About the Operator’s Gaits in the Passive Exoskeleton of the Lower Extremities when Using the Fixed Knee Mode

Abstract

A dynamic model of motion in the sagittal plane of the passive exoskeleton of the lower extremities, integrated with a similar model of a human operator that determines the movement of the whole structure, is considered. The exoskeleton is designed to help the operator to move additional point load, placed in the "backpack" on the back. The design of the exoskeleton does not have active propulsive elements in the joints; it is endowed with only a semi-automatic system for locking or releasing the knee joints at certain stages of movement, which, however, affect the overall gait pattern. The energy costs and peak values of the control torques that the human operator applies in the process of moving the exoskeleton on certain types of regular, flat, single-support walkings are studied. The results obtained allow us to estimate the effectiveness of the mode of locking-releasing the knee joint used by such devices. Both cases of impact-free transitions to the locked knee mode and transitions accompanied by the occurrence of shock effects in a dynamic system were investigated. In mathematical modeling, the mass inertial characteristics of the human body were taken into account in accordance with the data adopted in anthropology.