在过去的几年中,逆增强学习(\ textit {irl})问题已经迅速发展,在机器人技术,认知和健康等领域中具有重要的应用。在这项工作中,我们探讨了当前IRL方法从描述长马,复杂的顺序任务的专家轨迹中学习代理奖励函数的效率低下。我们假设,将IRL模型带入捕获基本任务的结构图案可以实现和提高其性能。随后,我们提出了一种新颖的IRL方法Smirl,该方法首先学习任务的(近似)结构为有限状态-Satate-automaton(FSA),然后使用结构基序来解决IRL问题。我们在离散网格世界和高维连续域环境上测试我们的模型。我们从经验上表明,我们提出的方法成功地学习了所有四个复杂的任务,其中两个基础IRL基准失败了。我们的模型还优于简单的玩具任务中样本效率的基准。我们进一步在具有组成奖励函数的任务上的经过修改的连续域中显示了有希望的测试结果。
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In inverse reinforcement learning (IRL), a learning agent infers a reward function encoding the underlying task using demonstrations from experts. However, many existing IRL techniques make the often unrealistic assumption that the agent has access to full information about the environment. We remove this assumption by developing an algorithm for IRL in partially observable Markov decision processes (POMDPs). We address two limitations of existing IRL techniques. First, they require an excessive amount of data due to the information asymmetry between the expert and the learner. Second, most of these IRL techniques require solving the computationally intractable forward problem -- computing an optimal policy given a reward function -- in POMDPs. The developed algorithm reduces the information asymmetry while increasing the data efficiency by incorporating task specifications expressed in temporal logic into IRL. Such specifications may be interpreted as side information available to the learner a priori in addition to the demonstrations. Further, the algorithm avoids a common source of algorithmic complexity by building on causal entropy as the measure of the likelihood of the demonstrations as opposed to entropy. Nevertheless, the resulting problem is nonconvex due to the so-called forward problem. We solve the intrinsic nonconvexity of the forward problem in a scalable manner through a sequential linear programming scheme that guarantees to converge to a locally optimal policy. In a series of examples, including experiments in a high-fidelity Unity simulator, we demonstrate that even with a limited amount of data and POMDPs with tens of thousands of states, our algorithm learns reward functions and policies that satisfy the task while inducing similar behavior to the expert by leveraging the provided side information.
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强化学习(RL)是人工智能中的核心问题。这个问题包括定义可以通过与环境交互学习最佳行为的人工代理 - 其中,在代理试图最大化的奖励信号的奖励信号中定义最佳行为。奖励机(RMS)提供了一种基于Automate的基于自动机的表示,该奖励功能使RL代理能够将RL问题分解为可以通过禁止策略学习有效地学习的结构化子问题。在这里,我们表明可以从经验中学习RMS,而不是由用户指定,并且可以使用所产生的问题分解来有效地解决部分可观察的RL问题。我们将学习RMS的任务作为离散优化问题构成,其中目标是找到将问题分解为一组子问题的RM,使得其最佳记忆策略的组合是原始问题的最佳策略。我们展示了这种方法在三个部分可观察的域中的有效性,在那里它显着优于A3C,PPO和宏碁,并讨论其优点,限制和更广泛的潜力。
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Hierarchical Reinforcement Learning (HRL) algorithms have been demonstrated to perform well on high-dimensional decision making and robotic control tasks. However, because they solely optimize for rewards, the agent tends to search the same space redundantly. This problem reduces the speed of learning and achieved reward. In this work, we present an Off-Policy HRL algorithm that maximizes entropy for efficient exploration. The algorithm learns a temporally abstracted low-level policy and is able to explore broadly through the addition of entropy to the high-level. The novelty of this work is the theoretical motivation of adding entropy to the RL objective in the HRL setting. We empirically show that the entropy can be added to both levels if the Kullback-Leibler (KL) divergence between consecutive updates of the low-level policy is sufficiently small. We performed an ablative study to analyze the effects of entropy on hierarchy, in which adding entropy to high-level emerged as the most desirable configuration. Furthermore, a higher temperature in the low-level leads to Q-value overestimation and increases the stochasticity of the environment that the high-level operates on, making learning more challenging. Our method, SHIRO, surpasses state-of-the-art performance on a range of simulated robotic control benchmark tasks and requires minimal tuning.
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我们研究了逆钢筋学习的问题(IRL),学习代理使用专家演示恢复奖励功能。大多数现有的IRL技术使代理商可以访问有关环境的完整信息,这使得经常不切实际的假设。我们通过在部分可观察到的马尔可夫决策过程(POMDPS)中开发IRL算法来消除此假设。该算法解决了现有技术的若干限制,这些技术不会考虑专家和学习者之间的信息不对称。首先,它采用因果熵作为专家演示的可能性,而不是在大多数现有的IRL技术中熵,避免了算法复杂性的共同来源。其次,它包含以时间逻辑表示的任务规范。除了演示之外,这些规范可以被解释为对学习者可用的侧面信息,并且可以减少信息不对称。然而,由于所谓的前向问题的内在非凸起,即计算最佳政策,在POMDPS中计算最佳政策,所得到的制剂仍然是非凸的。通过顺序凸编程来解决这种非凸起,并介绍几个扩展以以可扩展的方式解决前向问题。这种可扩展性允许计算策略,以牺牲添加的计算成本为代价也越优于无记忆策略。我们证明,即使具有严重限制的数据,算法也会了解满足任务的奖励函数和策略,并通过利用侧面信息并将内存结合到策略中来对专家引起类似的行为。
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当环境稀疏和非马克维亚奖励时,使用标量奖励信号的训练加强学习(RL)代理通常是不可行的。此外,在训练之前对这些奖励功能进行手工制作很容易指定,尤其是当环境的动态仅部分知道时。本文提出了一条新型的管道,用于学习非马克维亚任务规格,作为简洁的有限状态“任务自动机”,从未知环境中的代理体验情节中。我们利用两种关键算法的见解。首先,我们通过将其视为部分可观察到的MDP并为隐藏的Markov模型使用现成的算法,从而学习了由规范的自动机和环境MDP组成的产品MDP,该模型是由规范的自动机和环境MDP组成的。其次,我们提出了一种从学习的产品MDP中提取任务自动机(假定为确定性有限自动机)的新方法。我们学到的任务自动机可以使任务分解为其组成子任务,从而提高了RL代理以后可以合成最佳策略的速率。它还提供了高级环境和任务功能的可解释编码,因此人可以轻松地验证代理商是否在没有错误的情况下学习了连贯的任务。此外,我们采取步骤确保学识渊博的自动机是环境不可静止的,使其非常适合用于转移学习。最后,我们提供实验结果,以说明我们在不同环境和任务中的算法的性能及其合并先前的领域知识以促进更有效学习的能力。
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在许多顺序决策问题(例如,机器人控制,游戏播放,顺序预测),人类或专家数据可用包含有关任务的有用信息。然而,来自少量专家数据的模仿学习(IL)可能在具有复杂动态的高维环境中具有挑战性。行为克隆是一种简单的方法,由于其简单的实现和稳定的收敛而被广泛使用,但不利用涉及环境动态的任何信息。由于对奖励和政策近似器或偏差,高方差梯度估计器,难以在实践中难以在实践中努力训练的许多现有方法。我们介绍了一种用于动态感知IL的方法,它通过学习单个Q函数来避免对抗训练,隐含地代表奖励和策略。在标准基准测试中,隐式学习的奖励显示与地面真实奖励的高正面相关性,说明我们的方法也可以用于逆钢筋学习(IRL)。我们的方法,逆软Q学习(IQ-Learn)获得了最先进的结果,在离线和在线模仿学习设置中,显着优于现有的现有方法,这些方法都在所需的环境交互和高维空间中的可扩展性中,通常超过3倍。
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对于许多强化学习(RL)应用程序,指定奖励是困难的。本文考虑了一个RL设置,其中代理仅通过查询可以询问可以的专家来获取有关奖励的信息,例如,评估单个状态或通过轨迹提供二进制偏好。从如此昂贵的反馈中,我们的目标是学习奖励的模型,允许标准RL算法实现高预期的回报,尽可能少的专家查询。为此,我们提出了信息定向奖励学习(IDRL),它使用奖励的贝叶斯模型,然后选择要最大化信息增益的查询,这些查询是有关合理的最佳策略之间的返回差异的差异。与针对特定类型查询设计的先前主动奖励学习方法相比,IDRL自然地适应不同的查询类型。此外,它通过将焦点转移降低奖励近似误差来实现类似或更好的性能,从而降低奖励近似误差,以改善奖励模型引起的策略。我们支持我们的调查结果,在多个环境中进行广泛的评估,并具有不同的查询类型。
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Reinforcement learning (RL) gained considerable attention by creating decision-making agents that maximize rewards received from fully observable environments. However, many real-world problems are partially or noisily observable by nature, where agents do not receive the true and complete state of the environment. Such problems are formulated as partially observable Markov decision processes (POMDPs). Some studies applied RL to POMDPs by recalling previous decisions and observations or inferring the true state of the environment from received observations. Nevertheless, aggregating observations and decisions over time is impractical for environments with high-dimensional continuous state and action spaces. Moreover, so-called inference-based RL approaches require large number of samples to perform well since agents eschew uncertainty in the inferred state for the decision-making. Active inference is a framework that is naturally formulated in POMDPs and directs agents to select decisions by minimising expected free energy (EFE). This supplies reward-maximising (exploitative) behaviour in RL, with an information-seeking (exploratory) behaviour. Despite this exploratory behaviour of active inference, its usage is limited to discrete state and action spaces due to the computational difficulty of the EFE. We propose a unified principle for joint information-seeking and reward maximization that clarifies a theoretical connection between active inference and RL, unifies active inference and RL, and overcomes their aforementioned limitations. Our findings are supported by strong theoretical analysis. The proposed framework's superior exploration property is also validated by experimental results on partial observable tasks with high-dimensional continuous state and action spaces. Moreover, the results show that our model solves reward-free problems, making task reward design optional.
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With the development of deep representation learning, the domain of reinforcement learning (RL) has become a powerful learning framework now capable of learning complex policies in high dimensional environments. This review summarises deep reinforcement learning (DRL) algorithms and provides a taxonomy of automated driving tasks where (D)RL methods have been employed, while addressing key computational challenges in real world deployment of autonomous driving agents. It also delineates adjacent domains such as behavior cloning, imitation learning, inverse reinforcement learning that are related but are not classical RL algorithms. The role of simulators in training agents, methods to validate, test and robustify existing solutions in RL are discussed.
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我们研究自主代理如何学会从不同领域(例如不同环境或不同代理)中的示范中执行任务。这样的跨域模仿学习需要例如从人类专家的演示中培训人造代理。我们提出了一个可扩展的框架,该框架可以实现跨域模仿学习,而无需访问其他演示或进一步的领域知识。我们共同培训学习者的政策,并通过对抗性培训学习学习者和专家领域的映射。我们通过使用共同信息标准来找到包含与任务相关的信息的专家状态空间的嵌入,并且对域细节不变。此步骤大大简化了估计学习者和专家领域之间的映射,因此有助于端到端学习。我们证明了在相当不同的域之间成功转移了政策,而没有额外的示范,以及其他方法失败的情况。
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Deep Reinforcement Learning has been successfully applied to learn robotic control. However, the corresponding algorithms struggle when applied to problems where the agent is only rewarded after achieving a complex task. In this context, using demonstrations can significantly speed up the learning process, but demonstrations can be costly to acquire. In this paper, we propose to leverage a sequential bias to learn control policies for complex robotic tasks using a single demonstration. To do so, our method learns a goal-conditioned policy to control a system between successive low-dimensional goals. This sequential goal-reaching approach raises a problem of compatibility between successive goals: we need to ensure that the state resulting from reaching a goal is compatible with the achievement of the following goals. To tackle this problem, we present a new algorithm called DCIL-II. We show that DCIL-II can solve with unprecedented sample efficiency some challenging simulated tasks such as humanoid locomotion and stand-up as well as fast running with a simulated Cassie robot. Our method leveraging sequentiality is a step towards the resolution of complex robotic tasks under minimal specification effort, a key feature for the next generation of autonomous robots.
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本文考虑了从专家演示中学习机器人运动和操纵任务。生成对抗性模仿学习(GAIL)训练一个区分专家与代理转换区分开的歧视者,进而使用歧视器输出定义的奖励来优化代理商的策略生成器。这种生成的对抗训练方法非常强大,但取决于歧视者和发电机培训之间的微妙平衡。在高维问题中,歧视训练可能很容易过度拟合或利用与任务 - 核定功能进行过渡分类的关联。这项工作的一个关键见解是,在合适的潜在任务空间中进行模仿学习使训练过程稳定,即使在挑战高维问题中也是如此。我们使用动作编码器模型来获得低维的潜在动作空间,并使用对抗性模仿学习(Lapal)训练潜在政策。可以从州行动对脱机来训练编码器模型,以获得任务无关的潜在动作表示或与歧视器和发电机培训同时在线获得,以获得任务意识到的潜在行动表示。我们证明了Lapal训练是稳定的,具有近乎单的性能的改进,并在大多数运动和操纵任务中实现了专家性能,而Gail基线收敛速度较慢,并且在高维环境中无法实现专家的表现。
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Meta-Renifiltive学习(Meta-RL)已被证明是利用事先任务的经验,以便快速学习新的相关任务的成功框架,但是,当前的Meta-RL接近在稀疏奖励环境中学习的斗争。尽管现有的Meta-RL算法可以学习适应新的稀疏奖励任务的策略,但是使用手形奖励功能来学习实际适应策略,或者需要简单的环境,其中随机探索足以遇到稀疏奖励。在本文中,我们提出了对Meta-RL的后视抢购的制定,该rl抢购了在Meta培训期间的经验,以便能够使用稀疏奖励完全学习。我们展示了我们的方法在套件挑战稀疏奖励目标达到的环境中,以前需要密集的奖励,以便在Meta训练中解决。我们的方法使用真正的稀疏奖励功能来解决这些环境,性能与具有代理密集奖励功能的培训相当。
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通过加强学习(RL)掌握机器人操纵技巧通常需要设计奖励功能。该地区的最新进展表明,使用稀疏奖励,即仅在成功完成任务时奖励代理,可能会导致更好的政策。但是,在这种情况下,国家行动空间探索更困难。最近的RL与稀疏奖励学习的方法已经为任务提供了高质量的人类演示,但这些可能是昂贵的,耗时甚至不可能获得的。在本文中,我们提出了一种不需要人类示范的新颖有效方法。我们观察到,每个机器人操纵任务都可以被视为涉及从被操纵对象的角度来看运动的任务,即,对象可以了解如何自己达到目标状态。为了利用这个想法,我们介绍了一个框架,最初使用现实物理模拟器获得对象运动策略。然后,此策略用于生成辅助奖励,称为模拟的机器人演示奖励(SLDRS),使我们能够学习机器人操纵策略。拟议的方法已在增加复杂性的13个任务中进行了评估,与替代算法相比,可以实现更高的成功率和更快的学习率。 SLDRS对多对象堆叠和非刚性物体操作等任务特别有益。
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Reinforcement learning in partially observable domains is challenging due to the lack of observable state information. Thankfully, learning offline in a simulator with such state information is often possible. In particular, we propose a method for partially observable reinforcement learning that uses a fully observable policy (which we call a state expert) during offline training to improve online performance. Based on Soft Actor-Critic (SAC), our agent balances performing actions similar to the state expert and getting high returns under partial observability. Our approach can leverage the fully-observable policy for exploration and parts of the domain that are fully observable while still being able to learn under partial observability. On six robotics domains, our method outperforms pure imitation, pure reinforcement learning, the sequential or parallel combination of both types, and a recent state-of-the-art method in the same setting. A successful policy transfer to a physical robot in a manipulation task from pixels shows our approach's practicality in learning interesting policies under partial observability.
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强化学习的标准制定缺乏指定禁止和禁止行为的实用方式。最常见的是,从业者通过手动工程来指定行为规范的任务,这是一个需要几个迭代的反向直观的过程,并且易于奖励代理人。在这项工作中,我们认为,几乎完全用于安全RL的受限制的RL,也有可能大大减少应用加强学习项目中奖励规范所花费的工作量。为此,我们建议在CMDP框架中指定行为偏好,并使用拉格朗日方法,该方法寻求解决代理程序的策略和拉格朗日乘法器之间的最小问题,以自动称量每个行为约束。具体而言,我们研究了如何调整CMDP,以便解决基于目标的任务,同时遵守一组行为约束,并提出对Sac-Lagrangian算法的修改以处理若干约束的具有挑战性的情况。我们对这一框架进行了一系列持续控制任务,该任务与用于视频游戏中NPC设计的加固学习应用相关。
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马尔可夫决策过程通常用于不确定性下的顺序决策。然而,对于许多方面,从受约束或安全规范到任务和奖励结构中的各种时间(非Markovian)依赖性,需要扩展。为此,近年来,兴趣已经发展成为强化学习和时间逻辑的组合,即灵活的行为学习方法的组合,具有稳健的验证和保证。在本文中,我们描述了最近引入的常规决策过程的实验调查,该过程支持非马洛维亚奖励功能以及过渡职能。特别是,我们为常规决策过程,与在线,增量学习有关的算法扩展,对无模型和基于模型的解决方案算法的实证评估,以及以常规但非马尔维亚,网格世界的应用程序的算法扩展。
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从演示中学习的方法(LFD)通过模仿用户表现出在获取行为策略方面的成功。但是,即使对于一项任务,LFD也可能需要大量的演示。对于必须通过演示学习许多任务的多功能代理,如果孤立地学习每个任务,此过程将大大负担用户的负担。为了应对这一挑战,我们介绍了从演示中学习的新颖问题,该问题使代理商能够不断地基于从先前演示的任务中学到的知识,以加速学习新任务,从而减少所需的示范量。作为解决这个问题的一种解决方案,我们提出了第一种终身学习方法来进行逆强化学习,该方法通过演示学习连续的任务,不断地在任务之间转移知识以提高绩效。
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将有用的背景知识传达给加强学习(RL)代理是加速学习的重要方法。我们介绍了Rlang,这是一种特定领域的语言(DSL),用于将域知识传达给RL代理。与RL社区提出的其他现有DSL不同,该基础是决策形式主义的单个要素(例如,奖励功能或政策功能),RLANG可以指定有关马尔可夫决策过程中每个元素的信息。我们为rlang定义了精确的语法和基础语义,并提供了解析器实施,将rlang程序基于算法 - 敏捷的部分世界模型和政策,可以由RL代理利用。我们提供一系列示例RLANG程序,并演示不同的RL方法如何利用所得的知识,包括无模型和基于模型的表格算法,分层方法和深度RL算法(包括策略梯度和基于价值的方法)。
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