Analyzing Stress and Perceived Safety in Human-Cobot Collaboration: The Impact of Task Proximity, Interface Cues, and System Errors

Abstract

Collaborative robots (cobots) are increasingly deployed in shared workspaces, where effective interaction depends not only on physical safety but also on operator trust, transparency, and comfort. This study investigates how collaboration structure, feedback modality, and system reliability affect task performance, user experience, trust, perceived safety, and physiological responses during human–cobot interaction.Eighty participants performed collaborative assembly tasks under two scenarios: a low-collaboration turn-taking task and a high-collaboration synchronous task. Feedback conditions included visual, auditory, multimodal auditory–visual feedback, and a Projected Assistive Interface (PAI) in the high-collaboration scenario. In addition, controlled anomalies, including robot failures, communication errors, and motion errors, were introduced to evaluate system resilience.Subjective evaluations, task completion times, and heart-rate variability (HRV) measures were collected. Results show that feedback effectiveness depends strongly on both collaboration structure and system state. Multimodal feedback and PAI improved task understanding, comfort, and trust, particularly during high-collaboration tasks. Preliminary results indicate that system errors reduced trust and perceived safety while eliciting measurable physiological responses. Motion errors produced stronger stress reactions, whereas robot failures primarily reduced perceived reliability. Transparent multimodal feedback also facilitated trust recovery following error events.These findings suggest that feedback mechanisms should be designed not only to support task execution but also to maintain trust and resilience under imperfect operating conditions. The study provides practical design guidelines for human-centered collaborative robotic systems operating in both normal and failure conditions.

Keywords: Human–Robot Collaboration, Collaborative Robots, Trust, Perceived Safety, Feedback Modalities, Human–Robot Interaction

DOI: 10.54941/ahfe1008084