关于非线性系统辨识的恢复力曲面法和希尔伯特变换法

Two nonlinear system identification methods including the restoring force surface method and Hilbert transform one were compared based on experiments of a homogeneous plate and a piezoelectric bimorph one. The stiffness-displacement function was proposed to be used for data fitting instead of the restoring force-displacement function in the function approximation process. The experiment results of a homogeneous plate and a piezoelectric bimorph one showed that using the stiffness-displacement function can improve the function approximation accuracy at small displacements. The identification accuracy and data utilization rate obtained by the restoring force surface method were compared with those obtained by Hilbert transform one. The results showed that Hilbert transform method can effectively suppress irregular oscillations of the stiffness-displacement curve at small displacements, and it has a higher data utilization rate.