Risk-Sensitive Reinforcement Learning with Exponential Criteria

Fuente: arXiv
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Hauptverfasser: Noorani, Erfaun, Mavridis, Christos, Baras, John
Format: Preprint
Veröffentlicht: 2022
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author Noorani, Erfaun
Mavridis, Christos
Baras, John
author_facet Noorani, Erfaun
Mavridis, Christos
Baras, John
contents While reinforcement learning has shown experimental success in a number of applications, it is known to be sensitive to noise and perturbations in the parameters of the system, leading to high variance in the total reward amongst different episodes in slightly different environments. To introduce robustness, as well as sample efficiency, risk-sensitive reinforcement learning methods are being thoroughly studied. In this work, we provide a definition of robust reinforcement learning policies and formulate a risk-sensitive reinforcement learning problem to approximate them, by solving an optimization problem with respect to a modified objective based on exponential criteria. In particular, we study a model-free risk-sensitive variation of the widely-used Monte Carlo Policy Gradient algorithm and introduce a novel risk-sensitive online Actor-Critic algorithm based on solving a multiplicative Bellman equation using stochastic approximation updates. Analytical results suggest that the use of exponential criteria generalizes commonly used ad-hoc regularization approaches, improves sample efficiency, and introduces robustness with respect to perturbations in the model parameters and the environment. The implementation, performance, and robustness properties of the proposed methods are evaluated in simulated experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2212_09010
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Risk-Sensitive Reinforcement Learning with Exponential Criteria
Noorani, Erfaun
Mavridis, Christos
Baras, John
Systems and Control
Artificial Intelligence
Machine Learning
While reinforcement learning has shown experimental success in a number of applications, it is known to be sensitive to noise and perturbations in the parameters of the system, leading to high variance in the total reward amongst different episodes in slightly different environments. To introduce robustness, as well as sample efficiency, risk-sensitive reinforcement learning methods are being thoroughly studied. In this work, we provide a definition of robust reinforcement learning policies and formulate a risk-sensitive reinforcement learning problem to approximate them, by solving an optimization problem with respect to a modified objective based on exponential criteria. In particular, we study a model-free risk-sensitive variation of the widely-used Monte Carlo Policy Gradient algorithm and introduce a novel risk-sensitive online Actor-Critic algorithm based on solving a multiplicative Bellman equation using stochastic approximation updates. Analytical results suggest that the use of exponential criteria generalizes commonly used ad-hoc regularization approaches, improves sample efficiency, and introduces robustness with respect to perturbations in the model parameters and the environment. The implementation, performance, and robustness properties of the proposed methods are evaluated in simulated experiments.
title Risk-Sensitive Reinforcement Learning with Exponential Criteria
topic Systems and Control
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2212.09010