Iterative contouring controller design for biaxial feed drive systems

This article proposes a new approach for high speed and precision motion control of feed drive systems by considering both tracking and contour errors. Iterative learning control is used whereby the tracking error is considered in the feedback controller and the contour error in the feedforward controller. Without changing the original trajectory assigned by NC code, the proposed controller improves the tracking performance under sharp corner motion. The combination of errors and the use of iterative learning control lead to fast convergence within a few iterations. To analyse the performance, the conventional approach that uses only the tracking error has been considered for comparison. Simulation results show that the designed controller can significantly improve the performance of feed drive systems. The proposed method has demonstrated that the maximum contour error can be reduced by 46.3 %.