Multi-DOF compensation of piezoelectric actuators with recursive databases

摘要

Piezoelectric actuators are subject to nonlinear effects when voltage-driven in open-loop control. In particular, hysteresis and creep effects are dominating nonlinearities that significantly deteriorate performance in tracking control scenarios. In this paper, we present an online compensator suitable for piezoelectric actuators that is based on the modified Prandtl-Ishlinskii model and utilizes recursive databases for the compensation of nonlinearities. The compensator scheme is furthermore extended to systems with more than one degree of freedom (DOF) such as Cartesian manipulators by employing a decoupling control design to mitigate inherent cross-coupling disturbances. In order to validate our theoretical derivations, experiments are conducted with coupled trajectories on a commercial 3-DOF micro-positioning unit driven by piezoelectric actuators.