Control for therapeutic functional electrical stimulation

Abstract

We suggest in this review paper that control of assistive systems for individuals with disability caused by injury or disease of central nervous system has to be approached with rather sophisticated methods that are capable to deal with high redundancy, nonlinearities, time variations, adaptation to the environment, and perturbations. The use of three levels that provide interaction with user, coordination of multi joint activity, and biological actuators is likely to be the solution for future electrical stimulation assistive systems. This is especially important for therapeutic assistive systems that must mimic life-like movement. The top control level needs to be discrete and secure the recognition of intended movement and possibly some kind of feedback, the middle control level needs to be discrete and provide multi joint coordination that is based on temporal and spatial synergistic model of the movement. The lowest control level needs to be model-based in order to match the specifics of the musculo-skeletal system. The hierarchical hybrid control is inherently predictive adaptive controller that, if properly designed, could results with effective generation of segment movements that lead to life like function (e.g., walking, standing, manipulation, grasping, etc.).