332 research outputs found
Petri Net Plans A framework for collaboration and coordination in multi-robot systems
Programming the behavior of multi-robot systems is a challenging task which has a key role in developing effective systems in many application domains. In this paper, we present Petri Net Plans (PNPs), a language based on Petri Nets (PNs), which allows for intuitive and effective robot and multi-robot behavior design. PNPs are very expressive and support a rich set of features that are critical to develop robotic applications, including sensing, interrupts and concurrency. As a central feature, PNPs allow for a formal analysis of plans based on standard PN tools. Moreover, PNPs are suitable for modeling multi-robot systems and the developed behaviors can be executed in a distributed setting, while preserving the properties of the modeled system. PNPs have been deployed in several robotic platforms in different application domains. In this paper, we report three case studies, which address complex single robot plans, coordination and collaboration
A Hybrid Multi-Robot Control Architecture
Multi-robot systems provide system redundancy and enhanced capability versus single robot systems. Implementations of these systems are varied, each with specific design approaches geared towards an application domain. Some traditional single robot control architectures have been expanded for multi-robot systems, but these expansions predominantly focus on the addition of communication capabilities. Both design approaches are application specific and limit the generalizability of the system. This work presents a redesign of a common single robot architecture in order to provide a more sophisticated multi-robot system. The single robot architecture chosen for application is the Three Layer Architecture (TLA). The primary strength of TLA is in the ability to perform both reactive and deliberative decision making, enabling the robot to be both sophisticated and perform well in stochastic environments. The redesign of this architecture includes incorporation of the Unified Behavior Framework (UBF) into the controller layer and an addition of a sequencer-like layer (called a Coordinator) to accommodate the multi-robot system. These combine to provide a robust, independent, and taskable individual architecture along with improved cooperation and collaboration capabilities, in turn reducing communication overhead versus many traditional approaches. This multi-robot systems architecture is demonstrated on the RoboCup Soccer Simulator showing its ability to perform well in a dynamic environment where communication constraints are high
Arquitectura para coordenação em tempo-real de múltiplas unidades móveis autónomas
Doutoramento em Engenharia ElectrotécnicaInterest on using teams of mobile robots has been growing, due to their
potential to cooperate for diverse purposes, such as rescue, de-mining,
surveillance or even games such as robotic soccer. These applications require
a real-time middleware and wireless communication protocol that can support
an efficient and timely fusion of the perception data from different robots as well
as the development of coordinated behaviours. Coordinating several
autonomous robots towards achieving a common goal is currently a topic of
high interest, which can be found in many application domains. Despite these
different application domains, the technical problem of building an infrastructure
to support the integration of the distributed perception and subsequent
coordinated action is similar. This problem becomes tougher with stronger
system dynamics, e.g., when the robots move faster or interact with fast
objects, leading to tighter real-time constraints.
This thesis work addressed computing architectures and wireless
communication protocols to support efficient information sharing and
coordination strategies taking into account the real-time nature of robot
activities. The thesis makes two main claims. Firstly, we claim that despite the
use of a wireless communication protocol that includes arbitration mechanisms,
the self-organization of the team communications in a dynamic round that also
accounts for variable team membership, effectively reduces collisions within the
team, independently of its current composition, significantly improving the
quality of the communications. We will validate this claim in terms of packet
losses and communication latency. We show how such self-organization of the
communications can be achieved in an efficient way with the Reconfigurable
and Adaptive TDMA protocol.
Secondly, we claim that the development of distributed perception, cooperation
and coordinated action for teams of mobile robots can be simplified by using a
shared memory middleware that replicates in each cooperating robot all
necessary remote data, the Real-Time Database (RTDB) middleware. These
remote data copies, which are updated in the background by the selforganizing
communications protocol, are extended with age information
automatically computed by the middleware and are locally accessible through
fast primitives. We validate our claim showing a parsimonious use of the
communication medium, improved timing information with respect to the shared
data and the simplicity of use and effectiveness of the proposed middleware
shown in several use cases, reinforced with a reasonable impact in the Middle
Size League of RoboCup.O interesse na utilização de equipas multi-robô tem vindo a crescer, devido ao
seu potencial para cooperarem na resolução de vários problemas, tais como
salvamento, desminagem, vigilância e até futebol robótico. Estas aplicações
requerem uma infraestrutura de comunicação sem fios, em tempo real,
suportando a fusão eficiente e atempada dos dados sensoriais de diferentes
robôs bem como o desenvolvimento de comportamentos coordenados. A
coordenação de vários robôs autónomos com vista a um dado objectivo é
actualmente um tópico que suscita grande interesse, e que pode ser
encontrado em muitos domínios de aplicação. Apesar das diferenças entre
domínios de aplicação, o problema técnico de construir uma infraestrutura para
suportar a integração da percepção distribuída e das acções coordenadas é
similar. O problema torna-se mais difícil à medida que o dinamismo dos robôs
se acentua, por exemplo, no caso de se moverem mais rápido, ou de
interagirem com objectos que se movimentam rapidamente, dando origem a
restrições de tempo-real mais apertadas.
Este trabalho centrou-se no desenvolvimento de arquitecturas computacionais
e protocolos de comunicação sem fios para suporte à partilha de informação e
à realização de acções coordenadas, levando em consideração as restrições
de tempo-real. A tese apresenta duas afirmações principais. Em primeiro
lugar, apesar do uso de um protocolo de comunicação sem fios que inclui
mecanismos de arbitragem, a auto-organização das comunicações reduz as
colisões na equipa, independentemente da sua composição em cada
momento. Esta afirmação é validada em termos de perda de pacotes e latência
da comunicação. Mostra-se também como a auto-organização das
comunicações pode ser atingida através da utilização de um protocolo TDMA
reconfigurável e adaptável sem sincronização de relógio.
A segunda afirmação propõe a utilização de um sistema de memória
partilhada, com replicação nos diferentes robôs, para suportar o
desenvolvimento de mecanismos de percepção distribuída, fusão sensorial,
cooperação e coordenação numa equipa de robôs. O sistema concreto que foi
desenvolvido é designado como Base de Dados de Tempo Real (RTDB). Os
dados remotos, que são actualizados de forma transparente pelo sistema de
comunicações auto-organizado, são estendidos com a respectiva idade e são
disponibilizados localmente a cada robô através de primitivas de acesso
eficientes. A RTDB facilita a utilização parcimoniosa da rede e bem como a
manutenção de informação temporal rigorosa. A simplicidade da integração da
RTDB para diferentes aplicações permitiu a sua efectiva utilização em
diferentes projectos, nomeadamente no âmbito do RoboCup
MASL: a Language for Multi-Agent System
The classical approach for Multi-Agent System (MAS) Control, especially autonomous and robotic ones, deals first from a microscopic point of view: each agent embed a control program with communication/synchronization primitives that enable cooperation between agents. The emergence of a global behaviour from a macroscopic point of view can only be observed afterwards. In this context, MASL offers a macroscopic and unified approach with heterogeneous and distributed calculations over deliberative, reactive or hybrid agents. In this high level language, regardless of the runtime, each concurrent agent locally decides its participation in a collective execution block named an e-block. Each e-block is an anonymous collective program that runs over an agent network following local conditions. The orchestral mode (scalar, asynchronous, synchronous) is statically fixed by a shared block attribute. The communication use shared memory, events, synchronous messages passing, and asynchronous messages passing. Heterogeneous agents are managed with heritage and polymorphism. Permeability mechanism, dealing with agent autonomy, allows an agent to dynamically filter calls to its interface in respects to the sender position in the e-block hierarchy. In dynamic task allocation of agents, auto failover and recovery, agent replacement in a robot fleet (case of agent failure, loss of a mandatory functionality for the mission) an e-block is an entry point of a collaborative work. In the case of synchronous e-block, the programming paradigm is the data parallel model with iterative task for waves of agents. Finally, MASL offers advances in the field of MAS (dynamic belonging to groups, accuracy of the pace of actions to undertake to enable a desired cooperation) and for the management of errors
Towards Collaborative Simultaneous Localization and Mapping: a Survey of the Current Research Landscape
Motivated by the tremendous progress we witnessed in recent years, this paper
presents a survey of the scientific literature on the topic of Collaborative
Simultaneous Localization and Mapping (C-SLAM), also known as multi-robot SLAM.
With fleets of self-driving cars on the horizon and the rise of multi-robot
systems in industrial applications, we believe that Collaborative SLAM will
soon become a cornerstone of future robotic applications. In this survey, we
introduce the basic concepts of C-SLAM and present a thorough literature
review. We also outline the major challenges and limitations of C-SLAM in terms
of robustness, communication, and resource management. We conclude by exploring
the area's current trends and promising research avenues.Comment: 44 pages, 3 figure
Multi-robot coordination using flexible setplays : applications in RoboCup's simulation and middle-size leagues
Tese de Doutoramento. Engenharia Informática. Faculdade de Engenharia. Universidade do Porto. 201
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