[Research on control technology of functional electrical stimulation in wrist movements based on Hammerstein model]

For most of nonlinear systems, control strategy is complicated. The adaptive control methods based on the model identification can effectively improve the control precision and stability. According to the nonlinear and time-changeable characteristics of the wrist movement in the functional electrical stimulation, modeling and identification of wrist movement based on Hammerstein model were implemented. By using M sequence and invert-repeated M sequence as excitation signal, the wrist model is divided into the linear dynamic part and the nonlinear static part. The characteristics of nonlinear part being taken into consideration, an adaptive control method based on time-changeable characteristics of linear part is presented. This method simplifies the control strategy, and it is validated by the simulation experiment of FES.