For the RoboCup Physical Agent Challenge Phase I, we offer three specific challenges, essential not only for RoboCup but also for general mobile robotics research.
The fundamental issue for researchers who wish to build real robot systems to play a soccer game in RoboCup is how to obtain basic skills to control a ball in various kinds of situations. Typical examples are to shoot the ball into the goal, to intercept the ball from an opponent, and to pass the ball to a teammate. These skills are needed to realize cooperative behaviors with teammates and competitive ones against opponents in soccer game. Among basic skills to control the ball, we selected three challenges as the RoboCup Physical Agent Challenge Phase I:
These three challenges have many variations in different kinds of situations such as passing, shooting, dribbling, receiving, and intercepting the ball with/without opponents whose defensive skills vary from amateur to professional levels. Although they seem very specific to RoboCup, these challenges can be regarded as very general tasks in the field of mobile robotics research in a flat terrain environment. Since target reaching, obstacle avoidance, and their coordination are basic tasks in the area, the task of shooting the ball while avoiding opponents that try to block the player should be ranked as one of the most difficult challenges in the area. Once the robot succeeds in acquiring these skills, it can move anything to anywhere.
In another aspect, these three challenges can be regarded as a sequence of one task which leads to an increase of the complexity of the internal representation according to the complexity of the environment [Asada1996].
In the case of visual sensing, the agent can discriminate the static environment (and its own body if observed) from others by directly correlating the motor commands the agent sent and the visual information observed during the motor command executions. In other words, such observation can be classified as a self and stationary environment. In contrast, other active agents do not have a simple and straightforward relationship with the self motions. In the early stage, they are treated as noise or disturbance because of not having direct visual correlation with the self motor commands. Later, they can be found as having more complicated and higher correlation (cooperation, competition, and others). As a result, the complexity is drastically increased especially since between the two there is a ball which can be stationary or moving as a result of self or other agent motions.
The complexities of both the environment and the internal representation of the agent can be categorized as a cognitive issue in general, and such an issue is naturally involved in this challenge. In the following, we describe the challenges more concretely.