Development of sensorless based bimanual tele-rehabilitation robot for hemiparetic post-stroke patients

Abstract

Stroke patients experience difficulties doing bimanual activities due to loss of inter-limb coordination. This is commonly in arms, and most patients continue to suffer from paralysis in one arm after recovery from the stroke. Our focus is to implement the master-follower robotic system to regain the functionality of the paretic arm using the healthy arm to enhance the rehabilitation process. This robot includes two basic and important exercises: flexion & extension of elbow joint and internal & external rotation of shoulder joint. The system consists of two single Degrees of Freedom (DOF) robotic arms capable of giving resistance according to the torque profiles of a healthy arm. Both arms are moved simultaneously using bi-manual motor control, simulating the assistance from the therapist by virtual spring action. The study applied sensorless sensing techniques: the Reaction Torque Observer (RTOB) and the Disturbance Observer (DOB) for motor torque estimation and robust control respectively. Hence, with this robotic approach, the paper provides a comfortable and robust rehabilitation solution.