Introduction of a Model for Online Adjusting the Stimulation Pattern of Arm Muscles: Applicable to Compensate the FES Related Muscle Fatigue

Functional Electrical stimulation (FES) is one of the effective techniques which uses in rehabilitation method, but the rapid muscle fatigue is constraining. The objective of this study is to introduce a model to compensate the level of muscle fatigue with adjusting the stimulation pattern. The recorded data from arm muscles have been clustered into three clusters of non-fatigue, fatigue, and exhausted by using phase plane and Fuzzy C-means algorithm. The adaptive variable structure controller could produce a controlling signal to decrease the fatigue level. This controller was combined with Prandtl-Ishlinskii hysteresis model in order to control fatigue trend in the presence of muscle hysteresis. The results showed that the control signal can compensate the fatigue trend.