Using attractor dynamics to generate decentralized motion control of two mobile robots transporting a long object in coordination

Abstract

Dynamical systems theory is used here as a theoret-ical language and tool to design a distributed control architecture for a team of two mobile robots that must transport a long object and simultaneously avoid ob-stacles. In this approach the level of modeling is at the level of behaviors. A “dynamics ” of behavior is defined over a state space of behavioral variables (heading direction and path velocity). The environ-ment is also modeled in these terms by represent-ing task constraints as attractors (i.e. asymptotically stable states) or reppelers (i.e. unstable states) of behavioral dynamics. For each robot attractors and repellers are combined into a vector field that gov-erns the behavior. The resulting dynamical systems that generate the behavior of the robots may be non-linear. By design the systems are tuned so that the behavioral variables are always very close to one at-tractor. Thus the behavior of each robot is controled by a time series of asymptotically stable states. Com-puter simulations support the validity of our dynamic model architectures. 1