Novel approach to self-sensing actuation

Self-sensing approaches for controlling piezoelectric materials thus far have been composed of slight variations on a theme; the theme being a linear bridge technique for extracting the self-sensing signal. Linear bridge-based self- sensing however has always been plagued with problems of impedance mismatching, drift, and instability, all due to the nonlinearities inherent in piezomaterials. Additionally, all past self-sensing research has been limited to strictly ac sensing applications, hence the abundance of vibration suppression papers. We propose a novel self-sensing technique which shows promise in reducing most if not all of these problems. The approach dubbed OBSS (observer based self- sensing) is akin to state estimation techniques in that is uses electric field and electric displacement information coupled with the linear piezoelectric constitutive relations to estimate the material's stress and strain states. Additionally, since most piezomaterials exhibit significant hysteresis, a real-time compensation method using the generalized Maxwell slip hysteresis model must be employed to minimize this nonlinear effect. Theoretical development and experimental validation of the OBSS technique is presented.