Coevolving Soccer Softbots

Unlike other entrants that fashioned good softbot teams from a battery of relatively wellunderstood robotics techniques, our goal was to see if it was even possible to use evolutionary computation to develop high-level soccer behaviors that were competitive with the human-crafted strategies of other teams. Although evolutionary computation has been successful in many fields, evolving a computer algorithm has proven challenging, especially in a domain such as robot soccer. Our approach was to evolve a population of teams of Lisp s-expression algorithms, evaluating each team by attaching its algorithms to robot players and trying them out in the simulator. Early experiments tested individual players, but ultimately, the final runs pitted whole teams against each other using coevolution. After evaluation, a team's fitness assessment was based on its success relative to its opponent.