Exploration in environments with sparse rewards has been a persistent problem in reinforcement learning (RL). Many tasks are natural to specify with a sparse reward, and manually shaping a reward function can result in suboptimal performance. However, finding a non-zero reward is exponentially more difficult with increasing task horizon or action dimensionality. This puts many real-world tasks out of practical reach of RL methods. In this work, we use demonstrations to overcome the exploration problem and successfully learn to perform long-horizon, multi-step robotics tasks with continuous control such as stacking blocks with a robot arm. Our method, which builds on top of Deep Deterministic Policy Gradients and Hindsight Experience Replay, provides an order of magnitude of speedup over RL on simulated robotics tasks. It is simple to implement and makes only the additional assumption that we can collect a small set of demonstrations. Furthermore, our method is able to solve tasks not solvable by either RL or behavior cloning alone, and often ends up outperforming the demonstrator policy.

本研究利用示范来解决强化学习中稀疏奖励的探索问题，成功地学习了长期、多步骤的机器人任务，方法使用了DDPG和HER算法，提供了一种在仿真机器人任务上比以往RL算法快一个数量级的加速，方法易于实现，能够解决在行为克隆和RL算法中 都无法解决的任务，并且往往表现优于示范策略。

利用演示克服强化学习中的探索问题