Control methods for exoskeleton rehabilitation robot driven with pneumatic muscles

Abstract

Purpose The purpose of this paper is to present the control methods of the exoskeleton robotic arm for stroke rehabilitation. Design/methodology/approach The robotic arm is driven by the pneumatic muscle actuators. The control system provides independent control for the robot. The joint axes of the robotic arm are arranged to mimic the natural upper limb workspace. Findings Findings are the classification of training modes and control methods of rehabilitation training, and the characters of both the instant spasm and the sustaining one. Research limitations/implications This paper is a preliminary step in the control system and the kinematical characteristics should be analyzed to achieve high precision of movement. Originality/value Based on a hierarchical structure, the control system allows the execution of sequence of switching control methods: position, force, force/position and impedance. Patient‐active‐robot‐passive and patient‐passive‐robot‐active (PPRA) training modes are also presented in this paper. In PPRA mode, the robotic arm can provide pre‐specified resistances on the patient's arm. Both instant and sustaining spasms are taken into account for safety.