Model-Based Policy Gradients with Parameter-Based Exploration by Least-Squares Conditional Density Estimation
This work addresses the problem of sample efficiency in reinforcement learning for agents operating in unknown environments, presenting an incremental improvement by integrating existing techniques.
The paper tackles the challenge of expensive data collection in reinforcement learning by proposing a model-based method that combines policy gradients with parameter-based exploration and least-squares conditional density estimation for transition modeling, demonstrating practical usefulness in experiments.
The goal of reinforcement learning (RL) is to let an agent learn an optimal control policy in an unknown environment so that future expected rewards are maximized. The model-free RL approach directly learns the policy based on data samples. Although using many samples tends to improve the accuracy of policy learning, collecting a large number of samples is often expensive in practice. On the other hand, the model-based RL approach first estimates the transition model of the environment and then learns the policy based on the estimated transition model. Thus, if the transition model is accurately learned from a small amount of data, the model-based approach can perform better than the model-free approach. In this paper, we propose a novel model-based RL method by combining a recently proposed model-free policy search method called policy gradients with parameter-based exploration and the state-of-the-art transition model estimator called least-squares conditional density estimation. Through experiments, we demonstrate the practical usefulness of the proposed method.