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Ensembling Diverse Policies Improves Generalization of Deep Reinforcement Learning Algorithms to Environmental Changes in Continuous Control Tasks

  • Author / Creator
    Zhumabekov, Abilmansur
  • Deep Reinforcement Learning (DRL) algorithms have shown great success in solving continuous control tasks. However, they often struggle to generalize to changes in the environment. Although retraining may help policies adapt to changes, it may be quite costly in some environments.
    Ensemble methods, which are widely used in machine learning to boost generalization, have not been commonly adopted in DRL for continuous control applications. In this work, we introduce a simple ensembling technique for DRL policies with continuous action spaces. It aggregates actions by performing weighted averaging based on the uncertainty levels of the policies. We investigate its zero-shot generalization properties in a complex continuous control domain - the optimal control of home batteries in the CityLearn environment, the subject of a 2022 international AI competition.
    Our results indicate that the proposed ensemble has better generalization capacity than a single policy. Further, we show that promoting diversity among policies during training can reliably improve the zero-shot performance of the ensemble in the test phase.
    Finally, we examine the merits of the uncertainty-based weighted averaging in an ensemble by comparing it to two alternative approaches: unweighted averaging and selecting the action of the least uncertain policy.

  • Subjects / Keywords
  • Graduation date
    Fall 2023
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/r3-pj0r-2n31
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.