Person:

Egerstedt, Magnus B.

Permanent Link

https://hdl.handle.net/1853/72204

Associated Organization(s)

Organizational Unit

School of Electrical and Computer Engineering

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Publication Search Results

Now showing 1 - 10 of 15

Topology-Induced Connectivity Bounds in Leader-Follower Networks

(Georgia Institute of Technology, 2010-01) Gustavi, Tove ; Dimarogonas, Dimos V. ; Egerstedt, Magnus B. ; Hu, Xiaoming

In this paper we derive a set of constraints that are sufficient to guarantee maintained connectivity in a leader-follower multi- agent network with proximity based communication topology. In the scenario we consider, only the leaders are aware of the global mission, which is to converge to a known destination point. Thus, the followers need to stay in contact with the group of leaders in order to reach the goal. In the paper we show that we can maintain the initial network structure, and thereby connectivity, by setting up bounds on the ratio of leaders-to-followers and on the magnitude of the goal attraction force experienced by the leaders. The results are first established for an initially complete communication graph and then extended to an incomplete graph. The results are illustrated by computer simulations.
On the Number of Leaders Needed to Ensure Network Connectivity in Arbitrary Dimensions

(Georgia Institute of Technology, 2009-06) Gustavi, Tove ; Dimarogonas, Dimos V. ; Egerstedt, Magnus B. ; Hu, Xiaoming

We examine the leader-to-follower ratio needed to maintain connectivity in a leader-follower multi-agent network with proximity based communication topology. The paper extends the one-dimensional results of [2] to the two dimensional case. In the scenario we consider, only the leaders are aware of the global mission, which is to converge to a known destination point. Thus, the objective of the leaders is to drag the team to the desired goal. In the paper we obtain bounds on the number of leaders needed to complete the task. The results are first established for an initially complete communication graph and then extended to the incomplete case. Computer simulations support the derived theory.
A Control Lyapunov Function Approach to Multi-Agent Coordination

(Georgia Institute of Technology, 2002-10) Ögren, Petter ; Egerstedt, Magnus B. ; Hu, Xiaoming

In this paper, the multiagent coordination problem is studied. This problem is addressed for a class of robots for which control Lyapunov functions can be found. The main result is a suite of theorems about formation maintenance, task completion time, and formation velocity. It is also shown how to moderate the requirement that, for each individual robot, there exists a control Lyapunov function. An example is provided that illustrates the soundness of the method.
Formation Control Under Limited Sensory Range Constraints

(Georgia Institute of Technology, 2002-07) Egerstedt, Magnus B. ; Abubakr, M. ; Hu, Xiaoming

Based on the assumption that all robots in a given multi-agent scenario can evaluate a global formation function, we show how a model independent coordination strategy for multi-agent formation control can be obtained. The main theorem states that under a bounded tracking error assumption out method stabilizes the formation error. We furthermore complement this result with an investigation of how limited sensory range capabilities affect the group performance.
A Hybrid Control Approach to Action Coordination for Mobile Robots

(Georgia Institute of Technology, 2002-01) Egerstedt, Magnus B. ; Hu, Xiaoming

In this paper, the problem concerning how to coordinate the contributions from concurrent controllers, when controlling mobile robots, is investigated. It is shown how a behavior based control system for autonomous robots can be modeled as a hybrid automaton, where each node corresponds to a distinct robot behavior. This type of construction gives rise to chattering executions, but it is shown how regularized automata can be used to solve this problem. As an illustration, the obstacle-negotiation problem is solved by using a combination of a robust path-following behavior and a reactive obstacle-avoidance behavior that move the robot around a given obstacle at a predefined safety distance.
A Control Lyapunov Function Approach to Multi-Agent Coordination

(Georgia Institute of Technology, 2001-12) Ögren, Petter ; Egerstedt, Magnus B. ; Hu, Xiaoming

In this paper, the multi-agent coordination problem is studied. This problem is addressed for a class of robots for which control Lyapunov functions can be found. The main result is a suite of theorems about formation maintenance, task completion time, and formation velocity. It is also shown how to moderate the requirement that, for each individual robot, there exists a control Lyapunov function. An example is provided that illustrates the soundness of the method.
Formation Constrained Multi-Agent Control

(Georgia Institute of Technology, 2001-12) Egerstedt, Magnus B. ; Hu, Xiaoming

We propose a model independent coordination strategy for multi-agent formation control. The main theorem states that under a bounded tracking error assumption our method stabilizes the formation error. We illustrate the usefulness of the method by applying it to rigid body constrained motions.
Control of Mobile Platforms Using a Virtual Vehicle Approach

(Georgia Institute of Technology, 2001-11) Egerstedt, Magnus B. ; Hu, Xiaoming ; Stotsky, A.

Two model independent solutions to the problem of controlling wheel-based mobile platforms are proposed. These two algorithms are based on a so called virtual vehicle approach, where the motion of the reference point on the desired trajectory is governed by a differential equation containing error feedback. This, combined with the fact that the proven stable control algorithms are basically proportional regulators with arbitrary positive gains, make the solutions robust with respect to errors and disturbances, as demonstrated by the experimental results.
Formation Constrained Multi-Agent Control

(Georgia Institute of Technology, 2001-05) Egerstedt, Magnus B. ; Hu, Xiaoming

We propose a model independent coordination strategy for multi-agent formation control. The main theorem states that under a bounded tracking error assumption our method stabilizes the formation error. We illustrate the usefulness of the method by applying it to rigid body constrained motions, as well as to mobile manipulation.
Reactive Mobile Manipulation: Design and Implementation

(Georgia Institute of Technology, 2000-12) Ögren, Petter ; Egerstedt, Magnus B. ; Hu, Xiaoming

A solution to the trajectory tracking problem for mobile manipulators is proposed and implemented on a real robotic system. Given a trajectory for the gripper to follow, a tracking algorithm for the manipulator is designed, and at the same time the base motions are generated in such a way that the base is coordinated with the gripper while reactively avoiding obstacles. Furthermore, it is shown that the method allows arbitrary upper and lower bounds on the gripper-base distance to be set, and this can be achieved without introducing deadlocks into the system.