Neurorehabilitation robot system for neurological patients using H-infinity impedance controller

Abstract

Patients with paralyzed upper extremities due to central nervous system lesion after stroke, traumatic brain injury and spinal cord injury receive rehabilitation therapy. The rehabilitation robot is studied for the effective therapy. To train the patients more effectively, it is necessary to study not only mechanisms of robots but also control strategy for rehabilitation. The purpose of various control algorithms for therapy is to implement various training repetitively and intensively. Then, these control strategies can induce the plasticity of motors and brain and improve patient s motor recovery. In this paper, we propose the upper limb robot system for neurorehabilitation. This robot is combined with the path control algorithm applying H-infinity optimization to impedance control for virtual tunnel. We present the entire robot system, robot s mechanism and procedure of optimizing the path controller for robustness. Also, the robot system is verified by test with a healthy person before it applies to the paralyzed patients.

Configuration-Dependent Optimal Impedance Control of an Upper Extremity Stroke Rehabilitation Manipulandum

“…Other than LQR, H-infinity control approaches can be used to achieve optimal performance. In Kim et al ( 2015 ), an H-infinity impedance control is implemented for an upper extremity exoskeleton. Compared to an LQR controller, the H-infinity controller is more robust because it can handle uncertainties in the impedance model.…”