Challenges in Detecting and Analyzing EEG Error-Related Potentials: Lessons from a Case Study in HRI

Recently, electroencephalographic (EEG) signals have been used to enhance Human-Robot Interaction (HRI). In particular, Error-Related Potentials (ErrPs) have been exploited since very few years. These potentials are evoked when there is a mismatch between the command given by the subject and the movements of the robot, or if the user's expectation is different from the robot or other human behavior. These signals can be used to improve and customize the robot system, as feedback to better adapt the robot to human needs. This work aims to investigate and detect the ErrPs during different interaction tasks. We set up an experiment divided into five different tasks, where every task has 120 events with a 25%-35% probability of error. The robot used in the experiment is a Baxter robot and the commands from the subject to the robot are sent in two different ways: with a keyboard or with a motion capture device. This work aims to reproduce a simplified teleoperated pick and place task. However, the achieved results do not allow to correctly identify the ErrPs, but exhibit only some minor differences between trials with and without errors. Hence, we here analyze the reasons behind such negative results, focusing on the challenges of the structure and the setup of the experiment. We analyze the possible problems and provide some recommendations to overcome them in similar use cases.