<title>Distributed motion planning for modular robots</title>

On the software side of modular robotics, there are many challenging steps towards the ultimate intelligent and autonomous robot module (sub-component). Examples of such challenges are to derive distributed task planning, distributed motion planning and distributed control methods. In this paper we focus on the derivation of a distributed or truly modular local motion planner. Such a motion planner must as input take tasks for the assembled modular robot and without any central intelligence deliver the necessary robot motion. More specifically, we illustrate how the method of artificial forces together with a new description of the robot kinematics can be used for developing a distributed local motion planner. The motion planner is truly distributed as the software on each module only needs information about the module itself and of modules which are physically directly connected to it. Although the method is essentially very general, we for simplicity only illustrate it for planar K-linked modular robots. We present the motion planning algorithms for link and joint processors for this special case and we show output of simulations. Furthermore, we present results from applying the motion planner to a planar truly modular robot consisting of 4 links and 4 revolute joints each with their own on-board processor.