Comparative analysis of an electromechanical model of an exoskeleton with links of variable length and a model containing absolutely solid links

The plane motion of an exoskeleton with five links of variable length is considered. It is assumed that there is a person inside the exoskeleton, and the exoskeleton is equipped with sensors that read indicators of a person’s muscle activity, convert them into control signals for electric drives and instantly implement them in the exoskeleton. The novelty of the study is due to the model of changes in the lengths of sections of exoskeleton links. The relevance of the research lies in the possibility of restoring and enhancing the motor functions of the human body with the help of an exoskeleton and replacing people with anthropomorphic mechanisms in harmful and hazardous production that does not have the ability to use wheeled, tracked and other types of robots. The model specifies the design of links of variable length. Each link includes a weightless section with varying length, located between two absolutely solid weighty sections. Numerical and analytical modeling was carried out based on solving the inverse problem of dynamics for the mechanism under consideration. A method has been developed for controlling the proposed mechatronic robotic system in the form of a person in an exoskeleton based on specifying programmed movement and determining control moments localized in large hinge joints and longitudinal forces that determine changes in the lengths of the mechanism links. A comparison is made with the model containing absolutely rigid links, considered earlier. The problems that arise when taking into account changes in the lengths of links are identified. A model of the functioning of the human-exoskeleton biomechatronic system is proposed.