An Approach to Applying Feedback Error Learning for Functional Electrical Stimulation Controller: Computer Simulation Tests of Wrist Joint Control

Abstract

Feedback error-learning (FEL) controller that consists of a proportional-integral-derivative (PID) controller and an artificial neural network (ANN) had applicability to functional electrical stimulation (FES). Because of the integral (reset) windup, however, delay or overshoot sometimes occurred in feedback FES control, which was considered to cause inappropriate ANN learning and to limit the feasibility of the FEL controller for FES to controlling 1-DOF movements stimulating 2 muscles. In this paper, an FEL-FES controller was developed applying antireset windup (ARW) scheme that worked based on total controller output. The FEL-FES controller with the ARW was examined in controlling 2-DOF movements of the wrist joint stimulating 4 muscles through computer simulation. The developed FEL-FES controller was found to realize appropriately inverse dynamics model and to have a possibility of being used as an open-loop controller. The developed controller would be effective in multiple DOF movement control stimulating several muscles.