Learning Robust State Abstractions for Hidden-Parameter Block MDPs
Authors: Amy Zhang, Shagun Sodhani, Khimya Khetarpal, Joelle Pineau
Venue: ICLR 2021 Poster
Keywords: multi-task reinforcement learning, bisimulation, hidden-parameter mdp, block mdp
Abstract: Many control tasks exhibit similar dynamics that can be modeled as having common latent structure. Hidden-Parameter Markov Decision Processes (HiP-MDPs) explicitly model this structure to improve sample efficiency in multi-task settings.
However, this setting makes strong assumptions on the observability of the state that limit its application in real-world scenarios with rich observation spaces.  In this work, we leverage ideas of common structure from the HiP-MDP setting, and extend it to enable robust state abstractions inspired by Block MDPs. We  derive instantiations of this new framework for  both multi-task reinforcement learning (MTRL) and  meta-reinforcement learning (Meta-RL) settings. Further, we provide transfer and generalization bounds based on task and state similarity, along with sample complexity bounds that depend on the aggregate number of samples across tasks, rather than the number of tasks, a significant improvement over prior work. To further demonstrate efficacy of the proposed method, we empirically compare and show improvement over multi-task and meta-reinforcement learning baselines.