Conversational assistive robots can aid people, especially those with cognitive impairments, to accomplish various tasks such as cooking meals, performing exercises, or operating machines. However, to interact with people effectively, robots must recognize human plans and goals from noisy observations of human actions, even when the user acts sub-optimally. Previous works on Plan and Goal Recognition (PGR) as planning have used hierarchical task networks (HTN) to model the actor/human. However, these techniques are insufficient as they do not have user engagement via natural modes of interaction such as language. Moreover, they have no mechanisms to let users, especially those with cognitive impairments, know of a deviation from their original plan or about any sub-optimal actions taken towards their goal. We propose a novel framework for plan and goal recognition in partially observable domains -- Dialogue for Goal Recognition (D4GR) enabling a robot to rectify its belief in human progress by asking clarification questions about noisy sensor data and sub-optimal human actions. We evaluate the performance of D4GR over two simulated domains -- kitchen and blocks domain. With language feedback and the world state information in a hierarchical task model, we show that D4GR framework for the highest sensor noise performs 1% better than HTN in goal accuracy in both domains. For plan accuracy, D4GR outperforms by 4% in the kitchen domain and 2% in the blocks domain in comparison to HTN. The ALWAYS-ASK oracle outperforms our policy by 3% in goal recognition and 7%in plan recognition. D4GR does so by asking 68% fewer questions than an oracle baseline. We also demonstrate a real-world robot scenario in the kitchen domain, validating the improved plan and goal recognition of D4GR in a realistic setting.

对话式目标识别框架（Dialogue for Goal Recognition）通过询问关于噪声传感器数据和次优人类行动的澄清问题，使机器人能够纠正其对人类进展的信念，评估了 D4GR 在厨房和堆积领域的性能，结果显示 D4GR 框架在目标准确性方面比 HTN 高出 1%，在计划准确性方面比 HTN 高出 4-2%，比始终询问的预测模型在目标识别和计划识别方面表现更好，且比基线少问了 68% 的问题，文章还在厨房领域展示了一个真实世界机器人情景，验证了 D4GR 在现实环境中改进的计划和目标识别能力。

通过结合计划识别和语言反馈来改进人类意图推理