Dynamic modelling and tracking control of electro-responsive hydrogel with hysteresis and creep nonlinearity

The electro-responsive hydrogel (ERH) exhibits the rate-dependent hysteresis nonlinearity and creep nonlinearity, which brings significant challenges for its dynamic modelling and tracking control. To address these challenges, this paper dedicates to proposing effective dynamic modelling and trajectory tracking control methods of the ERH. First, a dynamic model is established by paralleling the Bouc-Wen model with the creep model, which is used to simultaneously describe the rate-dependent hysteresis nonlinearity and the creep nonlinearity of the ERH. Then, a tracking controller is designed to achieve the trajectory tracking control of the ERH. The designed tracking controller consists of an inverse dynamic feedforward controller and a proportional-integral feedback controller. Finally, a series of tracking control experiments with different target trajectories are conducted. The root-mean-square errors for the results of all tracking control experiments are less than 2.80%, which verifies the efficiency of the established dynamic model and designed tracking controller.