文摘
This paper presents a modified Bouc-Wen (MBW) model based Hammerstein-like structure to describe the hysteresis in piezoelectric actuators (PEAs) with asymmetric and rate-dependent characteristics. Firstly, a MBW model with a third-order input function is proposed to characterize the hysteresis with asymmetric feature. Then, to describe the rate-dependent behavior of the hysteresis in PEAs, the MBW model is cascaded with a linear dynamics model as a Hammerstein-like model structure. To derive the parameters of this model structure, three identification steps are performed with different input signals: (i) the delay time of the PEA-actuated nanopositioning stage is tested with a step signal input; (ii) the linear dynamics model is identified with a low-amplitude white noise input; (iii) with the identified delay time and linear dynamics model, nonlinear least squares optimization method is adopted to derive the parameters of the MBW model using a multiple-amplitude triangular signal input with low frequency. Finally, to evaluate the Hammerstein-like model structure, experiments are carried out on a PEA-actuated nanopositioning stage. The experimental results verify that the predicted responses of the MBW model based Hammerstein-like structure well match the system responses.