A Hybrid Two-layered Approach to Real-Time Motion Planning of Multiple Agents in Virtual Environments

Abstract

We proposed in a previous paper a hybrid technique, combining local steering behaviors and Coordination Graphs (CG), that allows real-time motion planning of multiple agents in a narrow passage. This hybrid technique not only avoids deadlocks, but also exhibits other interesting behaviors such as Leader Following, even though they are not explicitly coded in the algorithm. In this paper, we build upon the earlier result, and propose a two-layered approach to motion planning of multiple agents in virtual environments, consisting of open spaces connected by multiple narrow passages. The Discrete Generalized Voronoi Diagram (GVD) of the static environment is used to identify all narrow passages automatically. The global path of each agent is also planned using the GVD. As each agent moves along its global path, it is locally modified using the hybrid technique combining steering behaviors with Coordination Graphs. Experimental results show that the resulting planner is able to plan motions of 30 agents in a virtual environment with three narrow passages in real-time, and the pre-processing phase of our approach is extremely fast. Since all planning is done in real-time, the approach allows an agent to change its final destination at runtime.