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arXiv 1707.03034cs.ROcs.AIcs.LG
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通过模仿学习启发式搜索

Learning Heuristic Search via Imitation

Carnegie Mellon University(卡内基梅隆大学)

Mohak Bhardwaj, Sanjiban Choudhury, Sebastian Scherer

摘要:

机器人运动规划问题通常通过构建从开始到目标配置的有效机动的搜索树来解决。有限的机载计算和实时规划约束限制了搜索树的增长。在这种情况下,启发式算法发挥了至关重要的作用,引导搜索向潜在的好方向,从而最大限度地减少搜索工作。此外,它必须只使用搜索到那时为止所发现的信息以有效的方式推断出这样的方向。然而,现有技术的方法没有解决计算显式地最小化搜索努力的启发式的问题。在本文中,我们通过训练一个启发式策略来实现这一点,该策略映射来自搜索的部分信息,以决定扩展搜索树的哪个节点。不幸的是,天真地训练这样的策略会导致收敛缓慢和局部极小值不佳。我们提出了帆,一个有效的算法,训练启发式的政策,通过模仿“千里眼的神谕”-神谕,有充分的信息,世界和展示决策,最大限度地减少搜索工作。我们利用这样的神谕可以有效地计算使用动态规划的事实,并获得学习启发式的性能保证。我们验证了一系列环境的方法,这表明帆始终优于最先进的算法。我们的方法为学习具有随时随地性质的化学铺平了道路-快速找到可行的解决方案并随着时间的推移逐步完善。

英文摘要:

Robotic motion planning problems are typically solved by constructing a search tree of valid maneuvers from a start to a goal configuration. Limited onboard computation and real-time planning constraints impose a limit on how large this search tree can grow. Heuristics play a crucial role in such situations by guiding the search towards potentially good directions and consequently minimizing search effort. Moreover, it must infer such directions in an efficient manner using only the information uncovered by the search up until that time. However, state of the art methods do not address the problem of computing a heuristic that explicitly minimizes search effort. In this paper, we do so by training a heuristic policy that maps the partial information from the search to decide which node of the search tree to expand. Unfortunately, naively training such policies leads to slow convergence and poor local minima. We present SaIL, an efficient algorithm that trains heuristic policies by imitating "clairvoyant oracles" - oracles that have full information about the world and demonstrate decisions that minimize search effort. We leverage the fact that such oracles can be efficiently computed using dynamic programming and derive performance guarantees for the learnt heuristic. We validate the approach on a spectrum of environments which show that SaIL consistently outperforms state of the art algorithms. Our approach paves the way forward for learning heuristics that demonstrate an anytime nature - finding feasible solutions quickly and incrementally refining it over time.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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