Integral Non-singular Terminal Sliding Mode Control for Tri-axis Piezoelectric Stage

For multi-axis positioning, this paper develops a piezoelectric (PZT)-driven tri-axis positioning stage, which is equipped with a flexible mechanism to achieve the advantages of low interference, high speed and high precision. Firstly, the PZT stage is systematically identified to obtain the transfer function of the stage, and then the mathematical model of the stage is established to evaluate the control performance of the proposed control methods. The control method in this paper firstly uses integral non-singular terminal sliding mode control (INTSMC), which can converge in a finite-time and achieve the effect of eliminating chattering. Then, a disturbance observer (DO) is designed to estimate the system disturbance. The INTSMC combined with the DO control method can achieve a more perfect control effect for the xyz-stage. In this paper, the control experiment analysis is given to validate the tracking control performance of two proposed control schemes.