The Effect of an Active Upper-Limb Exoskeleton on Metabolic Parameters and Muscle Activity during a Repetitive Industrial Task

Abstract

In this paper, an experimental evaluation of an active upper-limb exoskeleton, where 12 subjects perform an overhead industrial task with and without the exoskeleton, is presented. The experimental laboratory test has been carried out to analyze the advantages of wearing the exoskeleton to carry out repetitive industrial tasks, assessing whether the proposed device reduces metabolic parameters and the muscular strain. The set of metrics to assess the effects of the exoskeleton included biomechanical parameters, such as electromyographic signals, and metabolic parameters, such as heart rate, heart rate variability, respiratory frequency, tidal volume, ventilation and oxygen consumption. The results show that the developed active upper-limb exoskeleton can reduce cardiorespiratory responses and muscular activity. In addition, statistical data analysis shows significant differences in oxygen consumption, heart rate and effort supported by muscles between conditions (when handling a load of 1.7 kg with and without the exoskeleton). It is observed that, wearing the exoskeleton reduces oxygen consumption by more than 24%, the heart rate decreases by 14%, and muscle activity is reduced by almost 37% in triceps and up to 64% in biceps compare to no wearing. Based on these results, the presented active upper-limb exoskeleton could be potentially useful to reduce muscular strain and fatigue in repetitive overhead tasks.