Design and control of robotic systems for upper extremity rehabilitation following stroke

Abstract

Stroke is the leading cause of serious, long-term disability in the United States. Each year, about 795,000 Americans experience a new or recurrent stroke, resulting in an estimated stroke population of 7 million in the USA. Upper extremity impairment is a prevalent outcome of stroke. Loss of arm and hand function due to neuromuscular disorders frequently prevents effective self-care and limits employment opportunities. In recent years, robot-assisted rehabilitation has been an active area of research. Various robotic systems and strategies have been developed to make robot an effective tool in stroke rehabilitation. This dissertation presents the research work to improve robot-assisted rehabilitation of the upper extremity. First, a high-level supervisory controller is designed to incorporate voice recognition to a robotic system for arm rehabilitation. The high-level controller monitors task execution and makes task adjustment according to the user¡¯s verbal feedback to impart effective rehabilitation therapies. The enhanced robotic system is able to improve the efficiency of arm rehabilitation therapy and reduce the workload of the therapist. Next, an integrated rehabilitation strategy of assist-as-needed and visual error augmentation is proposed and implemented on a robotic system. This strategy is evaluated in a crossover study with 20 subjects. The experimental results demonstrate that the proposed strategy has significantly improved the task performance of healthy subjects and has the potential to improve the efficiency of stroke rehabilitation. Last, an actuated hand exoskeleton is developed for hand rehabilitation study. The hand exoskeleton consists of an actuated finger exoskeleton (AFX) and an actuated thumb exoskeleton (ATX). It allows individual control of each joint of the index finger and the thumb with substantial joint torque and speed capacities that are necessary for stroke rehabilitation. The kinematic and kinetic performances of the AFX and the ATX have been tested and met all design requirements. This device will provide a platform that permits comprehensive research of different rehabilitation therapies and motor control studies of the hand. Contributions and future directions of the research work are discussed at the end of the dissertation.