Diffusion Model-Augmented Behavioral Cloning

Imitation learning addresses the challenge of learning by observing an expert's demonstrations without access to reward signals from the environment. Behavioral cloning (BC) formulates imitation learning as a supervised learning problem and learns from sampled state-action pairs. Despite its simplicity, it often fails to capture the temporal structure of the task and the global information of expert demonstrations. This work aims to augment BC by employing diffusion models for modeling expert behaviors, and designing a learning objective that leverages learned diffusion models to guide policy learning. To this end, we propose diffusion model-augmented behavioral cloning (Diffusion-BC) that combines our proposed diffusion model guided learning objective with the BC objective, which complements each other. Our proposed method outperforms baselines or achieves competitive performance in various continuous control domains, including navigation, robot arm manipulation, and locomotion. Ablation studies justify our design choices and investigate the effect of balancing the BC and our proposed diffusion model objective.