This thesis addresses situated, embodied agents interacting in complex domains. It focuses on two problems: 1) synthesis and analysis of intelligent group behavior, and 2) learning in complex group environments. Basic behaviors, control laws that cluster constraints to achieve particular goals and have the appropriate compositional properties, are proposed as effective primitives for control and learning. The thesis describes the process of selecting such basic behaviors, formally specifying them, algorithmically implementing them, and empirically evaluating them. All of the proposed ideas are validated with a group of up to 20 mobile robots using a basic behavior set consisting of: safe--wandering, following, aggregation, dispersion, and homing. The set of basic behaviors acts as a substrate for achieving more complex high--level goals and tasks. Two behavior combination operators are introduced, and verified by combining subsets of the above basic behavior set to implement collective flocking, foraging, and docking. A methodology is introduced for automatically constructing higher--level behaviors

This paper proposes the concept of basis behaviors as ubiquitous general building blocks for synthesizing artificial group behavior in multi--agent systems, and for analyzing group behavior in nature. We demonstrate the concept through examples implemented both in simulation and on a group of physical mobile robots. The basis behavior set we propose, consisting of avoidance, safe--wandering, following, aggregation, dispersion, and homing, is constructed from behaviors commonly observed in a variety of species in nature. The proposed behaviors are manifested spatially, but have an effect on more abstract modes of interaction, including the exchange of information and cooperation. We demonstrate how basis behaviors can be combined into higher--level group behaviors commonly observed across species. The combination mechanisms we propose are useful for synthesizing a variety of new group behaviors, as well as for analyzing naturally occurring ones. Key words: group behavior, robotics, eth...

The problem of synthesizing and analyzing collective autonomous agents has only recently begun to be practically studied by the robotics community. This paper overviews the most prominent directions of research, defines key terms, and summarizes the main issues. Finally, it briefly describes our approach to controlling group behavior and its relation to the field as a whole.

view. We suggest, based on work on situated, embodied systems (Agre 1988, Agre & Chapman 1990, Brooks 1991), that control and learning in multi-robot systems must be addressed as a separate, novel, and unified problem, not an additional "module" within a single-robot approach. We propose a bottom-up methodology that produces the desired system behavior as a result of the interaction dynamics between the robots and their environment (which includes other robots, and potentially the user) and the biases and constraints introduced by the system designer. This approach is in sharp contrast with the traditional "strong control" methodology that imposes top-down structure on the desired solution. We aim at removing the abstraction barrier between the agent and the group, and in some cases even more profoundly, between the different processing elements within an individual robot and between robots. The approach allows us to be more flexible and robust in response to ever-changing dynamics wi

Does coherent behaviour require an explicit mechanism of cooperation? In this dissertation, the relationship between local perception and global action in a system of multiple mobile robots was examined for a collective box-pushing task. The problem investigated was how local sensing could be used to coordinate the individual motor responses of a system of robots in a coherent manner, using only implicit communication through the task. The task was to move a large box from an initially unknown position to a specified goal location. The central thesis put forward, is that for the box-pushing task a coherent behaviour is possible, without an explicit mechanism of cooperation, by using the mass effect of a system of redundant robots. Preliminary work in collective robotics appeared to lend weight to the hypothesis that collective tasks, by multi-robot systems, are possible without centralized control or explicit inter-robot communications, two common control mechanisms used for cooperati...