Development and Repetitive-Compensated PID Control of a Nanopositioning Stage With Large-Stroke and Decoupling Property

Abstract

Piezoelectric-actuator-driven nanopositioning stages, with large stroke and low crosstalk, are quite appealing for fulfilling the through-silicon via lithography etching task. The motivation of this paper is to combine the ability to enable the nanopositioning stage running in a manner of millimeter scale workspace and nanometer scale positioning accuracy. Two pairs of flexure-guided kinematic modules with high displacement amplification ratio are adopted to construct a 4-PP (P is prismatic) XY nanopositioning stage. A new decoupling design is implemented to realize the decoupling behavior between the input actuators and output compliant limbs, respectively. Kinematics modeling including output compliance, input stiffness, displacement amplification ratio modeling, and workspace determination are carried out. After a series of mechanism dimension optimizations via particle swarm optimization algorithm, the performance of the optimized mechanism is analyzed and assessed by using the ANSYS workbench. Then, a repetitive-compensated PID controller and a single-input and single-output closed-loop control strategy are designed. Finally, a series of experimental tests in terms of crosstalk test, frequency characteristic analysis, damping property analysis, dynamic hysteresis nonlinearity characterization, signal trajectory tracking, workspace determination, and Bode diagram plotting are carried out in details. It indicates that the workspace of fabricated prototype has reached to 1.035 mm $\times$ 1.035 mm, the crosstalk ratio is kept within 0.5%, and the closed-loop positioning accuracy is determined as 400 nm.