Parametric POMDPs for planning in continuous state spaces

This work addresses the problem of decision-making under uncertainty for robot navigation. Since robot navigation is most naturally represented in a continuous domain, the problem is cast as a continuous-state POMDP. Probability distributions over state space, or beliefs, are represented in parametric form using low-dimensional vectors of sufficient statistics. The belief space, over which the value function must be estimated, has dimensionality equal to the number of sufficient statistics. Compared to methods based on discretising the state space, this work trades the loss of the belief space's convexity for a reduction in its dimensionality and an efficient closed-form solution for belief updates. Fitted value iteration is used to solve the POMDP. The approach is empirically compared to a discrete POMDP solution method on a simulated continuous navigation problem. We show that, for a suitable environment and parametric form, the proposed method is capable of scaling to large state-spaces. (C) 2006 Elsevier B.V. All rights reserved.