Difference between revisions of "SRSP"

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* the robotics system consists of a large group of autonomous robots;
 
* the robotics system consists of a large group of autonomous robots;
 
* robots cooperate to tackle a given task;
 
* robots cooperate to tackle a given task;
* robots are relatively homogeneous both hardware- and software-wise (i.e., they are either all identical or they belong to a few typologies);
 
 
* robots are situated in the environment and can act to modify it;
 
* robots are situated in the environment and can act to modify it;
 
* robots’ sensing and communication capabilities are local;
 
* robots’ sensing and communication capabilities are local;
 
* robots do not have access to centralized control and/or to global knowledge;
 
* robots do not have access to centralized control and/or to global knowledge;
  +
* robots are redundant;
 
* the behavior of the robot swarms results from the interactions of the robots with each other and with their environment, that is, the robot swarm self-organizes.
 
* the behavior of the robot swarms results from the interactions of the robots with each other and with their environment, that is, the robot swarm self-organizes.
   
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The characteristics of swarm robotics are deemed to promote the realization of systems which are robust, scalable and flexible.
 
The characteristics of swarm robotics are deemed to promote the realization of systems which are robust, scalable and flexible.
   
By '''robustness''', we mean that robot swarms are able to cope well with the failure of one or more of its individuals: the loss of individuals does not result in the failure of the whole swarm. Robustness is promoted by redundancy, that is, by having many homogeneous robots, and by the lack of a leader or centralized control.
+
A robot swarm is able to cope well with the failure of one or more of its individuals: the loss of individuals does not result in the failure of the whole swarm. This robustness to failures is promoted by redundancy, that is, by having many homogeneous robots, and by the lack of a leader or centralized control.
 
A robot swarms is also able to cope well with changes in its group size: the introduction or removal of individuals does not result in a drastic change in the performance of the swarm. Scalability is promoted by local sensing and communication and by the lack of a centralized control.
 
 
Finally, robot swarms are flexible, that is, are able to cope with a broad spectrum of different environment and tasks. Flexibility is promoted by redundancy, simplicity of the behaviors, the lack of global knowledge and mechanisms as, for example, task allocation.
By '''scalability''', we mean that robot swarms are able to cope well with changes in its group size: the introduction or removal of individuals does not result in a drastic change in the performance of the swarm. Scalability is promoted by local sensing and communication and by the lack of a centralized control.
 
 
By '''flexibility''', we mean that robot swarms are able to cope with a broad spectrum of different environment and tasks. Flexibility is promoted by redundancy, simplicity of the behaviors, the lack of global knowledge and mechanisms such as task allocation.
 
   
 
== Potential applications of swarm robotics systems==
 
== Potential applications of swarm robotics systems==

Revision as of 15:45, 18 September 2013

Swarm robotics studies how a large number of robots can be designed and controlled so that a desired collective behavior results from local interactions among the robots and between the robots and the environment in which they act (Dorigo and Sahin 2004; Sahin 2005). The design of swarm robotics systems is guided by swarm intelligence principles, which promote the realization of robot swarms that are robust, scalable and flexible.

Characteristics of swarm robotics

The main characteristics of a swarm robotics system are:

  • the robotics system consists of a large group of autonomous robots;
  • robots cooperate to tackle a given task;
  • robots are situated in the environment and can act to modify it;
  • robots’ sensing and communication capabilities are local;
  • robots do not have access to centralized control and/or to global knowledge;
  • robots are redundant;
  • the behavior of the robot swarms results from the interactions of the robots with each other and with their environment, that is, the robot swarm self-organizes.

Desirable properties of swarm robotics systems

The characteristics of swarm robotics are deemed to promote the realization of systems which are robust, scalable and flexible.

A robot swarm is able to cope well with the failure of one or more of its individuals: the loss of individuals does not result in the failure of the whole swarm. This robustness to failures is promoted by redundancy, that is, by having many homogeneous robots, and by the lack of a leader or centralized control. A robot swarms is also able to cope well with changes in its group size: the introduction or removal of individuals does not result in a drastic change in the performance of the swarm. Scalability is promoted by local sensing and communication and by the lack of a centralized control. Finally, robot swarms are flexible, that is, are able to cope with a broad spectrum of different environment and tasks. Flexibility is promoted by redundancy, simplicity of the behaviors, the lack of global knowledge and mechanisms as, for example, task allocation.

Potential applications of swarm robotics systems

The desired properties of swarm robotics systems make them suitable for several fields of application.

Dangerous applications

Dangerous applications expose humans to the risk of injuries or casualties. An example of such applications is demining, where human operators have to search and defuse manually land mines.

Tackling such applications with robots is a well suited solution, as this approach eliminates or reduces the risks for humans. However, since the risk of losing robots is high, a solution that is robust to failures is necessary, making dangerous applications an ideal field of application for robot swarms.

Example of dangerous applications that can be tackled using robot swarms are: demining, search and rescue, toxic cleaning, military applications.

Applications with unknown or varying size

Very often it is not possible to determine in advance the resources necessary to tackle a problem. For instance, in case of an oil leak it is very often difficult to estimate the oil output and foreseen its development. On the one hand, developing a solution for a small leak could be useless if the leak is discovered to be large or if it increases over time. On the other hand, a solution engineered for a large leak might be a waste of resources if the leak remains small.

Applications with unknown or varying size must be tackled with solutions whose scale can easily adapt such as robot swarms: robots can be added or removed to fit different requirements of the applications.

Example of applications with unknown or varying size: search and rescue, transportation of large objects, tracking, cleaning, military applications.

Applications in large and unstructured environments

Some applications take place over large extensions of space. Other applications deal with unstructured environments. Unstructured environments are usually characterized by the absence of pre-available communication networks, global localization mechanisms or detailed maps. In such cases, it is necessary to adopt solutions that do not rely on pre-available infrastructures or information.

Swarm robotics systems are well suited for applications in large and unstructured environments, since such systems can tackle them faster than single robots and without relying on local information and or any a priori infrastructure.

Examples of applications in unstructured and large environments are planetary or underwater exploration, military applications, surveillance, demining, cleaning, search and rescue.

Applications in dynamic environments

Some applications take place in environments that change over time. For instance, in a post earthquake situation, buildings can collapse changing the usable paths and creating new hazards to avoid. In applications with dynamic environments it is necessary to adopt solutions which are flexible and can react fast to events. Swarm robotics principles promote the development of flexible systems, making applications in dynamic environments an ideal field of application for robot swarms.

Example of applications in dynamic environments are surveillance, disaster recovery, search and rescue, cleaning, military applications.

Scientific implications of swarm robotics

Beside engineering applications, swarm robotics is also used as a scientific tool: in particular, many models derived from the analysis of natural swarm intelligence systems have been refined and validated using robot swarms. TODO: add a couple of examples.

Swarm robotics has been used also to investigate the evolutionary conditions for the emergence of adaptive behaviour in groups of interacting individuals. The use of robot swarms allow the researcher to identify, in a controlled environment, the evolutionary pressures that lead to complex social behaviors, such as communication (Ampatzis et al., 2008) or collective decision (Francesca et al., 2012).

Current research axis

Current research in swarm robotics is mainly focused on three axis: design, modeling and collective behaviors.

Design

The design of a robot swarm is a difficult task: requirements are usually expressed at the collective level, but, eventually, the developer needs to define what the individual robots should do so that their interactions result in the desired collective behavior.

Approaches to the design problem in swarm robotics can be divided in two categories: behavior-based design and automatic design.

Behavior-based design methods

Automatic design methods

Modeling

The analysis and verification of the properties of a robot swarm are usually done by means of models.

Most works on modeling can be categorized according to the level at which a robot swarm is analyzed: the individual level, or microscopic level, and the collective level, or macroscopic level.

Microscopic modeling

Macroscopic modeling

Collective behaviors

A large part of the research efforts in swarm robotics are directed towards the study of collective behaviors. Most collective behaviors can be categorized into four main groups: spatially organizing behaviors, navigation behaviors, collective decision-making.

Spatially organizing behaviors

Navigation behaviors

Collective decision-making

Open issues

  • Lack of an engineering methodology
  • Same as in the review?











References

E. Bonabeau, M. Dorigo, and G. Theraulaz. Swarm Intelligence: From Natural to Artificial System. Oxford University Press, New York, 1999.

J.-L. Deneubourg, S. Aron, S. Goss, and J.-M. Pasteels. The self-organizing exploratory pattern of the Argentine ant. Journal of Insect Behavior, 3:159–168, 1990.

G. Di Caro and M. Dorigo. AntNet: Distributed stigmergetic control for communications networks. Journal of Artificial Intelligence Research, 9:317–365, 1998.

M. Dorigo, V. Maniezzo, and A. Colorni. Positive feedback as a search strategy. Technical Report 91-016, Dipartimento di Elettronica, Politecnico di Milano, Milan, Italy, 1991. Revised version published as: M. Dorigo, V. Maniezzo, and A. Colorni. Ant System: Optimization by a colony of cooperating agents. IEEE Transactions on Systems, Man, and Cybernetics – Part B, 26(1):29–41, 1996.

M. Dorigo and E. Şahin (Eds.). Special Issue on Swarm Robotics. Autonomous Robots, 17:111–246.

M. Dorigo and T. Stützle. Ant Colony Optimization. MIT Press, Cambridge, MA, 2004.

J. Kennedy and R. C. Eberhart. Particle swarm optimization. Proceedings of IEEE International Conference on Neural Networks, IEEE Press, Piscataway, NJ, pp. 1942-1948, 1995.

J. Kennedy, R. C. Eberhart, and Y. Shi. Swarm Intelligence. Morgan Kaufmann, San Francisco, CA, 2001.

E. Lumer and B. Faieta. Diversity and adaptation in populations of clustering ants. Proceedings of the Third International Conference on Simulation of Adaptive Behavior: From Animals to Animats 3, MIT Press, Cambridge, CA, pp. 501-508, 1994.

R. Schoonderwoerd, O. Holland, J. Bruten and L. Rothkrantz. Ant-based Load Balancing in Telecommunications Networks. Adaptive Behavior, 5(2):169–207, 1996.

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