Mobile robots have recently appeared in public spaces such as shopping malls, airports, and urban sidewalks. These robots are designed with human-aware motion planning capabilities, but they are not designed to communicate with pedestrians. Pedestrians encounter these robots without any training or prior understanding of the robots’ behaviour, which can cause discomfort, confusion, and delay social acceptance. The two studies described in this thesis evaluate robot communication cues designed for human-robot spatial interactions in public spaces. By communicating robot behaviour to pedestrians, these cues aim to increase the social acceptability of mobile robots. Both studies use videos of the robot cues and online surveys to collect data from human participants.

Study 1 evaluates two different modalities for communicating a robot’s movement to pedestrians:​ flashing lights and light projection. Previous reviewed literature had not directly compared these two modalities of motion legibility cues. Study 1 also compares using these cues to communicate path information or goal information, which are contributing factors to legible robot motion. Previous reviewed literature had not compared path and goal information for motion legibility cues using visual modalities. Results show that light projection is a more socially acceptable modality than flashing lights, and that these cues are most socially acceptable when they communicate both path and goal information.

Study 2 evaluates different communication cues used by a robot to yield to a pedestrian at a doorway. The experiment compared decelerating, retreating, and rotating motions. These motions had not previously been directly compared in this context. Results show that a robot retreating behaviour was the most socially acceptable cue.

The results of this work help guide the development of mobile robots for public spaces.