Factors Affecting Workers' Mental Stress in Handover Activities During Human-Robot Collaboration.

Area of Science:

• Human-Robot Interaction
• Occupational Safety and Ergonomics
• Robotics and Automation

Background:

• Human-robot collaboration (HRC) is increasingly adopted in industrial settings.
• Identifying robot-induced stressors is vital for designing worker-friendly collaborative tasks.
• Minimizing worker mental stress enhances safety and productivity in HRC.

Purpose of the Study:

• To investigate how robot end-effector approach direction, speed, and trajectory influence worker mental stress during handover tasks.
• To quantify the impact of specific robot movement parameters on physiological and subjective stress indicators.
• To provide data-driven recommendations for designing less stressful HRC scenarios.

Main Methods:

• Mental stress was assessed using subjective self-reports and objective measures like galvanic skin response (GSR) and electromyography (EMG).
• The study analyzed the effects of varying robot approach directions, movement speeds, and end-effector trajectories.
• Statistical analysis was performed to determine the significance of each factor and their interactions on stress levels.

Main Results:

• Robot movement speed and approach direction significantly impacted subjective stress ratings, EMG, and GSR.
• High speeds and side approaches correlated with increased fear, reduced comfort, and higher stress indicators.
• Movement trajectory influenced GSR, with sudden stops causing a more pronounced response than constrained paths.

Conclusions:

• Worker mental stress during HRC is minimized when the robot's end-effector approaches within the worker's field of view.
• Slower robot movement speeds and constrained trajectories further reduce worker mental stress.
• These findings offer practical guidelines for designing safer and more comfortable HRC tasks.