Cyber Human Interaction: A Control Systems/Robotics Perspective on Functional Electrical Stimulation

Abstract

Application of an electric field across skeletal muscle causes muscle contractions that produce limb movement. Clinicians have long prescribed electrical stimulation as a means to strengthen muscle; however, clinicians have had a growing interest in electrical stimulation to evoke coordinated limb motions for functional tasks such as cycling. Motivation for such a cybernetic system includes advanced rehabilitative outcomes (i.e., neuroplasticity and restoration of function) for individuals with neurological disorders. A challenge to developing these outcomes is that muscle activation dynamics are uncertain and nonlinear, and the dynamics of limb motion also require the coordinated switching among multiple muscle groups. Moreover, artificial stimulation of the muscle is highly inefficient, leading to rapid muscle fatigue, which can limit the therapeutic outcomes. This talk focuses on how perspectives from and advances in robotics/automation/control systems can be used to overcome these challenges. Underlying theories and experimental results for various closed-loop electrical stimulation methods will be described, including recent advances in cybernetic cycling where a robotic bicycle is combined with an electrically stimulated person to facilitate various rehabilitative objectives.