How automation effect mental workload of novice operators in space rendezvous and docking

Abstract

The present study investigated the effect of automation on the mental workload of novice operators in manual rendezvous and docking (RVD). One within-subject experiment was designed and fifteen participants participated in the experiment. All participants were required to finish six RVD tasks of two automation levels: manual RVD and the automation-aided manual RVD. Workload of the participant during RVD tasks were assessed with subjective and physiological indicators. Subjective workload was measured by NASA Task Load Index (NASA-TLX). Physiological workload indicators included mean heart rate, the root mean square of successive differences (RMSSD), the low frequency (LFNU, 0.04 to 0.15 Hz) and high frequency (HFNU, 0.15 to 0.4 Hz) power spectrum component of heart rate variability (HRV, both in normalization form), the LF/HF ratio, and the total power (TP). The results showed that subjective workload rating were significantly lower in the automation- aided RVD as compared to that of manual RVD task. However cardiovascular measures showed different pattern. Mean heart rates, RMSSD and TP of participants did not change significantly with the change of automation level, LFNU was significantly higher, and HFNU was significantly lower in automation-aided RVD task as compared to that in manual RVD task. The results showed that despite a perceived workload reduction in automation-aided RVD, the objective measures of HRV reflected a workload increment. A possible reason is that novice operators were not familiar with automated system, thus it was difficult for them to understand and anticipate the intention and action of automation. The results inferred that application of automation to such complex and dynamic tasks for novice operators should be cautious; novice participants need more training to build deeper understanding of automation system.