A Literature Review on Safety Perception and Trust during Human-Robot Interaction with Autonomous Mobile Robots That Apply to Industrial Environments.

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.

The Effect of Prolonged Walking With Intermittent Standing on Erector Spinae and Soleus Muscle Oxygenation and Discomfort.

Prolonged periods of walking have been associated with musculoskeletal discomfort and injuries. Previous research has shown that muscle fatigue is related to decreases in muscle oxygenation during short term walking. The objective of the proposed research is to determine the impact of prolonged walking with intermittent standing on musculoskeletal discomfort and muscle oxygenation measures in young adults. Nine young adults walked for a period of 2 hours. Ratings of perceived discomfort were recorded using a questionnaire. Muscle oxygenation and hemoglobin levels were collected from the lower back erector spinae and soleus muscles using near infrared spectroscopy (NIRS). Subjective discomfort significantly increased throughout the 2 hours. Prolonged walking generally induced increased oxygenation of the erector spinae and soleus across walking periods, within walking periods and across standing periods. These increases were more pronounced at the beginning of the walking session and continued through the second or third periods. Erector spinae and soleus total hemoglobin increased within walking period one and two. Only the soleus total hemoglobin significantly increased after the first walking and standing periods and during all the transitions from walking to standing. Increased oxygenation and total hemoglobin during prolonged walking with intermittent standing are likely a result of the repeated dynamic contractions and exercise-induced blood volume expansion. Increased discomfort was found; however, this was not explained by detrimental changes in oxygenation or total hemoglobin.

Modeling Hand Trajectories during Sequential Reach Movements in a Pulley Threading Task.

Modeling of human motion is common in ergonomic analysis of industrial tasks and can help improve workplace design. We propose a method for modeling the trajectories of hand movements in the frontal plane during a sequential reach task that involves threading string through a system of pulleys. We model the motions as a combination of two consecutive phases, one where the hand is reaching between pulleys and another when the hand is engaged in threading a target pulley. Hand trajectories were modeled separately for each phase by fitting basis-splines to the observed data. Predicted trajectories were computed using task parameters as the input and compared to average trajectories from the 12 participants who completed the study.

A Pilot Study of the Effects of Pulley Location and Design Parameters on Hand Movements during Pulley Threading Operations.

Three healthy individuals participated in a laboratory experiment that required routing a thin continuous thread through a series of pulleys mounted on a vertical work surface. Task precision demand was manipulated by altering pulley outer diameter (38 mm, 76 mm, and 152 mm) and groove width (3 mm, 6 mm, and 9 mm). The target location of each destination pulley relative to the origin at the mid-sagittal plane was also manipulated. These factors were hypothesized to influence hand motion trajectories, peak speed, and task completion time. Smaller pulley diameters and larger groove widths, representing lower precision demands, were associated with smoother trajectories and a faster task completion time. These preliminary findings suggest a systematic influence of task precision demands on movement kinematics and task performance.