Evaluating the Impact of VR Training Strategies on HRI Cooperative Assembly Performance

Virtual Reality (VR) has emerged as a powerful tool for improving training strategies in advanced manufacturing through immersive experiences. Within this context, this study examines the impact of two training strategies, VR and Video-Based (VB) instructions, on system performance (execution time and human errors) in a cooperative Human-Robot Interaction (HRI) assembly task. Overall, 26 participants completed the task after receiving either VR or VB training, and a sub-sample of 6 people per group returned one month later to repeat the task, enabling an evaluation of performance over time. Objective and subjective metrics were collected, and statistical and effect size analyses were conducted to compare training effects across sessions. Results show that execution times and number of errors were comparable between VR and VB in the first real session. After one month, both groups exhibited improved performance, but VR-trained participants retained, on average, lower error rates, with a 71% reduction and the number of errors dropping to zero, and more stable error patterns, whereas VB-trained participants displayed greater variability and occasional accuracy degradation during repeated task execution. Moreover, within-group comparisons show that VR training is more effective for accuracy-critical cooperative HRI tasks. At the same time, VB remains a low-cost option for time-focused contexts, shedding light on how training modalities influence learning and forgetting in Industry 5.0.