Robust modeling of piezoelectric actuators for vibration drilling control

We present in this paper a new modeling approach on piezoelectric systems to get black-box pseudolinear models for the vibration drilling control. In these systems, complex phenomena occur, due to atypical changes of the process behavior, output noise or some hard non-linearities. Accordingly, identification methods to achieve the modeling task is preferred. The microdisplacements of the piezoelectric systems generate outliers in the output data, involving large errors in the estimated residuals. To deal efficiently with these data, a robust estimator is adopted. From the Huber´s p-norm in which the tuning constant is extended, we propose a parameterized robust estimation criterion (PREC) and we get the asymptotic covariance matrix of the M-estimator for the Output Error model structure. A new decisional tool for the models validation, named L₁-contribution function is proposed. Experimental results are presented and discussed.