🤖 AI Summary
To address the challenges of poor exploration and low sample efficiency in reinforcement learning (RL) for long-horizon robotic manipulation tasks—caused by sparse rewards and high-dimensional visual observations—this paper proposes a demonstration-augmented visual RL framework grounded in multi-stage task structure. Our method decomposes global goals into sequential sub-goals and automatically generates dense rewards per stage, enabling staged dense-reward learning. It further introduces a two-phase training paradigm that jointly optimizes demonstration-guided reward shaping, policy distillation, and a latent-space world model. Finally, it achieves efficient end-to-end mapping from raw visual observations to robot actions. Evaluated on 16 sparse-reward tasks—including humanoid visual control—our approach improves data efficiency by 40% on average and up to 70% on challenging tasks, achieving significant convergence with only five expert demonstrations.
📝 Abstract
Long-horizon tasks in robotic manipulation present significant challenges in reinforcement learning (RL) due to the difficulty of designing dense reward functions and effectively exploring the expansive state-action space. However, despite a lack of dense rewards, these tasks often have a multi-stage structure, which can be leveraged to decompose the overall objective into manageable subgoals. In this work, we propose DEMO3, a framework that exploits this structure for efficient learning from visual inputs. Specifically, our approach incorporates multi-stage dense reward learning, a bi-phasic training scheme, and world model learning into a carefully designed demonstration-augmented RL framework that strongly mitigates the challenge of exploration in long-horizon tasks. Our evaluations demonstrate that our method improves data-efficiency by an average of 40% and by 70% on particularly difficult tasks compared to state-of-the-art approaches. We validate this across 16 sparse-reward tasks spanning four domains, including challenging humanoid visual control tasks using as few as five demonstrations.