Robust tracking control of a novel piezodriven monolithic flexure-hinge stage

This study presents the controller design and tests of a piezo-driven system for precision motion of a novel two degree-of-freedom (DOF) monolithic stage. The computer-controlled system was developed, designed and employed for better displacement error compensation by PID controller based on Internal Model Control (IMC), Iterative Learning Control (ILC) and Disturbance Observer (DO). Experiments results shows that stage positioning is precisely controlled (error ≈ 1.42%) for tracking sinusoidal waveforms by IMC and P-type ILC with repeatable disturbance. With additional DO, experiment tests perform error ≈ 0.5% with non repeatable disturbance up to 16% of the maximum traveling length by in roughly 5 iterations. This is close to the hardware reproducibility level. Experimental results show the piezo-stage control system can be potentially used for nano technology applications for precision engineering in industrial systems.