Contouring accuracy improvement of a dual-axis micro-positioning stage powered by piezoelectric actuator

In industrial precision applications using dual-axis micro-positioning stages powered by piezoelectric actuators (PEA), the trajectory tracking and contour following performances are limited due to PEA´s inherent hysteretic nonlinearity and time varying parameters. In order to cope with this problem, a position control scheme based on reinforcement learning cerebellar model articulation controller (RLCMAC) is developed in this paper. In the proposed control scheme, for each individual-axis, a CMAC-based feedforward controller with reinforcement learning scheme and a conventional proportionalintegral (PI) feedback controller are used. Moreover, in order to reduce contour errors, a CMAC-based cross-coupled controller (CMAC-CCC) is applied to improve the contouring accuracy of a dual-axis micro-positioning stage. Finally, an integrated control scheme is proposed to improve the tracking and contouring accuracy. Experimental results verify the effectiveness of the proposed approach.