Online parameter identification of the asymmetrical Bouc–Wen model for piezoelectric actuators

The hysteresis of piezoelectric actuators (PAs) possesses the asymmetrical and frequency-dependent characteristics. In order to accurately model the hysteresis of a PA, an asymmetrical Bouc–Wen model is proposed and established in this paper. The recursive least-squares online identification method is used to real-time identify the parameters of the proposed model. Meanwhile, in order to avoid the data saturation phenomenon, the limited memory method is used to limit the number of the data sets. The experimental system is setup and the performance of this method is experimentally verified. Experimental results show that the proposed online identification method can effectively improve the modeling accuracy.