1 research outputs found
Computing the -resilience of a Synchronized Multi-Robot System
We study an optimization problem that arises in the design of covering
strategies for multi-robot systems. Consider a team of cooperating robots
traveling along predetermined closed and disjoint trajectories. Each robot
needs to periodically communicate information to nearby robots. At places where
two trajectories are within range of each other, a communication link is
established, allowing two robots to exchange information, provided they are
"synchronized", i.e., they visit the link at the same time. In this setting a
communication graph is defined and a system of robots is called
\emph{synchronized} if every pair of neighbors is synchronized.
If one or more robots leave the system, then some trajectories are left
unattended. To handle such cases in a synchronized system, when a live robot
arrives to a communication link and detects the absence of the neighbor, it
shifts to the neighboring trajectory to assume the unattended task. If enough
robots leave, it may occur that a live robot enters a state of
\emph{starvation}, failing to permanently meet other robots during flight. To
measure the tolerance of the system under this phenomenon we define the
\emph{-resilience} as the minimum number of robots whose removal may cause
surviving robots to enter a state of starvation. We show that the problem
of computing the -resilience is NP-hard if is part of the input, even if
the communication graph is a tree. We propose algorithms to compute the
-resilience for constant values of in general communication graphs and
show more efficient algorithms for systems whose communication graph is a tree