Design and Development of a 7 DOF Robot with Ergonomic Shoulder for Upper Limb Rehabilitation

Abstract

With the increase of stroke patients, the number of upper limb dysfunction is increasing day by day. Robotic intervention in upper limb (UL) rehabilitation of post-stroke patients has gained much traction in recent years. Though many research groups have developed exoskeletons, existing exoskeletons have limitations in both hardware design and control approaches. In most cases, rehabilitative robotic devices have not considered the movement of the shoulder joint’s center (center of glenohumeral joint); however, this movement leads to misalignment between human joints and robot joints, which is undesirable in any circumstances. To ensure better human-robot interaction (HRI), allowing mobility of shoulder joint’s (glenohumeral joint) center of rotation without reducing the range of motion (ROM) remains a great challenge for UL exoskeleton researchers. Furthermore, being able to function as end-effector setup and exoskeleton setup (i.e., dual functionality) is a crucial need for exoskeletons to provide joint-based exercises and end-point exercises depending on the patient’s condition, impairment level, and stage of rehabilitation. Moreover, interaction forces between user and robot have largely been ignored in passive rehabilitation. Force can also be used in performing active exercises. In this research, an upper limb robotic exoskeleton has been designed and developed to provide better HRI, dual functionality, safe and effective, and patient-tailored therapy. The experimental results have shown its potential to be used with stroke-patients in a hospital setting.