Deaf, Dumb, and Chatting Robots, Enabling Distributed Computation and Fault-Tolerance Among Stigmergic Robot

We investigate ways for the exchange of information (explicit communication) among deaf and dumb mobile robots scattered in the plane. We introduce the use of movement-signals (analogously to flight signals and bees waggle) as a mean to transfer messages, enabling the use of distributed algorithms among the robots. We propose one-to-one deterministic movement protocols that implement explicit communication. We first present protocols for synchronous robots. We begin with a very simple coding protocol for two robots. Based on on this protocol, we provide one-to-one communication for any system of n \geq 2 robots equipped with observable IDs that agree on a common direction (sense of direction). We then propose two solutions enabling one-to-one communication among anonymous robots. Since the robots are devoid of observable IDs, both protocols build recognition mechanisms using the (weak) capabilities offered to the robots. The first protocol assumes that the robots agree on a common direction and a common handedness (chirality), while the second protocol assumes chirality only. Next, we show how the movements of robots can provide implicit acknowledgments in asynchronous systems. We use this result to design asynchronous one-to-one communication with two robots only. Finally, we combine this solution with the schemes developed in synchronous settings to fit the general case of asynchronous one-to-one communication among any number of robots. Our protocols enable the use of distributing algorithms based on message exchanges among swarms of Stigmergic robots. Furthermore, they provides robots equipped with means of communication to overcome faults of their communication device

Evolving a Cooperative Transport Behavior for Two Simple Robots

SCOPUS: ar.kinfo:eu-repo/semantics/publishe

M.: Evolving a cooperative transport behavior for two simple robots

Abstract. This paper addresses the problem of cooperative transport of an object by a group of two simple autonomous mobile robots called s-bots. S-bots are able to establish physical connections between each other and with an object called the prey. The environment consists of a flat ground, the prey, and a light-emitting beacon. The task is to move the prey as far as possible in an arbitrary direction by pulling and/or pushing it. The object cannot be moved without coordination. There is no explicit communication among s-bots; moreover, the s-bots cannot sense each other. All experiments are carried out using a 3D physics simulator. The s-bots are controlled by recurrent neural networks that are created by an evolutionary algorithm. Evolved solutions attained a satisfactory level of performance and some of them exhibit remarkably low fluctuations under different conditions. Many solutions found can be applied to larger group sizes, making it possible to move bigger objects.

Swarm-bots to the rescue

We explore the problem of resource allocation in a system made up of autonomous agents that can either carry out tasks individually or, when necessary, cooperate by forming physical connections with each other. We consider a group transport scenario that involves transporting broken robots to a repair zone. Some broken robots can be transported by an individual 'rescue' robot, whereas other broken robots are heavier and therefore require the rescue robots to self-assemble into a larger and stronger composite entity. We present a distributed controller that solves this task while efficiently allocating resources. We conduct a series of real-world experiments to show that our system can i) transport separate broken robots in parallel, ii) trigger self-assembly into composite entities when necessary to overcome the physical limitations of individual agents, iii) efficiently allocate resources and iv) resolve deadlock situations. © 2011 Springer-Verlag.SCOPUS: cp.kinfo:eu-repo/semantics/publishe