In 2009, we have two basic technical challenges, similar to 2008. These two basic challenges are intended to compare technical abilities needed for successfully playing robot soccer. Both are designed to be scalable, i.e. every team can participate almost without much special preparation. Of course, teams who spend extra time on preparing the challenge will probably benefit from their work. Please note that both of these two challenges have changed slightly from their respective 2008 versions.

Additionally to the two basic challenges, we have an enhanced Challenge for Mixed Team Play which will also involve the usage of the new SSL Shared Vision System.

Basic Challenge 1 – Shooting and Passing

Put up two to three robots on the field and score as many goals as possible within 120 seconds. Points are awarded as follows:

  • 1 Point: Scoring a goal after two robots have touched the ball (i.e. after a pass)
  • 2 Points: Scoring a goal after the ball has been touched at least three times by alternating robots (i.e. after at least two passes)

The rules for this challenge:

  • To start, all robots must be placed within 1m from the own goal line.
  • Opponent robots will be placed on the field as obstacles.
  • A ball will be placed near one of the corners at the own side of the field.
  • A goal can be scored only when the kicking robot is in the opponent’s half.
  • Once a goal is scored or the ball has left the field, it will be placed again near one of the corners at the own side of the field.

Basic Challenge 2 – Navigation

Two sets of obstacles (all within 180mm diameter and marked with a standard blue or yellow center marker) are placed at each side of the field, at the approximate initial coordinates as shown in the attached sketch. One robot starts at the center of the field and must drive from one penalty mark of the field to the other as many times as possible within 120s. It must do so by alternating the side of entry between the two sets of obstacles, thus effectively driving a figure-eight. Every successful lap (from one set of obstacles to the other and back, while maintaining the figure-eight requirement) counts as one point. If it touches an obstacle, it gets a penalty of -1 points. Note, that the positions of the obstacles can change slightly during the execution of this challenge (e.g. by a robot bumping into them, or by a human repositioning them), so your system should accomodate for that.

Additionally, teams are allowed to use up to three robots in parallel and sum up their laps. If two robots touch each other, the penalty also applies (per touching event, not per robot, of course).

If a robot has driven at least one lap (independently of the number of collisions), the team’s minimum number of points will be 1.

The red line indicates an example trajectory of a robot performing this challenge.

Mixed Team Challenge

One of the aims of the Small Size League is to foster the development of cooperating agents. The current state of the art is to control all members of one team by a central intelligence instance which has a complete knowledge about the current state of each robot. Even in teams which have a distributed artificial intelligence component, every robot has detailed information about the behaviours of its team members and thus can deduce own actions which lead to an overall cooperative behaviour of the whole team. The aim of this challenge is to define a scenario for “real” cooperation, i.e. to let robots cooperate which do not have any knowledge about the internal state of all other robots of their team. This is intended to become realized by mixing existing teams which then have to accomplish a modified version of the “Shooting and Passing Challenge”.

Mixing Teams

First of all, a mixed team needs to be defined:

For the 2009 challenge, we consider a mixed team as a team of four robots originating from two different SSL teams. Each of these two sub-teams has to provide two robots. Every robot is controlled by its own software stack. Of course, all members of a mixed team have the same team marker colour. For this year, there will not be any communication between the different sub-teams. A mixed team must use the new SSL Shared Vision system.

As procedure for creating the mixed teams, the following approach will be applied:

  1. Until June 17th (two weeks before the start of the competition), each team that is interested in participating in the challenge has to announce its interest to the OC. This is necessary for the preparation of the schedule.
  2. Every team that intends to participate in the mixed team challenge has to successfully participate in the “Shooting and Passing Challenge”, i.e. to score at least three points. This is necessary to assure a minimum level of passing skills.
  3. After the round robin stage of the soccer competition (i.e. on Friday afternoon), the teams for the “Mixed Team Challenge” become generated semi-randomly. Since there are several field assignment constraints for the finals (see section about “Time and Fields”) not every pair of teams is reasonable from an organizational point of view.

The Challenge

The task to accomplish is almost identical to the “Shooting and Passing Challenge”. Except the different number of robots (exactly four instead of up to three), the only difference is the scoring scheme: A pass will only be considering as valid if it has involved robots originating from two different teams.

Time and Fields

The challenge will be conducted during the two final days. Among the finals and the Humanoid Small Size demonstrations, there will be – especially on Sunday – enough free time slots. These slots will become assigned dynamically on site. There will be four SSL fields at the competition site. One of these fields will be used for Humanoid Small Size demonstrations during the weekend. Two others (on Sunday only one) are needed for official games. The remaining field can be used exclusively for the challenge. The two game fields can also be used (e.g. by those teams still participating in the competition) but only in a way that minimally disturbs the preparations for the official games.

Optional Game Demo

If some teams volunteer to show a mixed full 5 vs. 5 SSL soccer match, we would strongly appreciate and support this. Nevertheless, this will not be considered for the overall challenge ranking.

Overall Challenge Ranking

The results from the three challenges will be combined to get an overall technical challenge ranking.

To combine the challenge results, we will use the following formula:

Let BALL_SUM be the sum of all points that all teams received in the ball challenge and BALL_TEAM the number of points a single team received. Assume the same for the other two challenge (NAV_* and MIXED_* respectively).