Direct Drive Hand Exoskeleton for Robot-assisted Post Stroke Rehabilitation

Abstract

This article introduces novel rehabilitation hand module development for the physiotherapy of the hand of patients suffering from spastic hemiplegia. Spasm is basically a muscle cramp, it practically involves the sudden, unintended and painful contraction of a muscle or muscle group, which is caused by nerve damage resulting from a stroke. Stroke is the main reason for permanent disability in adulthood, and so the social-and medical care systems require a huge amount of healthcare resources due to the inactivity of the patients concerned. The robotically facilitated rehabilitation assists the physicians in providing repeated therapies of great intensity, and so the patients may enjoy the benefits of rehabilitation, while the therapists may reduce their own workload at the same time. Furthermore, the robotic devices offer an objective and reliable opportunity for tracing and accurately assessing the improvement of the patients' motor skills. This article introduces the electrical-and mechanical design of a therapeutic device and the inverse kinematic and dynamic modules which control this device. The rehabilitation device is capable of moving the thumb, the index-, the middle-and the ring fingers, and allows the rehabilitation of the left-and right hands as well. The device is a completely new design with direct drive approach and several benefits. It has two components: a planar module with serial kinematics of rotational joints with three degrees of freedom (3DoF RRR), and another module with two degrees of freedom (2DoF). The modules integrated load cells, which are built in between each joint to measure the reaction forces. The 3DoF finger moves the index, the middle and the ring fingers, using a load distributor placed above the fingers. The finger orthoses are connected to the load distributor via magnets. The 2DoF finger moves the thumb performing the opening/closing along the plane tilted in two angles.