GORITE: A BDI Realisation of Behavior Trees

Abstract

Behavior trees are becoming increasingly used in both the computer games and robotics industries as a mechanism for non-programmers to specify individual entity (non-playing character or robot) behaviors. The tree representation that is employed is amenable to graphical representation and the availability of graphical editors has contributed significantly to the uptake of the approach. Working with graphical representations of behavior makes development by non-programmers easier. However, existing behavior tree representations are limited in their ability to represent team behavior and complex entity reasoning. Agent frameworks exist that address these issues and while they have been successfully employed in military war gaming applications, the underlying behavior representation that they use are fundamentally different to behavior trees. In this paper, we introduce GORITE, a BDI agent framework in which agent behavior is specified using goal-based process models which are representationally similar to behavior trees. Unlike behavior trees, process models can be used to represent both individual and team behaviors. Furthermore, GORITE provides support to enable an agent (or team of agents) to reason about the goals that it intends to pursue as well as the goals that it is currently pursuing. A simple example is used to demonstrate how team behavior can be modelled using GORITE process models.