Multi-Level Task Learning Based on Intention and Constraint Inference for Autonomous Robotic Manipulation

Abstract

To perform tasks in unstructured environments, robots need to be able to apply learned skills to different contexts and to autonomously make decisions online. We, therefore, developed a novel data-driven task learning approach that segments a task demonstration into simpler skills and structures them in a high-level task graph. In contrast to other state-of-the-art methods, the presented approach can not only infer the low-level skills and their respective subgoals but also multimodal feature constraints fitted individually to each skill. The inferred feature constraints allow to detect anomalies during autonomous task execution, which can be automatically resolved by a recovery behavior of the task graph. The subgoals encode each skill's intention and thereby enable to flexibly transition between skills and to generalize the behavior to new setups. By separating the subgoal and constraint inference, we achieve a reduced computational complexity and an increased performance compared to state-of-the-art task learning approaches. In a real-world manipulation task, we demonstrate the reusability of skills as well as the autonomous decision-making of our approach.