RECON: Reducing Causal Confusion with Human-Placed Markers

TL;DR

RECON introduces human-placed beacons to mark task-relevant objects, enabling robots to focus on important features, reducing causal confusion, and decreasing the number of demonstrations needed for effective imitation learning.

Contribution

The paper proposes a novel framework where humans mark key objects with beacons to guide robot learning, addressing causal confusion in imitation learning tasks.

Findings

RECON reduces the number of demonstrations needed for task learning.

The framework effectively filters out extraneous observations during robot training.

Experiments show improved learning efficiency in both simulation and real robot settings.

Abstract

Imitation learning enables robots to learn new tasks from human examples. One fundamental limitation while learning from humans is causal confusion. Causal confusion occurs when the robot's observations include both task-relevant and extraneous information: for instance, a robot's camera might see not only the intended goal, but also clutter and changes in lighting within its environment. Because the robot does not know which aspects of its observations are important a priori, it often misinterprets the human's examples and fails to learn the desired task. To address this issue, we highlight that -- while the robot learner may not know what to focus on -- the human teacher does. In this paper we propose that the human proactively marks key parts of their task with small, lightweight beacons. Under our framework (RECON) the human attaches these beacons to task-relevant objects before providing demonstrations: as the human shows examples of the task, beacons track the position of marked objects. We then harness this offline beacon data to train a task-relevant state embedding. Specifically, we embed the robot's observations to a latent state that is correlated with the measured beacon readings: in practice, this causes the robot to autonomously filter out extraneous observations and make decisions based on features learned from the beacon data. Our simulations and a real robot experiment suggest that this framework for human-placed beacons mitigates causal confusion. Indeed, we find that using RECON significantly reduces the number of demonstrations needed to convey the task, lowering the overall time required for human teaching. See videos here: https://youtu.be/oy85xJvtLSU