A Particle Filtering Based Approach to Approximating Interactive POMDPs

Prashant Doshi, Piotr J. Gmytrasiewicz

Abstract: POMDPs provide a principled framework for sequential planning in single agent settings. An extension of POMDPs to multi agent settings, called interactive POMDPs (I-POMDPs), replaces POMDP belief spaces with interactive hierarchical belief systems which represent an agent's belief about the physical world, about beliefs of the other agent(s), about their beliefs about others' beliefs, and so on. This modification makes the difficulties of obtaining solutions due to complexity of the belief and policy spaces even more acute. We describe a method for obtaining approximate solutions to IPOMDPs based on particle filtering (PF). We utilize the interactive PF which descends the levels of interactive belief hierarchies and samples and propagates beliefs at each level. The interactive PF is able to deal with the belief space complexity, but it does not address the policy space complexity. We provide experimental results and chart future work.