Human-dominated or human-robot joint teams? Impact of human-robot collaboration modes on safety performance

The application of robots in construction has made human-robot collaboration (HRC) increasingly common, but how collaboration modes perform under cognitive fatigue and task complexity conditions remains insufficiently understood. This paper defined two HRC modes, human-dominated team (HDT) and human-robot joint team (HRJT), and developed a simulated material-handling experiment. Using a within-subjects design, 32 participants completed tasks under cognitive-fatigue and task-complexity conditions in both modes. Safety performance was evaluated using completion time, route deviation frequency, and safety distance. Results showed that cognitive fatigue, task complexity, and HRC mode were associated with safety-performance changes, with patterns across indicators. Under simple tasks, HRJT showed advantages in temporal efficiency and spatial safety margins, whereas these advantages weakened or reversed in completion-time and safety-distance comparisons under complex tasks with higher fatigue. Route deviation frequency showed less clear mode differences. These findings reveal condition-dependent safety-performance patterns across HRC modes and support adaptive HRC design in construction.