Precise Contour Control of Biaxial Motion System Based on MPC

In order to realize accurate and fast contour tracking of biaxial motion system and ensure the smoothness of its path, this paper proposes a model predictive contour control strategy suitable for biaxial system based on the idea of unified modeling. The two permanent magnet synchronous motors driving the biaxial system are considered as a whole to build a unified model. Based on the unified model, a compact model predictive controller is designed, where the contour error, the tracking error, the control increment and the position increment are introduced into the cost function simultaneously, realizing the multivariable collaborative optimization control. In addition, to obtain the better dynamic response and steady-state performance, a method of real-time adaptive adjustment of the position increment weight coefficient and the control increment weight coefficient is proposed. At the same time, considering the constraints, a posteriori constraint limitation network with the current control increment is proposed. Furthermore, the closed-loop stability analysis of the model predictive contour control system is carried out according to the optimal control principle. The experimental results show that the proposed control strategy can not only track the trajectory accurately at steady state, but also improve the transient contour tracking performance.