Distributed Behavior Trees for Heterogeneous Robot Teams

Heterogeneous Robot Teams can provide a wide range of capabilities and, therefore, significant benefits when handling a mission. However, they also require new approaches to capability and mission definition that are suitable to handle heterogeneous capabilities and allow a combination or distribution of them with a coherent representation that does not limit the individual robot. Behavior Trees (BTs) offer many of the required properties, are growing in popularity for robot control, and have been proposed for multirobot coordination, but always as separate BTs, defined in advance and without consideration for a changing team. In this paper, we propose a new Behavior Tree approach that can handle complex real-world robotic missions and is geared towards a distributed execution by providing built-in functionalities for cost calculation, subtree distribution, and data wiring. We present a formal definition, its open source implementation as ros_bt_py library, and experimental verification of its capabilities.