Design of Tangential-Contouring Control for direct drive XY table based on H∞ velocity feedback

To improve the contour machining precision of XY table, the control strategy combining H∞ velocity feedback controller and Tangential-contouring Controller (TCC) was presented on the basis of analyzing the contour error of system. The H_∞ control theory was used to design a feedback controller in order to guarantee robust stability and robust performance of the closed-loop system under the condition of model perturbation and external disturbance. TCC makes the coupling effect between two axes eliminate and the design of contour controller become more direct and simple, to reduce the contour error furtherly. A compound controller combining the IP (proportion-integration) control with speed feed-forward control was used for the single axis system. The simulation results show that the designed control system possesses good tracking performance, strong robustness and high contour accuracy.