their sole discretion, the referee may require that the kick-off be retaken. The robot taking the kick off must kick the ball forwards, if the ball is kicked backwards the referee may demand that the kick be retaken, or award a kick off to the opposing team.
7.3. Placed Ball
For a placed ball, the referee picks up the ball and places it on the pitch, usually at a location unfavourable to a team that committed a foul. Play will not normally be stopped, but a placed ball can be used to restart play at the instruction of the referee.
If the ball is placed in a defense area, then only the team that owns that defense area should attempt to kick the ball.
The referee may require that some or all of the robots stay a given distance from the ball. For example, the referee may stop play and require all robots to halt, move any robots they see fit, place the ball, and then instruct play to resume.
7.4. Special Circumstances & Notes
If the ball remains stationary for 10 seconds, the referee may place the ball wherever on the pitch they deem suitable, and allow either team to approach and touch the ball.
For all restarts where the ball is in play when it is kicked and moves, e.g. kick-off, the robot must clearly tap or kick the ball to make it move. It is understood that the ball may remain in contact with the robot or be bumped by the robot multiple times over a short distance while the kick is being taken, but under no circumstances should the robot remain in contact or touch the ball after it has travelled 50mm, unless the ball has previously touched another robot. Robots may use dribbling and kicking devices in taking the free kick.
8. Scoring
A goal is scored when the whole of the ball passes over the goal line, between the goal walls, provided that no infringement of the rules of the game has been committed previously by the team scoring the goal.
The team scoring the greater number of goals during a match is the winner. If both teams score an equal number of goals, or if no goals are scored, the match is drawn.
For matches ending in a draw, the competition rules may specify that extra time, penalty kicks, or other procedures shall occur, for example during knockout stages.
9. Offside
There is no offside.
10. Fouls and Misconduct
As far as possible, the rules try to avoid stopping the game. If a robot commits a foul or behaves inappropriately, the ball will usually be given to the opposing team, and the robot may be penalised.
If a robot misbehaves too much it will get a yellow or red card, and will have to be taken off the pitch. The referee’s decision on this is final.
Some fouls also require the offending robot to have a timeout. For simplicity, the robot should just stay where it is on the pitch, without moving any motors. The referee may decide to place the robot for or during the timeout.
The referee may decide to alter the penalties for a robot at their discretion, for example by awarding a penalty kick instead of a placed ball. They may also stop the game and resume it as they see fit.
| Foul | Consequence |
|---|---|
| Holding ball for >15 seconds | Placed ball in opponent’s favour |
| Double touch at kick-off | Placed ball in opponent’s favour |
| Ball dribbled >200mm | Placed ball in opponent’s favour 10 second timeout |
| Ball kicked >1m/s | Placed ball in opponent’s favour |
| Deliberate contact | Placed ball in opponent’s favour 10 second timeout |
| Ball touched in opponent’s defense area | Placed ball in opponent’s favour |
| Multiple Defense | Offending robot movedPlaced ball in opponent’s favour |
| Dropping parts | Placed ball in opponent’s favour |
| Substantial contact | Placed ball in opponent’s favour 20 second timeout |
| Holding an opponent | Placed ball in opponent’s favour 20 second timeout |
| Robot not moving for >10s | Referee may penalise and/or order robot removed |
| Robot placed back onto pitch without referee’s permission | Yellow Card |
| Other misconduct or unsporting behaviour | Referee’s decision. |
10.1. Multiple Defense
Multiple defense occurs if more than one robot from the defending team enters its defence area with some part and substantially affects the game. The referee may instruct that a robot, usually the farthest one from the ball, be moved to a point elsewhere on the pitch, decided by the referee.
The referee could take this action at any time when both robots linger in their penalty area.
If multiple defense happens repeatedly, the referee may penalise the robots/team as they see fit.
11. Disciplinary Sanctions
11.1. Cautionable Offences
A team is cautioned and shown the yellow card if a robot on that team commits any of the following offences:
- is guilty of unsporting behaviour
- is guilty of serious and violent contact
- persistently infringes the rules of the game
- delays the restart of play
- fails the respect the required distance when play is restarted with a free kick
- modifies or damages the field or ball
- places a robot on the field which is clearly not capable of movement
Upon receipt of a yellow card, the offending robot is removed from play for a period ofone minute. The robot is removed immediately. As always, the robot handler must obtain the referee’s permission before placing the robot back on the field.
The referee may decide to warn a team regarding these offences, but persistent offenders should expect to be shown a yellow or red card.
11.2. Sending-Off Offences
A team is shown a red card if one of the robots on the team is guilty of severe unsporting behaviour. The offending robot must be immediately removed from the field for the remainder of the match. Play may restart once the robot has been removed.
12. Penalty Kicks
A penalty kick may be ordered by the referee at their discretion. The competition rules may also require that penalty kicks be used to decide the winner of a match, for example if the score is drawn at the end of extra time.
A goal may be scored from a penalty kick
Additional time is allowed for a penalty kick to be taken at the end of each half or at the end of periods of extra time.
Position of the ball and the robots
The ball is placed on the penalty mark, and the robot taking the penalty kick should be identified.
One robot from the defending team is designated as the goalkeeper. The defending goalkeeper remains between the goalposts, touches its goal line, and faces outward of the goal, until the ball has been kicked; it is allowed to move before the ball has been kicked, as long as its motion does not break any of these constraints.
The other robots should be inside the field of play and behind a line parallel to the goal line and 400mm behind the penalty mark.
Procedure
The referee does not signal for a penalty kick to be taken until the robots have taken up position in accordance with the rules. The referee decides when a penalty kick has been completed.
- the robot taking the penalty kicks the ball forward
- it does not play the ball again until the ball has touched another robot, contacted a pitch wall, or been stationary for more than 10 seconds
- the ball is in play when it is kicked and moves forward
13. Competition Rules
The format and structure of each tournament/match will be specified before the event, but is likely to consist of group stages followed by knockout stages.
- Extra Time
If the game is drawn at the end of the second half, and the game needs to end with a clear winner, two periods of extra time will be played. The teams will switch halves between the periods of extra time. Each period of extra time will normally be one minute long, and the teams should expect to start extra time within one minute of the second half finishing. The interval between the two periods of extra time should not exceed 30 seconds.
- Penalty Shoot Out
If the game is drawn after the second period of extra time, penalty kicks will be taken to decide who wins the game. The teams will take turns to kick three penalty kicks each. The teams may select which of their robots takes the penalty kicks, but the same robot should take all three .
If the score is even after both teams have taken their penalties, each team shall take one additional penalty kick, and so on.
- Abandoned Match / Victory by Default
If one of the teams abandons the match, before or during its course, the opponent will be awarded winner for all purposes. However, solely for the purpose of goal difference counting, the winner team can, at its decision, continue to play by itself, and the goals scored will continue to be computed.
If the two teams abandon the match, before or during its course, both teams are considered to have lost the match. Abandoned matches cannot result in ties.
The competition records will indicate the team(s) that abandoned the match. A team that refuses to make a good faith effort to participate in a scheduled game will be disqualified from the competition.
- Round Robin Ranking Criteria
During the round-robin phase of the competition, the ranking of each team in each group will be determined by the following criteria, in order:
- greatest number of points obtained in all group matches
- goal difference in all group matches
- greatest number of goals scored in all group matches
If two or more teams are equal on the basis of the above criteria, the tiebreaking procedure to determine their rankings will be determined by the following criteria, in order:
- greatest number of points obtained in the group matches between the teams concerned
- goal difference resulting from the group matches between the teams concerned
- greater number of goals scored in all group matches between the teams concerned
- drawing of lots by the Organising Committee
14. Robot Handlers and Operators
Each team should nominate one robot handler per robot, and one operator per DICE machine. All other team members should vacate the pitch room.
The robot handlers are responsible for interacting with their robot. This includes turning it on, placing it on the pitch, and removing it from the pitch. The robot handler should only enter the pitch area with the permission of the referee, and a robot handler who picks up or places their robot without the referee’s permission may incur penalties against their robot or team.
The referee may order the replacement of any robot handlers who consistently break these rules.
The robot operators should tend any software required to run the robots. They may calibrate their system while play is not ongoing, and may provide their system with contextual information - i.e. Kick off, penalty shot, fouls, etc. The operator must in no way remote-control their robot(s), nor manually input world-data, for example the position of objects on the pitch, during play.
15. Detailed penalty rules
If the referee gives the signal for a penalty kick to be taken and, before the ball is in play, one of the following situations occurs:
The robot taking the penalty kick infringes the Laws of the Game:
- the referee allows the kick to proceed
- if the ball enters the goal, the kick is retaken
- if the ball does not enter the goal, the kick is not retaken
The goalkeeper infringes the Laws of the Game:
- the referee allows the kick to proceed
- if the ball enters the goal, a goal is awarded
- if the ball does not enter the goal, the kick is retaken
A team-mate of the robot taking the kick enters the area 400 mm behind the penalty mark:
- the referee allows the kick to proceed
- if the ball enters the goal, the kick is retaken
- if the ball does not enter the goal, the kick is not retaken
- if the ball rebounds from the goalkeeper, the crossbar or the goal post and is touched by this robot, the referee stops play and restarts the match with an indirect free kick to the defending team
A team-mate of the goalkeeper enters the area 400 mm behind the penalty mark:
- the referee allows the kick to proceed
- if the ball enters the goal, a goal is awarded
- if the ball does not enter the goal, the kick is retaken