Learning Physics Priors for Deep Reinforcement Learing

While model-based deep reinforcement learning (RL) holds great promise for sample efficiency and generalization, learning an accurate dynamics model is challenging and often requires substantial interactions with the environment. Further, a wide variety of domains have dynamics that share common foundations like the laws of physics, which are rarely exploited by these algorithms. Humans often acquire such physics priors that allow us to easily adapt to the dynamics of any environment. In this work, we propose an approach to learn such physics priors and incorporate them into an RL agent. Our method involves pre-training a frame predictor on raw videos and then using it to initialize the dynamics prediction model on a target task. Our prediction model, SpatialNet, is designed to implicitly capture localized physical phenomena and interactions. We show the value of incorporating this prior through empirical experiments on two different domains – a newly created PhysWorld and games from the Atari benchmark, outperforming competitive approaches and demonstrating effective transfer learning.