Linearization of hysteresis in a piezobender actuator using fuzzy logic

In the control stage of electrohydraulic servovalves one can implement piezoelectric elements serving as nozzle flapper. During voltage control of a piezobender actuator attached by one side, the displacement of its free end depends on the difference in potentials U2 and U1 supplied to its plates and on the actuator’s previous states. In applying piezobenders as a drive, an important parameter is linearity of the position characteristics x of the free end of the actuator in the function of the input signal Uin (Fig. 2). A distortion having the biggest impact on this characteristics is hysteresis.