Positive position feedback based high-speed tracking control of piezo-actuated nanopositioning stages

Abstract

This paper presents a high-speed tracking control approach for third-order piezo-actuated nanopositioning stages, which extends the vibration control strategies tailored for damping the resonant modes of second-order systems (SOSs) to third-order systems (TOSs). The extension consists of three steps: i) decomposing the TOS into a SOS and a first-order system (FOS); ii) designing the vibration controller for the SOS; iii) extending the vibration controller to the TOS by cascading the controller with the inversion of the FOS. To illustrate the effectiveness of the proposed approach, the positive position feedback (PPF) controller cascaded with dc-gain inversion of FOS is designed. The extended PPF controller is adopted in the inner feedback loop to damp the resonant mode of the system. Then, in the outer loop, a high-gain proportional integral (PI) controller is utilized to minimize the tracking errors due to disturbances and modeling uncertainties. Experimental results on a piezo-actuated nanopositioning stage demonstrate that the proposed control approach achieves high-speed tracking by improving the control bandwidth from 80 Hz (with PI controller) to 322 Hz.