Impact of Trajectory Generation Methods on Viewer Perception of Robot Approaching Group Behaviors

Abstract

Mobile robots that approach free-standing conversational groups to join them should behave in a safe and socially-acceptable way. Existing trajectory generation methods focus on collision avoidance with pedestrians, and the models that generate approach behaviors into groups are evaluated in simulation. However, it is challenging to generate approach and join trajectories that avoid collisions with group members while also ensuring that they do not invoke feelings of discomfort. In this paper, we conducted an experiment to examine the impact of three trajectory generation methods for a mobile robot to approach groups from multiple directions: a Wizard-of-Oz (WoZ) method, a procedural social-aware navigation model (PM) and a novel generative adversarial model imitating human approach behaviors (IL). Measures also compared two camera viewpoints and static versus quasi-dynamic groups. The latter refers to a group whose members change orientation and position throughout the approach task, even though the group entity remains static in the environment. This represents a more realistic but challenging scenario for the robot. We evaluate three methods with objective measurements and subjective measurements from viewer perception, and results show that WoZ and IL have comparable performance, and both perform better than PM under most conditions.