About the Use of Gearless Electric Motors in the Construction of an Exoskeleton Walking on an Uneven Surface

Abstract

The regular walking (up or down) on a ladder (or an inclined plane) of a human operator with an exoskeleton of the lower extremities, carrying an additional load, is considered. It is assumed that the exoskeleton is equipped with high— torque electric motors without gearboxes — in the knee and, perhaps, in other joints. The modes of flat, single-support quasi-comfortable walking are considered, in the implementation of which both electric motors and a human operator with experience working with this mechanism participate. The nominal pattern of movement associated, in particular, with the circumvention of obstacles (steps) with a portable foot and placing it in the support position at the next step is set and supported by a person. The task of the algorithm controlling electric motors is to partially reduce the load that falls on the operator. From the point of view of minimizing human energy consumption, the supporting leg and especially its knee joint are the most important. In the knee joint of the supporting leg, an algorithm for controlling the corresponding electric motor is proposed, based on measuring the vertical reaction force of the support in combination, perhaps, with the angle in the knee and angular velocity. Feedback is constructed, the "successful" values of the coefficients of which can be predicted using a kind of least squares method along the nominal mode. The task of this feedback is actually the distribution of the load that falls to the share of the operator and the system of electric motors. It is shown by using numerical research methods to what benefits in terms of energy consumption in one regular step this can, in principle, lead. This principle of feedback construction extends further to the hip and ankle moments of the supporting leg. It is assumed that the portable leg is controlled everywhere only by the human operator’s own efforts, the absence of gearboxes allows this to be done without much friction loss, which in turn affects the smallness of energy costs and for the operator.