Effects of the Exoskeleton on Human Physiological Stress

Despite the advantages of powered exoskeletons for occupational safety, their design, including characteristics such as weight and volume, may induce localized physiological burdens on operators. The current understanding of how exoskeleton characteristics impact physiological stress is unclear. Therefore, this study designed an experimental exoskeleton with the capability for external feature expansion (EXOT). EXOT comprises four parts for the upper and lower limbs, each coupled to the human body through commonly used strapping methods in exoskeletons. The experiment utilized a polr heart rate monitor to collect heart rate variability (HRV), and Rating of Perceived Exertion (RPE) questionnaires were collected at the beginning and end of each task for physiological stress assessment. The results indicated a significant increase in the LF and HF ratio of HRV with an increase in load weight compared to the control group, with the highest activation observed in the upper limbs. The LF and HF ratio exhibited significant inter-group differences between M1 and M2 under varying walking speeds. Participants in the M1 and M2 configurations showed an increasing trend in RPE compared to the control group. This study suggests that higher exoskeleton mass exacerbates the physiological stress.