A Balanced Data Diet: Addressing the Exploration Bottleneck in Mega-Scale RL for Robot Control

Embodied AI and Robotics LLO SRT ML RL SRL
通用型机器人必须能够执行种类繁多的任务,从敏捷的运动控制到灵巧的操作操控皆在其列。尽管“仿真到真实”(sim-to-real)的强化学习(RL)已被证明是实现这一目标的有效工具,但当前的强化学习流程仍严重依赖于人工设计、任务定制的结构化先验知识,例如精心设计的奖励函数和专家示范。近期研究发现,结合多样化仿真环境重置策略与大规模并行仿真,可在若干操作类任务中显著减轻上述工程负担。然而,我们发现,若将这一范式简单地扩展至精度要求更高或动态性更强的问题上,依然面临诸多挑战,并非易事。虽然仿真环境重置有助于提升探索效率,但若在该重置分布上进行均匀采样,则会使得越来越多的学习经验被浪费在两类配置上:一类是策略已完全掌握的任务配置;另一类则是策略尚无法应对、甚至根本无法尝试的任务配置。这导致在批量训练过程中大量学习信号被无效消耗,因而难以真正发挥大规模并行仿真环境在强化学习中本应带来的预期收益。为缓解这一问题,我们提出了“成功引导采样”(Success Guided Sampling, SGS)方法——一种简洁而自适应的采样机制,其核心在于将强化学习训练聚焦于策略能力边界附近的任务配置。该机制使大规模仿真强化学习能够更充分地利用每一批次所生成的经验数据,从而显著提升其在超大规模并行仿真环境下的可扩展性与训练效率。在涵盖最多达 $2^{20}$(即逾一百万个)并行仿真环境的系列实验中,SGS 成功赋能强化学习算法,解决了以往方法均告失败的多地形四足机器人运动控制以及高接触频率装配等极具挑战性的任务。最后,我们将所学得的操作策略蒸馏为仅依赖 RGB 视觉输入的轻量级策略,并在真实硬件平台上实现了对多个复杂装配任务的零样本迁移(zero-shot transfer)。项目网站:https://sgs-rl.github.io/
General-purpose robots must perform a wide range of tasks from agile locomotion to dexterous manipulation. While sim-to-real reinforcement learning (RL) has proven to be a useful tool for this goal, current RL pipelines depend on engineering-heavy, per-task structural priors such as shaped rewards and demonstrations. Recent work has shown that diverse simulator resets, combined with massively parallel simulation, can alleviate much of this engineering burden on several manipulation problems. However, we find that naively scaling this paradigm to more precise or dynamic problems remains non-trivial. While simulator resets can help with exploration, uniformly sampling over this distribution wastes a growing fraction of learning experience on task configurations the policy has already mastered or cannot yet attempt. This makes it challenging to see the expected benefits of scaling parallel environments for RL, since much of the learning signal in a batch is wasted during learning. To mitigate this, we introduce Success Guided Sampling (SGS), a simple adaptive sampler that concentrates RL training on task configurations around the frontier of the policy's capabilities. Doing so allows large-scale simulated RL to make the most out of the experience in a batch, enabling much more effective scaling to large-scale parallel simulation. Across experiments using up to $2^{20}$ (over one million) parallel environments, SGS enables RL to solve challenging multi-terrain quadruped locomotion and contact-rich assembly tasks that prior methods fail to solve. Finally, we distill the learned manipulation policies into RGB-based policies and demonstrate zero-shot transfer to several challenging assembly tasks on real hardware. Project website: https://sgs-rl.github.io/.
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