Territorial and Effective Task Decomposition for Rearrangement Planning of Multiple Objects by Multiple Mobile Robots

Abstract

In this paper, we address a rearrangement task planning problem. The method proposed here is suitable for various environments with narrow corridors, and an unbalanced arrangement of robots and objects. As the solution space is too large for the search method to be applied directly, we will limit the search space. The proposed method develops an initial plan by using a simple rule and improves the task decomposition of the initial plan. That is, it effectively determines which object should be transported where. We employ the concept of the critical path method to select the task that should be modified and the concept of a territorial approach to set up new task decomposition. New task decomposition is set up so that a robot can operate without considering the movement of other robots. These concepts render our method fast. The proposed method is tested in a simulated environment with up to four robots and 12 movable objects. The simulation results show that in a feasible calculation time, our method can reduce the task time by 10% as compared to the previous method. In particular, the proposed method is much more applicable to the working environments than was the previous method.