ADAPTIVE COMPENSATION OF PIEZOELECTRIC SENSORIACTUATORS

An adaptive filter is used to estimate the feedthrough capacitance of a piezoelectric sensoriactuator in this work. The mechanical response of the piezostructure is resolved from the electrical response of the piezoelectric device through standard adaptive signal processing techniques. Two common adaptive algorithms are reviewed for the given application: the LMS and the RLS. For spectrally white inputs the adaptation of the digital compensator yields a filter output which is proportional to the electrical response of the piezoelectric device. Thus, the remaining electrical signal consists of the charge due to the mechanical response of the piezostructure. The adaptive filter converges to a combination of the feedthrough capacitance and the real portion of the mechanical piezostructure response, and the filter error is the quadrature component of the mechanical response. Preliminary results from the theoretical analysis and numerical simulations indicate that, under certain conditions, adaptive signal processing can be employed to realize an adaptive, sensoriactuator for simultaneous strain actuation and sensing.