Nested switching control design for fast PZT actuated nanopositioning

This paper studies a new nested switching control (NSC) scheme for piezoelectric (PZT) actuators to achieve fast nanopositioning. Conventional PZT controllers typically neglect the actuator saturation nonlinearity for design simplicity but at the cost of reduced performance. By optimizing a quadratic performance cost function that explicitly involves the actuator saturation, the NSC can not only guarantee the system stability in the presence of saturation but also improve the tracking speed. The simulation and experimental results on an actual PZT nanopositioner show that the new control scheme has outperformed the conventional control by more than 12% in settling time within the full PZT operational range and with nanoscale precision