Feedforward and IMC-feedback control of a nonlinear 2-DOF piezoactuator dedicated to automated micropositioning tasks

Abstract

This paper presents the characterization, modeling and precise control of a 2-dof piezoactuator dedicated to precise and automated micropositioning tasks. The piezoactuator is characterized by a strong hysteresis and a high coupling between the two axes making the synthesis of a controller very difficult. We therefore propose to compensate first the hysteresis (feedforward control) in order to obtain an approximate linear system. Afterwards, an internal model control (IMC) structure is applied (feedback control) to enhance the performances of the piezoactuator. The main advantage of the proposed approach is its simplicity both for computation and for implementation making it very convenient for real-time embedded systems. Finally, the experimental results demonstrate its efficiency and conveniency for precise positioning.