The Dead Zone Determination for Exoskeleton Arm with Double Mode Control System

The main goal of this paper is to determine the dead zone of control signal to provide the modes shift in the exoskeleton control system. The kinematic system consists of two subsystems for left and right hands. Each subsystem has 4 DOF and it is controlled individually. The control system for the designed exoskeleton device is based on bioelectric potentials processing. It uses the information about muscular activity to form the rotation speed of exoskeleton drives. The exoskeleton’s servo drive system is based on the feedback technique of acquiring information from the actuators and passing it to the control system via the HMI. The dead zone of control signal allows shifting control modes to let the exoskeleton device running in two modes – the setting speed mode and angle tracking mode. The dead zone of control signal also allows signal noise and positioning error reduction. The proposed idea is the definition of the dead zone as nonlinear function of joint coordinates.