Regression model of horizontal force for pushing and pulling exertions with passive lower-limb exoskeletons: Effects of gender, exertion height, action, and exoskeleton design

In this era of the modern industrial revolution, there is a growing demand for passive lower-limb exoskeletons in industrial settings. However, the current research landscape on passive lower-limb exoskeletons reveals a notable absence of comprehensive studies that simultaneously consider pushing and pulling forces, anthropometry parameters, and the development of regression models. This study aimed to address this gap by formulating a regression model to predict horizontal forces exerted by individuals in pushing and pulling actions while wearing passive lower-limb exoskeletons. Moreover, the study sought to determine the correlations between horizontal force and gender, exertion height, exoskeleton design, and pushing or pulling actions. A full-factorial design of experiment was employed, with the magnitude of horizontal force as the dependent variable. Independent variables included gender, exertion height, action, and exoskeleton design. The study involved 30 male and 30 female participants, with each group subjected to 12 combinations of experimental conditions. The key findings of this study are as follows: (1) The mean force values in pushing and pulling were generally lower compared to when no exoskeleton was worn. (2) Gender, action, and exoskeleton design were found to have a significant impact on horizontal force (p-value < 0.05). The R-squared value (85.57 %) of the regression statistics suggests that the combination of these variables explains approximately 85.57 % of the observed variation in horizontal force. (3) A strong positive relationship between body mass and horizontal force was identified, indicating that increased body mass corresponded to higher exerted force. These findings have significant implications for ergonomics practitioners and engineers, offering insights for designing more efficient sitting and optimizing tasks in industrial settings. This study contributes to reducing muscle strain and aligning work processes with ergonomics standards.