Heterogeneous and Homogeneous Robot Group Behavior

Dani Goldberg Brandeis University Computer Science Department Volen Center for Complex Systems, Room 261 Waltham, MA 02254 [email protected] When working with groups of robots it may be very di cult to determine what characteristics the group requires in order to perform a task most e ciently|i.e., in the least time. Some researchers have used groups of behaviorally di erentiated robots|where the robots do not perform the same actions|and others have used behaviorally homogeneous groups. None of this research, however, explicitly compares the behavior of heterogeneous and homogeneous groups of robots to determine which performs a task more e ciently. The research described here makes such a comparison and aims at developing guidelines to aid in the design of the heterogeneous/homogeneous characteristics that will allow a group of robots to perform a task e ciently. There are a number of issues that arise when one tries to de ne the homogeneous/heterogeneous nature of a group. These issues are mentioned in (Brooks 1991): Individuality and Cooperation: Individuality deals with how the behaviors of the various classes of robots di er and how many classes of robots there are, while cooperation deals with how these classes interact. Interference and Density Dependence: Any time more than one robot is present in a system there is the possibility that one will interfere with the actions of another. It is important to determine how many robots of each class, and how many total, produce the most e cient solution. Communication: Communication may be used to help coordinate the actions of individual robots or the classes they belong to. It can therefore impact all of the previous issues. Our research begins to explore some of these issues by implementing a hoarding task. The task requires the robots to search an 11 by 14 foot enclosure for pucks (small metal cylinders), collect them and bring them to a particular corner designated as Home (see gures). For this experiment we use four identical IS Robotics R2e robots. One experiment is with a homogeneous group. All of the robots are behaviorally identical (i.e. they belong to the same class) and there is no explicit communication between them. Each robot searches for pucks Home