420 research outputs found
A tuple space for data sharing in robot swarms
In this paper, we present a system to allow a swarm of robots to agree on a set of (key,value) pairs. This system enables a form of information sharing that has the potential to be an asset for coordination in complex environments, such as globally optimized task allocation. Taking inspiration from the environment-mediated communication of social insects, we call the system virtual stigmergy. Experimental evaluation indicates that virtual stigmergy can work in a wide variety of running conditions including heavy packet loss, and can cope with random motion trajectories
Towards formal models and languages for verifiable Multi-Robot Systems
Incorrect operations of a Multi-Robot System (MRS) may not only lead to
unsatisfactory results, but can also cause economic losses and threats to
safety. These threats may not always be apparent, since they may arise as
unforeseen consequences of the interactions between elements of the system.
This call for tools and techniques that can help in providing guarantees about
MRSs behaviour. We think that, whenever possible, these guarantees should be
backed up by formal proofs to complement traditional approaches based on
testing and simulation.
We believe that tailored linguistic support to specify MRSs is a major step
towards this goal. In particular, reducing the gap between typical features of
an MRS and the level of abstraction of the linguistic primitives would simplify
both the specification of these systems and the verification of their
properties. In this work, we review different agent-oriented languages and
their features; we then consider a selection of case studies of interest and
implement them useing the surveyed languages. We also evaluate and compare
effectiveness of the proposed solution, considering, in particular, easiness of
expressing non-trivial behaviour.Comment: Changed formattin
Collision-aware Task Assignment for Multi-Robot Systems
We propose a novel formulation of the collision-aware task assignment (CATA)
problem and a decentralized auction-based algorithm to solve the problem with
optimality bound. Using a collision cone, we predict potential collisions and
introduce a binary decision variable into the local reward function for task
bidding. We further improve CATA by implementing a receding collision horizon
to address the stopping robot scenario, i.e. when robots are confined to their
task location and become static obstacles to other moving robots. The
auction-based algorithm encourages the robots to bid for tasks with collision
mitigation considerations. We validate the improved task assignment solution
with both simulation and experimental results, which show significant reduction
of overlapping paths as well as deadlocks
Towards adaptive multi-robot systems: self-organization and self-adaptation
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The development of complex systems ensembles that operate in uncertain environments is a major challenge. The reason for this is that system designers are not able to fully specify the system during specification and development and before it is being deployed. Natural swarm systems enjoy similar characteristics, yet, being self-adaptive and being able to self-organize, these systems show beneficial emergent behaviour. Similar concepts can be extremely helpful for artificial systems, especially when it comes to multi-robot scenarios, which require such solution in order to be applicable to highly uncertain real world application. In this article, we present a comprehensive overview over state-of-the-art solutions in emergent systems, self-organization, self-adaptation, and robotics. We discuss these approaches in the light of a framework for multi-robot systems and identify similarities, differences missing links and open gaps that have to be addressed in order to make this framework possible
Guided Deep Reinforcement Learning for Swarm Systems
In this paper, we investigate how to learn to control a group of cooperative
agents with limited sensing capabilities such as robot swarms. The agents have
only very basic sensor capabilities, yet in a group they can accomplish
sophisticated tasks, such as distributed assembly or search and rescue tasks.
Learning a policy for a group of agents is difficult due to distributed partial
observability of the state. Here, we follow a guided approach where a critic
has central access to the global state during learning, which simplifies the
policy evaluation problem from a reinforcement learning point of view. For
example, we can get the positions of all robots of the swarm using a camera
image of a scene. This camera image is only available to the critic and not to
the control policies of the robots. We follow an actor-critic approach, where
the actors base their decisions only on locally sensed information. In
contrast, the critic is learned based on the true global state. Our algorithm
uses deep reinforcement learning to approximate both the Q-function and the
policy. The performance of the algorithm is evaluated on two tasks with simple
simulated 2D agents: 1) finding and maintaining a certain distance to each
others and 2) locating a target.Comment: 15 pages, 8 figures, accepted at the AAMAS 2017 Autonomous Robots and
Multirobot Systems (ARMS) Worksho
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