Design of a 6-DoF Cost-effective Differential-drive based Robotic system for Upper-Limb Stroke Rehabilitation

This paper discusses the design, construction, and characteristics of a six degree of freedom (6-DoF) robotic upper limb stroke rehabilitation device. The device is primarily designed to be used by stroke survivors suffering from hemi-paresis, post stroke therapy. The proposed device is aimed to substitute upper limb exoskeletons or end-effector robotic arm based rehabilitation systems, which are generally bulky, expensive due to customized design, and are used only in clinical settings. The device is capable of aiding patients perform rehabilitation exercises involving abduction, adduction, flexion, and extension movements for the wrist, shoulder joints and flexion, extension, pronation, supination for the elbow joint. The device has a mobile base and uses differential drive principles for movement. The device provides an end-effector plate having force-sensitive resistors (FSRs) on which the patient can rest their hand. The mobile base of the rehabilitation system enables it to aid for a greater range of movements when compared to other end-effector-based upper limb rehabilitation devices. Additionally, a camera is mounted on top of the 6-DoF robotic system to enable finger tracking from a remote system using the MediaPipe framework, and measure the hand instability metric over time to assess patient's performance. Clinical relevance – The 6-DoF rehabilitation system is capable of aiding different range of motions for upper limb. The low-cost generic system is applicable for different physical personalities, enabling quick adoption for large patient populations who are in need of rehabilitation systems. The 6-DoF system is aimed towards clinical, and domestic usage by patients.