Effects of robot arm design and movement speed during human-robot interaction.

The purpose of this experiment was to investigate the effect of robot arm size, movement speed, and degrees of freedom on perceived safety, trust, mental workload, human behaviors, and task performance in a collaborative pick-and-place task. Fifty-six participants completed the experiment in a virtual reality environment where they interacted with a robot manipulator. Robot arm speed had a greater impact on self-reported measures, compared to task performance and human behavior. Overall, mean ratings of surprise and fear significantly increased across speed levels of 60 deg/s (surprise = 1.19/6; fear = 1.18/6), 120 deg/s (surprise = 1.37/6; fear = 1.33/6), and 180 deg/s (surprise = 1.65/6; fear = 1.67/6). Conversely, robot arm size and degrees of freedom had a greater influence on task performance and human behavior than on the self-reported outcomes. These findings may provide insights for robot manufacturers and standard committees to improve perceived safety in the workplace.