The experimental investigation of the sensitivity in the exoskeleton control loop

Abstract

An exoskeleton system contains a human operator in the control loop, which imposes restrictions on the applied control algorithms and movement speed. Thus, the creation of exoskeleton device with an EMG-based control system that takes into account the interaction of humans and exoskeleton design elements becomes one of the most actual tasks of modern robotics.At the moment, there are a number of tasks in research projects towards exoskeleton control algorithms. These tasks include consideration of fatigue of a person arising from the control of the exoskeleton over long period of time. Operator's fatigue, as a result of the monotonous operations, leads to the fact that the control efficiency decreases, and the positioning error will increase over time. Another task when controlling using human biopotentials is compensation of the influence of the operator's tremor on the control signal. Also, a very important factor is the adaptation of actuators to a change in the transient characteristics of external and internal forces. The designed control algorithms should prevent possible injuries while using the exoskeleton device.This article describes the results of tests of an arm exoskeleton device with DC drive located in the elbow joint and a control algorithm based on an electromyogram of the biceps brachii and triceps brachii of the operator. The structure and features of the experimental stand developed in the laboratory of robotics and mechatronics of IPMech RAS are shown. The features of parameter settings during calibration of the exoskeleton control system are shown.