Abstract-The minimum variance principle is, generally, used for controller's synthesis. In this paper, we propose another use of this principle to identify the hysteresis property of piezoelectric actuators using the Extended Least Squares identification technique adapted for the ARMAX model. IndexTerms-Piezoelectric actuator, nonlinearity, hysteresis, identification.
I. INTRODUCTIONThe piezoelectric actuators (PEA) based on the inverse piezoelectric effect are used in many fields due to their properties. Indeed, for example they are very used in the ultra-precision applications [1]- [3]. However, the hysteresis property, existing in piezoelectric materials, makes the modeling and the control of PEA difficult. Many nonlinear models was developed in the literature to describe the hysteresis property of piezoelectric actuators such as the Preisach model and its modifications [4]-[8], the Duhem model [9], [10], the Maxwell Resistance Capacitor (MRC) model [11], the Bouc-Wen model [12]-[15], the PrandtlIshlinskii model [16]-[20] and the modified Rayleigh model [21]. A survey on these models can be found in [22]. Furthermore, the experimentation showed that the hysteresisnon-linearity in PEA is not symmetric and many models was proposed in [23]- [25] to describe the asymmetric hysteresis existing in PEA. To compensate the hysteresis behavior of PEA, many intelligent techniques was used such as fuzzy logic [26] [35]. The most previous models are nonlinear and difficult to implement in on-line which makes the controller synthesis and analysis difficult. To deal with this problem, the PEA can be described by linear models using identification algorithms [36], [37]. In this paper, we propose a technique for the description of the hysteresis property. This technique is based on the modification of the minimum variance controller algorithm to be used for identification purpose. This paper is organized as follows: the extended least squares recursive identification method is described in Section II, then, the proposed minimum variance identification scheme is presented in Section III and before concluding, the proposed approach is validated through simulation results. Manuscript received March 9, 2014; revised June 20, 2014. A. Rebai and B. Hemici are with the National Polytechnic School of Algiers, Algeria (e-mail: aissa.rebai@g.enp.edu.dz, bhemici@yahoo.fr).K. Guesmi is with the CReSTIC, Reims University, France (e-mail: guesmi01@univ-reims.fr).
II. THE EXTENDED LEAST SQUARES (ELS) IDENTIFICATION METHODSThe piezoelectric actuator can be described by the ARMAX model of the following expression:And y(t), u(t) are respectively the output and the input signals, e(t) is a white noise with zero mean value and constant variance and d is pure time delay.Hence, model (1) can be written as:( 1)
The prediction error between the real and the estimated output () εt is defined by:We define also the criterion J(t): International Journal of Computer and Electrical Engineering, Vol. 6, No. 4, August 2014 DOI: 10.7763/IJCEE.20...