Measurement and tracking control of the Z-tilts error compensating stage of the nano-measuring machine

Purpose: The purpose of this paper is to develop the multi-degree-of-freedom measurement system to test, verify, and control the nano-measuring machine. Design/methodology/approach: A generic differential model approach is constructed to numerically describe the hysteresis effects of piezoelectric actuators. Based on the generic differential model, a feedforward compensator with a proportional integral (PI) type controller is designed to compensate for the hysteresis nonlinearity of a piezoelectric actuated three degree-of-freedom coplanar nanostage which can provide high-precision applications. Findings: The Z-tilts (z, pitch, and roll motion) error compensation stage of the nano-measuring machine is accomplished. Moreover, a high-resolution laser interferometer is used to measure position accurately. Originality/value: This paper contributes to develop a tracking control design method for the piezoelectric motion platform which combines a closed-loop feedforward compensator with a PI type controller.