Precision tracking of a 2-DOF stick-slip positioner using modeling-free inversion-based iterative control and modified inverse hysteresis compensator

Abstract

This paper presents the precision control of a 2-DOF stick-slip positioning stage that exhibits friction nonlinearity, hysteresis nonlinearity, creep nonlinearity and cross-coupling phenomenon. Considering the complexity of friction nonlinearity model, the controller was established based on modeling-free inversion-based iterative control (MIIC), which could improve the tracking performance of repetitive trajectory. In order to reduce the influence of hysteresis and cross-coupling for data-based controller, the hysteresis compensator was added based on a modified inverse Prandtl-Ishlinkskii model, and the decoupling control strategy was utilized to eliminate the coupling error. In addition, the proportion-integration-differentiation (PID) controller was adopted to form the feedforward/feedback controller and guarantee the robustness. The developed controller was applied to a 2-DOF stick-slip positioner with comparative experiments. Experimental results indicate that the performance of proposed controller is superior to pure PID controller and even PID controller combined with hysteresis compensator. And comparing with conventional MIIC controller, the influence of nonlinear disturbance could be effectively reduced.