Results 1 - 10
of
30
Controlling connectivity of dynamic graphs,” in
- Proc. 44th IEEE Conference on Decision and Control and European Control Conference,
, 2005
"... Abstract Dynamic networks have recently emerged as an efficient way to model various forms of interaction within teams of mobile agents, such as sensing and communication. This article focuses on the use of graphs as models of wireless communications. In this context, graphs have been used widely i ..."
Abstract
-
Cited by 60 (5 self)
- Add to MetaCart
(Show Context)
Abstract Dynamic networks have recently emerged as an efficient way to model various forms of interaction within teams of mobile agents, such as sensing and communication. This article focuses on the use of graphs as models of wireless communications. In this context, graphs have been used widely in the study of robotic and sensor networks and have provided an invaluable modeling framework to address a number of coordinated tasks ranging from exploration, surveillance and reconnaissance, to cooperative construction and manipulation. In fact, the success of these stories has almost always relied on efficient information exchange and coordination between the members of the team, as seen, e.g., in the case of distributed state agreement where multi-hop communication has been proven necessary for convergence and performance guarantees.
Unifying geometric, probabilistic, and potential field approaches to multi-robot coverage control
- In Proc. ISRR
, 2009
"... This paper unifies and extends several different existing strategies for deploying groups of robots in an environment. A cost function is proposed that can be specialized to represent widely different multi-robot deployment tasks. It is shown that geometric and probabilistic deployment strategies th ..."
Abstract
-
Cited by 17 (4 self)
- Add to MetaCart
This paper unifies and extends several different existing strategies for deploying groups of robots in an environment. A cost function is proposed that can be specialized to represent widely different multi-robot deployment tasks. It is shown that geometric and probabilistic deployment strategies that were previously seen as distinct are in fact related through this cost function, and differ only in the value of a single parameter. These strategies are also related to potential field based controllers through the same cost function, though the relationship is not as simple. Distributed controllers are then obtained from the gradient of the cost function and are proved to converge to a local minimum of the cost function. Three special cases are derived as examples: a Voronoi based coverage control task, a probabilistic minimum variance task, and a task using artificial potential fields. The performance of the three different controllers are compared in simulation. A result is also proved linking multi-robot deployment to nonconvex optimization problems, and multi-robot consensus (i.e. all robots moving to the same point) to convex optimization problems, which implies that multi-robot deployment is inherently more difficult than multi-robot consensus. 1
Stabilization of a hierarchical formation of unicycle robots with velocity and curvature constraints
- IEEE Transactions on Robotics
, 2009
"... [30] H. Xiong, “Geometric mechanics, ideal hydrodynamics, and the locomo- ..."
Abstract
-
Cited by 9 (4 self)
- Add to MetaCart
[30] H. Xiong, “Geometric mechanics, ideal hydrodynamics, and the locomo-
1 Network Connectivity Preserving Formation Stabilization and Obstacle Avoidance via A Decentralized Controller
"... Abstract — A decentralized control method is developed to enable a group of agents to achieve a desired global configuration while maintaining global network connectivity and avoiding obstacles, using only local feedback and no radio communication between the agents for navigation. By modeling the i ..."
Abstract
-
Cited by 7 (4 self)
- Add to MetaCart
(Show Context)
Abstract — A decentralized control method is developed to enable a group of agents to achieve a desired global configuration while maintaining global network connectivity and avoiding obstacles, using only local feedback and no radio communication between the agents for navigation. By modeling the interaction among the agents as a graph, and given a connected initial graph with a desired neighborhood between agents, the developed method ensures the desired communication links remain connected for all time. To guide the agents to a desired configuration while avoiding obstacles, a decentralized controller is developed based on the navigation function formalism. By proving that the proposed controller is a qualified navigation function, convergence to the desired formation is guaranteed. I.
A Gradient Optimization Approach to Adaptive multi-robot control
, 2009
"... This thesis proposes a unified approach for controlling a group of robots to reach a goal configuration in a decentralized fashion. As a motivating example, robots are controlled to spread out over an environment to provide sensor coverage. This example gives rise to a cost function that is shown to ..."
Abstract
-
Cited by 7 (2 self)
- Add to MetaCart
This thesis proposes a unified approach for controlling a group of robots to reach a goal configuration in a decentralized fashion. As a motivating example, robots are controlled to spread out over an environment to provide sensor coverage. This example gives rise to a cost function that is shown to be of a surprisingly general nature. By changing a single free parameter, the cost function captures a variety of different multi-robot objectives which were previously seen as unrelated. Stable, distributed controllers are generated by taking the gradient of this cost function. Two fundamental classes of multi-robot behaviors are delineated based on the convexity of the underlying cost function. Convex cost functions lead to consensus (all robots move to the same position), while any other behavior requires a nonconvex cost function. The multi-robot controllers are then augmented with a stable on-line learning mechanism to adapt to unknown features in the environment. In a sensor cover-age application, this allows robots to learn where in the environment they are most needed, and to aggregate in those areas. The learning mechanism uses communica-
A Framework for Decentralised Feedback Connectivity Control with Application to Sensor Networks
, 2009
"... In this paper we propose a decentralised algorithm for connectivity maintenance in a distributed sensor network. Our algorithm uses the dynamics of a consensus algorithm to estimate the connectivity of a network topology in a decentralised manner. These estimates are then used to inform a decentrali ..."
Abstract
-
Cited by 6 (3 self)
- Add to MetaCart
In this paper we propose a decentralised algorithm for connectivity maintenance in a distributed sensor network. Our algorithm uses the dynamics of a consensus algorithm to estimate the connectivity of a network topology in a decentralised manner. These estimates are then used to inform a decentralised control algorithm that regulates the network connectivity to some desired level. Under certain realistic assumptions we show the closed loop dynamics can be described as a consensus algorithm with an input, and eventually reduces to a scalar system. Bounds are given to ensure the stability of the algorithm and examples are given to illustrate the efficacy of the proposed algorithm.
Adaptive exploitation of multipath fading for mobile sensors
- In IEEE International Conference on Robotics and Automation (ICRA
, 1934
"... Abstract-Mobile wireless sensors in indoor environments will experience multipath fading, causing rapid variations in the capacity of the radio link. We present a strategy that increases the throughput by modifying the trajectory of the sensor so it spends more time at positions where the capacity ..."
Abstract
-
Cited by 5 (0 self)
- Add to MetaCart
(Show Context)
Abstract-Mobile wireless sensors in indoor environments will experience multipath fading, causing rapid variations in the capacity of the radio link. We present a strategy that increases the throughput by modifying the trajectory of the sensor so it spends more time at positions where the capacity is high. While doing so, it still maintains some desired average velocity. Our approach includes closed-loop estimation of the parameters of the fading, which may change when moving between rooms. We prove stability of the feedback system and illustrate its behavior through simulations. Finally, we demonstrate robustness to errors in the channel model.
Distributed real-time fault detection and isolation for cooperative multi-agent systems
- in American Control Conference (ACC), 2012. IEEE
"... Abstract-In this paper we propose a distributed real-time fault detection, isolation and mitigation framework for multiagent systems performing cooperative tasks. Various system models and detection schemes with respect to communication and sensing are considered. Two communication protocols for fa ..."
Abstract
-
Cited by 2 (0 self)
- Add to MetaCart
(Show Context)
Abstract-In this paper we propose a distributed real-time fault detection, isolation and mitigation framework for multiagent systems performing cooperative tasks. Various system models and detection schemes with respect to communication and sensing are considered. Two communication protocols for fault detection are introduced first and proved to be effective. Then a scheme based on limited relative state measurements is developed. Furthermore, we propose fault isolation and mitigation steps to guarantee the accomplishment of a global objective. All schemes are distributed in the sense that at each step of the fault detection, isolation and mitigation every agent only uses locally available information. One key feature of the framework is the significant reduction of required computational resource when compared with the fault detection and isolation schemes based on unknown input observers. Later we show that the proposed framework can be applied to the consensus and other cooperative formation problems. Several computer simulations are presented to demonstrate the efficiency of the framework.
