Learning from Demonstrations with Energy based Generative Adversarial Imitation Learning

Traditional reinforcement learning methods usually deal with the tasks with explicit reward signals. However, for vast majority of cases, the environment wouldn't feedback a reward signal immediately. It turns out to be a bottleneck for modern reinforcement learning approaches to be applied into more realistic scenarios. Recently, inverse reinforcement learning has made great progress in making full use of the expert demonstrations to recover the reward signal for reinforcement learning. And generative adversarial imitation learning is one promising approach. In this paper, we propose a new architecture for training generative adversarial imitation learning which is so called energy based generative adversarial imitation learning (EB-GAIL). It views the discriminator as an energy function that attributes low energies to the regions near the expert demonstrations and high energies to other regions. Therefore, a generator can be seen as a reinforcement learning procedure to sample trajectories with minimal energies (cost), while the discriminator is trained to assign high energies to these generated trajectories. In detail, EB-GAIL uses an auto-encoder architecture in place of the discriminator, with the energy being the reconstruction error. Theoretical analysis shows our EB-GAIL could match the occupancy measure with expert policy during the training process. Meanwhile, the experiments depict that EB-GAIL outperforms other SoTA methods while the training process for EB-GAIL can be more stable.