Swarm Of Autonomous Robots Research Articles

Two different approaches to a macroscopic model of a bio-inspired robotic swarm

By compiling macroscopic models we analyze the adaptive behavior in a swarm of autonomous robots generated by a bio-inspired, distributed control algorithm. We developed two macroscopic models by taking two different perspectives: A Stock & Flow model, which is simple to implement and fast to simulate, and a spatially resolved model based on diffusion processes. These two models were compared concerning their prediction quality and their analytical power: One model allowed easy identification of the major feedback loops governing the swarm behavior. The other model allowed analysis of the expected shapes and positions of observable robot clusters. We found a high correlation in the challenges posed by both modeling techniques and we highlighted the inherent problems of inferring emergent macroscopic rules from a microscopic description of swarm behavior.

Overview of networking protocols for underwater wireless communications

Underwater wireless communications can enable many scientific, environmental, commercial, safety, and military applications. Wireless signal transmission is also crucial to remotely control instruments in ocean observatories and to enable coordination of swarms of autonomous underwater vehicles and robots, which will play the role of mobile nodes in future ocean observation networks by virtue of their flexibility and reconfigurability. To make underwater applications viable, efficient communication protocols among underwater devices, which are based on acoustic wireless technology for distances over one hundred meters, must be enabled because of the high attenuation and scattering that affect radio and optical waves, respectively. The unique characteristics of an underwater acoustic channel - such as very limited and distance-dependent bandwidth, high propagation delays, and time-varying multipath and fading - require new, efficient and reliable communication protocols to network multiple devices, either static or mobile, potentially over multiple hops. In this article, we provide an overview of recent medium access control, routing, transport, and cross-layer networking protocols.

Distributed algorithms for partitioning a swarm of autonomous mobile robots

A number of recent studies address systems of mobile autonomous robots from a distributed computing point of view. Although such systems employ robots that are relatively weak and simple (i.e., dimensionless, oblivious and anonymous), they are nevertheless expected to have strong fault tolerance capabilities as a group. This paper studies the partitioning problem, where n robots must divide themselves into k size-balanced groups, and examines the impact of common orientation on the solvability of this problem. First, deterministic crash-fault-tolerant algorithms are given for the problem in the asynchronous full-compass and semi-synchronous half-compass models, and a randomized algorithm is given for the semi-synchronous no-compass model. Next, the role of common orientation shared by the robots is examined. Necessary and sufficient conditions for the partitioning problem to be solvable are given in the different timing models. Finally, the problem is proved to be unsolvable in the no-compass synchronous model.

A geometric approach to deploying robot swarms

We discuss the fundamental problems and practical issues underlying the deployment of a swarm of autonomous mobile robots that can potentially be used to build mobile robotic sensor networks. For the purpose, a geometric approach is proposed that allows robots to configure themselves into a two-dimensional plane with uniform spatial density. Particular emphasis is paid to the hole repair capability for dynamic network reconfiguration. Specifically, each robot interacts selectively with two neighboring robots so that three robots can converge onto each vertex of the equilateral triangle configuration. Based on the local interaction, the self-configuration algorithm is presented to enable a swarm of robots to form a communication network arranged in equilateral triangular lattices by shuffling the neighbors. Convergence of the algorithms is mathematically proved using Lyapunov theory. Moreover, it is verified that the self-reparation algorithm enables robot swarms to reconfigure themselves when holes exist in the network or new robots are added to the network. Through extensive simulations, we validate the feasibility of applying the proposed algorithms to self-configuring a network of mobile robotic sensors. We describe in detail the features of the algorithm, including self-organization, self-stabilization, and robustness, with the results of the simulation.

自律移動ロボットの群移動制御のための座標系平均化手法

Previously, the authors have proposed a scheme for collective control of a swarm of autonomous mobile robots. It enables a human operator to effectively control the geometrical center of the swarm only via bird-view observation and a broadcast command. However, for such control, it seems necessary that the operator and the every agent of the swarm refers to the same coordinate system. In this paper, first, the influences of deviations of coordinates among the operator and the agents due to dead-reckoning are examined theoretically. The result shows that, though the deviation between the operator and the average of the agents can easily be compensated by the operator, those among the agents lead to poor maneuverability and performance of the collective manual control. Thus, a method called COMPASS-CC is introduced which can merge the coordinate systems close enough among all the agents in a fully distributed way and without any global localization scheme, by extending the previously proposed method COMPASS. Besides, its effectiveness is analyzed both theoretically and by simulation. The equation for the practical estimation of the steady-state performance is derived and verified. Finally, the validity of the method is confirmed through manual control experiments using a swarm control simulator.

Physics Simulation Environment for Swarms of Self-Assembly Autonomous Robots

Autonomous robots capable of independently moving about on rough terrain and capable of gathering and physically connecting to each other so as to form a collective entity acting as a whole is a rather new research topic in mechatronics. The work presented here shows how such devices called swarmbots are being simulated using Swarmbot3d, a programming environment specifically developed for them. Experiments show how close the response of the simulated robot is with respect to that given by the real devices.

Adaptive Shape Reconfiguration of a Decentralized Motile System Exploiting Molecular Dynamics and Stokesian Dynamics Methods

This paper discusses a fully decentralized algorithm able to create a coherent swarm of autonomous mobile robots from the viewpoint of computational physics. To this end, we focus on Molecular Dynamics and Stokesian Dynamics, both of which are widely used to investigate many-body systems. To verify the feasibility of our approach, this idea has been implemented to a swarm of 2-D radio-connected autonomous mobile robots as a practical example. Simulation results indicate that the proposed algorithm can control the shape of the swarm appropriately based on the current situation without losing the coherence of the swarm nor exchanging global information among modules. Furthermore, we found that local interaction used to exploit Stokesian Dynamics plays an essential role to maintain the coherence of the swarm particularly in an unstructured environment.