Multivariable Compensation of Hysteresis, Creep, Badly Damped Vibration, and Cross Couplings in Multiaxes Piezoelectric Actuators

This paper presents the control of a two-degree-of-freedom piezoelectric actuator that exhibits hysteresis non-linearity, creep nonlinearity, badly damped vibration, and cross couplings without using feedback sensors. The principle consists in compensating first the hysteresis, then the creep, and finally the vibration. The proposed compensation technique is multivariable and therefore is also able to reduce the cross couplings that are unwanted phenomena. The experimental tests demonstrate that the hysteresis that initially exceeds 19% is reduced to about 0.01%, while the creep is reduced from 5.5% to 0.04%. Regarding the vibration, the related overshoot that was initially 45% is completely removed.