Nonlinear and Robust Internal Model Control of a Piezoelectric Actuator Devoted to Characterization at the Micro/Nanoscale

In this paper, a nonlinear robust internal model control is suggested to control a piezoelectric actuator that is typified by hysteresis, creep phenomenon and badly damped behavior. The principle of the proposed methodology consists of combining three techniques: i) considering the creep as internal disturbance that can be rejected using a disturbance observer/compensator, ii) eliminating of hysteresis with a feedforward compensator, and iii) handling the dynamics and furnishing the global robustness using a feedback linear internal model controller. The overall nonlinear controller was implemented and verified through hardware-in-the-loop experimental tests to explore its efficiency. The results revealed that hysteresis nonlinearity in excess of 14% was reduced to less than 1%, creep in excess of 22% was completely removed, and finally oscillation with overshoot of 35% was completely damped.