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.

Occupational ApplicationsAutonomous mobile robots are used in manufacturing and warehousing industries, to transport material across the facility and deliver parts to work cells. Human workers might encounter or interact with these robots in aisle ways or at their workstation. It is important to consider factors that impact worker safety and trust when implementing autonomous mobile robots in the workplace. This paper reviews prior research that aims to improve the safety of human-robot interaction with autonomous mobile robots and identifies needs for future research. Researchers used a variety of questionnaires and behavioral assessment methods to measure perceived safety. Factors such as robot appearance, approach speed, and approach direction, significantly affect perceived safety. Additionally, projection of signals on the floor, turn signals, and haptic communication devices, can improve the predictability and overall safety of robot navigation. | Introduction: Autonomous mobile robots are rapidly emerging in the workplace, which potentially creates new hazards for human workers that interact with them.Purpose: We aimed to systematically review previous research on human-robot interaction with autonomous mobile robots that apply to industrial environments, and to identify research needs to improve worker safety and trust.Methods: We completed a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses methodology. We focused on articles that contained experiments with human participants and that included findings associated with improving safety and/or trust of workers who interact with mobile robots in industrial environments. We identified 50 articles that fit inclusion/exclusion criteria for the review.Results: Almost all of the reported experiments were conducted in a controlled laboratory setting. There were 27 different types of autonomous mobile robots. Only two studies involved industrial mobile robots that were commercially available and could be implemented in an industrial environment. Most studies used questionnaires, with the most common topic relating to participant perceptions of various robot traits, while few directly evaluated perceived safety and trust using questionnaires. Behavioral and physiological assessment methods were used in 70% and 8% of the studies, respectively. Separation distance between the participant and robot was the most common behavioral assessment method. A variety of robot characteristics were found to have a significant effect on human perception of safety and other similar concepts.Conclusions: Future research requires rigorous reporting of participant demographics and experience level with robots. We found that 34% and 44% of references failed to report the mean age of their participant sample and their experience with robots, respectively. Among several gaps that we identified in the literature were a lack of field experiments, sparse research involving multiple mobile robots, and limited use of industrial mobile robots in experiments with human participants. | eng