Safety is an essential component for deploying reinforcement learning (RL) algorithms in real-world scenarios, and is critical during the learning process itself. A natural first approach toward safe RL is to manually specify constraints on the policy's behavior. However, just as learning has enabled progress in large-scale development of AI systems, learning safety specifications may also be necessary to ensure safety in messy open-world environments where manual safety specifications cannot scale. Akin to how humans learn incrementally starting in child-safe environments, we propose to learn how to be safe in one set of tasks and environments, and then use that learned intuition to constrain future behaviors when learning new, modified tasks. We empirically study this form of safety-constrained transfer learning in three challenging domains: simulated navigation, quadruped locomotion, and dexterous in-hand manipulation. In comparison to standard deep RL techniques and prior approaches to safe RL, we find that our method enables the learning of new tasks and in new environments with both substantially fewer safety incidents, such as falling or dropping an object, and faster, more stable learning. This suggests a path forward not only for safer RL systems, but also for more effective RL systems.

为了将RL算法部署到实际场景中并在学习过程中确保安全性，我们提出了使用转移学习方法学习在一个任务环境中如何保持安全性，然后将所学用于约束在学习新任务时的行为，此方法在三个具有挑战性的领域中实证，相比于标准的深度RL技术和以前的安全RL方法，我们的方法不但减少了安全事故，还提高了学习的速度和稳定性。

学习保证安全：带安全评论家的深度强化学习