A coupling motional control method based on parametric predictive and variable universe fuzzy control for multi-axis CNC machine tools

摘要

The motional smoothness and contour precision of the CNC system are the key factors to ensuring the machining accuracy for multi-axis CNC machine tools. To improve the motional smoothness and contour precision for CNC machine tools, a control method based on parametric predictive and variable universe fuzzy control is presented. The model of the multi-axis drive system is established. The multi-axis model of parametric predictive control is proposed, where the model is structured, and output of the model is developed. A new improved quadratic performance index is proposed to guarantee the motional smoothness and contour precision, and the real-time calculation of the optimal control rate is deduced. A control approach of the nonlinear error compensation is presented to reduce contour error between the parametric predictive model and the actual output, where the adaptive error compensation controller is designed, and adaptive adjusting factors of variable universe are developed. The proposed control method is evaluated by simulations and experimentations. Simulation and experimental results have demonstrated that the proposed control approach can significantly improve the motional smoothness and machining precision for CNC machine tools.