论文标题

一种基于因果的方法来解释,预测和防止机器人任务中的失败

A Causal-based Approach to Explain, Predict and Prevent Failures in Robotic Tasks

论文作者

Diehl, Maximilian, Ramirez-Amaro, Karinne

论文摘要

在实际环境中工作的机器人需要适应意外的更​​改,以避免失败。这是一个开放而复杂的挑战,要求机器人及时预测和确定防止失败的原因。在本文中,我们提出了一种因果方法,该方法将使机器人能够预测何时可能发生错误,并通过执行纠正措施来防止发生错误。首先,我们提出了一种基于因果关系的方法,以通过学习因果贝叶斯网络(BN)来检测任务执行及其后果之间的因果关系。获得的模型从模拟数据传输到实际场景,以证明所获得的模型的鲁棒性和概括。基于因果BN,机器人可以预测执行的诉讼是否以及为什么在其当前状态下取得成功。然后,我们介绍了一种新颖的方法,该方法通过对比度广度搜索发现了最接近的状态替代方法,如果当前的动作被预测失败。我们评估了在两种情况下堆叠立方体的问题的方法; a)单个堆栈(堆叠一个立方体)和; b)多个堆栈(堆叠三个立方体)。在单栈情况下,我们的方法能够将错误率降低97%。我们还表明,我们的方法可以扩展以在一个模型中捕获多个动作,从而衡量及时移动的动作效应,例如第一个立方体对第三个立方体堆叠成功的不精确堆栈的影响。对于这些复杂的情况,我们的模型也能够防止堆叠错误的75%,即使对于具有挑战性的多堆栈方案也是如此。因此,证明我们的方法能够解释,预测和防止执行故障,甚至可以扩展到需要了解行动历史如何影响未来行动的复杂场景。

Robots working in real environments need to adapt to unexpected changes to avoid failures. This is an open and complex challenge that requires robots to timely predict and identify the causes of failures to prevent them. In this paper, we present a causal method that will enable robots to predict when errors are likely to occur and prevent them from happening by executing a corrective action. First, we propose a causal-based method to detect the cause-effect relationships between task executions and their consequences by learning a causal Bayesian network (BN). The obtained model is transferred from simulated data to real scenarios to demonstrate the robustness and generalization of the obtained models. Based on the causal BN, the robot can predict if and why the executed action will succeed or not in its current state. Then, we introduce a novel method that finds the closest state alternatives through a contrastive Breadth-First-Search if the current action was predicted to fail. We evaluate our approach for the problem of stacking cubes in two cases; a) single stacks (stacking one cube) and; b) multiple stacks (stacking three cubes). In the single-stack case, our method was able to reduce the error rate by 97%. We also show that our approach can scale to capture multiple actions in one model, allowing to measure timely shifted action effects, such as the impact of an imprecise stack of the first cube on the stacking success of the third cube. For these complex situations, our model was able to prevent around 75% of the stacking errors, even for the challenging multiple-stack scenario. Thus, demonstrating that our method is able to explain, predict, and prevent execution failures, which even scales to complex scenarios that require an understanding of how the action history impacts future actions.

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