Design and trajectory tracking control of a piezoelectric nano-manipulator with actuator saturations

Abstract

This paper presents the design of an XYZ nano-manipulator as well as the model based high precision tracking control of the nano-manipulating system. Aiming at large range and high mechanical bandwidth, the proposed mechanical design employs compound bridge-type amplifiers to increase the workspace without significant drop of stiffness. To further improve the system tracking performance and avoid possible actuator saturations, a robust anti-windup tracking control architecture combining a parallel internal-model based controller and an anti-windup compensator is adopted for the trajectory tracking of the designed nano-manipulating system. As a theoretical extension on a recent result [17], we further investigate the robust stability condition of the closed-loop system and formulate the optimization design of the anti-windup compensators as a two block H∞ optimization problem solvable with the Nehari approach. Real time control experiments demonstrate excellent tracking performance and saturation compensation capability with tracking precision error less than 0.28%, which significantly outperforms relevant algorithms in the literature.