Predictive Contour Control for Multi-axis Motion System with Unified Model

Abstract

In the framework of finite control set model predictive control (FCS-MPC), a multi-axis motion system predictive contour control strategy based on the idea of unified modeling is proposed in this paper. This method does not require any cascade PI controllers or cross-coupling controllers, which are generally adopted by vector-based multi-motor control system, can effectively improve the dynamic performance and accuracy of the contour trajectory. First, the candidate voltage vectors are selected by taking the tracking errors as the main index. Then taking the contour errors and the performance of motors as evaluation indexes, a unified predictive model and the cost function of multi-axis motion system are built to achieve the collaborative optimization of multi-objective variables. Meanwhile, optimal voltage vectors are picked out from the candidate vectors according to the principle of minimizing the cost function. Finally, experimental results verify that the proposed method is superior to the cascaded PI+CCC (cross-coupling controller) structure in terms of modeling intuitiveness, control complexity, contour tracking accuracy and dynamic response speed.