Control of hysteresis in a monolithic nanoactuator

Deals with the characterization and control of hysteresis in a piezoelectric nanoactuator. First, the notion of normalized ratio is introduced to quantitatively measure the strength of the hysteresis. This ratio is based on the harmonic contents of the actuator output signal and is approximately invariant under a range of input signal frequency and amplitude. Second, an analytic expression relating the harmonics to the plant parameters is derived. This expression is then applied to determine the plant parameters so that a nonlinear observer can be synthesized to cancel the hysteresis. Third, the observer-based compensator is tested in the experimental system. It is determined that the proposed compensation scheme produces significant attenuation of the hysteresis in the actuator