A useful metric for modular robot motion planning

In this paper we examine the problem of dynamic self-reconfiguration of a class of modular robotic systems referred to as metamorphic systems. A metamorphic robotic system is a collection of mechatronic modules, each of which has the ability to connect, disconnect, and climb over adjacent modules. We define a concept of distance between metamorphic robot configurations which satisfies the formal properties of a metric. This metric, called the optimal assignment metric, is then applied to the automatic self-reconfiguration of metamorphic systems from any initial to any final specified configuration. The technique of simulated annealing is used to drive the re-configuration process with the optimal assignment metric as the cost function. By driving the distance between the present and the goal configuration to zero, sequences of configurations are generated.