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A Scalable Method for Solving High-Dimensional Continuous POMDPs Using Local Approximation
Proceedings of the 26th Conference on Uncertainty in Artificial Intelligence, PMLR R8:176-183, 2010.
Abstract
Partially-Observable Markov Decision Processes (POMDPs) are typically solved by finding an approximate global solution to a corresponding belief-MDP. In this paper, we offer a new plan- ning algorithm for POMDPs with continuous state, action and observation spaces. Since such domains have an inherent notion of locality, we can find an approximate solution using local op- timization methods. We parameterize the belief distribution as a Gaussian mixture, and use the Extended Kalman Filter (EKF) to approximate the belief update. Since the EKF is a first-order filter, we can marginalize over the observations analytically. By using feedback control and state estimation during policy execution, we recover a behavior that is effectively conditioned on in- coming observations despite the unconditioned planning. Local optimization provides no guar- antees of global optimality, but it allows us to tackle domains that are at least an order of mag- nitude larger than the current state-of-the-art. We demonstrate the scalability of our algorithm by considering a simulated hand-eye coordination domain with 16 continuous state dimensions and 6 continuous action dimensions.